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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..6833f05 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,3 @@ +* text=auto +*.txt text +*.md text diff --git a/8296-8.txt b/8296-8.txt new file mode 100644 index 0000000..8c06b1b --- /dev/null +++ b/8296-8.txt @@ -0,0 +1,4526 @@ +Project Gutenberg's Scientific American Supplement, No. 303, by Various + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Scientific American Supplement, No. 303 + October 22, 1881 + +Author: Various + +Posting Date: October 10, 2012 [EBook #8296] +Release Date: June, 2005 +First Posted: July 4, 2003 + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPPL., NO. 303 *** + + + + +Produced by Olaf Voss, Don Kretz, Juliet Sutherland, Charles +Franks and the Online Distributed Proofreading Team. + + + + + + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 303 + + + + +NEW YORK, OCTOBER 22, 1881 + +Scientific American Supplement. Vol. XII, No. 303. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + + TABLE OF CONTENTS + +I. ENGINEERING AND MECHANICS.--New Eighty-ton Steam Hammer at the Saint + Chamond Works, France.--7 figures.--Elevation of hammer.--Profile-- + Transverse section.--Profile view of foundation, etc.--Plan of + plant.--General plan of the forging mill.--Details of truss and + support for the cranes. + + Great Steamers.--Comparative details of the Servia, the City of Rome, + the Alaska, and the Great Eastern. + + Improved Road Locomotive.--2 figures.--Side and end views + + American Milling Methods. By ALBERT HOPPIN.--Ten years' progress.--Low + milling.--Half high milling.--High milling.--Important paper read + before the Pennsylvania State Millers' Association. + + Machine for Dotting Tulles and other Light Fabrics.--3 figures. + +II. TECHNOLOGY AND CHEMISTRY.--The Reproduction and Multiplication of + Negatives. By ERNEST EDWARDS. + + A New Method of Making Gelatine Emulsion. By W. K. BURTON. + + The Pottery and Porcelain Industries of Japan. + + Crystallization Table. + + The Principles of Hop Analysis. By Dr. G. O. CECH. + + Water Gas.--A description of apparatus for producing cheap gas, and + some notes on the economical effects of using such gas with gas + motors, etc.--By J. EMERSON DOWSON. + + On the Fluid Density of Certain Metals. By Professors CHANDLER ROBERTS + and T. WRIGLESON. + +III. PHYSICS, ELECTRICITY, ETC.--Electric Power.--The nature and uses of + electricity.--Electricity vs. steam. + + On the Method of Obtaining and Measuring Very High Vacua with a + Modified Form of Sprengel Pump. By Prof OGDEN N. ROOD.--4 figures.-- + Apparatus for obtaining vacua of one four hundred-millionth of an + atmosphere--Construction.--Manipulation.--Calculations.--Results + +IV. ART, ARCHITECTURE, ETC.--Old Wrought Iron Gates, Guildhall. + Worcester, England. 1 figure. + + The French Crystal Palace, Park of St. Cloud, Paris. 1 full page + illustration. + + Suggestions in Architecture. A Castellated Chateau. Perspective and + plan. Chateau in the Ægean Sea. + +V. HYGIENE AND MEDICINE.--Hydrophobia Prevented by Vaccination. + + On Diptera as Spreaders of Disease. By J. W. SLATER. + + On the Relations of Minute Organisms to Certain Specific Diseases. + +VI. ASTRONOMY--The Centenary of the Discovery of Uranus. By F. W. DENNING. + 2 figures. Approximate place of Uranus among the stars at its + discovery, March l3, 1871.--Orbits of the Uranian Satellites. + +VII. BIOLOGY, ETC.--The Varying Susceptibility of Plants and Animals to + Poisons and Disease. + + Kind Treatment of Horses. + + * * * * * + + + + +NEW EIGHTY TON STEAM HAMMER AT THE SAINT CHAMOND WORKS + + +Ever since the improvements that have been introduced into the +manufacture of steel, and especially into the erection of works for its +production, have made it possible to obtain this metal in very large +masses, it has necessarily been preferred to iron for all pieces of +large dimensions, inasmuch as it possesses in the highest degree that +homogeneousness and resistance which are so difficult to obtain in the +latter metal. It has consequently been found necessary to construct +engines sufficiently powerful to effect the forging of enormous +ingots, as well as special furnaces for heating them and apparatus for +manipulating and transporting them. + +The greatest efforts in this direction have been made with a view to +supplying the wants of heavy artillery and of naval constructions; +and to these efforts is metallurgy indebted for the creation of +establishments on a scale that no one would have dared a few years ago +to think of. The forging mill which we are about to describe is one of +those creations which is destined to remain for a long time yet very +rare; and one which is fully able to respond, not only to all present +exigencies, but also, as far as can be foreseen, to all those that may +arise for a long period to come. The mill is constructed as a portion of +the vast works that the Compagnie des Forges et Aciéries de la Marine +own at Saint Chamond, and which embrace likewise a powerful steel works +that furnishes, especially, large ingots exceeding 100 tons in weight. + +The mill consists, altogether, of three hammers, located in the same +room, and being of unequal powers in order to respond to different +requirements. The largest of these hammers is of 80 tons weight, and +the other two weigh respectively 35 and 28 tons. Each of them has +a corresponding furnace for heating by gas, as well as cranes for +maneuvering the ingots and the different engines. The general plan view +in Fig. 4 shows the arrangement of the hammers, cranes, and furnaces in +the millhouse. + +[Illustration: FIG. A.--ELEVATION OF A HAMMER. FIG. B.--PROFILE VIEW] + +The gas generators which supply the gas-furnaces are located out of +doors, as are the steam-generators. The ingots are brought from the +steel factory, and the forged pieces are taken away, by special trucks +running on a system of rails. We shall now give the most important +details in regard to the different parts of the works. + +_The Mill-House_--This consists of a central room, 262 feet long, 98 +feet wide, and 68 feet in height, with two lean-to annexes of 16 feet +each, making the total width 100 feet. The structure is wholly of metal, +and is so arranged as to permit of advantage being taken of every foot +of space under cover. For this purpose the system of construction +without tie-beams, known as the "De Dion type," has been adopted. Fig. +1 gives a general view of one of the trusses, and Fig. 5 shows some +further details. The binding-rafters consist of four angle-irons +connected by cross-bars of flat iron. The covering of corrugated +galvanized iron rests directly upon the binding-rafters, the upper parts +of which are covered with wood for the attachment of the corrugated +metal. The spacing of these rafters is calculated according to the +length of the sheets of corrugated iron, thus dispensing with the use of +ordinary rafters, and making a roof which is at once very light and very +durable, and consequently very economical. Rain falling on the roof +flows into leaden gutters, from whence it is carried by leaders into a +subterranean drain. The vertical walls of the structure are likewise of +corrugated iron, and the general aspect of the building is very original +and very satisfactory. + +_The 80 Ton Hammer_--The three hammers, notwithstanding their difference +in power, present similar arrangements, and scarcely vary except in +dimensions. We shall confine ourselves here to a description of the 80 +ton apparatus. This consists, in addition to the hammer, properly so +called, of three cranes of 120 tons each, serving to maneuver the pieces +to be forged, and of a fourth of 75 tons for maneuvering the working +implements. These four cranes are arranged symmetrically around the +hammer, and are supported at their upper extremity by metallic stays. +Besides the foregoing there are three gas furnaces for heating the +ingots. Figs. 1, 2, and 3 show the general arrangement of the apparatus. + +_Foundations of the Hammer and Composition of the Anvil-Bed_--To obtain +a foundation for the hammer an excavation was made to a depth of 26 feet +until a bed of solid rock was reached, and upon this there was then +spread a thick layer of beton, and upon this again there was placed a +bed of dressed stones in the part that was to receive the anvil-stock +and hammer. + +On this base of dressed stones there was placed a bed formed of logs +of heartwood of oak squaring 16 inches by 3 feet in height, standing +upright, joined together very perfectly, and kept in close juxtaposition +by a double band of iron straps joined by bolts. The object of this +wooden bed was to deaden, in a great measure, the effect of the shock +transmitted by the anvil-stock. + +NEW EIGHTY-TON STEAM HAMMER AT THE ST CHAMOND WORKS. + +[Illustration: FIG. 1.--TRANSVERSE SECTION.] + +[Illustration: FIG. 2.--PLAN.] + +[Illustration: FIG. 3.--PROFILE VIEW.] + +[Illustration: FIG. 4.--GENERAL PLAN OF THE FORGING MILL.] + +[Illustration: FIG. 5.--DETAILS OF THE TRUSSAND SUPPORT FOR THE CRANE.] + +_The Anvil-Stock_.--The anvil-stock, which is pyramidal in shape, and +the total weight of which amounts to 500 tons, is composed of superposed +courses, each formed of one or two blocks of cast iron. Each course +and every contact was very carefully planed in order to make sure of +a perfect fitting of the parts; and all the different blocks were +connected by means of mortises, by hot bandaging, and by joints with +key-pieces, in such a way as to effect a perfect solidity of the parts +and to make the whole compact and impossible to get out of shape. + +The anvil-stock was afterwards surrounded by a filling-in of masonry +composed of rag-stones and a mortar made of cement and hydraulic lime. +This masonry also forms the foundation for the standards of the hammer, +and is capped with dressed stone to receive the bed-plates. + +_The Power-Hammer_ (Figs. A and B).--The power-hammer, properly +so-called, consists, in addition to the hammer-head, of two standards to +whose inner sides are bolted guides upon which slides the moving mass. +The bed-plates of cast iron are 28 inches thick, and are independent of +the anvil-stock. They are set into the bed of dressed stone capping the +foundation, and are connected together by bars of iron and affixed to +the masonry by foundation bolts. To these bedplates are affixed the +standards by means of bolts and keys. The two standards are connected +together by iron plates four inches in thickness, which are set into the +metal and bolted to it so as to secure the utmost strength and solidity. +The platform which connects the upper extremities of the standards +supports the steam cylinder and the apparatus for distributing the +steam. The latter consists of a throttle valve, twelve inches in +diameter, and an eduction valve eighteen inches in diameter, the +maneuvering of which is done by means of rods extending down to a +platform upon which the engineman stands. This platform is so situated +that all orders can be distinctly heard by the engineman, and so that +he shall be protected from the heat radiated by the steel that is +being forged. All the maneuvers of the hammers are effected with most +wonderful facility and with the greatest precision. + +The piston is of cast-steel, and the rod is of iron, 12 inches in +diameter. The waste steam is carried out of the mill by a pipe, and, +before being allowed to escape into the atmosphere, is directed into an +expansion pipe which it penetrates from bottom to top. Here a portion of +the water condenses and flows off, and the steam then escapes into +the open air with a greatly diminished pressure. The object of this +arrangement is to diminish to a considerable extent the shocks and +disagreeable noise that would be produced by the direct escape of the +steam at quite a high pressure and also to avoid the fall of condensed +water. + +The following are a few details regarding the construction of the +hammer: + + Total height of foundations........... 26 ft. + From the ground to the platform ...... 28 " + + Platform .............................. 3.25 " + Height of cylinder.................... 21 " + ________ + + Total height...................... 78.25 ft. + + Weight of anvil-stock................ 500 tons. + Weight of bed-plates................. 122 " + Weight of standards.................. 270 " + Weight of platform and cylinder...... 148 " + Piston, valves, engineman's platform, + hammer, etc........................ 160 " + __________ + + Total weight................... 1,200 tons. + + Weight of the hammer.................. 80 tons. + Maximum fall.......................... 25.75 ft. + Distance apart of the standards....... 21.6 " + Width of hammer....................... 6 " + Pressure of steam..................... 16 lb. + Effective pressure to lift 80 tons.... 7 " +_Description of Figures_.--A, the 80-ton hammer; B, B1, B2, cranes; C, +C1, C2, supports of cranes; D, D1, D2, gas furnaces; A1, the 35-ton +hammer; A2, the 28-ton hammer; EE, railways; F, engineman's platform; G, +lever for maneuvering the throttle valve; H, an ingot being forged. + + * * * * * + + + + +GREAT STEAMERS. + + +The _Brooklyn Eagle_ gives a very interesting description of the three +new steamships now almost completed and shortly to be placed in the New +York and Liverpool trade by the Cunard, Inman, and Williams and Guion +lines. The writer has prepared a table comparing the three vessels +with each other and with the Great Eastern, the only ship of greater +dimensions ever built. We give as much of the article as our space will +allow, and regret that we have not the room to give it entire: + + Line. Cunard. Inman. Guion. Admiralty. + Vessel. Servia City of Rome. Alaska. Great[1] + + Length 530 feet. 546 feet. 520 feet. 679 feet. + Breadth 52 feet. 52 ft. 3 in. 50 ft. 6 in. 82 feet. + Depth 44 ft. 9 in. 37 feet. 38 feet. 60 feet. + Gross ton'ge 8,500 8,300 8,000 13,344[2] + Horse pow'r 10,500 10,000 11,000 2,600 + Speed 17½ knots. 18 knots. 18 knots. 14 knots. + Sal'n pas- 320 and 52 + sengers. 450 300 2d class + Steerage 600 1,500 1,000 + Where Clydeb'nk Barrow in Clyde, + built. Thomson Furness Elder + Date of + sailing. October 22 October 13 November 5 + +[Footnote 1: To be sold at auction soon.] + +[Footnote 2: Net register.] + +In 1870 the total tonnage of British steam shipping was 1,111,375; the +returns for the year 1876 showed an increase to 2,150,302 tons, and from +that time to the present it has been increasing still more rapidly. But, +as can be seen from the above table, not only has the total tonnage +increased to this enormous extent, but an immense advance has been made +in increasing the size of vessels. The reason for this is, that it has +been found that where speed is required, along with large cargo and +passenger accommodation, a vessel of large dimensions is necessary, and +will give what is required with the least proportionate first cost as +well as working cost. Up to the present time the Inman line possessed, +in the City of Berlin, of 5,491 tons, the vessel of largest tonnage in +existence. Now, however, the Berlin is surpassed by the City of Rome by +nearly 3,000 tons, and the latter is less, by 200 tons, than the Servia, +of the Cunard line. It will be observed, too, that while there is not +much difference between the three vessels in point of length, the depth +of the Alaska and the City of Rome, respectively, is only 38 feet and 37 +feet, that of the Servia is nearly 45 feet as compared with that of the +Great Eastern of 60 feet. This makes the Servia, proportionately, the +deepest ship of all. All three vessels are built of steel. This metal +was chosen not only because of its greater strength as against iron, +but also because it is more ductile and the advantage of less weight is +gained, as will be seen when it is mentioned that the Servia, if built +of iron, would have weighed 620 tons more than she does of steel, and +would have entailed the drawback of a corresponding increase in draught +of water. As regards rig, the three vessels have each a different style. +The Cunard Company have adhered to their special rig--three masts, bark +rigged--believing it to be more ship shape than the practice of fitting +up masts according to the length of the ship. On these masts there is a +good spread of canvas to assist in propelling the ship. The City of Rome +is rigged with four masts; and here the handsome full-ship rig of the +Inman line has been adhered to, with the addition of the fore and aft +rigged jigger mast, rendered necessary by the enormous length of the +vessel. It will be seen that the distinctive type of the Inman line +has not been departed from in respect to the old fashioned but still +handsome profile, with clipper bow, figurehead, and bowsprit--which +latter makes the Rome's length over all 600 feet. For the figurehead +has been chosen a full length figure of one of the Roman Cæsars, in the +imperial purple. Altogether, the City of Rome is the most imposing and +beautiful sight that can be seen on the water. The Alaska has also four +masts, but only two crossed. + +The length of the City of Rome, as compared with breadth, insures long +and easy lines for the high speed required; and the depth of hold being +only 37 feet, as compared with the beam of 52 feet, insures great +stability and the consequent comfort of the passengers. A point calling +for special notice is the large number of separate compartments formed +by water tight bulkheads, each extending to the main deck. The largest +of these compartments is only about 60 feet long; and, supposing that +from collision or some other cause, one of these was filled with water, +the trim of the vessel would not be materially affected. With a view to +giving still further safety in the event of collision or stranding, the +boilers are arranged in two boiler rooms, entirely separated from each +other by means of a water tight iron bulkhead. This reduces what, in +nearly all full-powered steamships, is a vast single compartment, into +two of moderate size, 60 feet in length; and in the event of either +boiler room being flooded, it still leaves the vessel with half her +boiler power available, giving a speed of from thirteen to fourteen +knots per hour. The vessel's decks are of iron, covered with teak +planking; while the whole of the deck houses, with turtle decks and +other erections on the upper deck, are of iron, to stand the strains +of an Atlantic winter. Steam is supplied by eight cylindrical tubular +boilers, fired from both ends, each of the boilers being 19 feet long +and having 14 feet mean diameter. There are in all forty eight furnaces. +The internal arrangements are of the finest description. There are two +smoking rooms, and in the after deckhouse is a deck saloon for ladies, +which is fitted up in the most elegant manner, and will prevent the +necessity of going below in showery weather. At the sides of the +hurricane deck are carried twelve life boats, one of which is fitted as +a steam launch. The upper saloon or drawing-room is 100 feet long, the +height between decks being 9 feet. The grand dining-saloon is 52 feet +long, 52 feet wide, and 9 feet high, or 17 feet in the way of the large +opening to the drawing-room above. This opening is surmounted by a +skylight, and forms a very effective and elegant relief to the otherwise +flat and heavy ceiling. There are three large and fourteen small dining +tables, the large tables being arranged longitudinally in the central +part of the saloon, and the small tables at right angles on the sides. +Each diner has his own revolving arm chair, and accommodation is +provided for 250 persons at once. A large American organ is fixed at the +fore end of the room, and opening off through double spring doors at the +foot of the grand staircase is a handsome American luncheon bar, with +the usual fittings. On each side of the vessel, from the saloon to the +after end of the engine room, are placed staterooms providing for 300 +passengers. The arrangements for steerage passengers are of a superior +description. The berths are arranged in single tiers or half rooms, not +double, as is usually the custom, each being separated by a passage, +and having a large side light, thus adding greatly to the light, +ventilation, and comfort of the steerage passengers, and necessitating +the advantage of a smaller number of persons in each room. The City +of Rome is the first of the two due here; she sails from Liverpool on +October 13. + +In the Servia the machinery consists of three cylinder compound surface +condensing engines, one cylinder being 72 inches, and two 100 inches in +diameter, with a stroke of piston of 6 feet 6 inches. There are seven +boilers and thirty-nine furnaces. Practically the Servia is a five +decker, as she is built with four decks--of steel, covered with yellow +pine--and a promenade reserved for passengers. There is a music room on +the upper deck, which is 50 feet by 22 feet, and which is handsomely +fitted up with polished wood panelings. For the convenience of the +passengers there are no less than four different entrances from the +upper deck to the cabins. The saloon is 74 feet by 49 feet, with sitting +accommodations for 350 persons, while the clear height under the beams +is 8 feet 6 inches. The sides are all in fancy woods, with beautifully +polished inlaid panels, and all the upholstery of the saloon is of +morocco leather. For two-thirds of its entire length the lower deck is +fitted up with first class staterooms. The ship is divided into nine +water-tight bulkheads, and she is built according to the Admiralty +requirements for war purposes. There are in all twelve boats equipped +as life-boats. The Servia possesses a peculiarity which will add to her +safety, namely, a double bottom, or inner skin. Thus, were she to +ground on rocks, she would be perfectly safe, so long as the inner skin +remained intact. Steam is used for heating the cabins and saloons, and +by this means the temperature can be properly adjusted in all weathers. +In every part of the vessel the most advanced scientific improvements +have been adopted. The Servia leaves Liverpool on October 22. + +The Alaska, whose owners, it is understood, are determined to make her +beat all afloat in speed, does not sail until November 5, and therefore +it is premature to say anything about her interior equipments. She is +the sister of the celebrated Arizona, and was built by the well-known +firm of Elder & Co., on the Clyde. + + * * * * * + + + + +IMPROVED ROAD LOCOMOTIVE. + + +Several attempts have been made to connect the leading wheels of a +traction engine with the driving wheels, so as to make drivers of all of +them, and thus increase the tractive power of the engine, and to afford +greater facilities for getting along soft ground or out of holes. The +wheels with continuous railway and India-rubber tires have been employed +to gain the required adhesion, but these wheels have been too costly, +and the attempts to couple driving and leading wheels have failed. The +arrangement for making the leading wheels into drivers, illustrated +on page 4825, has been recently brought out by the Durham and North +Yorkshire Steam Cultivation Company, Ripon, the design being by Messrs. +Johnson and Phillips. The invention consists in mounting the leading +axle in a ball and long socket, the socket being rotated in fixed +bearings. The ball having but limited range of motion in the socket, is +driven round with it, but is free to move in azimuth for steering. + +This engine has now been in use more than twelve months in traction +and thrashing work, and, we are informed, with complete success. The +illustrations represent a 7-horse power, with a cylinder 8 in. diameter +by 12 in. stroke, and steam jacketed. The shafts and axles are of +Bowling iron. The boiler contains 140 ft. of heating surface, and is +made entirely of Bowling iron, with the longitudinal seams welded. The +gearing is fitted with two speeds arranged to travel at 1½ and 3 miles +per hour, and the front or hind road wheels can be put out of gear when +not required. The hind driving wheels are 5 ft. 6 in. diameter, and the +front wheels 5 ft.; weight of engine 8 tons.--_The Engineer._ + +[Illustration: IMPROVED ROAD LOCOMOTIVE] + +[Illustration: IMPROVED ROAD LOCOMOTIVE] + + * * * * * + + + + +AMERICAN MILLING METHODS. + +[Footnote 1: A paper read before the meeting of the Pennsylvania State +Millers Association at Pittsburgh, Pa., by Albert Hoppin, Editor of the +_Northwestern Miller_.] + +By ALBERT HOPPIN. + + +To speak of the wonderful strides which the art of milling has taken +during the past decade has become exceedingly trite. This progress, +patent to the most casual observer, is a marked example of the power +inherent in man to overcome natural obstacles. Had the climatic +conditions of the Northwest allowed the raising of as good winter wheat +as that raised in winter wheat sections generally, I doubt if we should +hear so much to-day of new processes and gradual reduction systems. So +long as the great bulk of our supply of breadstuffs came from the winter +wheat fields, progress was very slow; the mills of 1860, and I may even +say of 1870, being but little in advance, so far as processes were +concerned, of those built half a century earlier. The reason for this +lack of progress may be found in the ease with which winter wheat could +be made into good, white, merchantable flour. That this flour was +inferior to the flour turned out by winter wheat mills now is proven by +the old recipe for telling good flour from that which was bad, viz.: To +throw a handful against the side of the barrel, if it stuck there it was +good, the color being of a yellowish cast. What good winter wheat patent +to-day will do this? Still the old time winter wheat flour was the best +there was, and it had no competitor. The settling up of the Northwest +which could not produce winter wheat at all, but which did produce a +most superior article of hard spring wheat, was a new factor in the +milling problem. The first mills built in the spring wheat States tried +to make flour on the old system and made a most lamentable failure of +it. I can remember when the farmer in Wisconsin, who liked a good loaf +of bread, thought it necessary to raise a little patch of winter wheat +for his own use. He oftener failed than succeeded, and most frequently +gave it up as a bad job. Spring wheat was hard, with a very tender, +brittle bran. If ground fine enough to make a good yield a good share +of the bran went into the flour, making it dark and specky. If not +so finely ground the flour was whiter, but the large percentage of +middlings made the yield per bushel ruinously small. These middlings +contained the choicest part of the flour producing part of the berry, +but owing to the dirt, germ, and other impurities mixed with them, it +was impossible to regrind them except for a low grade flour. Merchant +milling of spring wheat was impossible wherever the flour came in +competition with winter wheat flours. At Minneapolis, where the millers +had an almost unlimited water power, and wheat at the lowest price, +merchant milling was almost given up as impracticable. It was certainly +unprofitable. To the apparently insurmountable obstacles in the way of +milling spring wheat successfully, we may ascribe the progress of modern +milling. Had it been as easy to raise good winter wheat in Wisconsin and +Minnesota as in Pennsylvania and Ohio, or as easy to make white flour +from spring as from winter wheat, we should not have heard of purifiers +and roller mills for years to come. + +The first step in advance was the introduction of a machine to purify +middlings. It was found that the flour made from these purified +middlings was whiter than the flour from the first grinding and brought +a better price than even winter wheat flours. Then the aim was to make +as many middlings as possible. To do this and still clean the bran so +as to make a reasonable yield the dress of the burrs was more carefully +attended to, the old fashioned cracks were left out, the faces and +furrows made smooth, true, and uniform, self-adjusting drivers +introduced, and the driving gear better fitted. Spring wheat patents +rapidly rose to the first place in the market, and winter wheat millers +waked up to find their vantage ground occupied by their hitherto +contemned rivals. To their credit it may be said that they have not +been slow in taking up the gauntlet, and through the competition of the +millers of the two climatically divided sections of this country with +each other and among themselves the onward march of milling progress has +been constantly accelerated. Where it will end no man can tell, and +the chief anxiety of every progressive miller, whether he lives in +Pennsylvania or Minnesota, is not to be left behind in the race. + +The millers of the more Eastern winter wheat States have a two-fold +question to solve. First, how to make a flour as good as can be found in +the market, and second, how to meet Western competition, which, through +cheap raw material and discriminating freight rates, is making serious +inroads upon the local markets. Whether the latter trouble can be +remedied by legislature, either State or national, or not, remains to be +proven by actual trial. That you can solve the first part of the problem +satisfactorily to yourselves depends upon your readiness to adopt new +ideas and the means you have at hand to carry them out. It is manifestly +impossible to make as good a flour out of soft starchy wheat as out of +that which is harder and more glutinous. It is equally impossible for +the small mill poorly provided with machinery to cope successfully +with the large merchant mill fully equipped with every appliance that +American ingenuity can suggest and money can buy. I believe, however, +that a mill of moderate size can make flour equally as good as the large +mill, though, perhaps, not as economically in regard to yield and cost +of manufacture. + +The different methods of milling at present in use may be generally +divided into three distinct processes, which, for want of any better +names, I will distinguish as old style, new process, and gradual +reduction. Perhaps the German division of low milling, half high +milling, and high milling is better. Old style milling was that in +general use in this country up to 1870, and which is still followed in +the great majority of small custom or grist mills. It is very simple, +consisting of grinding the wheat as fine as possible at the first +grinding, and separating the meal into flour, superfine or extra, +middlings, shorts, and bran. Given a pair of millstones and reel long +enough, and the wheat could be made into flour by passing through the +two. Because spring wheat was so poorly adapted to this crude process, +it had to be improved and elaborated, resulting in the new process. + +At first this merely consisted of purifying and regrinding the middlings +made in the old way. In its perfected state it may be said to be halfway +between the old style and gradual reduction, and is in use now in many +mills. In it mill stones are used to make the reductions which are only +two in number, in the first of which the aim of the miller is to make as +many middlings as he can while cleaning the bran reasonably well, and +in the second to make the purified middlings into flour. In the most +advanced mills which use the new process, the bran is reground and the +tailings from the coarse middlings, containing germ and large middlings +with pieces of bran attached, are crushed between two rolls. These +can hardly be counted as reductions, as they are simply the finishing +touches, put on to aid in working the stuff up clean and to permit of +a little higher grinding at first. Regarding both old style and new +process milling, you are already posted. Gradual reduction is newer, +much more extensive, and merits a much more thorough explanation. Before +entering upon this I will call your attention to one or two points which +every miller should understand. + +The two essential qualities of a good marketable flour are color and +strength. It should be sharply granular and not feel flat and soft to +the touch. A wheat which has an abundance of starch, but is poor in +gluten, cannot make a strong flour. This is the trouble with all soft +wheats, both winter and spring. A wheat which is rich in gluten is hard, +and in the case of our hard Minnesota wheat has a very tender bran. +It is comparatively easy to make a strong flour, but it requires very +careful milling to make a flour of good color from it. Probably the +wheat which combines the most desirable qualities for flour-making +purposes is the red Mediterranean, which has plenty of gluten and a +tough bran, though claimed by some to have a little too much coloring +matter, while the body of the berry is white. By poor milling a good +wheat can be made into flour deficient both in strength and color, and +by careful milling a wheat naturally deficient in strength may be made +into flour having all the strength there was in the wheat originally and +of good color. Good milling is indispensable, no matter what the quality +of the wheat may be. + +The idea of gradual reduction milling was borrowed by our millers from +the Hungarian mills. There is, however, this difference between the +Hungarian system and gradual reduction, as applied in this country, that +in the former, when fully carried out, the products of the different +breaks are kept separate to the end, and a large number of different +grades of flour made, while in the system, as applied in this country, +the separations are combined at different stages and usually only three +different grades of flour made, viz.: patent, baker's, or as it is +termed in Minnesota, clear flour, and low grade or red dog. In the +largest mills the patent is often subdivided into first and second, and +they may make different grades of baker's flour, these mills approaching +much nearer to the Hungarian system, though modifying it to American +methods and machinery. In mills of from three to five hundred barrels +daily capacity, it is hardly possible or profitable to go to this +subdivision of grades, owing to the excessive amount of machinery +necessary to handling the stuff in its different stages of completion. +The Hungarian system has, therefore, been greatly modified by American +millers and milling engineers to adapt it to the requirements of mills +of average capacity. This modified Hungarian system we call gradual +reduction. It can be profitably employed in any mill large enough to run +at all on merchant work. So far it has not been found practicable to use +it in mills of less than one hundred and twenty-five to one hundred and +fifty barrels capacity in twenty-four hours, and it is better to have +the mill of at least double this capacity. + +Gradual reduction, as its name implies, consists in reducing the +wheat to flour, shorts, and bran, by several successive operations or +reductions technically called breaks, the process going on gradually, +each break leaving the material a little finer than the preceding one. +Usually five reductions or breaks are made, though six or seven may be +used. The larger the number of breaks the more complicated the system +becomes, and it is preferable to keep it as simple as possible, for even +at its simplest it requires a good, wide-awake thinking miller to handle +it successfully. When it is thoroughly and systematically carried out in +the mill it is without question as much in advance of the new process as +that is ahead of the old style of milling. + +In order that I may convey to you as clear an idea of gradual milling +reduction as possible, I will give as fully as possible the programme of +a mill of one hundred and fifty barrels maximum daily capacity designed +to work on mixed hard and soft spring wheat, and which probably will +come much nearer to meeting the conditions under which you have to mill +than any other I have found readily obtainable. I have chosen a mill of +this size, first, because following out the programme of a larger one +would require too much time and too great a repetition of details and +not give you any clearer idea of the main principles involved, and +secondly, because I thought it would come nearer meeting the average +requirements of the members of your association. Your worthy secretary +cautioned me that I must remember that I was going to talk to winter +wheat millers. The main principles and methods of gradual reduction are +the same, whether applied to spring or winter wheat; the details may +have to be varied to suit the varying conditions under which different +mills are operated. For this programme I am indebted to Mr. James Pye, +of Minneapolis, who is rapidly gaining an enviable and well deserved +reputation as a milling engineer, and one who has given much study to +the practical planning and working of gradual reduction mills. + +And right here let me say that no miller should undertake to build +a gradual reduction mill, or to change over his mill to the gradual +reduction system, until he has consulted with some good milling engineer +(the term millwright means very little nowadays), and obtained from him +a programme which shall fit the size of the mill, the stock upon which +it has to work, and the grade of flour which it is to make. This +programme is to the miller what a chart is to the sailor. It shows him +the course he must pursue, how the stuff must be handled, and where it +must go. Without it he will be "going it blind," or at best only feeling +his way in the dark. A gradual reduction mill, to be successful, must +have a well-defined system, and to have this system, the miller must +have a definite plan to work by. But to go on with my programme. + +The wheat is first cleaned as thoroughly as possible to remove all +extraneous impurities. In the cleaning operations care should be taken +to scratch or abrade the bran as little as possible, for this reason: +The outer coating of the bran is hard and more or less friable. Wherever +it is scratched a portion is liable to become finely comminuted in the +subsequent reductions, so finely that it is impossible to separate it +from the flour by bolting, and consequently the grade of the latter is +lowered. The ultimate purpose of the miller being to separate the flour +portion of the berry from dirt, germ, and bran it is important that he +does not at any stage of the process get any dirt or fine bran speck or +dust mixed in with his flour, for if he does he cannot get rid of it +again. So it must be borne in mind that at all stages of flouring, any +abrasion or comminution of the bran is to be avoided as far as possible. + +After the wheat is cleaned, it is by the first break or reduction split +or cut open, in order to liberate the germ and crease impurities. As +whatever of dirt is liberated by this break becomes mixed in with the +flour, it is desirable to keep the amount of the latter as small as +possible. Indeed, in all the reductions the object is to make as little +flour and as many middlings as possible, for the reason that the latter +can be purified, while the former cannot, at least by any means at +present in use. After the first break the cracked wheat goes to a +scalping reel covered with No. 22 wire cloth. The flour, middlings, +etc., go through the cloth, and the cracked wheat goes over the tail of +the reel to the second machine, which breaks it still finer. After this +break the flour and middlings are scalped out on a reel covered with +No. 22 wire cloth. The tailings go to the third machine, and are still +further reduced, then through a reel covered with No. 24 wire cloth. The +tailings go to the fourth machine, which makes them still finer, then +through a fourth scalping reel the same as the third. The tailings from +this reel are mostly bran with some middlings adhering, and go to the +fifth machine, which cleans the bran. From this break the material +passes to a reel covered with bolting cloth varying in fineness from No. +10 at the head to No. 00 at the tail. What goes over the tail of this +reel is sent to the bran bin, and that which goes through next to the +tail of the reel, goes to the shorts bin. The middlings from this reel +go to a middlings purifier, which I will call No. 1, or bran middlings +purifier. The flour which comes from this reel is sent to the chop reel +covered at the head with say No. 9, with about No. 5 in the middle and +No 0 at the tail. You will remember that after each reduction the flour +and middlings were taken out by the scalping reels. This chop, as it is +now called, also goes to the same reel I have just mentioned. The +coarse middlings which go over the tail of this reel go to a middlings +purifier, which I will designate as No. 2. These go through the No. 0 +cloth at the tail of the reel purifier No. 3; those which go through No. +5 cloth got to purifier No. 4; while all that goes through the No. 9 +cloth at the head of the reel is dropped to a second reel clothed with +Nos. 13 to 15 cloth with two feet of No. 10 at the tail. The flour from +this reel goes to the baker's flour packer; that which drops through the +No. 10 is sent to the middlings stone, while that which goes over the +tail of the reel goes to purifier No. 4. We have now disposed of all the +immediate products of the first five breaks, tracing them successively +to the bran and shorts bins, to the baker's flour packer and to the +middlings purifiers, a very small portion going to the middlings stone +without going through the purifiers. + +The middlings are handled as follows in the purifiers. From the No. 1 +machine, which takes the middlings from the fifth break, the tailings go +to the shorts bin, the middlings which are sufficiently well purified go +to the middlings stone, while those from near the tail of the machine +which contain a little germ and bran specks go to the second germ rolls, +these being a pair of smooth rolls which flatten out the germ and crush +the middlings, loosening adhering particles from the bran specks. From +the second germ rolls the material goes to a reel, where it is separated +into flour which goes into the baker's grade, fine middlings which are +returned to the second germ rolls at once, some still coarser which go +to a pair of finely corrugated iron rolls for red dog, and what goes +over the tail of the reel goes to the shorts bin. The No. 2 purifier +takes the coarse middlings from the tail of the first or chop reel as +already stated. The tailings from this machine go to the shorts bin, +some few middlings from next the tail of the machine are returned to the +head of the same machine, while the remainder are sent to the first germ +rolls. The reason for returning is more to enable the miller to keep a +regular feed on the purifiers than otherwise. The No. 3 purifier takes +the middlings from the 0 cloth on the chop reel. From purifier No. 3 +they drop to purifier No. 5. A small portion that are not sufficiently +well purified are returned to the head of No. 3, while those from the +head of the machine, which are well purified, are sent to the middlings +stones. The remainder, which contain a great deal of the germ, are taken +to the first germ rolls, in passing which they are crushed lightly to +flatten the germ without making any more flour than necessary. The No. 4 +purifier takes the middlings from No. 2 and also from No. 5 cloth on +the chop reel and from the No. 10 on the tail of the baker's reel. The +middlings from the head of this machine go to the middlings stones, and +the remainder to purifier No. 6. The tailings from Nos. 3, 4, 5, and 6 +go to the red dog rolls. A small portion not sufficiently well purified +are returned from No. 6 to the head of No. 4, while the cleaned +middlings go to the middlings stones. + +The portions of the material which have not been traced either to the +baker's flour or the bran and shorts bins are the middlings which have +gone to the middlings stones, the germy middlings which have gone to the +first germ rolls, and the tailings from purifiers Nos. 3, 4, 5, and 6, +and some little stuff not quite poor enough for shorts from the reel +following the second germ rolls. Taking these _seriatim_: the middlings +after passing through the middlings stones, go to the first patent reel +covered with eleven feet of No. 13 and four feet of No. 8. The flour +from the head of the reel goes to the patent packer, that from the +remainder of the reel is dropped to another reel, while the tailings go +to the No. 4 purifier. The lower patent reel is clothed with No. 14 and +two feet of No. 10 cloth; from the head of the reel the flour goes to +the patent packer, the remainder that passes through the No. 10 cloth +which will not do to go into the patent, being returned to the middlings +stones, while the tailings are sent to the No. 4 purifier. + +The germ middlings, after being slightly crushed as before stated, are +sent to a reel covered with five feet of No. 13 cloth, five feet of No. +14, and the balance with cloth varying in coarseness from No. 7 to No. +00. The flour from this reel goes into the patent, the tailings to the +red dog rolls, the middlings from next the tail of the reel which still +contain some germ to the second germ rolls, while the middlings which +are free from germ go to the middlings stones. + +The tailings from purifiers 3, 4, 5, and 6, the material from the reel +following the second germ rolls, which is too good for shorts, but not +good enough to be returned into middlings again, and the tailings from +the reel following the first germ rolls are sent to the red dog rolls, +which, as I have stated, are finely corrugated. Following these rolls is +the red dog reel. The flour goes to the red dog bin, the tailings to +the shorts bin, while some stuff intermediate between the two, not fine +enough for the flour but too good for shorts, is returned to the red dog +rolls. + +This finishes the programme. I have not given it as one which is exactly +suited to winter wheat milling. However, as I said before, the general +principles are the same in either winter or wheat gradual reduction +mills, and the various systems of gradual reduction, although they +differ in many points, and although there are probably no two engineers +who would agree as to all the details of a programme, the main ideas +are essentially the same. The system has been well described as one of +gradual and continued purification. In the programme above given the +idea was to fit up a mill which should do a maximum amount of work of +good quality with a minimum amount of expenditure and machinery. In a +larger mill or even in a mill of the same capacity where money was not +an object, the various separations would probably be handled a little +differently, the flour and middlings from the first and fifth breaks +being handled together, and those from the second, third, and fourth +breaks being also handled together. The reason for this separation being +that the flour from the first and fifth breaks contain, the first a +great deal of crease dirt, and the fifth more bran dust than that from +the other breaks, the result being a lower grade of flour. The object +all along being to keep the amount of flour with which dirt can get +mixed as small as possible, and not to lower the grade of any part of +the product by mixing it with that which is inferior, always bearing in +mind that the aim is to make as many middlings as possible, for they can +be purified while the flour can not, and that whenever any dirt is once +eliminated it should be kept out afterwards. This leads me to say that +if a miller thinks the adoption of rolls or reduction machines is all +there is of the system, he is very much mistaken. If anything, more of +the success of the mill depends upon the careful handling of the stuff +after the breaks are made, and here the miller who is in earnest to +master the gradual reduction system will find his greatest opportunities +for study and improvement. A few years back it was an axiom of the trade +that the condition of the millstone was the key to successful +milling. This was true because the subsequent process of bolting was +comparatively simple. Now the mere making of the breaks is a small +matter compared with the complex separations which come after. In +the foregoing programme we had five breaks or successive reductions. +Although this is better than a smaller number, I will here say that +it is not absolutely essential, for very good work is done with four +breaks. The mill for which this programme was made, including the +building, cost about $15,000, and is designed to make about sixty per +cent. of patent, thirty-five per cent. of baker's, and five per cent. +of low grade, results which are in advance of many larger and more +pretentious mills. + +One difficulty in the way of adapting the gradual reduction system to +mills of very small capacity is that the various machines require to be +loaded to a certain degree in order to work at their best. It is only a +matter of short time when our milling inventors will design machinery +especially for small mills; in fact they are now doing it, and every +day brings it more within the power of the small miller to improve his +manner of milling. To show what can be done in this direction I will +briefly describe a mill of about ninety barrels maximum capacity per +twenty-four hours, which is as small as can be profitably worked. I will +premise this description by saying it is designed with a view to the +greatest economy of cost, the best trade of work, and to reduce the +amount of machinery and the handling of the stuff as much as possible. +This latter point is of much importance in any mill, either large or +small, no matter upon what system it is operated, for it takes power to +run elevators and conveyors, and especially in elevating and conveying +middlings, especially those made from winter wheat, their quality is +inured and a loss incurred, by the unavoidable amount of flour made by +the friction of the particles against each other. So much is this the +case that in one of our largest mills it is deemed preferable to move +the middlings from one end of the mill to the other by means of a hopper +bin on a car which runs on a track spiked to the floor, rather than to +employ a conveyor. A mill built as I am going to describe would require +from fifty to sixty horse-power to run it, and including steam power and +building would cost from $10,000 to $12,000, according to location. I +give it as of interest to those among your number who own small mills +and may contemplate improving them. + +The building is four stories high, including basement, and thirty-two +feet square. It would be some better to have it larger, but it is made +this small to show how small a space a mill of this size can be made to +occupy. No story is less than twelve feet high. The machinery Is very +conveniently arranged, and there is plenty of room all around. The +system is a modification of the gradual reduction system, the middlings +being worked upon millstones. The first break is on one pair of 9 x +18 inch corrugated iron rolls, eight corrugations to the inch, the +corrugations running parallel with the axis of the rolls. The second +break on rolls having twelve corrugations to the inch, the third +sixteen, and the fourth twenty to the inch, while the fifth break, where +the bran is finally cleaned, has twenty-four corrugations to the inch. +The basement contains the line shaft and pulleys for driving rolls, +stones, cockle machine, and separator. The only other machinery in the +basement is the cockle machine. The line shaft runs directly through +the center of the basement, the power being from engine or water wheel +outside the building. The first floor has the roller mills in a line +nearly over the line shaft below, the middlings stones, two in number, +at one side opposite the entrance to the mill, the receiving bin at +one side of the entrance in the corner of the mill, and the two flour +packers for the baker's and patent flour in the other corner. This +arrangement leaves over half of the floor area for receiving and packing +purposes. The bolting chests, one with six reel and the other with three +reel begin on the second floor and reach up into the attic. An upright +shaft from the line shaft in the basement geared to a horizontal shaft +running through the attic parallel with the line shaft below, comprise +about all the shafting there is in the mill. There is a short shaft on +the second floor from which the two purifiers on this floor and the two +in the attic are driven, and another short shaft on the first floor to +drive the packers. There are four purifiers, two on the second floor, +and two more directly over them in the attic. The elevator heads are all +directly upon the attic line shaft, and the bolting chests are driven by +uprights dropped from this shaft. The combined smutter and brush machine +is on the third floor at one end of the bolting chests and directly over +the stock hoppers. This comprises all the machinery in the mill. The +programme is about as follows: + +The break reels are clothed as follows: First break No. 20, wire cloth, +second break No. 22, third break No. 24, and fourth break No. 24. The +material passing through these scalping reels, now called chop, goes to +a series of reels, the first clothed with Nos. 6, 4, and 0. The material +passing over the tail is sent to the germ purifier, that passing through +Nos. 4 and 0, to the coarse middlings purifier, and that through the No. +6 goes to the reel below clothed with Nos. 12 and 13. Some nice granular +flour is taken off from this reel; the remainder, which passes over the +tail and through the cutoffs, goes to the next reel below clothed with +Nos. 14, 15, and 9. Some good flour comes from the 14 and 15; that which +passes through the 9 goes at once to the stones without purifying, while +that which passes over the tail is sent to the fine middlings purifiers. + +After the purification, the middlings are ground on stones and bolted +on Nos. 13 and 14 cloth, after having been scalped on No 8. The germ +middlings are crushed on smooth rolls and bolted on Nos. 12 and 13. What +is not crushed fine enough goes with poor tailings to the second germ +rolls, and from these to a reel by themselves or to the fifth reduction +or bran reel. A mill of this kind could be made much more perfect by an +expenditure of two or three thousands dollars more. I have instanced it +to show what can be done with gradual reduction in a very small way. + +In mills of from three hundred to five hundred barrels capacity and +still larger, the programme differs considerably from that I have +sketched, the middlings being graded and handled with little, if any, +returning, and are sized down on the smooth rolls, a much larger +percentage of the work of flouring being done on millstones. For a three +hundred barrel roller mill, the following plant is requisite: five +double corrugated roller mills, five double smooth roller mills, three +pairs of four foot burrs sixteen purifiers, four wire scalping reels, +six feet long, one reel for the fifth break, one reel for low grade +flour, eight chop reels, seven reels for flour from smooth rolls, three +reels for the stone flour, two grading reels, three flour packers, and +necessary cleaning machinery. The reels are eighteen feet thirty-two +inches. The programme is necessarily more complicated. + +When it comes to the machinery to be employed in making the reductions +or breaks, the miller has several styles from which to choose. Which is +best comes under the head of what I don't know, and moreover, of that +which I have found no one else who does know. Each machine has its good +points, and the mill owner must make his own decision as to which is +best suited to his purpose. The main principles involved are to abrade +the bran as little as possible while cleaning it thoroughly, and to make +as little break flour, and as many middlings as possible, the latter to +be made in such shape as to be the most easily purified. Regarding +the difference between spring and winter wheat for gradual reduction +milling, it may be stated something after this manner: Spring wheat +has a thinner and more tender bran, makes more middlings because it is +harder, and for the same reason the flour is more inclined to be coarse +and granular. In milling with winter wheat, especially the better +varieties, there will be more break flour made, the middlings will be +finer with fewer bran specks, and the bran more easily cleaned, because +it will stand harsher treatment. Winter wheat, moreover, requires more +careful handling in making the breaks, not because of the bran, but to +avoid breaking down the middlings, and making too much and too fine and +soft break flour. In order to keep the flour sharp and granular, coarser +cloths are used in bolting, and because the middlings are finer the +bolting is not so free and a larger bolting surface is required. In +milling either spring or winter wheat there should be ample purifying +capacity, it being very unwise to limit the number of machines, so that +any of them will be overtaxed. The day has gone by when one purifier +will take care of all the middlings in the mill. + +There is one point which is of much interest to mill owners who wish to +change their mills over to the gradual reduction process, that is, how +far they can utilize their present plan of milling machinery in making +the change. Of course the cleaning machinery is the same In both cases, +so are the elevators, conveyors, bolting chests, etc. But to use the +millstone is a debatable question. After carefully considering the +matter I have come to the conclusion that it has its place, and an +important one at that, under the new regime, viz., that of reducing +the finer purified middlings to flour. The reason for this lies in the +peculiar construction of the wheat berry. If the interior of the berry +were one solid mass of flour, needing only to be broken up to the +requisite fineness, it could be done as well on the rolls. But instead +of this, as is well known, the flour part of the berry is made up of +a large number of granules or cells, the walls of which are cellular +tissue, different from the bran in that it is soft and white instead of +hard and dark colored. It is also fibrous to a certain extent, and when +the fine middlings are passed between the rolls instead of breaking +down and becoming finer, it has a tendency to cake up and flatten out, +rendering the flour soft and flaky. It does not hurt the color, but it +does hurt the strength. When the millstone is used in place of the roll +the flour is of equally good color, and more round and granular. I +know that in this the advocates of smooth rolls will differ from my +conclusions, but I believe that the final outcome will be the use of +millstones on the finer middlings, and in fact on all the middlings that +are thoroughly freed from the germ. + +It has been said that that which a man gives the most freely and +receives with the worst grace is advice. I will, however, close with a +little of the article which may not be wholly put of place. If you have +a mill do not imagine that the addition of a few pairs of rolls, a +purifier or two, and a little overhauling of bolting-chests, is going to +make it a full-fledged Hungarian roller mill. If you are going to change +an old mill or build a new one, do not take the counsel or follow the +plans of every itinerant miller or millwright who claims to know all +about gradual reduction. No matter what kind of a mill you want to +build, go to some milling engineer who has a reputation for good work, +tell him how large a mill you want, show him samples of the wheat it +must use and the grades of flour it must make, and have him make a +programme for the mill and plan the machinery to fit it. Then have the +mill built to fit the machinery. When it starts follow the programme, +whether it agrees with your preconceived notions or not, and the mill +will, in ninety-nine cases out of one hundred, do good work. + + * * * * * + + +MACHINE FOR DOTTING TULLES AND OTHER LIGHT FABRICS. + +Dotted or chenilled tulles are fabrics extensively used in the toilet +of ladies, and the ornamentation of which has hitherto been done by +the application to the tissue, by hand, either of chenille or of small +circles previously cut out of velvet. This work, which naturally takes +considerable time, greatly increases the cost price of the article. + +A few trials at doing the work mechanically have been made, but without +any practical outcome. The workwomen who do the dotting are paid at +Lyons at the rate of 80 centimes per 100 dots; so that if we take +tulle with dots counter-simpled 0.04 of an inch, which is the smallest +quincunx used, and suppose that the tissue is 31 inches wide and that +the daily maximum production is one yard, we find that 400 dots at 80 +centimes per 100 = 3 francs and 20 centimes (about 63 cents), the cost +of dotting per yard. It is true that the workwoman furnishes the velvet +herself. + +Mr. C. Ricanet, of Lyons, has recently invented a machine with which he +effects mechanically the different operations of dotting, not only on +tulles but also upon gauzes or any other light tissues whatever, such +as those of cotton, silk, wool, etc. Aided by a talented mechanic, Mr. +Ricanet has succeeded in constructing one of those masterpieces of +wonderfully accurate mechanism of which the textile industry appears +to have the monopoly--at least it is permissible to judge so from the +remarkable inventions of Vaucanson, Jacquard, Philippe de Girard, +Heilmann, and others. + +The object of this new machine, then, which has been doing its wonderful +work for a few days only, is to reproduce artificially chenille +embroidered on light tissues, by mechanically cutting out and gluing +small circles of velvet upon these fabrics. + +For this purpose all kinds of velvet may be employed, and, in order to +facilitate the cutting, they are previously coated on the reverse side +with any glue or gum whatever, which gives the velvet a stiffness +favorable to the action of the punch. To effect the object desired the +apparatus has three successive operations to perform: first, cutting the +circles; second, moistening; and third, fastening down the dots upon the +tissue according to a definite order and spacing. The machine may be +constructed upon any scale whatever, although at present it is only made +for operating on pieces 31 inches wide, that being the normal width of +dotted tulles. The quincuncial arrangement of the dots is effected by +the punching, moistening, and fastening down of odd and even dots, +combined with the forward movement of the tissue to be chenilled. + +The principal part of the machine is the cam-shaft, A (Figs. 1, 2, and +3), which revolves in the direction of the arrows and passes in the +center of 80 cam-wheels, 40 of which are odd and 40 even, alternately +opposed to each other. This shaft actuates, through its two extremities, +the different combined motions in view of the final object to be +attained, and also carries the motive pulleys, PP'. Figs. 1 and 2 show +the profile of two of these opposed cam-wheels--the arrangement by means +of which two rows of dots (odd and even) are laid down upon the tissue +during one revolution of the shaft or drum, A. Each of the wheels +carries three cams (Figs. 1 and 3), the first, (_a_), corresponding to +the punching; the second, (_a'_), to the moistening, and the third, +(_a''_), to the gluing down of the dots. + +The annexed figure, one-quarter actual size, shows in section the +details of the cutting mechanism. To each cam-wheel there corresponds +one punch, and the eighty punches are arranged side by side and parallel +upon a shaft, B, a spring, _b_, holding them constantly against the +circumference of the cam-wheels. In Fig. 2 only one of these details is +shown. The punching arrangement consists of an ordinary punch, _c_, of +variable diameter, screwed to the extremity of a tube, _d_, which is +itself suspended from the end of the lever, _p_, but which can receive +from it at the desired moment the pressure necessary to effect the +cutting. The vertical position of these multiple tubes is insured by +a guide, _e_, which is thoroughly indispensable. Through each of the +tubes, _d_, there passes a plunger designed for expelling from the punch +the piece that has been cut out of the velvet, and for gluing it down to +the fabric. The two small springs, _b'_ and _b''_, tend continually to +lift the tubes as well as the plunger. The whole mechanism is affixed to +solid cast-iron frames, and the machine itself may be mounted on wooden +supports or a metal frame. + +The punching is effected on a bronze straight-edge, C, which slides in a +cast-iron channel, D. This presents alternately, in its movement, entire +and punctured spaces, the former for receiving the blow of the punch and +the latter for allowing passage at the desired moment to the plunger +as it goes to fasten the dots upon the tulle which is passing along +underneath the channel, D. The punching is done primarily and +principally by pressure, but, in order to facilitate the complete +detachment of filaments which might retain the punched-out piece, the +punch is likewise given at the same time a slight rotary motion, thus +imitating mechanically what is performed by hand in the maneuver of all +punches. This rotary motion is communicated to the punches by means of +levers actuated by an eccentric, E, and which move the frame, _h_, whose +bars engage with the horizontal lever, _g_, soldered to the tube, _d_, +thus causing the latter at the very moment the punch descends to revolve +from right to left. The forty punches in operation cause the frame to +return to its initial position through the action of the springs, _b'_. +We say forty, since the inventor, in principle, has admitted 80 punches, +operating 40 as odd and 40 as even; obtaining in this way a dotting in +a regular quincunx of one yard, that is to say, 80 dots arranged in two +rows on a fabric 31 inches wide. But it is evident that a much larger +quincunx may be had by putting in play only a half, a third, or a +fourth of the punches, and causing the tulle and velvet to advance +proportionally. For this purpose it is only necessary to unscrew the +punches which are not to act, and to substitute for the ratchet wheel +which controls the unrolling of the I tulle, another having a number of +teeth proportioned to the desired spacing of the dots. + +The punching having been executed, and the drum, A, continuing to +revolve, the punches rise a little owing to the conformation of the +cam-wheel, and through the action of the springs, _b_, and allow the +moistener to move forward to dampen the little circles which remain at +the orifice of the punches. The moistener or dampener is a sort of pad +equal in length to the field of action of the punches, and is affixed +to a cross-bar, F, which is connected at its two extremities with the +levers, G, that are actuated by the cam-wheels, H. These cam-wheels, or +eccentrics, H, which are mounted on the shaft of the drum, A, cause the +moistener to move forward as soon as the punches rise after operating, +and, when it arrives beneath the punches, the larger cams, _a_, of +the cam-wheels, A, press the latter upon the pad and thus effect the +dampening of the circles of velvet. + +Immediately afterwards, the same eccentrics, H, acting on a lever, I, +uncover the holes in the straight-edge, C, and the channel, D. The +large cams, _a"_, of the wheel, A, then acting very powerfully upon the +respective punches, cause these latter to pass through the orifices so +that the extremity of each punch comes within about one twenty-fifth of +an inch of the fabric to be dotted. In this passage of the tube, _d_, a +small rod, _i_, connected by a lever with the plunger, _f_, is made to +abut against the guide, _e_, thus causing the descent of the plunger to +a sufficient degree to push the velvet "dot" out of the tube and to glue +it upon the fabric. The manner in which these operations are performed +being now well enough understood, let us for a moment examine the +motions of the fabrics to be cut and dotted--the first being velvet or +any other material, even metal (goldleaf, for example), and the second, +the tulle. + +The latter has but one motion, and that is in the direction of its +length, while the velvet has, in addition to this same motion, another +slight one from right to left in the direction of its width in order to +diminish waste as much as possible. + +The tulle to be dotted is first wound around a roller, R, from whence it +passes over the glass guide-roller, R', and between the channel, D, and +the table, T, to the roller, R", which is heated by steam. + +The hot air which is radiated dries the dots, and from thence the fabric +is taken up by other rollers or by any other method. The steam roller, +R", carries at one of its extremities a ratchet wheel whose teeth vary +in number according to the greater or less rapidity with which the tulle +is unrolled. It is actuated by a lever which receives its motion from +the eccentric, K. + +[Illustration: IMPROVED MACHINE FOR DOTTING TULLAND OTHER LIGHT +FABRICS.] + +In the table, T, there is a rectangular receptacle, _t_, containing +rasped or powdered velvet for the purpose of forming a reverse of the +dot. This powder attaches itself to the gum and imitates on the wrong +side of the fabric a dot similar to that on the upper or right side. The +velvet is wound upon the roller, _r_, and from thence passes under the +guiding roller, _r'_, the punches, and the second roller, _r"_. These +two latter rollers are solidly connected by a straight-edge fixed at the +extremity of the lever, L, whose other end is in continuous correlation +with the eccentric, M, which controls the lateral displacements; +while the eccentric, O, actuates, by means of the screw, Q, and the +ratchet-wheel, S, the longitudinal advance of the velvet. The eccentric, +M, is fixed upon an axle, A', which carries a wheel, U, having teeth +inclined with respect to its axis, and which derives its motion from the +Archimedean screw, N, fixed at one of the extremities of the cam-shaft, +A. + +We have stated above that the maximum daily hand production of tulle +dotted in quincunxes of 0.04 of an inch is about one yard. At the rate +of 30 revolutions per minute, and for the same article as that just +mentioned, this dotting machine is capable of producing, theoretically, +360 yards per 10 hours; but practically this production is reduced to +about 250 yards, which, however, is sufficiently satisfactory. + + * * * * * + + + + +THE REPRODUCTION AND MULTIPLICATION OF NEGATIVES. + +By ERNEST EDWARDS, B.A. + + +A question, relative to the subject of reproducing negatives, which was +put at a meeting of one of your New York societies, prompts me to make a +few remarks on the subject. + +Among the numerous and widely diversified ramifications of our business +(the Heliotype Printing Company) we have very often to reproduce and +multiply negatives in both a direct and reversed form. Various methods +for doing this have been tried, and I may here say that I am quite well +aware of all the methods that have hitherto been suggested for the +purpose, but that which I am to describe is the one to which preference +has been given, and which is that known as the carbon process. + +A sheet of carbonized paper or "tissue," having been sensitized by +immersion in a bath of bichromate of potash, is dried in the dark and +placed away for future use, although it is undesirable that it be kept +for more than four or five days. This is placed in a printing frame in +contact with the negative and exposed for a few minutes, after which it +is immersed in water, squeegeed down upon a glass plate, and developed +with warm water in the way so well known to carbon printers. The result +is a transparency which, owing to having received a sufficient exposure, +should show every detail of the negative. The nature of the tissue +employed for such a purpose must be such as to give no strong contrasts, +but everything reproduced with soft and fine gradation of tone. + +The transparency thus obtained forms the _cliché_ by which the negatives +are subsequently made; and a negative of any size may be obtained by +the camera on wet or dry plates. The transparency must, of course, be +pointed to the sky and the light transmitted through it, no other light +being allowed to reach the lens except that which passes through the +carbon transparency. Care must also be taken that the transparency is +_uniformly_ lighted. If it is not possible to obtain a northern light, +which is best, a reflector of white paper or card may be used which must +be sufficiently large and placed at an angle of about forty-five degrees +to the transparency. + +If the repeated negative is to be of the same size as the original it +may be readily produced by repeating the operation of printing on carbon +tissue, using the transparency in place of the negative, or using a dry +plate in place of the tissue. But on the whole I have satisfied myself +that the best results are to be obtained by the first method. There is +a greater softness in the latter method, but a greater character and +similarity to the original in the former method. There is no doubt that +the use of the carbon transparency removes the hardness and riffidness +of the outlines peculiar to the older method of a collodion +transparency, while with carbon as the medium it is difficult for +any but the most experienced eye to distinguish the copy from the +original.--_Photo Times._ + + * * * * * + + + + +A NEW METHOD OF MAKING GELATINE EMULSION. + + +Since gelatine emulsion first came into use one of the greatest troubles +in connection with the manufacture of it has been that of washing. +According to the first methods the time taken for this part of the +process was, I believe, about twenty-four hours. It was very much +reduced and the ease of manufacture greatly facilitated by the methods +now most generally used, and which were, I believe, first communicated +by Messrs. Wratten and Wainright. I refer to those of precipitating with +alcohol and of straining the emulsion, when set, through canvas, so +as to divide it very finely. When the latter method is resorted to a +comparatively short time is sufficient to wash it. This method, although +a great improvement upon the older ones, yet leaves much to be desired, +especially for those who are not in the habit of making emulsion +regularly, but only an occasional batch. When the weather is at all warm +it takes a long time for the emulsion to set, unless ice be used, and +when once it is set the washing process is an exceedingly "messy" one +unless the water be cooled with ice; and the amount of water taken up +during washing is often so great that there is considerable difficulty +in getting the emulsion to set on the plates. In fact, even in cold +weather, it is not an easy process to conduct in the necessary near +approach to total darkness. + +Considerable suspicion has of late been thrown upon the thoroughness of +the alcohol method, unless the emulsion has, previous to precipitation, +been freed of the greater part of the soluble salts by washing; that is +to say, it is doubtful whether the whole of the soluble salts can be +eliminated by the process, and, therefore, unless in exceptionally hot +weather, it would seem best not to trust to it, except as a further +security against soluble bromide and nitrate after washing. Besides +this, the consumption of alcohol is very large. Almost three times the +amount of the emulsion precipitated is required, and this, even when +methylated spirit is used, adds considerably to the expense. With a view +of doing away with the washing altogether, or, rather, of washing of +the silver bromide when not incorporated with the gelatine, several +processes have been invented. By these silver bromide is obtained in a +very fine state of division, ready to mix with gelatine and water in any +proportion. + +The best known of them is Captain Abney's very ingenious glycerine +method, which seems to have been thoroughly successful in his hands, +although it has not been in every one's. The silver bromide obtained by +his process is not highly sensitive, and requires boiling with gelatine +before it is in a fit state to make a rapid plate. + +We have lately had described in these columns a method of obtaining +bromide in a highly-sensitive state by means of the use of an acid, +whereby, after emulsifying and boiling, the viscosity of the gelatine +was destroyed, and the bromide in time deposited itself. During the late +hot weather, when washing became almost impossible, I was led to cast +about for some method of eliminating the soluble salts less tedious and +"sloppy" than that of washing, more certain and less expensive than that +of precipitating the whole of gelatine with alcohol, and which would +take less time than the method of obtaining the bromide in a pure form. + +My first idea was to make up the solutions used in emulsifying in a very +concentrated form, and, after emulsifying, boiling, and allowing to +cool, to add to the thin emulsion thus obtained gelatine to the amount +of twenty grains to the ounce, and to precipitate this with alcohol, +the rest of the gelatine required to make up the bulk being afterwards +added, and the whole thoroughly incorporated by warming and shaking. +I was thus successful in reducing the amount of alcohol required to +one-third of what would be necessary if the whole of the emulsion were +precipitated; but still I found that, if a reliable emulsion were +required, the pellicle as formed had to be washed to free it from the +last trace of soluble salts. + +It now struck me that it might be possible to precipitate the bromide of +silver direct from a very weak solution of gelatine, and obtain it in +such a form that it might be filtered, washed, and in every way treated +as an ordinary precipitate. I tried the following experiment. I took-- + + 1. Silver nitrate....................... 200 grains + Water............................... 1½ ounce. + 2. Ammonia bromide...................... 120 grains. + Water................................ 1½ ounce. + Gelatine............................. 12 grains. + +I emulsified the two together in the usual way, allowed the whole +to cool, and then poured the thin emulsion into about ten ounces +of alcohol, stirring the while. As I had anticipated, a flocculent +precipitate was formed, which settled to the bottom of the vessel in a +few minutes. This was, in fact, sensitive bromide of silver mixed with +a very small quantity of gelatine (about five per cent.), and could, I +found, be treated in the same manner as a bromide precipitate from +an aqueous solution; it might be washed, either by decantation or by +filtration, easily dried, and doubtless could, when dry, be kept for an +indefinite time, and be at any time used by mixing with gelatine and +water in any proportion thought fit. + +I found that a less amount of gelatine than four grains to the ounce was +sufficient to carry the bromide down, while five grains to the ounce +carried it down in something which I considered too near an approach to +a plastic mass. + +It will be noticed that in the experiments which I have described the +emulsion had not been boiled, so that the sensitiveness of the bromide +was probably not great. As the experiment was done in daylight it was +of no practical use for making emulsion; but I have since made several +batches in this manner and have found them most satisfactory. + +When sensitiveness is sought by boiling I rind it necessary to add a +small quantity of gelatine after boiling and before precipitating, as +that which has been kept for some time at a high temperature seems to +have lost the viscosity necessary to carry down the silver bromide in +such a form that it can he easily separated from the alcohol and water. + +The practical manner of making an emulsion by this method may be as +follows. Make up the following mixtures: + + I. + Silver nitrate...........................................400 grains. + Water..................................................... 3 ounces. + + II. + + Ammonia bromide..........................................240 grains. + Gelatine..................................................24 grains + Water..................................................... 3 ounces. + Hydrochloric acid enough to slightly acidify the solution. + + III. + Gelatine................................................. 20 grains. + Water.................................................... ½ ounce. + IV. + + Hard gelatine (say Nelson's X opaque, + or Mr. A. L. Henderson's)................................240 grains. + Soft gelatine (Nelson's No.1)........................... 240 grains. + Water.....................................................24 ounces. + +Nos. II., III., and IV. are allowed to stand until the gelatine is +softened. No. I is then warmed in a hock bottle until the gelatine is +just melted, when No. II. is poured into it, a little at a time, with +vigorous shaking, until the whole is emulsified. It is then transferred +to an ordinary jelly can, which is placed in a saucepan half full of +water over a ring Bunsen burner in the dark room, and boiled for half an +hour. It is then allowed to cool to about 100° Fahr., when No. III. is +added. The whole is then allowed to get quite cool, when it is poured, +with stirring, into about one pint of methylated spirit. If it be wished +the precipitate may now be filtered out and washed at once like an +ordinary filtrate, but I prefer to allow it to settle, which it will do +in about five minutes. The supernatant fluid is then gently poured off. + +This fluid will have the appearance of still containing a considerable +amount of the silver bromide; but if it be kept and filtered it will be +seen that the quantity is really so small that it may be disregarded. We +all know what an alarming quantity of silver seems to be going down the +sink when we wash vessels to which a very small quantity of emulsion is +adhering. If filtering be resorted to the liquid which comes through +will be quite clear. This was somewhat unexpected by me, as, if an +emulsion containing the whole of the gelatine be precipitated into +alcohol in the usual way, the alcohol becomes milky with a substance +which could not, I imagine, be filtered from it. + +Two or three ounces of methylated spirit are now added to the vessel +containing the silver bromide, and the latter well mixed with it. This +makes the precipitate "firmer"--if such an expression be allowable--and +this time it will sink to the bottom almost immediately after the +stirring has ceased, and the alcohol may be poured off. + +I consider that the bromide in this state is practically free from +soluble salts, but it may be washed with one or two changes of water if +desired. + +No. IV. is now gently heated till the gelatine is melted and the +precipitate mixed with it. It must be kept warm for some time, and +shaken vigorously until all granularity has disappeared, This is, of +course, ascertained by placing a drop of the emulsion on a piece of +glass, and examining it. If it be wished to keep the bromide of silver +for future use it may be placed on a piece of muslin stretched in the +drying-box, when it will dry in a very short time; and, although I +cannot speak from experience on this point, it will, I have no doubt, +keep for an indefinite time so long as light is kept from it. + +If it be desired the ammonio-nitrate method may be used instead of the +boiling one, although in my hands it does not give such sensitiveness. +If it be desired to use this method, solution Nos. I, II., and IV. are +made up exactly as for the boiling method, except that No. II. is not +acidified. Liquid ammonia is then poured with stirring into the silver +solution, until it blackens and again clears. Emulsification is +performed exactly as described above, but instead of boiling, the +emulsion is kept at a temperature of about 100° Fahr. for half an hour, +when it is poured into the alcohol, no addition of gelatine being +previously made. + +I think I may claim for the method which I have just described that it +is less troublesome and more certain than either the ordinary washing +method or the usual one of precipitating with alcohol, while it affords +an easy method of making sensitive silver bromide in such a form that it +can be more easily stored and afterwards manipulated than if it were in +the form of pellicle. The whole of the soluble salts are eliminated, +and also any gelatine which may have been destroyed in the cooking. +The amount of alcohol used is comparatively small; in fact, to prepare +silver bromide for a pint of emulsion very little more than a pint of +methylated spirit is required. Besides this I do not think that I would +be wrong in saying that the chance of green fog is reduced to a minimum. + +Let me take this opportunity of thanking Captain Abney for his prompt +reply to my question about the connection between the proportion +of bromide to gelatine in emulsions, and the density of resulting +images.--_W. K. Burton, in British Journal of Photography_. + + * * * * * + +[Illustration: Old Wrought Iron Gates, Guildhall.] + + * * * * * + + + + +THE POTTERY AND PORCELAIN INDUSTRIES OF JAPAN. + + +Japanese chronicles claim that the first pottery was made in the year +660 B.C.; it was not, however, until the Christian era that the art made +any considerable advances. In the year 1223 A.D., great improvements +were made in manufacture and decoration of the ware. From that date to +the sixteenth century the great potteries of Owari, Hizen, Mino, Kioto, +Kaga, and Satsuma were established. The Rahn-Yaki, or crackled ware, was +first made at Kioto, at the commencement of the sixteenth century. The +best old Hizen ware, that which is still the most admired, was made +at Arita Hizen, in 1580 to 1585; the old Satsuma dates from 1592. +Consul-General Van Buren states that porcelain clays are found in nearly +all parts of the country, and the different kinds are usually found +in close proximity, and close to canals and rivers, which is of +considerable advantage, as affording a means of transport. In all cases +every variety of clay used in the manufacture of pottery is found in a +natural state; there is no necessity to manufacture the quartzose or +fusible clays as is done in other parts of the world, and which adds +considerably to the cost of the ware. One of the peculiarities in the +clay found in Japan is that it contains both the fusible and infusible +materials in such proportions as to make a light, beautiful, +translucent, and durable porcelain. At Arita, in Hizen, there is a clay +found which contains 783/4 per cent, of silica, and l73/4 per cent, of +alumina; from this clay is made the delicate, translucent eggshell ware, +without the addition of any other matter. From an adjoining bluff a clay +is taken which has 50 per cent, of silica, and 38 per cent, of alumina; +from this the common porcelain is made. + +Potter's clay is found in very large quantities in the provinces of +Yamashiro, Hoki, Turoo Iyo, Hizen, Higo, Owari, Mikaera, Idyn, Musashi, +and Mino. In the whole of Japan there are 283 localities where the clay +is deposited; many of these only furnish inferior clays, but they are +all fitted for use in some of the various kinds of pottery. These clays +are thoroughly powdered by means of what is called "balance pounders," +worked in some localities by water-power, but the work is often done by +hand. The powder is then dried, and stored on boards or in flat boxes. +This dough does not go through the process of fermentation. The shaping +is almost exclusively done on the potter's wheel, which is set on a +pivot working in a porcelain eye. As a rule, the wheel is turned by the +potter himself, but in Hizen it is kept in motion by means of a band +connected with its pivot and another wheel turned by a boy. In making +dishes of other shape than round, a crude mould is sometimes used. After +the clay has been shaped on the wheel, it is set away for drying, and +usually in two or three days it is considered sufficiently dry for +smoothing, which is done on the wheel with a sharp curved knife. The +material is now made into "bisque," or biscuit, by a preliminary baking +in small ovens, when it is ready for painting, if it is to be painted +on the biscuit; if not, it is ready for the glazing. In either event it +will then go to the large furnace for the final baking. The kilns for +this purpose are always built on hill sides, and are joined together, +increasing in size from the lower to the higher ones, and in number from +four to twenty five; these kilns are so constructed that the draught is +from the lowest one, in addition to which each kiln has its own firing +place. The result of this construction is that the upper ones are by +far the most heated, and the ware is arranged accordingly; that which +requires the least baking, in the lower kiln, and that which requires +the greatest heat, in the upper. These connecting kilns have the merit +of being heat saving, but they are usually small and badly constructed, +and the heat in none of them is uniform. + +The glaze is made from the silicious clay and potash extracted from wood +ashes. This potash is not a pure white, and this accounts for the dirty +color usually to be observed in unpainted Japanese ware. In different +districts the painting varies. For instance, in Owari, the greater part +of the ware is painted a cobalt blue--the cobalt ore being found in the +bluffs near the clay deposits, and is used for painting the cheaper +wares, and for this purpose German cobalt is also employed. The painting +with cobalt is generally done on the biscuit before glazing. In several +districts a very handsome ware is made, and painted on the glaze. For +this kind of painting the colors are mixed with a silicate of lead +and potash, and baked the third time in a small furnace at a low +temperature. The coloring oxides in use are those of copper, cobalt, +iron, antimony, manganese, and gold. Japanese porcelain painting may be +divided into two categories, decorative and graphic; the first is used +to improve the vessel upon which it is placed, and this class includes +all the ware except that of the province of Kaga, which would come under +the head of graphic, as it delineates all the trades, occupations, +sports, customs, and costumes of the people, as well as the scenery, +flora, and fauna of the country. "Owari ware" is made in the province +of that name; it is not as translucent, but stronger and more tenacious +than some of the Hizen manufacture. + +The principal potteries are at a village called Sèto, twelve miles from +the sea; in this village there are more than 200 kilns. The ware is +mostly painted a cobalt blue, and is merely of a decorative kind, +consisting of branches of trees, grass, flowers, birds, and insects, all +these being copied by the artist from nature. All the Owari ware is true +hard porcelain, and is strong and durable. In Hizen, a number of wares +are manufactured, the best known kind being the "Eurari," which is made +at Arita, but painted at Eurari. The colors in use are red, blue, green, +and gold; these are combined in various proportions, but, as a rule, the +red predominates. Generally the surface of the vessel is divided into +medallions of figures, which alternately have red, blue, or white +back-ground, with figures in green or blue and gold. + +The egg-shell porcelain sold at Nagasaki is made in this province from +Arita clay, and this is made from clay with no admixture of fusible +matter except that contained by the clay naturally. The province of +Satsuma is noted for crackled ware. It is only within a very few years +that large vases have been manufactured, and in earlier days the old +ware was confined to small vessels. The glaze is a silicate of alumina +and potash, and the best ware has a complete network of the finest +crackles; the painting is of birds and flowers, and noted for its +delicate lines of green, red, and gold. + +In Kioto, the ware manufactured is very similar to that produced in +Satsuma, but it is lighter and more porous; the decorations are also +nearly the same, being of birds and flowers. There is a description of +ware made in Kioto, called "Eraku," the whole body of which is covered +with a red oxide of iron, and over this mythical figures of gold are +traced. That produced in Kagja is _faïence_, and in the style of +painting is unlike any other in Japan, the predominating color being +a light red, used with green and gold. The designs with which it is +profusely decorated are trees, grasses, flowers, birds, and figures of +all classes of people, with their costumes, occupations, and pastimes. +The "Banko" ware is made at the head of the Owari Bay; it is an unglazed +stone-ware, very light and durable, made on moulds in irregular shapes, +and decorated with figures in relief. On the island of Awadji, a +delicate, creamy, crackled, soft paste porcelain is made. The figures +used in decoration are birds and flowers, but outlined by heavy, dark +lines. + +Consul Van Buren is of opinion that, at no distant day, Japan will be +one of the foremost competitors in the pottery markets of the world, +on account of the great variety and excellence of the clays, their +proximity to the sea, the cheapness of labor, and the beauty and +originality of the decorations. Already this important industry has been +greatly stimulated by the foreign demand, and by the success of +Japanese exhibitors at the Exhibitions of Vienna, Philadelphia, and +Paris.--_Journal of the Society of Arts_. + + * * * * * + +Professor Julius E. Hilgard, for twenty years assistant in charge of the +office, has been placed in temporary charge of the Coast and Geodetic +Survey. It is understood that he will be appointed superintendent to +succeed the late Captain Carlile P. Patterson. + + * * * * * + + + + +THE FRENCH CRYSTAL PALACE. + + +The first idea of the French Crystal Palace was suggested by the English +structure of the same name at Sydenham, about eight miles from London. +Such a structure, as may be readily conceived, requires a site of vast +extent, and one that shall be easy of access and possess the most +agreeable surroundings. To the promoter of the project, those portions +of the park of St. Cloud in the vicinage of the old chateau appeared to +combine within themselves all the conditions that were desirable, and +he, therefore, on the 15th of December, 1879, addressed the Ministers of +Public Works and of Finances asking for the necessary concessions. The +extensive specifications have been finally completed and will probably +be shortly submitted for the approval of the parliament. The moment has +arrived then for the public press to take cognizance of a project which +concerns so great interests. + +[Illustration: THE FRENCH CRYSTAL PALACE--PARK OF ST CLOUD, PARIS.] + +At present we shall say a few words _à propos_ of the engraving we +present herewith. The French Crystal Palace will consist of one great +nave, two lateral naves, two surrounding galleries, and a vast rotunda +behind. The principal entrance, located at the head of the avenue +leading from the present ruins (which will, ere long, be transformed +into a most interesting museum), will exhibit a very striking aspect +with its monumental fountain and the dome which it is proposed to erect +over the very entrance itself. The whole structure will cover about +nineteen acres of ground, thus being two and a half times the extent of +the Palace of Industry in the Champs Elysees. The great nave of honor +will be nearly 1,650 ft. in length, 78 ft. in width, and 98 ft. in +height. The dome will measure exactly 328 ft. in height, or 105 ft. more +than the towers of Notre Dame. The structure, with the exception of +basement and foundation, will be of glass and iron. + +The project which we publish to-day has been studied and gotten up, +according to the general plans and dimensions suggested by the promoter, +by Mr. Dumoulin, the architect. We are informed that the builder is to +be Mr. Alfred Hunnebelle, a contractor well known from the extensive +works that he has executed, and who is president of the Syndical Chamber +of Contractors of Paris. + +Among the annexes of this palace we may note a "Palace of the Republic," +to be built on the ruins and designed for illustrious or distinguished +visitors, such as the President of the Republic, the Ministers, the +Municipal Council of Paris, foreign delegates, etc.; a farm house for +special exhibitions and a field for experiments; galleries, cottages, +etc. + +As for the programme, which embraces six divisions and numerous +subdivisions, we are unable to give it at present for want of space; we +need only say that it satisfies perfectly all the conditions of so vast +an undertaking. + +In the hands of the projector, Mr. Nicole, who is well known from his +long experience in such matters, the exhibition will undoubtedly prove +a success and be instrumental in adding prosperity to all French +industries. + + * * * * * + +THE GREAT HEAT OF THE SUN.--Prof. S. P. Langley has made the following +calculation: A sunbeam one centimeter in section is found in the clear +sky of the Alleghany Mountains to bring to the earth in one minute +enough heat to warm one gramme of water by 1° C. It would, therefore, +if concentrated upon a film of water 1/500th of a millimeter thick, +1 millimeter wide, and 10 millimeters long, raise it 83 1/3° in one +second, provided all the heat could be maintained. And since the +specific heat of platinum is only 0.0032 a strip of platinum of the same +dimensions would, on a similar supposition, be warmed _in one second_ to +2,603° C.--a temperature sufficient to melt it! + + * * * * * + + + + +CHATEAU IN THE AEGEAN SEA. + + +From the site of this building, magnificent views are obtained over the +island-dotted sea and the mainland of Asia Minor: but, "though every +prospect pleases," it is a land of earthquakes, and unfortunately, the +works at the chateau have been suspended, owing to the dreadful calamity +which has recently fallen upon the district. The building is intended +for the residence of an English lady of exalted rank. It is to be built +of local white stone, the hall, staircase, etc., being lined and paved +with marbles. The hall is a large apartment about 25 ft. high, with +paneled ceiling, having galleries on two sides, giving access to the +rooms surrounding it on first floor, and to the turret staircase leading +to roofs, etc. With the exception of sanitary apparatus, painted +windows, etc. (which will be supplied by English firms), the whole of +the work will be executed by native labor. The architect is Mr. Edwin T. +Hall, London.--_Building News_. + +[Illustration: SUGGESTIONS IN ARCHITECTURE--A CASTELLATED CHATEAU.] + + * * * * * + + + + +ELECTRIC POWER. + + +Just now nothing save electricity is talked about in scientific circles. +During the meeting of the British Association the greatest possible +prominence was given to electrical questions and propositions The +success of the electric light, the introduction of the Faure battery +with a great flourish of trumpets, and the magnificent display of +electrical instruments and machinery at Paris, have all operated to the +same end. The daily press has taken the subject up, and journals which +were nothing hitherto if not political, now indulge in magnificent +rhapsodies concerning the future of electricity. Even eminent engineers, +carried away by the intoxication of the moment, have not hesitated to +say that the steam engine is doomed, and that its place will be taken by +the electricity engine. In the midst of all this noise and clamor and +blowing of personal trumpets, it is not easy to keep one's head clear, +and mistakes may be made which will cause disappointment to many and +retard the progress of electrical science. We confidently expect that +electricity will prove a potent agent by and by in the hands of the +speculator for extracting gold from the pockets of the public, and we +write now to warn our readers in time, and to endeavor to clear the air +of some of the mists with which it is obscured. There is, no doubt, +a great future before electricity; but it is equally certain that +electricity can never do many things which the half informed may be +readily made to believe it will do. We propose here to say enough +on this point to enlighten our readers, without troubling them with +perplexing problems and speculations. + +No one at this moment knows what electricity is; but for our present +purpose we may regard it as a fluid, non-elastic, and without weight, +and universally diffused through the universe. To judge by recently +published statements, a large section of the reading public are taught +that this fluid is a source of power, and that it may be made to do the +work of coal. This is a delusion. So long as electricity remains in what +we may call a normal state of repose, it is inert. Before _we can get +any work out of electricity a somewhat greater amount of work must be +done upon it_. If this fundamental and most important truth be kept in +view it will not be easy to make a grave mistake in estimating the value +of any of the numerous schemes for making electricity do work which will +ere long be brought before the public. To render our meaning clearer, +we may explain that in producing the electric light, for instance, a +certain quantity of electricity passes in through one wire to the lamp, +and precisely the same quantity passes out through the other wire, and +on to the earth or return wire completing the circuit. Not only is the +quantity the same, the velocity is also unchanged. But in going through +the lamp the current has done something. It has overcome the resistance +of the carbons, heated them to a dazzling white heat, and so performed +work. In doing this the current of electricity has lost something. Led +from the first lamp to a second, it is found powerless--if the first +lamp be of sufficient size. What is it that the electricity has lost? +It has parted with what electricians would term "potential," or the +capacity for performing work. What this is precisely, or in what way the +presence or absence of potential modifies the nature of the electric +current, no one knows; but it is known that this potential can only be +conferred on electricity by doing work on the electricity in the first +instance. The analogy between electricity and a liquid like water will +now be recognized. So long as the water is at rest, it is inert. If we +pump it up to a height, we confer on it the equivalent of potential. +We can let the water fall into the buckets of an overshot wheel. Its +velocity leaving the tail race may be identical with that at which it +left the supply trough to descend on the wheel. Its quantity will be +the same. It will be in all respects unchanged, just as the current +of electricity passing through a lamp is unchanged; but it has, +nevertheless, lost something. It has parted with its potential--capacity +for doing work--and it becomes once more inert. But the duty which it +discharged in turning the mill wheel was somewhat less than the precise +equivalent of the work done in pumping it up to a level with the top of +the wheel. In the same way the electric current never can do work equal +in amount to the work done on it in endowing it with potential. + +It will thus be seen that electricity can only be used as a means of +transmitting power from one place to another, or for storing power up +at one time to be used at a subsequent period; but it cannot be used to +originate power in the way coal can be used. It possesses no inherent +potential. It is incapable of performing work unless something is done +to it first. We have spoken of it as a fluid, but only for the sake of +illustration. As we have said, no one knows what it is, but the theory +which bids fair for acceptance is that it is a mode of motion of the +all-pervading ether. Very curious and instructive experiments are now +being carried out in Paris by Dr. Bjerkness, of Christiania, in the +Norwegian section of the electrical exhibition. This gentleman submerges +thin elastic diaphragms in water, and causes them to vibrate, or rather +pulsate, by compressed air. He finds that if they pulsate synchronously +they attract each other. If the pulsations are not simultaneous, the +disks repel each other. From this and other results he has obtained, +it may be argued that the ether plays the part of the water in Dr. +Bjerkness' tank, and that when special forms of vibration are set up +in bodies they become competent to attract or repel other bodies. This +being so, it will be seen that the power of attraction or repulsion of +an electrical body depends in the first instance on the motion set up +in the body attracted or repulsed, and this motion is, of course, some +function of the work originally done on the body. We need not pursue +this argument further. Among the most scientific investigators of the +day it is admitted that the efficiency of electricity as a doer of work, +or a producer of action at a distance, must depend for its value on the +performance of work in some one way or another on the electricity itself +in the first instance. It may be worth while here to dispel a popular +delusion. It is held very generally that electricity can be made, as, +for instance, by the galvanic battery. There is no reason to believe +anything of the kind; but whether it is or is not true that electricity +is actually made by the combustion of zinc in a galvanic trough, it is +quite certain that this electricity, unless it possesses potential, can +do no work, no matter how great its quantity. Of course, it is to be +understood that all electric currents possess potential. If they did +not, their presence would be unknown; but the potential of a current +is in all cases the result of work done on electricity, either by the +oxidation of zinc, or in some other way. This is a broad principle, but +it is strictly consistent in every respect with the truth. Electricity, +then, is, as we have said, totally different from coal; and it can never +become a substitute for it alone. Water power, air power, or what we +may, for want of a better phrase, call chemical power, combined with +electricity, can be used as a substitute for coal; but electricity +cannot of itself be employed to do work. It is true, however, that +electricity, on which work has already been done, may be found in +nature. Atmospheric electricity, for example, may perhaps yet be +utilized. It is by no means inconceivable that the electricity contained +in a thunder cloud might be employed to charge a Faure battery; but up +to the present no one has contemplated the obtaining of power from the +clouds, and whether it is or is not practicable to utilize a great +natural force in this way does not affect our statement. The use of +electricity must be confined to its power of transmitting or storing up +energy, and this truth being recognized, it becomes easy to estimate the +future prospects of electricity at something like their proper value. + +It has been proved to a certain extent that electricity can be used to +transmit power to a distance, and that it can be used to store it up. +Thus far the man of pure science. The engineer now comes on the stage +and asks--Can practical difficulties be got over? Can it be made to pay? +In trying to answer these questions we cannot do better than deal with +one or two definite proposals which have been recently made. That with +which we shall first concern ourselves is that trains should be worked +by Faure batteries instead of by steam. It is suggested that each +carriage of a train should be provided with a dynamo motor, and that +batteries enough should be carried by each to drive the wheels, and so +propel the train. Let us see how such a scheme would comply with working +conditions. Let us take for example a train of fifteen coaches on the +Great Northern Railway, running without a stop to Peterborough in one +hour and forty minutes. The power required would be about 500 horses +indicated. To supply this for 100 minutes, even on the most absurdly +favorable hypothesis, no less than 25 tons of Faure batteries would be +required. Adding to these the weight of the dynamo motors, and that +unavoidably added to the coaches, it will be seen that a weight equal to +that of an engine would soon be reached. The only possible saving would +be some 28 to 30 tons of tender. In return for this all the passengers +would have to change coaches at Peterborough, as the train could not be +delayed to replace the expended with fresh batteries. This is out of +the question. The Faure batteries must all be carried on one vehicle or +engine, which could be changed for another, like a locomotive. Even then +no advantage would be gained. As to cost, it is very unlikely that the +stationary engines which must be provided to drive the dynamo machines +for charging the batteries would be more economical than locomotive +engines; and if we allow that the dynamo machine only wasted 10 per +cent. of the power of the engine, the Faure batteries 10 per cent. of +the power of the dynamo machines, and the dynamo motors 10 per cent. of +the power of the batteries--all ridiculously favorable assumptions--yet +the stationary engines would be handicapped with a difference in net +efficiency between themselves and the locomotive--admitting the original +efficiency per pound of coal in both to be the same--of some 27 per +cent., we think we may relegate this scheme to the realms of oblivion. +Another idea is that by putting up turbines and dynamo machines the +steam engine might be superseded by water power. Now it so happens that +if all the water power of England were quadrupled it would not nearly +suffice for our wants. It may be found worth while perhaps to construct +steam engines close to coalpits and send out power from these engines by +wire; but the question will be asked, Which is the cheaper of the two, +to send the coal or to send the power? On the answer to this will +depend the decision of the mill owners. Another favorite scheme is that +embodied in the Siemens electrical railway. We believe that there is a +great future in store for electricity as a worker of tramway traffic; +but the traffic on a great line like the Midland or Great Northern +Railway could not be carried on by it. As Robert Stephenson said of the +atmospheric system, it is not flexible enough. The working of points +and crossings, and the shunting of trains and wagons, would present +unsurmountable difficulties. We have cited proposals enough, we think, +to illustrate our meaning. Sir William Armstrong, Sir Frederick +Bramwell, Dr. Siemens, Sir W. Thomson, and many others may be excused if +they are a little enthusiastic. They are just now overjoyed with success +attained; but when the time comes for sober reflection they will, no +doubt, see good reason to moderate their views. No one can say, of +course, what further discoveries may bring to light; but recent speakers +and writers have found in what is known already, materials for sketching +out a romance of electricity. It is but romancing to assert that the end +of the steam engine is at hand. Wonderful and mystical as electricity +is, there are some very hard and dry facts about it, and these facts are +all opposed to the theory that it can become man's servant of all work. +Ariel-like, electricity may put a girdle round the earth in forty +minutes; but it shows no great aptitude for superseding the useful old +giant steam, who has toiled for the world so long and to such good +purpose--_The Engineer_. + + * * * * * + + + + +ON A METHOD OF OBTAINING AND MEASURING VERY HIGH VACUA WITH A MODIFIED +FORM OF SPRENGEL-PUMP. + +By Ogden N. Rood, Professor of Physics in Columbia College. + + +In the July number of this Journal for 1880, I gave a short account of +certain changes in the Sprengel-pump by means of which far better vacua +could be obtained than had been previously possible. For example, the +highest vacuum at that time known had been reached by Mr. Crookes, and +was about 1/17,000,000, while with my arrangement vacua of 1/100,000,000 +were easily reached. In a notice that appeared in _Nature_ for August, +1880, p. 375, it was stated that my improvements were not new, but had +already been made in England four years previously. I have been unable +to obtain a printed account of the English improvements, and am willing +to assume that they are identical with my own; but on the other hand, +as for four years no particular result seems to have followed their +introduction in England, I am reluctantly forced to the conclusion that +their inventor and his customers, for that period of time, have remained +quite in ignorance of the proper mode of utilizing them. Since then I +have pushed the matter still farther, and have succeeded in obtaining +with my apparatus vacua as high as 1/390,000,000 without finding +that the limit of its action had been reached. The pump is simple in +construction, inexpensive, and, as I have proved by a large number of +experiments, certain in action and easy of use; stopcocks and grease are +dispensed with, and when the presence of a stopcock is really desirable +its place is supplied by a movable column of mercury. + +_Reservoir_.--An ordinary inverted bell-glass with a diameter of 100 mm. +and a total height of 205 mm. forms the reservoir; its mouth is closed +by a well-fitting cork through which passes the glass tube that forms +one termination of the pump. The cork around tube and up to the edge of +the former is painted with a flexible cement. The tube projects 40 mm. +into the mercury and passes through a little watch-glass-shaped piece of +sheet-iron, W, figure 1, which prevents the small air bubbles that creep +upward along the tube from reaching its open end; the little cup is +firmly cemented in its place. The flow of the mercury is regulated +by the steel rod and cylinder, CR, Figure 1. The bottom of the steel +cylinder is filled out with a circular piece of pure India-rubber, +properly cemented; this soon fits itself to the use required and answers +admirably. The pressure of the cylinder on the end of the tube is +regulated by the lever, S, Figure 1; this is attached to a circular +board which again is firmly fastened over the open end of the +bell-glass. It will be noticed that on turning the milled head, S, the +motion of the steel cylinder is not directly vertical, but that it tends +to describe a circle with c as a center; the necessary play of the +cylinder is, however, so small, that practically the experimenter does +not become aware of this theoretical defect, so that the arrangement +really gives entire satisfaction, and after it has been in use for a few +days accurately controls the flow of the mercury. The glass cylinder is +held in position, but not supported, by two wooden _adjustable_ clamps, +_a a_, Figure 2. The weight of the cylinder and mercury is supported by +a shelf, S, Figure 2, on which rests the cork of the cylinder; in this +way all danger of a very disagreeable accident is avoided. + +[Illustration: MODIFIED FORM OF SPRENGEL PUMP.] + +_Vacuum-bulb_.--Leaving the reservoir, the mercury enters the +vacuum-bulb, B, Figure 2, where it parts with most of its air and +moisture; this bulb also serves to catch the air that creeps into the +pump from the reservoir, even when there is no flow of mercury; its +diameter is 27 mm. The shape and inclination of the tube attached to +this bulb is by no means a matter of indifference; accordingly Figure +3 is a separate drawing of it; the tube should be so bent that a +horizontal line drawn from the proper level of the mercury in the bulb +passes through the point, _o_, where the drops of mercury break off. The +length of the tube, EC, should be 150 mm., that of the tube, ED, 45 mm.; +the bore of this tube is about the same as that of the fall-tube. + +_Fall-tube and bends_.--The bore of the fall-tube in the pump now used +by me is 1.78 mm.; its length above the bends (U, Figure 2) is 310 mm.; +below the bends the length is 815 mm. The bends constitute a fluid valve +that prevents the air from returning into the pump; beside this, the +play of the mercury in them greatly facilitates the passage of the +air downward. The top of the mercury column representing the existing +barometric pressure should be about 25 mm. below the bends when the pump +is in action. This is easily regulated by an adjustable shelf, which is +also employed to fill the bends with mercury when a measurement is taken +or when the pump is at rest. On the shelf is a tube, 160 mm. high and 20 +mm. in diameter, into which the end of the fall-tube dips; its side has +a circular perforation into which fits a small cork with a little tube +bent at right angles. With the hard end of a file and a few drops of +turpentine the perforation can be easily made and shaped in a few +minutes. By revolving the little bent tube through 180° the flow of the +mercury can be temporarily suspended when it is desirable to change the +vessel that catches it. + +_Gauge_.--For the purpose of measuring the vacua I have used an +arrangement similar to McLeod's gauge, Figure 4; it has, however, some +peculiarities. The tube destined to contain the compressed air has a +diameter of 1.35 mm. as ascertained by a compound microscope; it is not +fused at its upper extremity, but closed by a fine glass rod that fits +into it as accurately as may be, the end of the rod being ground flat +and true. This rod is introduced into the tube, and while the latter +is gently heated a very small portion of the cement described below is +allowed to enter by capillary attraction, but not to extend beyond the +end of the rod, the operation being watched by a lens. The rod is +used for the purpose of obtaining the compressed air in the form of a +cylinder, and also to allow cleansing of the tube when necessary. The +capacity of the gauge-sphere was obtained by filling it with mercury; +its external diameter was sixty millimeters; for measuring very high +vacua this is somewhat small and makes the probable errors rather +large; I would advise the use of a gauge-sphere of about twice as great +capacity. The tube, CB, Figure 4, has the same bore as the measuring +tube in order to avoid corrections for capillarity. The tube of the +gauge, CD, is not connected with an India-rubber tube, as is usual, +but dips into mercury contained in a cylinder 340 mm. high, 58 mm. in +diameter, which can be raised and lowered at pleasure. This is best +accomplished by the use of a set of boxes of various thicknesses, made +for the purpose and supplemented by several sheets of cardboard and even +of writing-paper. These have been found to answer well and enable the +experimenter to graduate with a nicety the pressure to which the gas is +exposed during measurement. By employing a cylinder filled with mercury +instead of the usual caoutchouc tubing small bubbles of air are +prevented from entering the gauge along with the mercury. An adjustable +brace or support is used which prevents accident to the cylinder when +the pump is inclined for the purpose of pumping out the vacuum-bulb. The +maximum pressure that can be employed in the gauge used by me is 100 mm. + +All the tubing of the pump is supported at a distance of about 55 mm. +from the wood-work; this is effected by the use of simple adjustable +supports and adjustable clamps; the latter have proved a great +convenience. The object is to gain the ability to heat with a Bunsen +burner all parts of the pump without burning the wood-work. Where glass +and wood necessarily come in contact the wood is protected by metal or +simply painted with a saturated solution of alum. The glass portions +of the pump I have contrived to anneal completely by the simple means +mentioned below. If the glass is not annealed it is certain to crack +when subjected to heat, thus causing vexation and loss of time. The +mercury was purified by the same method that was used by W. Siemens +(Pogg. Annalen, vol. ex., p. 20), that is, by a little strong sulphuric +acid to which a few drops of nitric acid had been added; it was dried by +pouring it repeatedly from one hot dry vessel to another, by filtering +it while quite warm, the drying being completed finally by the action of +the pump itself. All the measurements were made by a fine cathetometer +which was constructed for me by William Grunow; see this Journal, Jan., +1874, p. 23. It was provided with a well-corrected object-glass having a +focal length of 200 mm. and as used by me gave a magnifying power of 16 +diameters. + +_Manipulation_.--The necessary connections are effected with a cement +made by melting Burgundy pitch with three or four per cent of gutta +percha. It is indispensable that the cement when cold should be so hard +as completely to resist taking any impression from the finger nail, +otherwise it is certain to yield gradually and finally to give rise to +leaks. The connecting tubes are selected so as to fit as closely as +possible, and after being put into position are heated to the proper +amount, when the edges are touched with a fragment of cold cement which +enters by capillary attraction and forms a transparent joint that can +from time to time be examined with a lens for the colors of thin plates, +which always precede a leak. Joints of this kind have been in use by me +for two months at a time without showing a trace of leakage, and the +evidence gathered in another series of unfinished experiments goes to +show that no appreciable amount of vapor is furnished by the resinous +compound, which, I may add, is never used until it has been repeatedly +melted. As drying material I prefer caustic potash that has been in +fusion just before its introduction into the drying tube; during the +process of exhaustion it can from time to time be heated nearly to the +melting point: if actually fused in the drying tube the latter almost +invariably cracks. The pump in the first instance is to be inclined at +an angle of about 10 degrees, the tube of the gauge being supported by +a semicircular piece of thick pasteboard fitted with two corks into the +top of the cylinder. This seemingly awkward proceeding has in no case +been attended with the slightest accident, and owing to the presence of +the four leveling-screws, the pump when righted returns, as shown by the +telescope of the cathetometer, almost exactly to its original place. In +the inclined position the exhaustion of the vacuum bulb is accomplished +along with that of the rest of the pump. The exhaustion of the +vacuum-bulb when once effected can be preserved to a great extent for +use in future work, merely by allowing mercury from the reservoir to +flow in a rapid stream at the time that air is allowed to re-enter the +pump. During the first process of exhaustion the tube of the gauge is +kept hot by moving to and fro a Bunsen burner, and is in this way +freed from those portions of air and moisture that are not too firmly +attached. After a time the vacuum-bulb ceases to deliver bubbles of +air; it and the attached tube are now to be heated with a moving Bunsen +burner, when it will be found to furnish for 15 or 20 minutes a large +quantity of bubbles mainly of vapor of water. After then production +ceases the pump is righted and the exhaustion carried farther. In spite +of a couple of careful experiments with the cathetometer I have not +succeeded in measuring the vacuum in the vacuum bulb, but judge from +indications, that is about as high as that obtained in an ordinary +Geissler pump. Meanwhile the various parts of the pump can be heated +with a moving Bunsen burner to detach air and moisture, the cement being +protected by wet lamp-wicking. In one experiment I measured the amount +of air that was detached from the walls of the pump by heating them for +ten minutes somewhat above l00° C., and found that it was 1/1,000,000 +of the air originally present. I have also noticed that a still larger +amount of air is detached by electric discharges. This coincides with an +observation of E. Bessel-Hagen in his interesting article on a new form +of Töpler's mercury-pump (Annalen der Physik und Chemie, 1881, vol. +xii.). Even when potash is used a small amount of moisture always +collects in the bends of the fall tube; this is readily removed by a +Bunsen burner; the tension of the vapor being greatly increased, it +passes far down the fall-tube in large bubbles and is condensed. Without +this precaution I have found it impossible to obtain a vacuum higher +than 1/25,000,000; in point of fact the bends should always be heated +when a high exhaustion is undertaken even if the pump has been standing +well exhausted for a week; the heat should of course never be applied at +a late stage of the exhaustion. Conversely, I have often by the aid of +heat completely and quickly removed quite large quantities of the vapor +of water that had been purposely introduced. The exhaustion of the +vacuum-bulb is of course somewhat injured by the act of using the pump +and also by standing for several days, so that it has been usual with me +before undertaking a high exhaustion to incline the pump and re-exhaust +for 20 minutes; I have, however, obtained very high vacua without using +this precaution. + +During the process of exhaustion not more than one-half of the mercury +in the reservoir is allowed to run out, other wise when it is returned +bubbles of air are apt to find their way into the vacuum-bulb. In order +to secure its quiet entrance it is poured into a silk bag provided with +several holes. When the reservoir is first filled its walls for a day +or two appear to furnish air that enters the vacuum-bulb; this action, +however, soon sinks to a minimum and then the leakage remains quite +constant for months together. + +_Measurement of the vacuum_.--The cylinder into which the gauge-tube +dips is first elevated by a box sufficiently thick merely to close the +gauge, afterwards boxes are placed under it sufficient to elevate the +mercury to the base of the measuring tube; when the mercury has reached +this point, thin boards and card-boards are added till a suitable +pressure is obtained. The length of the inclosed cylinder of air is +then measured with the cathetometer, also the height of the mercurial +"meniscus," and the difference of the heights of the mercurial columns +in A and B, figure 4. To obtain a second measure an assistant removes +some of the boxes and the cylinder is lowered by hand three or four +centimeters and then replaced in its original position. In measuring +really high vacua, it is well to begin with this process of lowering and +raising the cylinder, and to repeat it five or six times before taking +readings. It seems as though the mercury in the tube, B, supplies to the +glass a coating of air that allows it to move more freely; at all events +it is certain that ordinarily the readings of B become regular, only +after the mercury has been allowed to play up and down the tube a number +of times. This applies particularly to vacua as high 1/50,000,000 and to +pressures of five millimeters and under. It is advantageous in making +measurements to employ large pressures and small volumes; the correct +working of the gauge can from time to time be tested by varying the +relations of these to each other. This I did quite elaborately, and +proved that such constant errors as exist are small compared with +inevitable accidental errors, as, for example, that there was no +measurable correction for capillarity, that the calculated volume of the +"meniscus" was correct, etc. It is essential in making a measurement +that the temperature of the room should change as little as possible, +and that the temperature of the mercury in the cylinder should be at +least nearly that of the air near the gauge-sphere. The computation is +made as follows + + n = height of the cylinder inclosing the air; + c = a factor which, multiplied by n, converts it into cubic + millimeters; + S = cubic contents of the meniscus; + d = difference of level between A and B, fig. 4; + = the pressure the air is under; + N = the cubic contents of the gauge in millimeters; + x = a fraction expressing the degree of exhaustion obtained; then + + x=1/([N (760/d)]/[nc - S]) + +It will be noticed that the measurements are independent of the actual +height of the barometer, and if several readings are taken continuously, +the result will not be sensibly affected by a simultaneous change of the +barometer. Almost all the readings were taken at a temperature of about +20° C., and in the present state of the work corrections for temperature +may be considered a superfluous refinement. + +_Gauge correction_.--It is necessary to apply to the results thus +obtained a correction which becomes very important when high vacua are +measured. It was found in an early stage of the experiments that the +mercury, in the act of entering the highly exhausted gauge, gave out +invariably a certain amount of air which of course was measured along +with the residuum that properly belonged there; hence to obtain the true +vacuum it is necessary to subtract the volume of this air from nc. By a +series of experiments I ascertained that the amount of air introduced by +the mercury in the acts of entering and leaving the gauge was sensibly +constant for six of these single operations (or for three of these +double operations), when they followed each other immediately. The +correction accordingly is made as follows: the vacuum is first measured +as described above, then by withdrawing all the boxes except the lowest, +the mercury is allowed to fall so as nearly to empty the gauge; it is +then made again to fill the gauge, and these operations are repeated +until they amount in all to six; finally the volume and pressure are a +second time measured. Assuming the pressure to remain constant, or that +the volumes are reduced to the same pressure, + + v = the original volume; v' = the final volume; + V' = volume of air introduced by the first entry of the mercury; + V = corrected volume; then + + V' = (v'-v)/6 + V = v - [(v'-v)/6] + +It will be noticed that it is assumed in this formula that the same +amount of air is introduced into the gauge in the acts of entry and +exit; in the act of entering in point of fact more fresh mercury is +exposed to the action of the vacuum than in the act exit, which might +possibly make the true gauge-correction rather larger than that given by +the formula. It has been found that when the pump is in constant use the +gauge-correction gradually diminishes from day to day; in other words, +the air is gradually pumped out of the gauge-mercury. Thus on December +21, the amount of air entering with the mercury corresponded to an +exhaustion of + + 1/27,308,805 .......Dec. 21. + + 1/38,806,688 ...... Dec. 29. + + 1/78,125,000 .......Jan. 15. + + 1/83,333,333 .......Jan. 23 + + 1/128,834,063 ......Feb. 1. + + 1/226,757,400 ..... Feb. 9. + + 1/232,828,800 ..... Feb. 19. + + 1/388,200,000 ......March 7. + +That this diminution is not due to the air being gradually withdrawn +from the walls of the gauge or from the gauge-tube, is shown by the fact +that during its progress the pump was several times taken to pieces, and +the portions in question exposed to the atmosphere without affecting +the nature or extent of the change that was going on. I also made one +experiment which proves that the gauge-correction does not increase +sensibly, when the exhausted pump and gauge are allowed to stand unused +for twenty days. + +_Rate of the pump's work_.--It is quite important to know the rate of +the pump at different degrees of exhaustion, for the purpose of enabling +the experimenter to produce a definite exhaustion with facility; also if +its maximum rate is known and the minimum rate of leakage, it becomes +possible to calculate the highest vacuum attainable with the instrument. +Examples are given in the tables below; the total capacity was about +100,000 cubic mm. + + Time. Exhaustion. Ratio. + + 1/78,511 + 10 minutes }........ 1:1/3.53 + 1/276,980 + 10 minutes }........ 1:1/6.10 + 1/1,687,140 + 10 minutes }........ 1:1/4.15 + 1/7,002,000 + +Upon another occasion the following rates and exhaustions were obtained: + + Time. Exhaustion. Rate. + + 1/7,812,500 + 10 minutes }........ 1:1/3.18 + 1/24,875,620 + 10 minutes }........ 1:1/2.69 + 1/67,024,090 + 10 minutes }........ 1:1/1.22 + 1/81,760,810 + 10 minutes }........ 1:1.67 + 1/136,986,300 + 10 minutes }........ 1:1.23 + 1/170,648,500 + +The _irregular_ variations in the rates are due to the mode in which the +flow of the mercury was in each case regulated. + +_Leakage_.--We come now to one of the most important elements in the +production of high vacua. After the air is detached from the walls of +the pump the leakage becomes and remains nearly constant. I give below a +table of leakages, the pump being in each case in a condition suitable +for the production of a very high vacuum: + + Duration of the Leakage per hour in + experiment cubic mm., press., + 760 mm. + + 18½ hours............................ 0.000853 + 27 hours............................ 0.001565 + 26½ hours.............................0.000791 + 20 hours.............................0.000842 + 19 hours.............................0.000951 + 19 hours.............................0.001857 + 7 days..............................0.001700 + 7 days..............................0.001574 + + Average.................... 0.001266 + +I endeavored to locate this leakage, and proved that one-quarter of +it is due to air that enters the gauge from the top of its column of +mercury, thus: + + Duration of the Gauge-leakage per hour + experiment. in cubic mm., press. + 760 mm. + + 18 hours.................................0.0002299 + 7 days..................................0.0004093 + 7 days..................................0.0003464 + + Average.......................0.0003285 + +This renders it very probable that the remaining three quarters are due +to air given off from the mercury at B, Fig. 4, from that in the bends +and at the entrance of the fall-tube, _o_, Fig. 3. + +Further on some evidence will be given that renders it probable that the +leakage of the pump when in action is about four times as great as the +total leakage in a state of rest. + +The gauge, when arranged for measurement of gauge-leakage, really +constitutes a barometer, and a calculation shows that the leakage would +amount to 2.877 cubic millimeters per year, press. 760 mm. If this air +were contained in a cylinder 90 mm. long and 15 mm. in diameter it would +exert a pressure of 0.14 mm. To this I may add that in one experiment +I allowed the gauge for seven days to remain completely filled with +mercury and then measured the leakage into it. This was such as would +in a year amount to 0.488 cubic millimeter, press. 760 mm., and in a +cylinder of the above dimensions would exert a pressure of 0.0233 mm. + +_Reliability of the results: highest vacuum._ + +The following are samples of the results obtained. In one case sixteen +readings were taken in groups of four with the following result: + + Exhaustion. + 1 / 74,219,139 + 1 / 78,533,454 + 1 / 79,017,272 + 1 / 68,503,182 + Mean 1 / 74,853,449 + +Calculating the probable error of the mean with reference to the above +four results it is found to be 2.28 per cent of the quantity involved. + +A higher vacuum measured in the same way gave the following results: + + 1 / 146,198,800 + 1 / 175,131,300 + 1 / 204,081,600 + 1 / 201,207,200 + +The mean is 1 / 178,411,934, with a probable error of 5.42 per cent of +the quantity involved. I give now an extreme case; only five single +readings were taken; these corresponded to the following exhaustions: + + 1 / 379,219,500 + 1 / 371,057,265 + 1 / 250,941,040 + 1 / 424,088,232 + 1 / 691,082,540 + +The mean value is 1 / 381,100,000, with a probable error of 10.36 per +cent of the quantity involved. Upon other occasions I have obtained +exhaustions of 1 / 373,134,000 and 1 / 388,200,000. Of course in these +cases a gauge-correction was applied; the highest vacuum that I have +ever obtained irrespective of a gauge-correction was 1 / 190,392,150. In +these cases and in general, potash was employed as the drying material; +I have found it practical, however, to attain vacua as high as 1 / +50,000,000 in the total absence of all such substances. The vapor of +water which collects in bends must be removed from time to time with a +Bunsen burner while the pump is in action. + +It is evident that the final condition of the pump is reached when +as much air leaks in per unit of time as can be removed in the same +interval. The total average leakage per ten minutes in the pump used by +me, when at rest, was 0.000211 cubic millimeter at press. 760 mm. Let +us assume that the leakage when the pump is in action is four times +as great as when at rest; then in each ten minutes 0.000844 cubic +millimeter press., 760 mm., would enter; this corresponds in the pump +used by me to an exhaustion of 1 / 124,000,000; if the rate of the pump +is such as to remove one-half of the air present in ten minutes, then +the highest attainable exhaustion would be 1 / 248,000,000. In the same +way it may be shown that if six minutes are required for the removal of +half the air the highest vacuum would be 1 / 413,000,000 nearly, and +rates even higher than this have been observed in my experiments. An +arrangement of the vacuum-bulb whereby the entering drops of mercury +would be exposed to the vacuum in an isolated condition for a somewhat +longer time would doubtless enable the experimenter to obtain +considerably higher vacua than those above given. + +_Exhaustion obtained with a plain Sprengel Pump._--I made a series of +experiments with a plain Sprengel pump without stopcocks, and arranged, +as far as possible, like the instrument just described. The leakage per +hour was as follows: + + Duration of the Leakage per hour in + experiment. cubic mm. at press. + 760 mm. + + 22 hours 0.04563 + 2 days 0.04520 + 2 days 0.09210 + 4 days 0.06428 + ------- + Mean 0.06180 + +Using the same reasoning as above we obtain the following table + + Time necessary for removal Greatest attainable + of half the air. exhaustion. + + 10 minutes 1 / 5,000,000 + 7.5 minutes 1 / 7,000,000 + 6.6 minutes 1 / 12,000,000 + +In point of fact the highest exhaustion I ever obtained with this pump +was 1 / 5,000,000; from which I infer that the leakage during action +is considerably greater than four times that of the pump at rest. The +general run of the experiments tends to show that the leakage of a plain +Sprengel pump, without stopcocks or grease, is, when in action, about 80 +times as great as in the form used by me. + +_Note on annealing glass tubes._--It is quite necessary to anneal all +those parts of the pump that are to be exposed to heat, otherwise they +soon crack. I found by inclosing the glass in heavy iron tubes and +exposing it for five hours to a temperature somewhat above that of +melting zinc, and then allowing an hour or two for the cooling process, +that the strong polarization figure which it displays in a polariscope +was completely removed, and hence the glass annealed. A common +gas-combustion furnace was used, the bends, etc, being suitably inclosed +in heavy metal and heated over a common ten-fold Bunsen burner. Thus far +no accident has happened to the annealed glass, even when cold drops of +mercury struck in rapid succession on portions heated considerably above +100° C. + +I wish, in conclusion, to express my thanks to my assistant, Dr. +Ihlseng, for the labor he has expended in making the large number of +computations necessarily involved in work of this kind.--_Amer. Jour. of +Science._ + + * * * * * + + + + +CRYSTALLIZATION TABLE. + + +The following table, prepared by E. Finot and Arm. Bertrand for the +_Jour. de Ph. et de Chim._, shows the point at which the evaporation of +certain solutions is to be interrupted in order to procure a good crop +of crystals on cooling. The density is according to Baumé's scale, the +solution warm: + + Aluminum sulphate 25 | Nickel acetate 30 + Alum (amm. or pot.) 20 | " ammon. sulphate 18 + Ammonium acetate 14 | " chloride 50 + " arsenate 5 | " sulphate 40 + " benzoate 5 | Oxalic acid 12 + " bichromate 28 | Potass. and sod. tartrate 36 + " bromide 30 | Potassium arsenate 36 + " chloride 12 | " benzoate 2 + " nitrate 29 | " bisulphate 35 + " oxalate 5 | " bromide 40 + " phosphate 35 | " chlorate 22 + " sulphate 28 | " chloride 25 + " sulphocyanide 18 | " chromate 38 + " tartrate 25 | " citrate 36 + Barium ethylsulphate 43 | " ferrocyanide 38 + " formate 32 | " iodide 17 + " hyposulphite 24 | " nitrate 28 + " nitrate 18 | " oxalate 30 + " oxide 12 | " permanganate 25 + Bismuth nitrate 70 | " sulphate 15 + Boric acid 6 | " sulphite 25 + Cadmium bromide 65 | " sulphocyanide 35 + Calcium chloride 40 | " tartrate 48 + " ethylsulphate 36 | Soda 28 + " lactate 8 | Sodium acetate 22 + " nitrate 55 | " ammon. phosp. 17 + Cobalt chloride 41 | " arsenate 36 + " nitrate 50 | " borate 24 + " sulphate 40 | " bromide 55 + Copper acetate 5 | " chlorate 43 + " ammon. sulph. 35 | " chromate 45 + " chloride 45 | " citrate 36 + " nitrate 55 | " ethylsulphate 37 + " sulphate 30 | " hyposulphite 24 + Iron-ammon. oxalate 30 | " nitrate 40 + " ammon. sulphate 31 | " phosphate 20 + " sulphate 31 | " pyrophosphate 18 + " tartrate 40 | " sulphate 30 + Lead acetate 42 | " tungstate 45 + " nitrate 50 | Stroutium bromide 50 + Magnesium chloride 35 | " chlorate 65 + " lactate 6 | " chloride 34 + " nitrate 45 | Tin choride (stannous) 75 + " sulphate 40 | + Manganese chloride 47 | Zinc acetate 20 + " lactate 8 | " ammon. chloride 43 + " sulphate 44 | " nitrate 55 + Mercury cyanide 20 | " sulphate 45 + + * * * * * + + + + +THE PRINCIPLES OF HOP-ANALYSIS. + +By Dr. G. O. CECH + +[Footnote: 'Zeitschrift fur Analyt. Chemie,' 1881.] + + +Hop flowers contain a great variety of different substances susceptible +of extraction with ether, alcohol, and water, and distinguishable from +one another by tests of a more or less complex character. The substances +are: Ethereal oil, chlorophyl, hop tannin, phlobaphen, a wax-like +substance, the sulphate, ammoniate, phosphate, citrate and malates of +potash, arabine, a crystallized white and an amorphous brown resin, and +a bitter principle. That the characteristic action of the hops is due to +such of these constituents only as are of an organic nature is easy to +understand; but up to the present we are in ignorance whether it is upon +the oil, the wax, the resin, the tannin, the phlobaphen, or the bitter +principle individually, or upon them all collectively, that the effect +of the hops in brewing depends. + +It is the rule to judge the strength and goodness of hops by the amount +of farina--the so-called lupuline; and as this contains the major +portion of the active constituents of the hop, there is no doubt that +approximately the amount of lupuline is a useful quantitative test. But +here we are confronted by the question whether the lupuline is to be +regarded as containing _all_ that is of any value in the hops and the +leaves, the organic principles in which pass undetected under such a +test, as supererogatory for brewers' purposes? Practical experience +negatives any such conclusion. Consequently, we are justified in +assuming that the concurrent development and the presence of the several +organic principles--the oil, the wax, the bitter, the tannin, the +phlobaphen, in the choicer sorts--are subject, within certain limits, to +variations depending on skilled culture and careful drying, and that the +aggregate of these principles has a certain attainable maximum in +the finer sorts, under the most favorable conditions of culture, and +another, lower maximum in less perfectly cultivated and wild sorts. The +difference in the proportion of active organic substance in each sort +must be determined by analysis. There then remains to be discovered +which of the aforesaid substances plays the leading role in brewing, and +also whether the presence of chlorophyl and inorganic salts in the hop +extract influences or alters the results. + +That in brewing hops cannot be replaced by lupuline alone, even when the +latter is employed in relatively large quantities is well known, as also +that a considerable portion of the bitter principle of the hop is found +in the floral leaves. Neither can the lupuline be regarded as the only +active beer agent, as both the hop-tannin and the hop-resin serve to +precipitate the albuminous matter, and clarify and preserve the beer. + +Both chemists and brewers would gladly welcome some method of testing +hops, which should be expeditious, and afford reliable results in +practical hands. To accomplish this account must be taken of all the +active organic constituents of the hops, which can be extracted either +with ether, alcohol, or water containing soda (for the conversion of the +hop tannin in phlobaphen).[1] It should further be ascertained whether +the chlorophyl percentage in the hop bells, new and old, is or is not +the same in cultivated and in wild hops, and whether the aggregate +percentages of organic and constituent observe the same limits. + +[Footnote 1: See C. Etti, in "Dingler's Polytech. Journ.," 1878, p. +354.] + +As wild hops nowadays are frequently introduced in brewing, the +proportion of chlorophyl and organic and inorganic constituents in them +should be compared with those of cultivated sorts, taking the best +Bavarian or Bohemian hops as the standard of measurement. The chlorophyl +is of minor importance, as it has little effect on the general results. + +By a series of comparative analysis of cultivated and wild hops, in +which I would lay especial stress on parity of conditions in regard +of age and vegetation, the extreme limits of variation of which their +active organic principles are susceptible could be determined. + +There is every reason to suppose that the chlorophyl and inorganic +constituents do not differ materially in the most widely different sorts +of hops. The more important differences lie in the proportions of hop +resin and tannin. When this is decided, the proportion of tannin or +phlobaphen in the hop extract or the beer can be determined by analysis +in the ordinary way. But whenever some quick and sure hop test shall +have been found, _appearance and aroma_ will still be most important +factors in any estimate of the value of hops. Here a question arises as +to whether hops from a warm or even a steppe climate, like that of +South Russia, contain the same proportion of ethereal oil--that is, of +aroma--as those from a cooler climate, like Bavaria and Bohemia, or +like certain other fruit species of southern growth, they are early +in maturing, prolific, large in size, and abounding in farina, but +_deficient in aroma_. + +The bearings of certain experimental data on this point I reserve for +consideration upon a future occasion.--_The Analyst_. + + * * * * * + + + + +WATER GAS. + +A DESCRIPTION OF APPARATUS FOR PRODUCING CHEAP GAS, AND SOME NOTES ON +THE ECONOMICAL EFFECT OF USING SUCH GAS WITH GAS MOTORS, ETC. + +[Footnote: Abstract of paper read in Section G. British Association, +York] + +By MR. J. EMERSON DOWSON, C.E., of London. + + +In many countries and for many years past, inventors have sought +some cheap and easy means of decomposing steam in the presence of +incandescent carbon in order to produce a cheap heating gas; and working +with the same object the writer has devised an apparatus which has been +fitted up in the garden of the Industrial Exhibition, and is there +making gas for a 3½ horse power (nominal) Otto gas engine. The retort or +generator consists of a vertical cylindrical iron casing which incloses +a thick lining of ganister to prevent loss of heat and oxidation of the +metal, and at the bottom of this cylinder is a grate on which a fire is +built up. Under the grate is a closed chamber, and a jet of superheated +steam plays into this and carries with it by induction a continuous +current of air. The pressure of the steam forces the mixture of steam +and air upward through the fire, so that the combustion of the fuel is +maintained while a continuous current of steam is decomposed, and in +this way the working of the generator is constant, and the gas is +produced without fluctuations in quality. The well-known reactions +occur, the steam is decomposed, and the oxygen from the steam and air +combines with the carbon of the fuel to form carbon dioxide (CO_2), +which is reduced to the monoxide (CO) on ascending the fuel column. +In this way the resulting gases form a mixture of hydrogen, carbon, +monoxide, and nitrogen, with a small percentage of carbon dioxide which +usually escapes without reduction. The steam should have a pressure of +1½ to 2 atmospheres, and is produced and superheated in a zigzag coil +fed with water from a neighboring boiler. The quantity of water required +is very small, being only about 7 pints for each 1,000 cubic feet of +gas, and, except on the first occasion when the apparatus is started, +the coil is heated by some of the gas drawn from the holder, so that +after the gas is lighted under the coil the superheater requires no +attention. + +For boiler and furnace work the gas can be used direct from the +generator; but where uniformity of pressure is essential, as for gas +engines, gas burners, etc., the gas should pass into a holder. The +latter somewhat retards the production, but the steam injector causes +gas to be made so rapidly that a holder is easily filled against a back +pressure of 1 in. to 1½ in. of water, and at this pressure the generator +can pass gas continuously into the holder, while at the same time it is +being drawn off for consumption. + +The nature of the fuel required depends on the purpose for which the gas +is used. If for heating boilers, furnaces, etc, coke or any kind of coal +maybe used; but for gas engines or any application of the gas requiring +great cleanliness and freedom from sulphur and ammonia it is best to use +anthracite, as this does not yield condensable vapors, and is very free +from impurities. Good qualities of this fuel contain over 90 per cent of +carbon and so little sulphur that, for some purposes, purification is +not necessary. For gas engines, etc., it is, however, better to pass +the gas through some hydrated oxide of iron to remove the sulphureted +hydrogen. The oxide can be used over and over again after exposure to +the air, and the purifying is thus effected without smell or appreciable +expense. Gas made by this process and with anthracite coal has no tar +and no ammonia, and the small percentage of carbon dioxide present does +not sensibly affect the heating power. A further advantage of this gas +is that it cannot burn with a smoky flame, and there is no deposition of +soot even when the object to be heated is placed over or in the flame, +and this is of importance for the cylinder and valves of a gas engine. + +To produce 1,000 cubic feet only 12 lb. of anthracite are required, +allowing 8 to 10 per cent, for impurities and waste; thus a generator +A size, which produces 1,000 cubic feet per hour, needs only 12 lb. in +that time, and this can be added once an hour or at longer intervals. No +skilled labor is necessary, and in practice it is usual to employ a man +who has other work to attend to near the generator, and to pay him a +small addition to his usual wages. + +The comparative explosive force of coal gas and the Dowson gas +calculated in the usual way is as 3.4:1, i. e., coal gas has 3.4 times +more energy than the writer's gas. Messrs. Crossley, of Manchester, the +makers of the Otto gas engines, have made several careful trials of this +gas with some of their 3½ horse power (nominal) engines, and in one +trial they took diagrams every half-hour for nine consecutive days. +These practical trials have shown that without altering the cylinder of +the engine it is possible to admit enough of the Dowson gas to give +the same power as with ordinary coal gas. It has been seen that the +comparative explosive force of the two gases is as 3.4:1, but as it is +well known the combustion of carbon monoxide proceeds at a comparatively +slow rate, and for this reason, and because of the diluents present in +the cylinder which affect the weaker gas more than coal gas, experience +has shown that it is best to allow five volumes of the Dowson gas for +one volume of coal gas, and then the same uniform power is obtained as +with the latter. + +This gives very important economical results; for if the cost of the +Dowson gas given in the tables as 4¼d., 3-1/3d., and 2¾d. per 1,000 +cubic feet, be multiplied by 5 there will be 1s. 9¼d., 1s. 4¾d., and 1s. +2¾d., or a mean of 1s. 5½d. for the equivalent of 1,000 cubic feet of +coal gas, which usually costs from 3s. to 4s., and this represents an +actual saving of about 50 to 60 per cent, in working cost. Another +practical consideration is that coal gas requires 224 lb. to 250 lb. of +coal per 1,000 cubic feet of gas, but the writer requires only 12 lb. +per 1,000 cubic feet, and multiplying this by 5 to give the equivalent +of 1,000 cubic feet of coal gas, for engine work, there are 60 lb. +instead of 224 lb. to 250 lb. This is only 24 to 27 per cent, of the +weight of the coal required for coal gas, and in many outlying districts +this will effect an appreciable saving in the cost of transport. + + +APPENDIX. + + TABLE I. + + _Generator A Size_ (producing 1,000 cubic feet per hour): + Anthracite to make gas at the rate of 1,000 s. d. + cubic feet per hour=l2 lb x 9 working + hours=l08 lb., or say, 1 cwt. at 20s. a + ton.................................... 1 0 + Allowance for wages of attendant......... 1 0 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent. on £l25)= + per working day........................ 0 5 + Interest on capital outlay, ditto........ 0 5 + ______ + + Total........................... 2 10 + cub. ft. + + Gas produced............................. 9.000 + Less gas used for generating and + superheating steam..................... 1,000 + _____ + Total effective gas for 2s. 10d. 8,000 + + Net cost 4¼ d. per 1,000 cubic feet. + + TABLE II. + + _Generator B Size_ (producing 1,500 cubic feet per hour) + Anthracite to make gas at the rate of 1,500 s. d. + cubic feet per hour=18 lb. x 9 working + hours=162 lb., or, say, 1½ cwt. 20s. + a ton.................................. 1 6 + Allowance for wages of attendant......... 1 0 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent, on £140) + =per working day....................... 0 5½ + Interest on capital outlay, ditto........ 0 5½ + ___ ___ + Total........................... 3 5 + cub. ft. + Gas produced............................. 13,500 + Less gas used for generating and + superheating steam..................... 1,200 + ______ + Total effective gas for 3s. 5d.. 12,300 + + Net cost 3 1/3d. per 1,000 cubic feet. + + TABLE III. + + _Generator C Size_ (producing 2,500 cubic feet per hour): + Anthracite to make gas at the rate of 2,500 s. d. + cubic feet per hour=30 lb. x 9 working + hours=270 lb. at 20s. a ton............ 2 4½ + Allowance for wages of attendant....... 1 6 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent, on £160)= + per working day...................... 0 6½ + Interest on capital outlay, ditto...... 0 6½ + _______ + Total......................... 4 11½ + + cub. ft. + Gas produced........................... 22,500 + Less gas used for generating and + superheating steam................... 1,500 + ______ + Total effective gas for 4s. 11½d 21,000 + + Net cost, say, 2¾ d. per 1,000 cubic feet. + + * * * * * + + + + +ON THE FLUID DENSITY OF CERTAIN METALS. + +[Footnote: Abstract of paper read before Section C (Chemical Science), +British Association meeting, York.] + +By PROFESSOR W. CHANDLER ROBERTS, F.R.S., and T. WRIGHTSON. + + +The authors described their experiments on the fluid density of metals +made in continuation of those submitted to Section B at the Swansea +meeting of the Association. Some time since one of the authors gave an +account of the results of experiments made to determine the density of +metallic silver, and of certain alloys of silver and copper when in a +molten state. The method adopted was that devised by Mr. R. Mallet, and +the details were as follows: A conical vessel of best thin Lowmoor plate +(1 millimeter thick), about 16 centimeters in height, and having an +internal volume of about 540 cubic centimeters, was weighed, first +empty, and subsequently when filled with distilled water at a known +temperature. The necessary data were thus afforded for accurately +determining its capacity at the temperature of the air. Molten silver +was then poured into it, the temperature at the time of pouring being +ascertained by the calorimetric method. The precautions, as regards +filling, pointed out by Mr. Mallet, were adopted; and as soon as the +metal was quite cold, the cone with its contents was again weighed. +Experiments were also made on the density of fluid bismuth; and two +distinctive determinations gave the following results: + + 10.005 ) + ) mean 10.039. + 10.072 ) + +The invention of the oncosimeter, which was described by one of the +authors in the "Journal of the Iron and Steel Institute" (No. II., +1879, p. 418), appeared to afford an opportunity for resuming the +investigation on a new basis, more especially as the delicacy of the +instrument had already been proved by experiments on a considerable +scale for determining the density of fluid cast iron. The following is +the principle on which this instrument acts: + +If a spherical ball of any metal be plunged below the surface of a +molten bath of the same or another metal, the cold ball will displace +its own volume of molten metal. If the densities of the cold and molten +metal be the same, there will be equilibrium, and no floating or sinking +effect will be exhibited. If the density of the cold be greater than +that of the molten metal, there will be a sinking effect, and if less a +floating effect when first immersed. As the temperature of the submerged +ball rises, the volume of the displaced liquid will increase or decrease +according as the ball expands or contracts. In order to register these +changes the ball is hung on a spiral spring, and the slightest change in +buoyancy causes an elongation or contraction of this spring which can +be read off on a scale of ounces, and is recorded by a pencil on a +revolving drum. A diagram is thus traced out, the ordinates of which +represent increments of volume, or, in other words, of weight of fluid +displaced--the zero line, or line corresponding to a ball in a liquid of +equal density, being previously traced out by revolving the drum without +attaching the ball of metal itself to the spring, but with all other +auxiliary attachments. By means of a simple adjustment the ball is kept +constantly depressed to the same extent below the surface of the liquid; +and the ordinate of this pencil line, measuring from the line of +equilibrium, thus gives an exact measure of the floating or sinking +effect at every stage of temperature, from the cold solid to the state +when the ball begins to melt. + +If the weight and specific gravity of the ball be taken when cold, +there are obtained, with the ordinate on the diagram at the moment of +immersion, sufficient data for determining the density of the fluid +metal; for + +W / W1 = D / D1 + +the volumes being equal. And remembering that + +W (weight of liquid) = W1 (weight of ball) + x + +(where x is always measured as +_ve_ or -_ve_ floating effect), there is +obtained the equation: + + D1 x ( W1 + x) + D = --------------- . + W1 + +[TEX: D = \frac{D_1 \times (W_1 +x)}{W_1}] + +The results obtained with metallic silver are perhaps the most +interesting, mainly from the fact that the metal melts at a higher +temperature, which was determined with great care by the illustrious +physicist and metallurgist, the late Henri St. Claire Deville, whose +latest experiments led him to fix the melting point at 940° Cent. The +authors of the paper showed that the density of the fluid metal was 9.51 +as compared with 10.57, the density of the solid metal. Taking their +results generally, it is found that the change of volume of the +following metals in passing from the solid to the liquid state may be +thus stated: + + Specific Specific + Metal. Gravity, Gravity, Percentage of + Solid. Liquid. Change. + + Bismuth 9.82 10.055 Decrease of volume 2.3 + Copper 8.8 8.217 Increase " 7.1 + Lead 11.4 10.37 " " 9.93 + Tin. 7.5 7.025 " " 6.76 + Zinc 7.2 6.48 " " 11.10 + Silver 10.57 9.51 " " 11.20 + Iron 6.95 6.88 " " 1.02 + + * * * * * + + + + +HYDROPHOBIA PREVENTED BY VACCINATION. + + +M. Pasteur and other French savants have lately been devoting special +attention to hydrophobia. The great authority on germs has, in fact, +definitely announced that he does not intend to rest until he has made +known the exact nature and life-history of this terrible disease, and +discovered a means of preventing or curing it. The most curious result +yet attained in this direction, however, has been announced by Professor +V. Galtier, of the Lyons Veterinary School. This inquirer has found, in +the first place, that if the virus of rabies be injected into the veins +of a sheep, the animal does not subsequently exhibit any symptoms of +hydrophobia. This in itself would be a sufficiently curious result +to justify attention, though its importance, except as confirmatory +testimony, becomes less striking when it is remembered that M. Pasteur +has lately shown that the special _nidus_ of the disease appears to be +the nervous tissue, and particularly the ganglionic centers. But there +is this further curious consequence: sheep who have thus been treated +through the blood, and who are afterwards inoculated in the ordinary +way through the cellular tissue, as if by a bite, are proof against +the disease. It is as though the injection into the veins acted as a +vaccine. Twenty sheep were experimented upon; ten only were treated to +the venous injection, and then all were inoculated through the cellular +tissue. The ten which had been first "vaccinated" continue alive and +well; they have not even shown any adverse symptoms. The other ten have +all died of rabies. It remains to say why M. Galtier experimented +upon sheep, and not upon dogs and cats, which usually communicate the +disease. The incubation of the disease is much more rapid and less +capricious in the sheep than in the dog or in man, and hence M. Galtier +was able to get his results more certainly within a short period. Having +succeeded so far, he is now justified in undertaking the more protracted +series of observations which experiments upon the canine species will +involve; and this he proposes to do. Experiments of this nature are not +without a serious risk, and admiration is almost equally due to the +courage and the intelligence of the experimentalist. But what will the +anti-vaccinator say?--_Pall Mall Gazette_. + + * * * * * + + + + +ON DIPTERA AS SPREADERS OF DISEASE. + +By J.W. SLATER. + + +The two-winged flies, in their behavior to man, stand in a marked +contrast to all the other orders of insects. The Lepidoptera, the +Coleoptera, the Neuroptera, the Hymenoptera no doubt occasion, in some +of their forms at least, much damage to our crops. But none of them are +parasitic in or upon our bodies; none of them persistently intrude into +our dwellings, hover around us in our walks, and harass us with noise +and constant attempts to bite, or at least to crawl upon us. Even the +ants, except in a few tropical districts, rarely act upon the offensive. +The Hemiptera contain one semi-parasitic species which has attained a +"world-wide circulation," and one degraded, purely parasitic group. +But the Diptera, among which the fleas are now generally included as a +degenerated type, comprise more forms personally annoying to man than +all the remaining insect orders put together. These hostile species are, +further, incalculably numerous, and occur in every part of the globe. +Mosquitoes swarm not merely in the swampy forests of the Orinoco or the +Irrawaddy, but in the Tundras of Siberia, en the storm-beaten rocks of +the Loffodens, and are even encountered by voyagers in quest of the +North Pole. The common house fly was probably at one time peculiar to +the Eastern Continent, but it followed the footsteps of the Pilgrim +Fathers, and is now as great a nuisance in the United Slates and the +Dominion as in any part of Europe. It is curious, but distressing, to +note the tendency of evils to become international. We have communicated +to America the house-fly and the Hessian fly, the "cabbage-white," +the small pox, and the cholera. She, in return, has given us the +_Phylloxera_, a few visitations of yellow fever, the _Blatta gigantea_, +and, climate allowing, may perhaps throw in the Colorado beetle as a +make-weight. In this department, at least, free trade reigns undisputed. +It is a singular thing that no beautiful, useful, or even harmless +species of bird or insect seems capable of acclimatizing itself as do +those characterized by ugliness and noisomeness. + +But, returning from this digression, we find in the Diptera the habit of +obtrusion and intrusion, of coming in actual contact with our food and +our persons, combined with another propensity--that of feeding upon +carrion, excrement, blood, pus, and morbid matter of all kinds. This +is a combination far more serious than is generally imagined. If the +fly--which may at any moment settle upon our lips, our eyes, or upon +an abraded part of our skin--were cleanly in its habits, we need feel +little annoyance at its visits. Or if it were the most eager carrion +devourer, but did not, after having dined, think it necessary to +seek our company, we might hold it, as is done too hastily by some +naturalists, a valuable scavenger. I fear, however, that I have already +made too great a concession. So long as very many persons are suffering +from disease--so long as many diseases are capable of being transmitted +from the sick to the healthy--so long must any creature which is in the +habit of flying about, and touching first one person and then another, +be a possible medium of infection and death. + +Let us take the following case, by no means imaginary, but a +generalization from occurrences far too frequent: A healthy man, sitting +in his house or walking in the fields, especially in countries where the +insectivorous birds have been shot down, suddenly feels a sharp prick on +his neck or his cheek. Putting his hand to the place he perhaps crushes, +perhaps merely brushes away, a fly which has bitten him so as to draw +blood. The man thinks little of so trifling a hurt, but the next morning +he finds the puncture exceedingly painful. An inflamed pimple forms, +which quickly gets worse, while constitutional symptoms of a feverish +kind come on. In alarm he seeks medical advice. The doctor tells him +that it is a malignant pustule, and takes at once the most active +measures. In spite of all possible skill and care the patient too often +succumbs to the bite of a _mouche charbonneuse_, or carbuncle-fly. But +has any kind of fly the property of producing malignant pustule by +some specific inherent power of its own? Surely not. The antecedent +circumstances are these: A sheep or heifer is attacked with the disease +known in France as _charbon_, in Germany as _milz-brand_, and in England +as _splenic fever_. Its blood on examination would be found plentifully +peopled with bacteria. If a lancet were plunged into the body of the +animal, and were then used to slightly scratch or cut the skin of a man, +he would be inoculated with "charbon." The bite of the fly is precisely +similar in its action. Its rostrum has been smeared with the poisoned +blood, an infinitesimal particle of which is sufficient to inclose +several of the disease "germs," and these are then transferred to the +blood of the next man or animal which the fly happens to bite. The +disease is reproduced as simply and certainly as the spores of some +species of fern give rise to their like if scattered upon soil suitable +for their growth. But flies which do not bite may transfer infection. +Every one must know that if blood be spilt upon the ground a crowd of +flies will settle upon and eagerly absorb it. Animals suffering from +splenic fever in the later stages of the disease sometimes emit bloody +urine. Often they are shot or slaughtered by way of stamping out the +plague, and their carcasses are buried deep in the ground. But some loss +of blood is sure to happen, and this will mostly be left to soak into +the ground. Here again the flies will come, and their feet and mouth +will become charged with the contagion. Such a fly, settling upon +another animal or a man, and selecting--as it will do by preference, if +such exist--a wound, or a place where the skin is broken, will convey +the disease. + +Again, M. Pasteur has thoughtfully pointed out that if an animal has +died of splenic fever, and has been carefully buried, the earth-worms +may bring up portions of infectious matter to the surface, so that sheep +grazing, or merely being folded over the spot in question, may take the +plague and die. Hence be wisely counsels that the bodies of such animals +should be buried in sandy or calcareous soils where earth-worms are not +numerous. But it is perfectly legitimate to go a step farther. If such +worm-borings retain the slightest savor of animal matter, flies will +settle upon them and will convey the infectious dust to the most +unexpected places, giving wings to the plague. + +Now it is very true that no one has seen a fly feasting upon the blood +of a heifer or sheep dying or just dead of splenic fever, has then +watched it settle upon and bite some person, and has traced the +following stages of the disease. But it is positively known that a +person has been bitten by a fly, and has then exhibited all the symptoms +of charbon, the place of the bite being the primary seat of the +infection. We know also, beyond all doubt, the eagerness with which +flies will suck up blood, and we likewise know the strange persistence +of the disease "germs." + +Again, the avidity of flies for purulent matter is not a thing of mere +possibility. In Egypt, where ophthalmia is common, and where the "plague +of flies" seems never to have been removed, it is reported as almost +impossible to keep these insects away from the eyes of the sufferers. +The infection which they thus take up they convey to the eyes of persons +still healthy, and thus the scourge is continually multiplied. + +A third case which seems established beyond question is the agency of +mosquitoes in spreading elephantiasis. These so-called sanitary agents +suck from the blood of one person the Filariae, the direct cause of the +disease, and transfer them to another. The manner in which this process +is effected will appear simple enough if we reflect that the mosquito +begins operations by injecting a few drops of fluid into its victim, so +as to dilute the blood and make it easier to be sucked. + +So much being established it becomes in the highest degree probable that +every infectious disease may be, and actually is, at times propagated +by the agency of flies. Attention turned to this much neglected quarter +will very probably go far to explain obscure phenomena connected with +the distribution of epidemics and their sudden outbreaks in unexpected +quarters. I have seen it stated that in former outbreaks of pestilence +flies were remarkably numerous, and although mediaeval observations on +Entomology are not to be taken without a grain of salt, the tradition +is suggestive. Perhaps the Diptera have their seasons of unusual +multiplication and emigration. A wave of the common flea appears to have +passed over Maidstone in August, 1880. + +We now see the way to some practical conclusions not without importance. +Recognizing a very considerable part of the order of Diptera, or +two-winged flies, as agents in spreading disease, it surely follows +that man should wage war against them in a much more systematic and +consistent manner than at present. The destruction of the common +house-fly by "_papier Moure_," by decoctions of quassia, by various +traps, and by the so-called "catch 'em alive," is tried here and there, +now and then, by some grocer, confectioner, or housewife angry at the +spoliation and defilement caused by these little marauders. But there +is no concerted continuous action--which after all would be neither +difficult nor expensive--and consequently no marked success. Experiments +with a view of finding out new modes of fly-killing are few and far +between. + +Every one must occasionally have seen, in autumn, flies as if cemented +to the window-pane, and surrounded with a whitish halo. That in some +seasons numbers of flies thus perish--that the phenomenon is due to a +kind of fungus, the spores of which readily transfer the disease from +one fly to another--we know. But here our knowledge is at fault. We +have not learnt why this fly-epidemic is more rife in some seasons than +others. We are ignorant concerning the methods of multiplying this +fungus at will, and of launching it against our enemies. We cannot tell +whether it is capable of destroying _Stomoxys calcitram_, the blowflies, +gadflies, gnats, mosquitoes, etc. Experiment on these points is rendered +difficult by the circumstance that the fungus is rarely procurable +except in autumn, when some of the species we most need to destroy are +not to be found. Another question is whether the fungus, if largely +multiplied and widely spread, might not prove fatal to other than +Dipterous insects, especially to the Hymenoptera, so many of which, +in their character of plant-fertilizers, are highly useful, or rather +essential to man. + +Another fungus, the so-called "green muscardine" (_Isaria destructor_), +has been found so deadly to insects that Prof. Metschnikoff, who is +experimenting upon it, hopes to extirpate the _Phylloxera_, the Colorado +beetle, etc., by its agency. + +Coming to better known and still undervalued fly-destroyers, we have +interfered most unwisely with the balance of nature. The substitution of +wire and railings for live fences in so many fields has greatly lessened +the cover both for insectivorous birds and for spiders. The war waged +against the latter in our houses is plainly carried too far. Whatever +may be the case at the Cape, in Australia, or even in Southern Europe, +no British species is venomous enough to cause danger to human beings. +Though cobwebs are not ornamental, save to the eye of the naturalist, +there are parts of our houses where they might be judiciously tolerated: +their scarcity in large towns, even where their prey abounds, is +somewhat remarkable. + +But perhaps the most effectual phase of man's war against the flies will +be negative rather than positive, turning not so much on putting to +death the mature individuals as in destroying the matter in which the +larvae are nourished. Or if, from other considerations, we cannot +destroy all organic refuse, we may and should render it unfit for the +multiplication of these vermin. We have, indeed, in most of our large +towns and in their suburbs, abolished cesspools, which are admirable +breeding-places for many kinds of Diptera, and which sometimes presented +one wriggling mass of larvae. We have drained many marshes, ditches, +and unclean pools, rich in decomposing vegetable matter, and have thus +notably checked the propagation of gnats and midges. I know an instance +of a country mansion, situate in one of the best wooded parts of the +home counties, which twenty years ago was almost uninhabitable, owing to +the swarms of gnats which penetrated into every room. But the present +proprietor, being the reverse of pachydermatous, has substituted covered +drains for stagnant ditches, filled up a number of slimy ponds as +neither useful nor ornamental, and now in most seasons the gnats no +longer occasion any annoyance. + +But if we have to some extent done away with cesspools and ditches, and +have reaped very distinct benefit by so doing, there is still a grievous +amount of organic matter allowed to putrefy in the very heart of our +cities. The dust bins--a necessary accompaniment of the water-carriage +system of disposing of sewage--are theoretically supposed to be +receptacles mainly for organic refuse, such as coal-ashes, broken +crockery, and at worst the sweepings from the floors. In sober fact +they are largely mixed with the rinds, shells, etc., of fruits and +vegetables, the bones and heads of fish, egg-shells, the sweepings out +of dog-kennels and henhouses, forming thus, in short, a mixture of evil +odor, and well adapted for the breeding-place of not a few Diptera. + +The uses to which this "dust" is put when ultimately fetched away are +surprising: without being freed from its organic refuse it is used to +fill up hollows in building-ground, and even for the repair of roads. A +few weeks ago I passed along a road which was being treated according +to the iniquity of Macadam. Over the broken stones had been shot, to +consolidate them, a complex of ashes, cabbage-leaves, egg and periwinkle +shells, straw, potato-parings, a dead kitten (over which a few +carrion-flies were hovering), and other promiscuous nuisances. The road +in question, be it remarked, is highly "respectable," if not actually +fashionable. The houses facing upon it are severely rated, and are +inhabited chiefly by "carriage people." What, then, may not be expected +in lower districts? + +Much attention has lately been drawn to the fish trade of London. It has +_not_, however, come out in evidence that the fish retailers, if they +find a quantity of their perishable wares entering into decomposition, +send out late in the evening a messenger, who, watching his opportunity, +throws his burden down in some plot of building land, or over a fence. +When I say that I have seen in one place, close alongside a public +thoroughfare, a heap of about fifty herrings, in most active +putrefaction and buzzing with flies, and some days afterward, in another +place, some twenty soles, it will be understood that such nuisances +can only be occasioned by dealers. To get rid of, or at least greatly +diminish, carrion-flies, house-flies, and the whole class of winged +travelers in disease, it will be, before all things, essential to +abolish such loathsome malpractices. The dustbins must cease being made +the receptacle for putrescent and putrescible matter, the destruction of +which by fire should be insisted upon. + +The banishment of slaughter-houses to some truly rural situation, where +the blood and offal could be at once utilized, would be another step +toward depriving flies of their pabulum in the larva state. An equally +important movement would be the substitution of steam or electricity for +horsepower in propelling tram-cars and other passenger carriages, with a +view to minimize the number of horses kept within greater London. Every +large stable is a focus of flies--_Journal of Science_. + + * * * * * + + + + +ON THE RELATIONS OF MINUTE ORGANISMS TO CERTAIN SPECIFIC DISEASES. + + +At the recent Medical Congress in London, Professor Klebs undertook to +answer the question: "Are there specific organized causes of disease?" + +A short historical review of the various opinions of mankind as to the +origin of disease led, the speaker thought, to the presumption that +these causes were specific and organized. + +If we now, he said, consider the present state of this question, the +three following points of view present themselves as those from which +the subject may be regarded: + +I.--We have to inquire whether the lower organisms, which are found in +the diseased body, may arise there spontaneously; or whether even they +may be regarded as regular constituents of the body. + +II.--The morphological relations of these organisms have to be +investigated, and their specific nature in the different morbid +processes has to be determined. + +III.--We have to inquire into their biological relations, their +development inside and outside the body, and the conditions under which +they are able to penetrate into the body, and there to set up disease. + +_First_.--With regard to the first question, that of the possibility of +spontaneous generation, the speaker gave a decided negative. + +_Second and third_.--There is in microscopic organisms a difference of +form corresponding, as a rule, to difference of function. The facts +regarding these various lower forms are briefly reviewed. + +"Three groups of hyphomycetae, algae, and schizomycetae, have been +demonstrated to occur in the animal and human organism in infective +diseases. Their significance increases with the increase of their +capacity for development in the animal body. This depends partly upon +their natural or ordinary conditions of life, but partly also, and that +in a very high degree, upon their power of adaptation, which, as Darwin +has shown, is a property of all living things, and causes the production +of new species with new active functions. + +"1. The hyphomycetae, on account of their needing an abundant supply +of oxygen, give rise to but few morbid processes, and these run their +course on the surface of the body, and are hence relatively of less +importance. It will be sufficient here to refer to the forms, achorion, +trichophyton, oïdium, aspergillus, and the diseases produced by them, +favus, ringworm, and thrush, to show this peculiarity. Nevertheless, we +see that these organisms also (as was proved by the older observations +of Hannover and Zenker) may, under certain circumstances, penetrate into +the interior of the organs. Grawitz, moreover, has recently shown that +their faculty of penetrating into the interior of the organism, and +there undergoing further development, depends on their becoming +accustomed to nitrogenous food. + +"2. Only one of the algae, viz., leptothrix, has as yet acquired any +importance as a producer of disease. It gives rise to the formation of +concretions, and that not only in the mouth, but also, as I have shown, +in the salivary ducts and urinary bladder. + +"Another alga, the sarcina of Goodsir, may indeed pass through the +organism, without, however, producing in its passage either direct +or indirect disturbances. It seems more worthy of note that many +schizomycetae, and especially the group of bacilli, are evidently nearly +allied to the algae in their morphological and vegetative relations--so +as to be assigned to this class by several authors, and especially by +Cienkowski. + +"The schizomycetae furnish, without doubt, by far the most numerous +group of infective diseases. We distinguish within this group two +widely different series of forms, which we will speak of as bacilli and +cocco-bacteria respectively. The former, which was first exhaustively +described by Ferdinand Cohn, and the pathological importance of which, +especially in relation to the splenic disease of cattle, was first shown +by Koch, consist of threads, in the interior of which permanent or +resting-spores are developed. These spores becoming free, are able, +under suitable conditions of life, again to develop into threads. The +whole development of these organisms, and especially the formation +of spores, is completed on the surface of the fluids, and under the +influence of an abundant supply of oxygen. + +"The number of affections in which these organisms have been found, +and which may be to a certain extent produced artificially by the +introduction of these organisms into healthy animal bodies, has been +largely increased since the discovery of Koch, that the bacteria of +splenic fever (anthrax) belong to this group. Under this head must be +placed the bacillus malarise (Klebs and Tommassi-Crudeli), the bacillus +typhi abdominalis (Klebs, Ebert), the bacillus typhi exanthematici +(Klebs, observations not yet published), the bacillus of hog-cholera +(Klein), and, finally the bacillus leprosus (Neisser). It would exceed +the time appointed were I to attempt to describe these forms more +minutely. This may, perhaps, be better reserved for discussion and +demonstration. + +"Alongside of these general infective diseases produced by bacilli, +local affections also occur, which indicate the presence of these +organisms at the point where disease begins. As an example of these +processes, which probably occur in various organs, I would mention +gastritis bacillaris, of which I shall show you preparations. In this, +we can trace the entrance of the bacilli into the peptic glands, as well +as their further distribution in the walls of the stomach, and in the +vascular system. + +"The second group of the pathogenetic schizomycetae I propose to call, +with Billroth, cocco-bacteria, because they consist of collections of +micrococci, which are capable of transforming themselves into short +rods. The former usually form groups united by zoögloea; by prolongation +of the cocci rods are formed, which sprout out, break up by division +into chains, and further lead again to the formation of resting masses +of cocci. I distinguish, further, in this group, two genera--the +microsporina and the monadina; in the former of which the micrococci are +collected into spherical lumps, in the latter into layers. The one class +is developed in artificial cultivation fluid, the other on the surface. +The former requires a medium poor in oxygen, the latter a medium rich in +oxygen, for their development. + +"Among the affections produced by microsporina, I reckon especially the +septic processes, and also true diphtheria. On the other hand, to the +processes produced by monadina belong especially a large series of +diseases, which according to their clinical and anatomical features, +may be characterized as inflammatory processes, acute exanthemata, and +infective tumors, or leucocytoses. Of inflammatory processes, those +belong here which do not generally lead to suppuration, such as +rheumatic affections, including the heart, kidney, and liver affections, +which accompany this process, sequelae which, as is well known, +lead more especially to formation of connective tissue, and not to +suppuration. Here, also, belong croupous pneumonia, the allied disease +erysipelas, certain puerperal processes, and finally, parotitis +epidemica, or mumps. + +"Among the acute exanthemata, the following may, up to the present time, +be placed in this group; variola-vaccina, scarlatina, and measles. + +"The group of infective tumors is represented by tuberculosis, syphilis, +and glanders. Throughout the whole group of cocco-bacteria the +demonstration of organisms in the diseased parts encounters difficulties +which vary considerably in the different kinds." + +The speaker concluded by describing the methods (now well known) by +which the powers of the different organisms are tested. + +He also referred to Pasteur's, Chauveau's, and Toussaint's recent +experiments. + +His conclusion was that the specific communicable diseases are produced +by specific organisms. + + * * * * * + + + + +THE CENTENARY OF THE DISCOVERY OF URANUS. + +By W. F. DENNING, F.R.A.S. + + +The year 1781 was signalized by an astronomical discovery of great +importance, and one which marked the epoch as memorable in the annals +of science. A musician at Bath, William Herschel by name, who had been +constructing some excellent telescopes and making a systematic survey of +the heavens, observed an object on the night of March 13 of that year, +which ultimately proved to be a large planet revolving in an orbit +exterior to that of Saturn. The discovery was as unique as it was +significant. Only five planets, in addition to the Earth, had hitherto +been known; they were observed by the ancients, and by each succeeding +generation, but now a new light burst upon men. The genius of Herschel +had singled out from the host of stars which his telescope revealed +an object the true character of which had evaded human perception for +thousands of years! + +[Illustration: FIG. 1.--APPROXIMATE PLACE OF URANUS AMONGST THE STARS AT +ITS DISCOVERY ON MARCH 13, 1781] + +The centenary of this remarkable advance in knowledge naturally recalls +to mind the circumstances of the discovery, and makes us inquisitive to +know what new facts have been gleaned of Herschel's planet, now that +a hundred years have passed away, and we are enabled to look back and +review the vast amount of labor which has been accomplished in this wide +and attractive field of astronomical research. We may learn what new +features have been discerned of the new body, and what additional +discoveries in connection with other planets unknown in Herschel's day, +have been effected by aid of the powerful telescopes which have been +devoted to the work. We do not, however, intend dealing with the general +question of planetary discovery, for at a glance we are impressed with +its magnitude. While a century ago five planets only were known, we now +have some two hundred and thirty of these bodies, and the stream of +discovery flows on without abatement through each succeeding year. The +detection of Uranus seems, indeed, to have been the prelude to many +similar discoveries, and to have offered the incentive to greater +diligence and energy on the part of observers in various parts of the +world. + +[Illustration: Fig. 2.--ORBITS OF THE URANIAN SATELLITES.] + +Many great discoveries have resulted from accident; and the leading +facts attending that of Uranus prove that, in a large measure, the +result was brought about in a similar way. Herschel, as he unwearyingly +swept the heavens night after night, was in quest of sidereal +wonders--such as double stars and nebulae--and he happened to alight +upon the new planet in a purely chance way. He had no expectation of +finding such a remarkable object, and indeed, when he had found it, +wholly mistook its character. There could be no doubt that it was a body +wholly dissimilar to the fixed stars, and it was equally certain that it +could not be a nebula. It had a perceptible disk, for when it had first +come under the critical eye of its discoverer he had noticed immediately +that its appearance differed widely from the multitude of objects which +crossed the field of his telescope. He had been accustomed to see hosts +of stars pass in review, and their aspect was in one respect similar, +namely, they were invariably presented as points of light incapable of +being sensibly magnified, even with the highest powers. True, there was +a great variety of apparent brightness in these objects and a singular +diversity of configuration, but there was no exception to the invariable +feature referred to. The point of light was constant, and no striking +exception was anticipated until one night--March 13, 1781--Herschel +being intently engaged in the examination of some small stars in the +region of Gemini, brought an object under the range of, his telescope, +which his eye at once selected as one of anomalous character. + +Applying a higher power, he noticed that it exhibited a planetary disk, +but his instrument failed to define it with sufficient distinctness, and +hence he became doubtful as to its real nature. The object was found to +be in motion, and subsequent observations led him to the assumption that +it must be a comet of rather exceptional type. This appeared to be the +best explanation of the strange body, for history contained many records +of curious comets, some of which were observed as nearly circular +patches of nebulous light, and probably of similar aspect to the object +then visible; and apart from this it must be remembered that the idea of +a large planet exterior to Saturn was a fact of such momentous import +that Herschel, with a due regard to that modesty which accompanies +true genius, refrained from attaching such an interpretation to his +observations. He was content to direct the notice of astronomers to it +as a phenomenon requiring close attention, and suggested that it might +be a comet in consequence of its motion and the faint and somewhat +ill-defined character of its appearance. + +From the earliest ages five planets only were known, and the discovery +of another large planet beyond the sphere of Saturn must at once +revolutionize existing ideas as to the range of the solar system, and +immediately take rank as a scientific event of equal interest to the +discovery of the moons of Jupiter or the rings of Saturn, which each in +their day impressed men with new ideas of the celestial mechanism. But +the truth could not long be delayed. The new body being watched and its +orbit rigorously computed from a series of observed positions revealed +its true character, and Herschel was awarded the honor due to the author +of a discovery of such importance. His diligence and pertinacity alone +had enabled him to search out from among the multitude of stars thickly +strewn over the firmament this unknown and well-nigh invisible planet +which, during all the preceding years of the world's history, had eluded +human perception. Men had been all unconscious of its existence as it +had been slowly completing its circuits around the sun, obedient to the +same laws as the other planets of the solar system, and awaiting the +hour when the unfailing eve of Herschel should introduce it as the faint +and far-off planet girding our system within its expansive folds. + +As soon as the existence of the new orb was confirmed and the fact +rendered indisputable, the question naturally arose whether it had ever +been seen in former years by the authors of star catalogues, who could +hardly have overlooked an object like this though its planetary nature +had manifestly escaped detection. It was just perceptible to the naked +eye, shining like a star of the sixth magnitude, and ought to have been +distinguished by those who had reviewed the heavens with the purpose +of determining and mapping the positions of the stars. Reference was, +therefore, made to the chief catalogues, when it was found at once that +the planet had been unquestionably observed by Tobias Mayer, Le Monnier, +Bradley, and Flamsteed. It was several times noted by these observers: +by Le Monnier no less than twelve times, and by Flamsteed on six +occasions; and it is remarkable that in every instance its true +character escaped detection. Neither its special appearance nor its +motion attracted attention, so that it was merely catalogued as an +ordinary fixed star. Thus Herschel was not anticipated in his discovery. +It remained for him, in 1781, to note its exceptional aspect, and to +specify it as an object requiring critical investigation. But the early +observations above alluded to served a useful purpose in testing the +accuracy of the computed orbit, for without waiting many years to +compare the theoretical and observed positions, astronomers had in these +old records a reliable series of points through which the previous +course of the planet could be traced. + +The calculations showed that its mean distance from the sun was some +1,750,000,000 miles, and that a revolution was completed in about +eighty-four years. It was also found to be a very large planet, greatly +exceeding either Mercury, Venus, the Earth, or Mars, though considerably +inferior to either Jupiter or Saturn. + +Here, then, was a discovery of the utmost importance, and one of the +most salient additions to our knowledge which the telescope had ever +achieved. The new planet was now definitely assigned its proper place in +the solar system, and was regarded as of equal significance with the +old planets. True, the new planet of Herschel could not be compared as +regards its visible aspect with the other previously known members of +our system, but it was nevertheless an object of equal weight. Its vast +distance alone rendered it faint. It formed one of the constituent parts +of the solar system, which, though separated by immense intervals of +space, are yet coherent by the far-reaching effects of gravitation. +There is, indeed, a bond of harmony between the series of planetary +orbits, which exhibit a marked degree of regularity in their successive +distances from the sun; and though they are not connected by any visible +links, they are firmly held together by unseen influences, and their +motions are subject to certain laws which have been revealed by +centuries of observation. + +The question of suitably naming the new planet soon came to the fore. +Herschel himself proposed to designate it the "Georgium Sidus," in honor +of his patron, George III., just as Galileo had called the satellites +of Jupiter the "Medicean stars," after Cosmo de' Medici. But La Place +proposed that the planet should be named after its discoverer; and thus +it was frequently referred to as "Herschel," and sometimes as "The +Herschelian planet." Astronomers on the continent objected to this +system of personal nomenclature, and argued that the new body should +receive an appellative in accordance with those adopted for the old +planets, which had been selected from the heathen mythology. Several +names were suggested as suitable (on the basis of this principle), and +ultimately the one advanced by Bode received the most favor, and the +planet thereafter was called "Uranus." + +The varying positions of the new body as observed on successive nights +were determined by comparisons with a group of six small stars, termed +by Herschel [Greek: alpha, beta, gamma, delta, epsilon] and afterwards +formed into a constellation under the designation of "Britannia," though +it does not appear that this little asterism is acknowledged as one of +our constellations. Its position is about midway between Taurus and +Gemini, and the following are the principal stars computed for 1881.0, +as given by Mr. Marth: + + Star. Magnitude. Right Ascension. Declination. + h. m. s. + alpha 9.0 5 42 6.06 23° 35' 6.7" N. + eta 8.7 5 43 17.82 23 26' 7.2 N. + theta 8.8 5 44 0.99 23 53' 30.8 N. + epsilon 8.8 5 45 40.68 23 34' 46.8 N. + +The stars are therefore merely telescopic, and are confined to a small +area of space, so that the propriety of adopting the group as a distinct +constellation is very questionable. Their positions close to Uranus at +the time of its discovery, and the fact that the planet's motion was +detected by means of comparisons with them, has given to these stars an +historical interest which in future years must often attract the student +to their reobservation. But it would be unwise, as forming a bad +precedent, to accept a group of stars of this inferior type as meriting +to rank among the old constellations, when we have numbers of richer +groups, situated on their confines, which first deserve such a +distinction. However special or unique the circumstances connected with +certain telescopic stars may be, and however necessary it may appear +to signalize them by a specific title, we are inclined to question the +adoption of such means as likely to exercise a wrong influence, +inasmuch as it may hereafter originate further innovations of a similar +character, and ultimate complications will be certain to arise. + +Soon after the discovery of Uranus it was suspected that the planet +was encircled, like Saturn, by a luminous ring, but on subsequent +observation this was not confirmed, and no such appendage has ever been +revealed in the more perfected instruments of our own times. Indeed, if +Uranus displays a peculiarity of constitution in any way analogous to +the ring system of Saturn, it must be of the most minute character so as +to have thus evaded telescopic scrutiny during a hundred years. + +The discovery soon attracted the notice of royalty, and the reigning +sovereign, George III., anxious to practically express his appreciation +of the valuable labors of Herschel, awarded him a pension of £200 a year +and furnished him with a residence at Slough, near Windsor, and the +means to erect a gigantic telescope with which he might be enabled +to continue his important researches. This instrument consisted of a +reflector on the "Front-view" construction, with a speculum 4 feet in +diameter and of 40 feet focal length. Upon its completion, Herschel +immediately began to observe the region of the new planet with the idea +of discovering any satellites which might belong to it, for analogy +suggested that it was surrounded by a numerous retinue of such bodies. +He was soon successful, for, on the night of January 11, 1787. he saw +two minute objects near the planet, which renewed observations revealed +to be satellites; and he detected two additional ones in 1790, and two +others in 1794, making six in all. But the observations were of extreme +difficulty. The path of the planet frequently passed near minute stars, +and it became hard to distinguish between them and the suspected +satellites. Herschel, however, considered he had obtained conclusive +evidence of the existence of six satellites with sidereal periods +ranging from 5d. 21h. 25m. to 107d. 16h. 39m., and his means of +observation being much superior to those possessed by any of his +contemporaries it was impossible to have corroborative testimony. + +The matter was thus allowed to rest until the middle of the present +century, when Lassell, in the pure sky at Malta, endeavored to reobserve +the satellites with a two-foot reflector. This instrument was considered +superior to Herschel's telescope; and the atmosphere at this station +being decidedly more suitable for such delicate observations than +in England, it was removed there for the express purpose of dealing +successfully with objects of extreme difficulty. The results were very +important. Mr. Lassell became convinced that Uranus had only four +satellites, and that if any others existed they remained to be +discovered. Two of these were found to be identical with those seen by +Herschel in 1787, and now called Titania and Oberon. The other two, +Ariel and Umbriel, could not be identified with any of those alleged to +have been previously detected by Herschel, so that the inference was +that they were new bodies, and that the priority of discovery was due to +Mr. Lassell; whence it also followed that the older observations were +erroneous, and that in fact Herschel had been entirely mistaken with +regard to the four satellites he believed he had detected subsequently +to 1787. + +In November, 1873, a fine twenty-six-inch object glass, by Alvan Clark, +was mounted at the U. S. Naval Observatory at Washington, and it was +soon employed upon the difficult task of solving the problem as to the +exact periods of the Uranian satellites. This was very satisfactorily +effected, and with distinct and conclusive favor to Mr. Lassell, whose +observations were fully corroborated. Only four satellites could be +distinguished by the American observers, and their periods, as computed +from a valuable series of measures, agreed with those previously derived +at Malta. In Appendix I. to the "Washington Observations" for 1873, +Prof. Newcomb gave a valuable summary of results--the first obtained, be +it noted, with that splendid instrument which soon afterward, in 1877, +revealed the satellites of Mars--which included the elements of the +satellites of Uranus as follows: + + Mean Longitude. + + Satellite. Epoch 1871. Radius of Period of + Dec. 31, W.M.T. Orbit. Revolution in days. + I. Ariel........ 21.83° 13.78" 2.52038 + II. Umbriel..... 13.52 19.20 4.14418 + III. Titania..... 229.93 31.48 7.70590 + IV. Oberon...... 154.83 42.10 13.43327 + +Speaking of the comparative brightness of the satellites, Prof. Newcomb +says: + +"The greater proximity of the inner satellites to the planet makes it +difficult to compare them photometrically with the outer ones, as actual +feebleness of light cannot be distinguished from difficulty of seeing +arising from the proximity of the planet. However, that Umbriel is +intrinsically fainter than Titania is evinced by the fact that, although +the least distance of the latter is somewhat less than the greatest +distance of the former, there is never any difficulty in seeing it in +that position. From their relative aspects in these respective positions +I judge Umbriel to be about half as bright as Titania. Ariel must be +brighter than Umbriel, because I have never seen the latter unless it +was farther from the planet than the former at its maximum distance.... +I think I may say with considerable certainty that there is no satellite +within 2' of the planet, and outside of Oberon, having one-third the +brilliancy of the latter, and therefore that none of Sir William +Herschel's supposed outer satellites can have any real existence. The +distances of the four known satellites increase in so regular a way that +it can hardly be supposed that any others exist between them. Of what +may be inside of Ariel it is impossible to speak with certainty, since +in the state of atmosphere which prevails during our winter all the +satellites named disappear at 10" from the planet." + +Prof. Newcomb mentions that no systematic search for new satellites +was undertaken because it must have interfered with the fullness and +accuracy of the micrometer measures of the old satellites, which +constituted the main purpose of the observations. Some faint objects +were occasionally glimpsed near the planet, and their relative places +determined, but they were never found to accompany Uranus. The fact, +therefore, that no additional satellites were discovered is not to +be regarded as a strong point in favor of the theory of their +non-existence, because the great power and excellence of the telescope +was expressly directed to the attainment of other ends; and moreover the +season in which the planet came to opposition was distinctly unfavorable +for the prosecution of a rigorous search for new satellites. There +can, however, be no doubt that the analogies of the planetary systems +interior to Uranus plainly suggest that this planet is attended by +several satellites which the power of our greatest telescopes has +hitherto failed to reveal; and that it is in this direction and that of +Neptune we may anticipate further discoveries in future years when the +conditions are more auspicious and the work is entered upon with special +energy, aided by instruments of even greater capacity than those which +have already so far conduced to our knowledge of the heavenly bodies. + +Notwithstanding the extreme difficulty with which the Uranian satellites +are observed, the two brighter ones, Titania and Oberon, discovered by +William Herschel in 1787, have been occasionally detected in telescopes +of moderate power, and identified by means of an ephemeris which has +shown that the computed positions approximately agree with those +observed. During the last few years Mr. Marth has published ephemerides +of the satellites of both Saturn and Uranus, and many amateurs have to +acknowledge the valuable aid rendered by these tables, which supply a +ready means of identifying the satellites, and thus act as an incentive +to observers who are induced to pursue such work for the sake of the +interesting comparisons to be made afterward. In one exceptional +instance the two outer satellites of Uranus appear to have been glimpsed +with an object glass of only 43 inches aperture, and the facts are given +in detail in the "Monthly Notices of the R.A.S.," April 1876, pp. 294-6. +The observations were made in January, February, and March, 1876, by +Mr. J.W. Ward, of Belfast; and the positions of the satellites, as he +estimated them on several nights, are compared with those computed, the +two sets presenting tolerably good agreement. Indeed the corroborations +are such as to almost wholly negative any skepticism, though such +extraordinary feats should always be received with caution. + +In this particular case the chances of being misled are manifold; even +Herschel himself fell into error in taking minute stars to be satellites +and actually calculating their periods; so that when we remember the +difficulties of the question our doubts are not altogether dispelled. +Extreme acuteness of vision will, in individual instances, lead to +success of abnormal character, and certainly in Mr. Ward's case the +remarkable accordances in the observed and calculated positions appear +to be conclusive evidence that he was not mistaken. + +It will be readily inferred that the great distance and consequent +feebleness of Uranus must render any markings upon the disk of the +planet beyond the reach of our best telescopes; and indeed this appears +to have been a matter of common experience. Though the surface has been +often scanned for traces of spots, we seldom find mention that any have +been distinguished. Consequently the period of rotation has yet to be +determined. It is true that an approximate value was assigned by Mr. +T.H. Buffham from observations with a nine-inch reflector in 1870 and +1872. but the materials on which the computation was based were slender +and necessarily somewhat uncertain, so that his period of about twelve +hours stands greatly in need of confirmation. The bright spots and zones +seen on the disk in the years mentioned appear to have entirely eluded +other observers, though they are probably phenomena of permanent +character and within reach of instruments of moderate size. Mr. Buffham +[1] thus describes them: + +[Footnote 1: "Monthly Notices K. A. S.," January, 1873.] + +"1870, Jan. 25, 11h. to 12h. in clear and tolerably steady air; power +132 showed that the disk was not uniform. With powers 202 and 3.0, two +round, bright spots were perceived, not quite crossing the center but a +little nearer to the eastern side of the planet, the position angle of a +line passing through their centers being about 20° and 200--ellipticity +of Uranus seemed obvious, the major axis lying parallel to the line of +the spots. + +"Jan. 27, 10h. to 10½h.; some fog, and definition not good, but the +appearance of the spots was almost exactly the same as on the 25th." + +On March 19 glimpses were obtained of a light streak and two spots. +On April 1, 4, 6, and 8, a luminous zone was seen on the disk, and +in February and March, 1872, when observations were resumed, certain +regions were noted brighter than others, and underwent changes +indicating the rotation of the planet in a similar direction to that +derived from the results obtained in 1870. Mr. Buffham points out that, +if this is admitted, then the plane of the planet's equator is not +coincident with the plane of the orbits of the satellites. Nor need we +be surprised at this departure from the general rule, where such an +anomalous inclination exists. In singular confirmation of this is Mr. +Lassell's observation of 1862, Jan. 29, where he says: "I received an +impression which I am unable to render certain of an equatorial dark +belt, and of an ellipticity of form." + +Some observations made in 1872-3 with the great six-foot reflector of +Lord Rosse may here be briefly referred to. A number of measures, both +of position and distance, of Oberon and Titania, were made, [1] and a +few of Umbriel and Ariel, but "the shortness of the time available (40 +minutes) each night for the observation of the planet with the six-foot +instrument, the atmospheric disturbance, so often a source of annoyance +in using so large an aperture, and other unfavorable circumstances, +tended to affect the value of the observations, and to make the two +inner satellites rarely within detection." + +[Footnote 1: "Monthly Notices R. A. S.," March, 1875.] + +On Feb. 10, 1872, Lord Rosse notes that all four satellites were seen on +the same side of the planet. On Jan. 16, 1873, when definition was good, +no traces of any markings were seen. Diameter of Uranus = 5.29". Power +414 was usually employed, though at times the inner satellites could be +more satisfactorily seen with 625. + +It may be mentioned as an interesting point that, some fifty years +after the first discovery of Uranus by Herschel, it was accidentally +rediscovered by his son, Sir John Herschel, who recognized it by +its disk, and had no idea as to the identity of the object until an +ephemeris was referred to. Sir John mentions the fact as follows, in a +letter to Admiral Smyth, written in 1830, August 8: + +"I have just completed two twenty-foot reflectors, and have got some +interesting observations of the satellites of Uranus. The first sweep +I made with my new mirror I _re-discovered_ this planet by its _disk_, +having blundered upon it by the merest accident for 19 Capricorni." + +In commenting upon the centenary of an important scientific discovery we +are naturally attracted to inquire what progress has been made in the +same field during the comparatively short interval of one hundred years +which has elapsed since it occurred. We have called it a short interval, +because it cannot be considered otherwise from an astronomical or +geological point of view, though, as far as human life is concerned, +it can only be regarded as a very lengthy period, including several +generations within its limits. + +Since Herschel, in 1781, discovered Uranus, astronomy has progressed +with great rapidity, so that it would be impossible to enumerate in a +brief memoir the many additional discoveries which have resulted from +assiduous observation. A century ago only five planets were known +(excluding the Earth), now we are acquainted with about two hundred and +thirty of these bodies; and one of these, found in 1846, is a large +planet whose orbit lies exterior to that of Uranus. In fact, the state +of astronomical knowledge a century ago has undergone wonderful changes. +It has been rendered far more complete and comprehensive by the +diligence of its adherents and by the unwearying energy with which both +in theory and practice it has been pursued. A zone of small planets has +been discovered between Mars and Jupiter just where the analogies of the +planetary distances indicated the probable existence of a large planet. +The far-off Neptune was revealed in 1846 by a process of analytical +reasoning as unique as it was triumphant, and which proved how well +the theory of planetary perturbations was understood. The planet was +discovered by calculation, its position in the heavens assigned, and the +telescope was then employed merely as the instrument of its detection. +The number of satellites which a century ago numbered only ten has now +reached twenty, and the discovery in 1877 of two moons accompanying Mars +shows that the work is being continued with marked success. + +In other departments we also find similar evidence of increasing +knowledge. The periodicity of the sun spots, the existence of systems of +binary stars, meteor showers, and their affinity with cometary orbits +may be mentioned as among the more important, while a host of new +comets, chiefly telescopic, have been detected. Large numbers of nebulæ +and double stars have been catalogued, and we have evidence every year +of the activity with which these several branches are being followed up. + +In fine, it matters little to what particular department of astronomical +investigation we look for traces of advancement during the past hundred +years, for it is evident throughout them all, and sufficiently proves +that the interest formerly taken in the science has not only been well +sustained but has become more general and popular, and is extending its +attractive features to all classes of the community. + +In Herschel's day large telescopes were rare. A man devoting himself to +the study of the heavenly bodies as a means of intellectual recreation +was considered a phenomenon, and indeed that appellation might be +fittingly applied to the few isolated individuals who really occupied +themselves in such work. How different is the case now that the pleasant +ways of science have called so many to her side and so far perfected her +means of research as to make them accessible to all who care to see and +investigate for themselves the unique and wonderful truths so easily +within reach! Large telescopes have become common enough, and there is +no lack of hands and eyes to utilize them, nor of understanding, ever +ready to appreciate, in sincerity and humbleness, those objects which +display in an eminent degree the all-wise conceptions of a great +Creator! It is, therefore, a most gratifying sign to notice this rapid +development of astronomy, and to see year by year the increasing number +of its advocates and the record of many new facts gleaned by vigorous +observation. + +The character of recent discoveries distinctly intimates that, in future +years, some departments of the science will become very complicated, +owing to the necessity of dealing with a large number of minute bodies, +for the tendency of modern researches has been to reveal objects which +by their faintness had hitherto eluded detection. And when we consider +that these bodies are rapidly increasing year by year, the idea is +obviously suggested that, inasmuch as their numbers are comparatively +illimitable, and there is likely to be no immediate abatement in the +enthusiasm of observers, difficulties will arise in identifying them +apart and forming them into catalogues with their orbital elements +attached, so that the individual members may be redetected at any time. + +In this connection we allude particularly to minor planets, to +telescopic comets, and to meteoric streams, which severally form a very +numerous group of bodies of which the known members are accumulating to +a great extent. As complications arise, some remedies must be applied to +their solution, and one probable effect will be that astronomers will be +induced each one to have a specialty or branch to which his energies are +mainly directed. The science will become so wide in its application and +so intricate in its details that it will become more than ever necessary +for observers to select or single out definite lines of investigation +and pursue them closely, for success is far more likely to attend such +exertions than those which are not devoted to any special end, but +employed rather in a general survey of phenomena. + +We have already before us some excellent instances in which individual +energies have been aptly utilized in the prosecution of original work +in some specific branch of astronomy, and we are strongly disposed to +recommend such exclusive labors to those who have the means and the +desire to achieve something useful. Observers who find one subject +monotonous and then take up another for the sake of variation are not +likely to get far advanced in either. In the case of amateurs who use a +telescope merely for amusement, and indiscriminately apply it to nearly +every conspicuous object in the firmament without any particular purpose +other than to satisfy their curiosity, the matter is somewhat different, +and our remarks are not applicable to them. We refer more pointedly +to those who have a regard for the interests of the science and whose +enthusiasm enables them to work habitually and with some pertinacity. + +History tells us that the Great Alexander wept when he found he had no +other worlds to conquer, and we fear that some astronomers will lament +that they have little prospect of discovering anything fresh in a sphere +to which our giant telescopes have been so often directed, but this is +founded on a palpable misconception. Certain objects, such as comets for +example, do not require great power, and the revelation of new meteor +showers is entirely a question for the naked eye. In fact, it may be +confidently asserted that observations undertaken with energy and +persistency will, if rightly directed, more than compensate for defects +of instrumental power. + +It is true, however, that in certain quarters we must look to large +instruments alone for new discoveries. It would be useless searching for +an ultra-Neptunian planet, or for additional satellites to Uranus or +Neptune, or for the materials to determine the rotation periods of these +planets with a small telescope. Every observer will find objects suited +to the capacity of his instrument, and he may not only employ it +usefully but possibly make a discovery of nearly equal import with that +which rendered the name of Herschel famous a century ago.--_Popular +Science Review_. + + * * * * * + + + + +THE VARYING SUSCEPTIBILITY OF PLANTS AND ANIMALS TO POISONS AND +DISEASES. + + +Much attention is being devoted to the causes which determine the +aptitude or immunity with animals for maladies. This is in a general +sense called medical geography, as a physician who has prescribed for +patients in various parts of the world, and belonging to different +races--the white, yellow, and black--has been able to note the +diversities in the same disease, and the contradictions in the remedies +employed. + +The true social peril, hardly discovered before we became aware how +to conjure it, lies in those legions of animalcules or microbes that +surround us and in the middle of which we live. M. Pasteur has revealed +them to us as the factors in infectious diseases. Claude Bernard +has demonstrated the community which exists between animals and +vegetables--phenomena of movement, of sensibility, of production of +heat, of respiration, of digestion even, for there are the _Drosera_ and +kindred carnivorous plants. Iron cures chlorosis in vegetables as well +as in animals, and chloroform and ether render both insensible. There +resemblances are more striking still between animals. After Baudrimont, +insects are, in presence of alcohols, chloroform, and irrespirable +gases, similarly affected as man. Many maladies, too, are common to +man and several species of animals; and this organic identity is best +illustrated in the relationship between epidemics and epizootias, +cancer, asthma, phthisis, smallpox, rabies, glanders, charbon, etc., +afflict alike man and many species of animals. + +The differences between races are not less remarkable--odor and taste, +for example. According to anthropophagy, negroes are best, and white +people most detestable. Broca remarked, that, in the dissecting room, +the muscles of the negro putrefied less rapidly than those of whites. It +is perhaps to these anatomical differences that the diverse action of +the same poison, in the case of races or species, may be attributed. On +certain rodentia belladonna exercises no influence; morphine for a horse +is a violent stimulant; a snail remains insensible to digitalis; goats +eat tobacco with impunity; and in the Tarentin the inhabitants rear only +black sheep, because a plant abounds which is noxious for white sheep. + +The nature of these conditions is a mystery for science. The _Solanæ_ +tribe of plants furnish a principle which, as its name implies, produces +consolation or forgetfulness, by acting on the tissues of the brain +where resides the organ of thought; now, on the authority of Professor +Bouchardat, these opiates have the less of effect in proportion as the +animals possess the less of intelligence. + +To the same anatomical peculiarities must be ascribed the choice that +disease makes in such or such a race. Glanders, for instance, so +virulent with the horse, the ass, and man, produce in the case of the +dog only a local accident; peripneumonia, so contagious among horned +cattle, is more benign in its action on Dutch than other breeds of +stock; the cattle plague that decimates so many farms is communicated by +cattle to each other from the slightest contact, while the closest and +most constant association is necessary to communicate the disease +to sheep, and even when they are affected its action is not severe. +Further, that plague only attacks ruminant animals--oxen, goats, sheep, +zebras, gazelles, etc. Ten years ago this plague broke out in the Jardin +d'Acclimatation; not a ruminant escaped, and also one animal not of that +class, a little tenant nearly related to the pig--the _peccari_. + +Now, Dr. Condereau has demonstrated recently that the stomach of the pig +has a rudimentary organization recalling that of the ruminants. Clearly, +the stomach of the peccari, and perhaps that of the pig, present a +favorable medium for the parasitical microbe peculiar to the rinderpest. +In the potato disease, again, all the varieties are not affected with +the same degree of violence; it is more marked in its action on the +round yellows than the reds, and on the latter rather than the pink. But +the symptoms even of the same malady differ, the parasite's attacks on +the tissues being dissimilar. Oak galls are produced from the prickings +of insects; now around the same larva often four varieties of galls are +recognized. In the case of consumption in cattle, the disease marches +slowly; in that of pigs it takes the galloping form, as with man. + +Each people or nation has its peculiar pathology and also its peculiar +cures. A negro can take a dose of tartar ten times more excessive than a +white; the same dose of brandy given to a black, a yellow, and a white, +will not produce on the three men either drunkenness at the same moment, +or intoxication at all. Mulattoes can sustain more drastic aperients +than other races; the negro does not suffer from yellow fever, but he +readily falls to phthisis; he will catch the cholera more quickly than a +white. Human races, where they may catch the same intermittent fever at +the identical moment and in the same swamp, will not the less display +different types of fever. Dr. Crevaux has shown that a certain insect +with the North American Indian is not the same as with the negro or the +maroon, and both differ from that peculiar to Europeans. + +M. Pasteur's beautiful experiments have conclusively demonstrated that +fowls do not catch the _charbon_; now the vital warmth of birds is from +seven to nine degrees higher than in the case of mammiferous animals; +he imagined that if the fowl was cooled down by baths to the lower +temperature, it would be liable equally to become affected; he tried, +and the result proved he was correct. + +The absence, then, of a certain temperature would be the reason why +birds are exempt. The microbes are the agents of infectious disease; +when these swarm in the blood of an individual they seem to leave there +something pernicious for parasites resembling themselves, or to bring +away with them something necessary to the life of their successors. A +glass of sugar and water, where leaven has already fermented and yielded +alcohol, is incapable of producing a second crop of leaven; similarly +the blood of an individual, once contaminated, becomes uninhabitable +afterward for like microbes. The individual has acquired immunity. Such +is the principle of vaccination.--_Paris Correspondent of the Kansas +City Review_. + + * * * * * + + + + +KIND TREATMENT OF HORSES. + + +It has been observed by experienced horse trainers that naturally +vicious horses are rare, and that among those that are properly trained +and kindly treated when colts they are the exception. + +It is superfluous to say that a gentle and docile horse is always the +more valuable, other qualities being equal, and it is almost obvious +that gentle treatment tends to develop this admirable quality in the +horse as well as in the human species, while harsh treatment has the +contrary tendency. Horses have been trained so as to be entirely +governed by the words of his driver, and they will obey and perform +their simple but important duties with as much alacrity as the child +obeys the direction of the parent. + +It is true that all horses are not equally intelligent and tractable, +but it is probable that there is less difference among them in this +regard than there is among his human masters, since there are many +incitements and ambitions among men that do not affect animals. + +The horse learns to know and to have confidence in a gentle driver, and +soon discovers how to secure for himself that which he desires, and +to understand his surroundings and his duties. The tone, volume, and +inflection of his master's voice indicate much, perhaps more than the +words that are spoken. Soothing tones rather than words calm him if +excited by fear or anger, and angry and excited tones tend to excite or +anger him. In short, bad masters make bad horses. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. Six dollars a year, sent, prepaid, to any foreign +country. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. Price, 10 cents each. + +All the back volumes of THE SUPPLEMENT can likewise be supplied. Two +volumes are issued yearly. 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Thus, we do not necessarily +keep eBooks in compliance with any particular paper edition. + +Most people start at our Web site which has the main PG search facility: + + www.gutenberg.org + +This Web site includes information about Project Gutenberg-tm, +including how to make donations to the Project Gutenberg Literary +Archive Foundation, how to help produce our new eBooks, and how to +subscribe to our email newsletter to hear about new eBooks. diff --git a/8296-8.zip b/8296-8.zip Binary files differnew file mode 100644 index 0000000..143b5a5 --- /dev/null +++ b/8296-8.zip diff --git a/8296-h.zip b/8296-h.zip Binary files differnew file mode 100644 index 0000000..864a4fe --- /dev/null +++ b/8296-h.zip diff --git a/8296-h/8296-h.htm b/8296-h/8296-h.htm new file mode 100644 index 0000000..569b849 --- /dev/null +++ b/8296-h/8296-h.htm @@ -0,0 +1,4957 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html> +<head> +<meta name="generator" content="HTML Tidy, see www.w3.org"> +<meta http-equiv="Content-Type" content= +"text/html; charset=ISO-8859-1"> +<title>The Project Gutenberg eBook of Scientific American +Supplement, October 22, 1881</title> +<style type="text/css"> +<!-- +body {margin-left: 15%; margin-right: 15%; background-color: white} +img {border: 0;} +h1,h2,h3 {text-align: center;} +.ind {margin-left: 10%; margin-right: 10%;} +hr {text-align: center; width: 50%;} +.ctr {text-align: center;} +--> +</style> +</head> +<body> + + +<pre> + +Project Gutenberg's Scientific American Supplement, No. 303, by Various + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Scientific American Supplement, No. 303 + October 22, 1881 + +Author: Various + +Posting Date: October 10, 2012 [EBook #8296] +Release Date: June, 2005 +First Posted: July 4, 2003 + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPPL., NO. 303 *** + + + + +Produced by Olaf Voss, Don Kretz, Juliet Sutherland, Charles +Franks and the Online Distributed Proofreading Team. + + + + + + +</pre> + + +<p class="ctr"><a href="images/1a.png"><img src= +"images/1a_th.png" alt=""></a></p> + +<h1>SCIENTIFIC AMERICAN SUPPLEMENT NO. 303</h1> + +<h2>NEW YORK, OCTOBER 22, 1881</h2> + +<h4>Scientific American Supplement. Vol. XII, No. 303.</h4> + +<h4>Scientific American established 1845</h4> + +<h4>Scientific American Supplement, $5 a year.</h4> + +<h4>Scientific American and Supplement, $7 a year.</h4> + +<hr> +<table summary="Contents" border="0" cellspacing="5"> +<tr> +<th colspan="2">TABLE OF CONTENTS</th> +</tr> + +<tr> +<td valign="top">I.</td> +<td><a href="#1">ENGINEERING AND MECHANICS.--New Eighty-ton Steam +Hammer at the Saint Chamond Works, France.--7 figures.--Elevation +of hammer.--Profile-- Transverse section.--Profile view of +foundation, etc.--Plan of plant.--General plan of the forging +mill.--Details of truss and support for the cranes.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#2">Great Steamers.--Comparative details of the +Servia, the City of Rome, the Alaska, and the Great +Eastern.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#3">Improved Road Locomotive.--2 figures.--Side and +end views</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#4">American Milling Methods. By ALBERT HOPPIN.--Ten +years' progress.--Low milling.--Half high milling.--High +milling.--Important paper read before the Pennsylvania State +Millers' Association.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#5">Machine for Dotting Tulles and other Light +Fabrics.--3 figures.</a></td> +</tr> + +<tr> +<td valign="top">II.</td> +<td><a href="#6">TECHNOLOGY AND CHEMISTRY.--The Reproduction and +Multiplication of Negatives. By ERNEST EDWARDS.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#7">A New Method of Making Gelatine Emulsion. By W. K. +BURTON.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#8">The Pottery and Porcelain Industries of +Japan.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#9">Crystallization Table.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#10">The Principles of Hop Analysis. By Dr. G. O. +CECH.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#11">Water Gas.--A description of apparatus for +producing cheap gas, and some notes on the economical effects of +using such gas with gas motors, etc.--By J. EMERSON +DOWSON.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#12">On the Fluid Density of Certain Metals. By +Professors CHANDLER ROBERTS and T. WRIGLESON.</a></td> +</tr> + +<tr> +<td valign="top">III.</td> +<td><a href="#13">PHYSICS, ELECTRICITY, ETC.--Electric Power.--The +nature and uses of electricity.--Electricity vs. steam.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#14">On the Method of Obtaining and Measuring Very +High Vacua with a Modified Form of Sprengel Pump. By Prof OGDEN N. +ROOD.--4 figures.-- Apparatus for obtaining vacua of one four +hundred-millionth of an +atmosphere--Construction.--Manipulation.--Calculations.--Results</a></td> +</tr> + +<tr> +<td valign="top">IV.</td> +<td><a href="#15">ART, ARCHITECTURE, ETC.--Old Wrought Iron Gates, +Guildhall. Worcester, England. 1 figure.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#16">The French Crystal Palace, Park of St. Cloud, +Paris. 1 full page illustration.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#17">Suggestions in Architecture. A Castellated +Chateau. Perspective and plan. Chateau in the Ægean +Sea.</a></td> +</tr> + +<tr> +<td valign="top">V.</td> +<td><a href="#18">HYGIENE AND MEDICINE.--Hydrophobia Prevented by +Vaccination.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#19">On Diptera as Spreaders of Disease. By J. W. +SLATER.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#20">On the Relations of Minute Organisms to Certain +Specific Diseases.</a></td> +</tr> + +<tr> +<td valign="top">VI.</td> +<td><a href="#21">ASTRONOMY--The Centenary of the Discovery of +Uranus. By F. W. DENNING. 2 figures. Approximate place of Uranus +among the stars at its discovery, March l3, 1871.--Orbits of the +Uranian Satellites.</a></td> +</tr> + +<tr> +<td valign="top">VII.</td> +<td><a href="#22">BIOLOGY, ETC.--The Varying Susceptibility of +Plants and Animals to Poisons and Disease.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#23">Kind Treatment of Horses.</a></td> +</tr> +</table> + +<hr> +<p><a name="1"></a></p> + +<h2>NEW EIGHTY TON STEAM HAMMER AT THE SAINT CHAMOND WORKS</h2> + +<p>Ever since the improvements that have been introduced into the +manufacture of steel, and especially into the erection of works for +its production, have made it possible to obtain this metal in very +large masses, it has necessarily been preferred to iron for all +pieces of large dimensions, inasmuch as it possesses in the highest +degree that homogeneousness and resistance which are so difficult +to obtain in the latter metal. It has consequently been found +necessary to construct engines sufficiently powerful to effect the +forging of enormous ingots, as well as special furnaces for heating +them and apparatus for manipulating and transporting them.</p> + +<p>The greatest efforts in this direction have been made with a +view to supplying the wants of heavy artillery and of naval +constructions; and to these efforts is metallurgy indebted for the +creation of establishments on a scale that no one would have dared +a few years ago to think of. The forging mill which we are about to +describe is one of those creations which is destined to remain for +a long time yet very rare; and one which is fully able to respond, +not only to all present exigencies, but also, as far as can be +foreseen, to all those that may arise for a long period to come. +The mill is constructed as a portion of the vast works that the +Compagnie des Forges et Aciéries de la Marine own at Saint +Chamond, and which embrace likewise a powerful steel works that +furnishes, especially, large ingots exceeding 100 tons in +weight.</p> + +<p>The mill consists, altogether, of three hammers, located in the +same room, and being of unequal powers in order to respond to +different requirements. The largest of these hammers is of 80 tons +weight, and the other two weigh respectively 35 and 28 tons. Each +of them has a corresponding furnace for heating by gas, as well as +cranes for maneuvering the ingots and the different engines. The +general plan view in Fig. 4 shows the arrangement of the hammers, +cranes, and furnaces in the millhouse.</p> + +<p class="ctr"><a href="images/1b.png"><img src= +"images/1b_th.png" alt= +"FIG. A.--ELEVATION OF A HAMMER. FIG. B.--PROFILE VIEW"></a></p> + +<p class="ctr">FIG. A.--ELEVATION OF A HAMMER. FIG. B.--PROFILE +VIEW</p> + +<p>The gas generators which supply the gas-furnaces are located out +of doors, as are the steam-generators. The ingots are brought from +the steel factory, and the forged pieces are taken away, by special +trucks running on a system of rails. We shall now give the most +important details in regard to the different parts of the +works.</p> + +<p><i>The Mill-House</i>--This consists of a central room, 262 feet +long, 98 feet wide, and 68 feet in height, with two lean-to annexes +of 16 feet each, making the total width 100 feet. The structure is +wholly of metal, and is so arranged as to permit of advantage being +taken of every foot of space under cover. For this purpose the +system of construction without tie-beams, known as the "De Dion +type," has been adopted. Fig. 1 gives a general view of one of the +trusses, and Fig. 5 shows some further details. The binding-rafters +consist of four angle-irons connected by cross-bars of flat iron. +The covering of corrugated galvanized iron rests directly upon the +binding-rafters, the upper parts of which are covered with wood for +the attachment of the corrugated metal. The spacing of these +rafters is calculated according to the length of the sheets of +corrugated iron, thus dispensing with the use of ordinary rafters, +and making a roof which is at once very light and very durable, and +consequently very economical. Rain falling on the roof flows into +leaden gutters, from whence it is carried by leaders into a +subterranean drain. The vertical walls of the structure are +likewise of corrugated iron, and the general aspect of the building +is very original and very satisfactory.</p> + +<p><i>The 80 Ton Hammer</i>--The three hammers, notwithstanding +their difference in power, present similar arrangements, and +scarcely vary except in dimensions. We shall confine ourselves here +to a description of the 80 ton apparatus. This consists, in +addition to the hammer, properly so called, of three cranes of 120 +tons each, serving to maneuver the pieces to be forged, and of a +fourth of 75 tons for maneuvering the working implements. These +four cranes are arranged symmetrically around the hammer, and are +supported at their upper extremity by metallic stays. Besides the +foregoing there are three gas furnaces for heating the ingots. +Figs. 1, 2, and 3 show the general arrangement of the +apparatus.</p> + +<p><i>Foundations of the Hammer and Composition of the +Anvil-Bed</i>--To obtain a foundation for the hammer an excavation +was made to a depth of 26 feet until a bed of solid rock was +reached, and upon this there was then spread a thick layer of +beton, and upon this again there was placed a bed of dressed stones +in the part that was to receive the anvil-stock and hammer.</p> + +<p>On this base of dressed stones there was placed a bed formed of +logs of heartwood of oak squaring 16 inches by 3 feet in height, +standing upright, joined together very perfectly, and kept in close +juxtaposition by a double band of iron straps joined by bolts. The +object of this wooden bed was to deaden, in a great measure, the +effect of the shock transmitted by the anvil-stock.</p> + +<p>NEW EIGHTY-TON STEAM HAMMER AT THE ST CHAMOND WORKS.</p> + +<p class="ctr"><a href="images/1c.png"><img src= +"images/1c_th.png" alt="FIG. 1.--TRANSVERSE SECTION."> +</a></p> + +<p class="ctr">FIG. 1.--TRANSVERSE SECTION.</p> + +<p class="ctr"><a href="images/2a.png"><img src= +"images/2a_th.png" alt="FIG. 2.--PLAN."></a></p> + +<p class="ctr">FIG. 2.--PLAN.</p> + +<p class="ctr"><a href="images/1d.png"><img src= +"images/1d_th.png" alt="FIG. 3.--PROFILE VIEW."></a></p> + +<p class="ctr">FIG. 3.--PROFILE VIEW.</p> + +<p class="ctr"><a href="images/2b.png"><img src= +"images/2b_th.png" alt= +"FIG. 4.--GENERAL PLAN OF THE FORGING MILL."></a></p> + +<p class="ctr">FIG. 4.--GENERAL PLAN OF THE FORGING MILL.</p> + +<p class="ctr"><a href="images/2c.png"><img src= +"images/2c_th.png" alt= +"FIG. 5.--DETAILS OF THE TRUSSAND SUPPORT FOR THE CRANE."></a></p> + +<p class="ctr">FIG. 5.--DETAILS OF THE TRUSSAND SUPPORT FOR THE +CRANE.</p> + +<p><i>The Anvil-Stock</i>.--The anvil-stock, which is pyramidal in +shape, and the total weight of which amounts to 500 tons, is +composed of superposed courses, each formed of one or two blocks of +cast iron. Each course and every contact was very carefully planed +in order to make sure of a perfect fitting of the parts; and all +the different blocks were connected by means of mortises, by hot +bandaging, and by joints with key-pieces, in such a way as to +effect a perfect solidity of the parts and to make the whole +compact and impossible to get out of shape.</p> + +<p>The anvil-stock was afterwards surrounded by a filling-in of +masonry composed of rag-stones and a mortar made of cement and +hydraulic lime. This masonry also forms the foundation for the +standards of the hammer, and is capped with dressed stone to +receive the bed-plates.</p> + +<p><i>The Power-Hammer</i> (Figs. A and B).--The power-hammer, +properly so-called, consists, in addition to the hammer-head, of +two standards to whose inner sides are bolted guides upon which +slides the moving mass. The bed-plates of cast iron are 28 inches +thick, and are independent of the anvil-stock. They are set into +the bed of dressed stone capping the foundation, and are connected +together by bars of iron and affixed to the masonry by foundation +bolts. To these bedplates are affixed the standards by means of +bolts and keys. The two standards are connected together by iron +plates four inches in thickness, which are set into the metal and +bolted to it so as to secure the utmost strength and solidity. The +platform which connects the upper extremities of the standards +supports the steam cylinder and the apparatus for distributing the +steam. The latter consists of a throttle valve, twelve inches in +diameter, and an eduction valve eighteen inches in diameter, the +maneuvering of which is done by means of rods extending down to a +platform upon which the engineman stands. This platform is so +situated that all orders can be distinctly heard by the engineman, +and so that he shall be protected from the heat radiated by the +steel that is being forged. All the maneuvers of the hammers are +effected with most wonderful facility and with the greatest +precision.</p> + +<p>The piston is of cast-steel, and the rod is of iron, 12 inches +in diameter. The waste steam is carried out of the mill by a pipe, +and, before being allowed to escape into the atmosphere, is +directed into an expansion pipe which it penetrates from bottom to +top. Here a portion of the water condenses and flows off, and the +steam then escapes into the open air with a greatly diminished +pressure. The object of this arrangement is to diminish to a +considerable extent the shocks and disagreeable noise that would be +produced by the direct escape of the steam at quite a high pressure +and also to avoid the fall of condensed water.</p> + +<p>The following are a few details regarding the construction of +the hammer:</p> + +<pre> + Total height of foundations........... 26 ft. + From the ground to the platform ...... 28 " +<br> + Platform .............................. 3.25 " + Height of cylinder.................... 21 " + ________ +<br> + Total height...................... 78.25 ft. +<br> + Weight of anvil-stock................ 500 tons. + Weight of bed-plates................. 122 " + Weight of standards.................. 270 " + Weight of platform and cylinder...... 148 " + Piston, valves, engineman's platform, + hammer, etc........................ 160 " + __________ +<br> + Total weight................... 1,200 tons. +<br> + Weight of the hammer.................. 80 tons. + Maximum fall.......................... 25.75 ft. + Distance apart of the standards....... 21.6 " + Width of hammer....................... 6 " + Pressure of steam..................... 16 lb. + Effective pressure to lift 80 tons.... 7 " +</pre> + +<i>Description of Figures</i>.--A, the 80-ton hammer; B, B1, B2, +cranes; C, C1, C2, supports of cranes; D, D1, D2, gas furnaces; A1, +the 35-ton hammer; A2, the 28-ton hammer; EE, railways; F, +engineman's platform; G, lever for maneuvering the throttle valve; +H, an ingot being forged. + +<hr> +<p><a name="2"></a></p> + +<h2>GREAT STEAMERS.</h2> + +<p>The <i>Brooklyn Eagle</i> gives a very interesting description +of the three new steamships now almost completed and shortly to be +placed in the New York and Liverpool trade by the Cunard, Inman, +and Williams and Guion lines. The writer has prepared a table +comparing the three vessels with each other and with the Great +Eastern, the only ship of greater dimensions ever built. We give as +much of the article as our space will allow, and regret that we +have not the room to give it entire:</p> + +<pre> + Line. Cunard. Inman. Guion. Admiralty. + Vessel. Servia City of Rome. Alaska. Great[1] +<br> + Length 530 feet. 546 feet. 520 feet. 679 feet. + Breadth 52 feet. 52 ft. 3 in. 50 ft. 6 in. 82 feet. + Depth 44 ft. 9 in. 37 feet. 38 feet. 60 feet. + Gross ton'ge 8,500 8,300 8,000 13,344[2] + Horse pow'r 10,500 10,000 11,000 2,600 + Speed 17½ knots. 18 knots. 18 knots. 14 knots. + Sal'n pas- 320 and 52 + sengers. 450 300 2d class + Steerage 600 1,500 1,000 + Where Clydeb'nk Barrow in Clyde, + built. Thomson Furness Elder + Date of + sailing. October 22 October 13 November 5 +</pre> + +<p>[Footnote 1: To be sold at auction soon.]</p> + +<p>[Footnote 2: Net register.]</p> + +<p>In 1870 the total tonnage of British steam shipping was +1,111,375; the returns for the year 1876 showed an increase to +2,150,302 tons, and from that time to the present it has been +increasing still more rapidly. But, as can be seen from the above +table, not only has the total tonnage increased to this enormous +extent, but an immense advance has been made in increasing the size +of vessels. The reason for this is, that it has been found that +where speed is required, along with large cargo and passenger +accommodation, a vessel of large dimensions is necessary, and will +give what is required with the least proportionate first cost as +well as working cost. Up to the present time the Inman line +possessed, in the City of Berlin, of 5,491 tons, the vessel of +largest tonnage in existence. Now, however, the Berlin is surpassed +by the City of Rome by nearly 3,000 tons, and the latter is less, +by 200 tons, than the Servia, of the Cunard line. It will be +observed, too, that while there is not much difference between the +three vessels in point of length, the depth of the Alaska and the +City of Rome, respectively, is only 38 feet and 37 feet, that of +the Servia is nearly 45 feet as compared with that of the Great +Eastern of 60 feet. This makes the Servia, proportionately, the +deepest ship of all. All three vessels are built of steel. This +metal was chosen not only because of its greater strength as +against iron, but also because it is more ductile and the advantage +of less weight is gained, as will be seen when it is mentioned that +the Servia, if built of iron, would have weighed 620 tons more than +she does of steel, and would have entailed the drawback of a +corresponding increase in draught of water. As regards rig, the +three vessels have each a different style. The Cunard Company have +adhered to their special rig--three masts, bark rigged--believing +it to be more ship shape than the practice of fitting up masts +according to the length of the ship. On these masts there is a good +spread of canvas to assist in propelling the ship. The City of Rome +is rigged with four masts; and here the handsome full-ship rig of +the Inman line has been adhered to, with the addition of the fore +and aft rigged jigger mast, rendered necessary by the enormous +length of the vessel. It will be seen that the distinctive type of +the Inman line has not been departed from in respect to the old +fashioned but still handsome profile, with clipper bow, figurehead, +and bowsprit--which latter makes the Rome's length over all 600 +feet. For the figurehead has been chosen a full length figure of +one of the Roman Cæsars, in the imperial purple. Altogether, +the City of Rome is the most imposing and beautiful sight that can +be seen on the water. The Alaska has also four masts, but only two +crossed.</p> + +<p>The length of the City of Rome, as compared with breadth, +insures long and easy lines for the high speed required; and the +depth of hold being only 37 feet, as compared with the beam of 52 +feet, insures great stability and the consequent comfort of the +passengers. A point calling for special notice is the large number +of separate compartments formed by water tight bulkheads, each +extending to the main deck. The largest of these compartments is +only about 60 feet long; and, supposing that from collision or some +other cause, one of these was filled with water, the trim of the +vessel would not be materially affected. With a view to giving +still further safety in the event of collision or stranding, the +boilers are arranged in two boiler rooms, entirely separated from +each other by means of a water tight iron bulkhead. This reduces +what, in nearly all full-powered steamships, is a vast single +compartment, into two of moderate size, 60 feet in length; and in +the event of either boiler room being flooded, it still leaves the +vessel with half her boiler power available, giving a speed of from +thirteen to fourteen knots per hour. The vessel's decks are of +iron, covered with teak planking; while the whole of the deck +houses, with turtle decks and other erections on the upper deck, +are of iron, to stand the strains of an Atlantic winter. Steam is +supplied by eight cylindrical tubular boilers, fired from both +ends, each of the boilers being 19 feet long and having 14 feet +mean diameter. There are in all forty eight furnaces. The internal +arrangements are of the finest description. There are two smoking +rooms, and in the after deckhouse is a deck saloon for ladies, +which is fitted up in the most elegant manner, and will prevent the +necessity of going below in showery weather. At the sides of the +hurricane deck are carried twelve life boats, one of which is +fitted as a steam launch. The upper saloon or drawing-room is 100 +feet long, the height between decks being 9 feet. The grand +dining-saloon is 52 feet long, 52 feet wide, and 9 feet high, or 17 +feet in the way of the large opening to the drawing-room above. +This opening is surmounted by a skylight, and forms a very +effective and elegant relief to the otherwise flat and heavy +ceiling. There are three large and fourteen small dining tables, +the large tables being arranged longitudinally in the central part +of the saloon, and the small tables at right angles on the sides. +Each diner has his own revolving arm chair, and accommodation is +provided for 250 persons at once. A large American organ is fixed +at the fore end of the room, and opening off through double spring +doors at the foot of the grand staircase is a handsome American +luncheon bar, with the usual fittings. On each side of the vessel, +from the saloon to the after end of the engine room, are placed +staterooms providing for 300 passengers. The arrangements for +steerage passengers are of a superior description. The berths are +arranged in single tiers or half rooms, not double, as is usually +the custom, each being separated by a passage, and having a large +side light, thus adding greatly to the light, ventilation, and +comfort of the steerage passengers, and necessitating the advantage +of a smaller number of persons in each room. The City of Rome is +the first of the two due here; she sails from Liverpool on October +13.</p> + +<p>In the Servia the machinery consists of three cylinder compound +surface condensing engines, one cylinder being 72 inches, and two +100 inches in diameter, with a stroke of piston of 6 feet 6 inches. +There are seven boilers and thirty-nine furnaces. Practically the +Servia is a five decker, as she is built with four decks--of steel, +covered with yellow pine--and a promenade reserved for passengers. +There is a music room on the upper deck, which is 50 feet by 22 +feet, and which is handsomely fitted up with polished wood +panelings. For the convenience of the passengers there are no less +than four different entrances from the upper deck to the cabins. +The saloon is 74 feet by 49 feet, with sitting accommodations for +350 persons, while the clear height under the beams is 8 feet 6 +inches. The sides are all in fancy woods, with beautifully polished +inlaid panels, and all the upholstery of the saloon is of morocco +leather. For two-thirds of its entire length the lower deck is +fitted up with first class staterooms. The ship is divided into +nine water-tight bulkheads, and she is built according to the +Admiralty requirements for war purposes. There are in all twelve +boats equipped as life-boats. The Servia possesses a peculiarity +which will add to her safety, namely, a double bottom, or inner +skin. Thus, were she to ground on rocks, she would be perfectly +safe, so long as the inner skin remained intact. Steam is used for +heating the cabins and saloons, and by this means the temperature +can be properly adjusted in all weathers. In every part of the +vessel the most advanced scientific improvements have been adopted. +The Servia leaves Liverpool on October 22.</p> + +<p>The Alaska, whose owners, it is understood, are determined to +make her beat all afloat in speed, does not sail until November 5, +and therefore it is premature to say anything about her interior +equipments. She is the sister of the celebrated Arizona, and was +built by the well-known firm of Elder & Co., on the Clyde.</p> + +<hr> +<p><a name="3"></a></p> + +<h2>IMPROVED ROAD LOCOMOTIVE.</h2> + +<p>Several attempts have been made to connect the leading wheels of +a traction engine with the driving wheels, so as to make drivers of +all of them, and thus increase the tractive power of the engine, +and to afford greater facilities for getting along soft ground or +out of holes. The wheels with continuous railway and India-rubber +tires have been employed to gain the required adhesion, but these +wheels have been too costly, and the attempts to couple driving and +leading wheels have failed. The arrangement for making the leading +wheels into drivers, illustrated on page 4825, has been recently +brought out by the Durham and North Yorkshire Steam Cultivation +Company, Ripon, the design being by Messrs. Johnson and Phillips. +The invention consists in mounting the leading axle in a ball and +long socket, the socket being rotated in fixed bearings. The ball +having but limited range of motion in the socket, is driven round +with it, but is free to move in azimuth for steering.</p> + +<p>This engine has now been in use more than twelve months in +traction and thrashing work, and, we are informed, with complete +success. The illustrations represent a 7-horse power, with a +cylinder 8 in. diameter by 12 in. stroke, and steam jacketed. The +shafts and axles are of Bowling iron. The boiler contains 140 ft. +of heating surface, and is made entirely of Bowling iron, with the +longitudinal seams welded. The gearing is fitted with two speeds +arranged to travel at 1½ and 3 miles per hour, and the front +or hind road wheels can be put out of gear when not required. The +hind driving wheels are 5 ft. 6 in. diameter, and the front wheels +5 ft.; weight of engine 8 tons.--<i>The Engineer.</i></p> + +<p class="ctr"><img src="images/3a.png" alt= +"IMPROVED ROAD LOCOMOTIVE"></p> + +<p class="ctr">IMPROVED ROAD LOCOMOTIVE</p> + +<p class="ctr"><a href="images/3b.png"><img src= +"images/3b_th.png" alt="IMPROVED ROAD LOCOMOTIVE"></a></p> + +<p class="ctr">IMPROVED ROAD LOCOMOTIVE</p> + +<hr> +<p><a name="4"></a></p> + +<h2>AMERICAN MILLING METHODS.</h2> + +<p>[Footnote 1: A paper read before the meeting of the Pennsylvania +State Millers Association at Pittsburgh, Pa., by Albert Hoppin, +Editor of the <i>Northwestern Miller</i>.]</p> + +<h3>By ALBERT HOPPIN.</h3> + +<p>To speak of the wonderful strides which the art of milling has +taken during the past decade has become exceedingly trite. This +progress, patent to the most casual observer, is a marked example +of the power inherent in man to overcome natural obstacles. Had the +climatic conditions of the Northwest allowed the raising of as good +winter wheat as that raised in winter wheat sections generally, I +doubt if we should hear so much to-day of new processes and gradual +reduction systems. So long as the great bulk of our supply of +breadstuffs came from the winter wheat fields, progress was very +slow; the mills of 1860, and I may even say of 1870, being but +little in advance, so far as processes were concerned, of those +built half a century earlier. The reason for this lack of progress +may be found in the ease with which winter wheat could be made into +good, white, merchantable flour. That this flour was inferior to +the flour turned out by winter wheat mills now is proven by the old +recipe for telling good flour from that which was bad, viz.: To +throw a handful against the side of the barrel, if it stuck there +it was good, the color being of a yellowish cast. What good winter +wheat patent to-day will do this? Still the old time winter wheat +flour was the best there was, and it had no competitor. The +settling up of the Northwest which could not produce winter wheat +at all, but which did produce a most superior article of hard +spring wheat, was a new factor in the milling problem. The first +mills built in the spring wheat States tried to make flour on the +old system and made a most lamentable failure of it. I can remember +when the farmer in Wisconsin, who liked a good loaf of bread, +thought it necessary to raise a little patch of winter wheat for +his own use. He oftener failed than succeeded, and most frequently +gave it up as a bad job. Spring wheat was hard, with a very tender, +brittle bran. If ground fine enough to make a good yield a good +share of the bran went into the flour, making it dark and specky. +If not so finely ground the flour was whiter, but the large +percentage of middlings made the yield per bushel ruinously small. +These middlings contained the choicest part of the flour producing +part of the berry, but owing to the dirt, germ, and other +impurities mixed with them, it was impossible to regrind them +except for a low grade flour. Merchant milling of spring wheat was +impossible wherever the flour came in competition with winter wheat +flours. At Minneapolis, where the millers had an almost unlimited +water power, and wheat at the lowest price, merchant milling was +almost given up as impracticable. It was certainly unprofitable. To +the apparently insurmountable obstacles in the way of milling +spring wheat successfully, we may ascribe the progress of modern +milling. Had it been as easy to raise good winter wheat in +Wisconsin and Minnesota as in Pennsylvania and Ohio, or as easy to +make white flour from spring as from winter wheat, we should not +have heard of purifiers and roller mills for years to come.</p> + +<p>The first step in advance was the introduction of a machine to +purify middlings. It was found that the flour made from these +purified middlings was whiter than the flour from the first +grinding and brought a better price than even winter wheat flours. +Then the aim was to make as many middlings as possible. To do this +and still clean the bran so as to make a reasonable yield the dress +of the burrs was more carefully attended to, the old fashioned +cracks were left out, the faces and furrows made smooth, true, and +uniform, self-adjusting drivers introduced, and the driving gear +better fitted. Spring wheat patents rapidly rose to the first place +in the market, and winter wheat millers waked up to find their +vantage ground occupied by their hitherto contemned rivals. To +their credit it may be said that they have not been slow in taking +up the gauntlet, and through the competition of the millers of the +two climatically divided sections of this country with each other +and among themselves the onward march of milling progress has been +constantly accelerated. Where it will end no man can tell, and the +chief anxiety of every progressive miller, whether he lives in +Pennsylvania or Minnesota, is not to be left behind in the +race.</p> + +<p>The millers of the more Eastern winter wheat States have a +two-fold question to solve. First, how to make a flour as good as +can be found in the market, and second, how to meet Western +competition, which, through cheap raw material and discriminating +freight rates, is making serious inroads upon the local markets. +Whether the latter trouble can be remedied by legislature, either +State or national, or not, remains to be proven by actual trial. +That you can solve the first part of the problem satisfactorily to +yourselves depends upon your readiness to adopt new ideas and the +means you have at hand to carry them out. It is manifestly +impossible to make as good a flour out of soft starchy wheat as out +of that which is harder and more glutinous. It is equally +impossible for the small mill poorly provided with machinery to +cope successfully with the large merchant mill fully equipped with +every appliance that American ingenuity can suggest and money can +buy. I believe, however, that a mill of moderate size can make +flour equally as good as the large mill, though, perhaps, not as +economically in regard to yield and cost of manufacture.</p> + +<p>The different methods of milling at present in use may be +generally divided into three distinct processes, which, for want of +any better names, I will distinguish as old style, new process, and +gradual reduction. Perhaps the German division of low milling, half +high milling, and high milling is better. Old style milling was +that in general use in this country up to 1870, and which is still +followed in the great majority of small custom or grist mills. It +is very simple, consisting of grinding the wheat as fine as +possible at the first grinding, and separating the meal into flour, +superfine or extra, middlings, shorts, and bran. Given a pair of +millstones and reel long enough, and the wheat could be made into +flour by passing through the two. Because spring wheat was so +poorly adapted to this crude process, it had to be improved and +elaborated, resulting in the new process.</p> + +<p>At first this merely consisted of purifying and regrinding the +middlings made in the old way. In its perfected state it may be +said to be halfway between the old style and gradual reduction, and +is in use now in many mills. In it mill stones are used to make the +reductions which are only two in number, in the first of which the +aim of the miller is to make as many middlings as he can while +cleaning the bran reasonably well, and in the second to make the +purified middlings into flour. In the most advanced mills which use +the new process, the bran is reground and the tailings from the +coarse middlings, containing germ and large middlings with pieces +of bran attached, are crushed between two rolls. These can hardly +be counted as reductions, as they are simply the finishing touches, +put on to aid in working the stuff up clean and to permit of a +little higher grinding at first. Regarding both old style and new +process milling, you are already posted. Gradual reduction is +newer, much more extensive, and merits a much more thorough +explanation. Before entering upon this I will call your attention +to one or two points which every miller should understand.</p> + +<p>The two essential qualities of a good marketable flour are color +and strength. It should be sharply granular and not feel flat and +soft to the touch. A wheat which has an abundance of starch, but is +poor in gluten, cannot make a strong flour. This is the trouble +with all soft wheats, both winter and spring. A wheat which is rich +in gluten is hard, and in the case of our hard Minnesota wheat has +a very tender bran. It is comparatively easy to make a strong +flour, but it requires very careful milling to make a flour of good +color from it. Probably the wheat which combines the most desirable +qualities for flour-making purposes is the red Mediterranean, which +has plenty of gluten and a tough bran, though claimed by some to +have a little too much coloring matter, while the body of the berry +is white. By poor milling a good wheat can be made into flour +deficient both in strength and color, and by careful milling a +wheat naturally deficient in strength may be made into flour having +all the strength there was in the wheat originally and of good +color. Good milling is indispensable, no matter what the quality of +the wheat may be.</p> + +<p>The idea of gradual reduction milling was borrowed by our +millers from the Hungarian mills. There is, however, this +difference between the Hungarian system and gradual reduction, as +applied in this country, that in the former, when fully carried +out, the products of the different breaks are kept separate to the +end, and a large number of different grades of flour made, while in +the system, as applied in this country, the separations are +combined at different stages and usually only three different +grades of flour made, viz.: patent, baker's, or as it is termed in +Minnesota, clear flour, and low grade or red dog. In the largest +mills the patent is often subdivided into first and second, and +they may make different grades of baker's flour, these mills +approaching much nearer to the Hungarian system, though modifying +it to American methods and machinery. In mills of from three to +five hundred barrels daily capacity, it is hardly possible or +profitable to go to this subdivision of grades, owing to the +excessive amount of machinery necessary to handling the stuff in +its different stages of completion. The Hungarian system has, +therefore, been greatly modified by American millers and milling +engineers to adapt it to the requirements of mills of average +capacity. This modified Hungarian system we call gradual reduction. +It can be profitably employed in any mill large enough to run at +all on merchant work. So far it has not been found practicable to +use it in mills of less than one hundred and twenty-five to one +hundred and fifty barrels capacity in twenty-four hours, and it is +better to have the mill of at least double this capacity.</p> + +<p>Gradual reduction, as its name implies, consists in reducing the +wheat to flour, shorts, and bran, by several successive operations +or reductions technically called breaks, the process going on +gradually, each break leaving the material a little finer than the +preceding one. Usually five reductions or breaks are made, though +six or seven may be used. The larger the number of breaks the more +complicated the system becomes, and it is preferable to keep it as +simple as possible, for even at its simplest it requires a good, +wide-awake thinking miller to handle it successfully. When it is +thoroughly and systematically carried out in the mill it is without +question as much in advance of the new process as that is ahead of +the old style of milling.</p> + +<p>In order that I may convey to you as clear an idea of gradual +milling reduction as possible, I will give as fully as possible the +programme of a mill of one hundred and fifty barrels maximum daily +capacity designed to work on mixed hard and soft spring wheat, and +which probably will come much nearer to meeting the conditions +under which you have to mill than any other I have found readily +obtainable. I have chosen a mill of this size, first, because +following out the programme of a larger one would require too much +time and too great a repetition of details and not give you any +clearer idea of the main principles involved, and secondly, because +I thought it would come nearer meeting the average requirements of +the members of your association. Your worthy secretary cautioned me +that I must remember that I was going to talk to winter wheat +millers. The main principles and methods of gradual reduction are +the same, whether applied to spring or winter wheat; the details +may have to be varied to suit the varying conditions under which +different mills are operated. For this programme I am indebted to +Mr. James Pye, of Minneapolis, who is rapidly gaining an enviable +and well deserved reputation as a milling engineer, and one who has +given much study to the practical planning and working of gradual +reduction mills.</p> + +<p>And right here let me say that no miller should undertake to +build a gradual reduction mill, or to change over his mill to the +gradual reduction system, until he has consulted with some good +milling engineer (the term millwright means very little nowadays), +and obtained from him a programme which shall fit the size of the +mill, the stock upon which it has to work, and the grade of flour +which it is to make. This programme is to the miller what a chart +is to the sailor. It shows him the course he must pursue, how the +stuff must be handled, and where it must go. Without it he will be +"going it blind," or at best only feeling his way in the dark. A +gradual reduction mill, to be successful, must have a well-defined +system, and to have this system, the miller must have a definite +plan to work by. But to go on with my programme.</p> + +<p>The wheat is first cleaned as thoroughly as possible to remove +all extraneous impurities. In the cleaning operations care should +be taken to scratch or abrade the bran as little as possible, for +this reason: The outer coating of the bran is hard and more or less +friable. Wherever it is scratched a portion is liable to become +finely comminuted in the subsequent reductions, so finely that it +is impossible to separate it from the flour by bolting, and +consequently the grade of the latter is lowered. The ultimate +purpose of the miller being to separate the flour portion of the +berry from dirt, germ, and bran it is important that he does not at +any stage of the process get any dirt or fine bran speck or dust +mixed in with his flour, for if he does he cannot get rid of it +again. So it must be borne in mind that at all stages of flouring, +any abrasion or comminution of the bran is to be avoided as far as +possible.</p> + +<p>After the wheat is cleaned, it is by the first break or +reduction split or cut open, in order to liberate the germ and +crease impurities. As whatever of dirt is liberated by this break +becomes mixed in with the flour, it is desirable to keep the amount +of the latter as small as possible. Indeed, in all the reductions +the object is to make as little flour and as many middlings as +possible, for the reason that the latter can be purified, while the +former cannot, at least by any means at present in use. After the +first break the cracked wheat goes to a scalping reel covered with +No. 22 wire cloth. The flour, middlings, etc., go through the +cloth, and the cracked wheat goes over the tail of the reel to the +second machine, which breaks it still finer. After this break the +flour and middlings are scalped out on a reel covered with No. 22 +wire cloth. The tailings go to the third machine, and are still +further reduced, then through a reel covered with No. 24 wire +cloth. The tailings go to the fourth machine, which makes them +still finer, then through a fourth scalping reel the same as the +third. The tailings from this reel are mostly bran with some +middlings adhering, and go to the fifth machine, which cleans the +bran. From this break the material passes to a reel covered with +bolting cloth varying in fineness from No. 10 at the head to No. 00 +at the tail. What goes over the tail of this reel is sent to the +bran bin, and that which goes through next to the tail of the reel, +goes to the shorts bin. The middlings from this reel go to a +middlings purifier, which I will call No. 1, or bran middlings +purifier. The flour which comes from this reel is sent to the chop +reel covered at the head with say No. 9, with about No. 5 in the +middle and No 0 at the tail. You will remember that after each +reduction the flour and middlings were taken out by the scalping +reels. This chop, as it is now called, also goes to the same reel I +have just mentioned. The coarse middlings which go over the tail of +this reel go to a middlings purifier, which I will designate as No. +2. These go through the No. 0 cloth at the tail of the reel +purifier No. 3; those which go through No. 5 cloth got to purifier +No. 4; while all that goes through the No. 9 cloth at the head of +the reel is dropped to a second reel clothed with Nos. 13 to 15 +cloth with two feet of No. 10 at the tail. The flour from this reel +goes to the baker's flour packer; that which drops through the No. +10 is sent to the middlings stone, while that which goes over the +tail of the reel goes to purifier No. 4. We have now disposed of +all the immediate products of the first five breaks, tracing them +successively to the bran and shorts bins, to the baker's flour +packer and to the middlings purifiers, a very small portion going +to the middlings stone without going through the purifiers.</p> + +<p>The middlings are handled as follows in the purifiers. From the +No. 1 machine, which takes the middlings from the fifth break, the +tailings go to the shorts bin, the middlings which are sufficiently +well purified go to the middlings stone, while those from near the +tail of the machine which contain a little germ and bran specks go +to the second germ rolls, these being a pair of smooth rolls which +flatten out the germ and crush the middlings, loosening adhering +particles from the bran specks. From the second germ rolls the +material goes to a reel, where it is separated into flour which +goes into the baker's grade, fine middlings which are returned to +the second germ rolls at once, some still coarser which go to a +pair of finely corrugated iron rolls for red dog, and what goes +over the tail of the reel goes to the shorts bin. The No. 2 +purifier takes the coarse middlings from the tail of the first or +chop reel as already stated. The tailings from this machine go to +the shorts bin, some few middlings from next the tail of the +machine are returned to the head of the same machine, while the +remainder are sent to the first germ rolls. The reason for +returning is more to enable the miller to keep a regular feed on +the purifiers than otherwise. The No. 3 purifier takes the +middlings from the 0 cloth on the chop reel. From purifier No. 3 +they drop to purifier No. 5. A small portion that are not +sufficiently well purified are returned to the head of No. 3, while +those from the head of the machine, which are well purified, are +sent to the middlings stones. The remainder, which contain a great +deal of the germ, are taken to the first germ rolls, in passing +which they are crushed lightly to flatten the germ without making +any more flour than necessary. The No. 4 purifier takes the +middlings from No. 2 and also from No. 5 cloth on the chop reel and +from the No. 10 on the tail of the baker's reel. The middlings from +the head of this machine go to the middlings stones, and the +remainder to purifier No. 6. The tailings from Nos. 3, 4, 5, and 6 +go to the red dog rolls. A small portion not sufficiently well +purified are returned from No. 6 to the head of No. 4, while the +cleaned middlings go to the middlings stones.</p> + +<p>The portions of the material which have not been traced either +to the baker's flour or the bran and shorts bins are the middlings +which have gone to the middlings stones, the germy middlings which +have gone to the first germ rolls, and the tailings from purifiers +Nos. 3, 4, 5, and 6, and some little stuff not quite poor enough +for shorts from the reel following the second germ rolls. Taking +these <i>seriatim</i>: the middlings after passing through the +middlings stones, go to the first patent reel covered with eleven +feet of No. 13 and four feet of No. 8. The flour from the head of +the reel goes to the patent packer, that from the remainder of the +reel is dropped to another reel, while the tailings go to the No. 4 +purifier. The lower patent reel is clothed with No. 14 and two feet +of No. 10 cloth; from the head of the reel the flour goes to the +patent packer, the remainder that passes through the No. 10 cloth +which will not do to go into the patent, being returned to the +middlings stones, while the tailings are sent to the No. 4 +purifier.</p> + +<p>The germ middlings, after being slightly crushed as before +stated, are sent to a reel covered with five feet of No. 13 cloth, +five feet of No. 14, and the balance with cloth varying in +coarseness from No. 7 to No. 00. The flour from this reel goes into +the patent, the tailings to the red dog rolls, the middlings from +next the tail of the reel which still contain some germ to the +second germ rolls, while the middlings which are free from germ go +to the middlings stones.</p> + +<p>The tailings from purifiers 3, 4, 5, and 6, the material from +the reel following the second germ rolls, which is too good for +shorts, but not good enough to be returned into middlings again, +and the tailings from the reel following the first germ rolls are +sent to the red dog rolls, which, as I have stated, are finely +corrugated. Following these rolls is the red dog reel. The flour +goes to the red dog bin, the tailings to the shorts bin, while some +stuff intermediate between the two, not fine enough for the flour +but too good for shorts, is returned to the red dog rolls.</p> + +<p>This finishes the programme. I have not given it as one which is +exactly suited to winter wheat milling. However, as I said before, +the general principles are the same in either winter or wheat +gradual reduction mills, and the various systems of gradual +reduction, although they differ in many points, and although there +are probably no two engineers who would agree as to all the details +of a programme, the main ideas are essentially the same. The system +has been well described as one of gradual and continued +purification. In the programme above given the idea was to fit up a +mill which should do a maximum amount of work of good quality with +a minimum amount of expenditure and machinery. In a larger mill or +even in a mill of the same capacity where money was not an object, +the various separations would probably be handled a little +differently, the flour and middlings from the first and fifth +breaks being handled together, and those from the second, third, +and fourth breaks being also handled together. The reason for this +separation being that the flour from the first and fifth breaks +contain, the first a great deal of crease dirt, and the fifth more +bran dust than that from the other breaks, the result being a lower +grade of flour. The object all along being to keep the amount of +flour with which dirt can get mixed as small as possible, and not +to lower the grade of any part of the product by mixing it with +that which is inferior, always bearing in mind that the aim is to +make as many middlings as possible, for they can be purified while +the flour can not, and that whenever any dirt is once eliminated it +should be kept out afterwards. This leads me to say that if a +miller thinks the adoption of rolls or reduction machines is all +there is of the system, he is very much mistaken. If anything, more +of the success of the mill depends upon the careful handling of the +stuff after the breaks are made, and here the miller who is in +earnest to master the gradual reduction system will find his +greatest opportunities for study and improvement. A few years back +it was an axiom of the trade that the condition of the millstone +was the key to successful milling. This was true because the +subsequent process of bolting was comparatively simple. Now the +mere making of the breaks is a small matter compared with the +complex separations which come after. In the foregoing programme we +had five breaks or successive reductions. Although this is better +than a smaller number, I will here say that it is not absolutely +essential, for very good work is done with four breaks. The mill +for which this programme was made, including the building, cost +about $15,000, and is designed to make about sixty per cent. of +patent, thirty-five per cent. of baker's, and five per cent. of low +grade, results which are in advance of many larger and more +pretentious mills.</p> + +<p>One difficulty in the way of adapting the gradual reduction +system to mills of very small capacity is that the various machines +require to be loaded to a certain degree in order to work at their +best. It is only a matter of short time when our milling inventors +will design machinery especially for small mills; in fact they are +now doing it, and every day brings it more within the power of the +small miller to improve his manner of milling. To show what can be +done in this direction I will briefly describe a mill of about +ninety barrels maximum capacity per twenty-four hours, which is as +small as can be profitably worked. I will premise this description +by saying it is designed with a view to the greatest economy of +cost, the best trade of work, and to reduce the amount of machinery +and the handling of the stuff as much as possible. This latter +point is of much importance in any mill, either large or small, no +matter upon what system it is operated, for it takes power to run +elevators and conveyors, and especially in elevating and conveying +middlings, especially those made from winter wheat, their quality +is inured and a loss incurred, by the unavoidable amount of flour +made by the friction of the particles against each other. So much +is this the case that in one of our largest mills it is deemed +preferable to move the middlings from one end of the mill to the +other by means of a hopper bin on a car which runs on a track +spiked to the floor, rather than to employ a conveyor. A mill built +as I am going to describe would require from fifty to sixty +horse-power to run it, and including steam power and building would +cost from $10,000 to $12,000, according to location. I give it as +of interest to those among your number who own small mills and may +contemplate improving them.</p> + +<p>The building is four stories high, including basement, and +thirty-two feet square. It would be some better to have it larger, +but it is made this small to show how small a space a mill of this +size can be made to occupy. No story is less than twelve feet high. +The machinery Is very conveniently arranged, and there is plenty of +room all around. The system is a modification of the gradual +reduction system, the middlings being worked upon millstones. The +first break is on one pair of 9 x 18 inch corrugated iron rolls, +eight corrugations to the inch, the corrugations running parallel +with the axis of the rolls. The second break on rolls having twelve +corrugations to the inch, the third sixteen, and the fourth twenty +to the inch, while the fifth break, where the bran is finally +cleaned, has twenty-four corrugations to the inch. The basement +contains the line shaft and pulleys for driving rolls, stones, +cockle machine, and separator. The only other machinery in the +basement is the cockle machine. The line shaft runs directly +through the center of the basement, the power being from engine or +water wheel outside the building. The first floor has the roller +mills in a line nearly over the line shaft below, the middlings +stones, two in number, at one side opposite the entrance to the +mill, the receiving bin at one side of the entrance in the corner +of the mill, and the two flour packers for the baker's and patent +flour in the other corner. This arrangement leaves over half of the +floor area for receiving and packing purposes. The bolting chests, +one with six reel and the other with three reel begin on the second +floor and reach up into the attic. An upright shaft from the line +shaft in the basement geared to a horizontal shaft running through +the attic parallel with the line shaft below, comprise about all +the shafting there is in the mill. There is a short shaft on the +second floor from which the two purifiers on this floor and the two +in the attic are driven, and another short shaft on the first floor +to drive the packers. There are four purifiers, two on the second +floor, and two more directly over them in the attic. The elevator +heads are all directly upon the attic line shaft, and the bolting +chests are driven by uprights dropped from this shaft. The combined +smutter and brush machine is on the third floor at one end of the +bolting chests and directly over the stock hoppers. This comprises +all the machinery in the mill. The programme is about as +follows:</p> + +<p>The break reels are clothed as follows: First break No. 20, wire +cloth, second break No. 22, third break No. 24, and fourth break +No. 24. The material passing through these scalping reels, now +called chop, goes to a series of reels, the first clothed with Nos. +6, 4, and 0. The material passing over the tail is sent to the germ +purifier, that passing through Nos. 4 and 0, to the coarse +middlings purifier, and that through the No. 6 goes to the reel +below clothed with Nos. 12 and 13. Some nice granular flour is +taken off from this reel; the remainder, which passes over the tail +and through the cutoffs, goes to the next reel below clothed with +Nos. 14, 15, and 9. Some good flour comes from the 14 and 15; that +which passes through the 9 goes at once to the stones without +purifying, while that which passes over the tail is sent to the +fine middlings purifiers.</p> + +<p>After the purification, the middlings are ground on stones and +bolted on Nos. 13 and 14 cloth, after having been scalped on No 8. +The germ middlings are crushed on smooth rolls and bolted on Nos. +12 and 13. What is not crushed fine enough goes with poor tailings +to the second germ rolls, and from these to a reel by themselves or +to the fifth reduction or bran reel. A mill of this kind could be +made much more perfect by an expenditure of two or three thousands +dollars more. I have instanced it to show what can be done with +gradual reduction in a very small way.</p> + +<p>In mills of from three hundred to five hundred barrels capacity +and still larger, the programme differs considerably from that I +have sketched, the middlings being graded and handled with little, +if any, returning, and are sized down on the smooth rolls, a much +larger percentage of the work of flouring being done on millstones. +For a three hundred barrel roller mill, the following plant is +requisite: five double corrugated roller mills, five double smooth +roller mills, three pairs of four foot burrs sixteen purifiers, +four wire scalping reels, six feet long, one reel for the fifth +break, one reel for low grade flour, eight chop reels, seven reels +for flour from smooth rolls, three reels for the stone flour, two +grading reels, three flour packers, and necessary cleaning +machinery. The reels are eighteen feet thirty-two inches. The +programme is necessarily more complicated.</p> + +<p>When it comes to the machinery to be employed in making the +reductions or breaks, the miller has several styles from which to +choose. Which is best comes under the head of what I don't know, +and moreover, of that which I have found no one else who does know. +Each machine has its good points, and the mill owner must make his +own decision as to which is best suited to his purpose. The main +principles involved are to abrade the bran as little as possible +while cleaning it thoroughly, and to make as little break flour, +and as many middlings as possible, the latter to be made in such +shape as to be the most easily purified. Regarding the difference +between spring and winter wheat for gradual reduction milling, it +may be stated something after this manner: Spring wheat has a +thinner and more tender bran, makes more middlings because it is +harder, and for the same reason the flour is more inclined to be +coarse and granular. In milling with winter wheat, especially the +better varieties, there will be more break flour made, the +middlings will be finer with fewer bran specks, and the bran more +easily cleaned, because it will stand harsher treatment. Winter +wheat, moreover, requires more careful handling in making the +breaks, not because of the bran, but to avoid breaking down the +middlings, and making too much and too fine and soft break flour. +In order to keep the flour sharp and granular, coarser cloths are +used in bolting, and because the middlings are finer the bolting is +not so free and a larger bolting surface is required. In milling +either spring or winter wheat there should be ample purifying +capacity, it being very unwise to limit the number of machines, so +that any of them will be overtaxed. The day has gone by when one +purifier will take care of all the middlings in the mill.</p> + +<p>There is one point which is of much interest to mill owners who +wish to change their mills over to the gradual reduction process, +that is, how far they can utilize their present plan of milling +machinery in making the change. Of course the cleaning machinery is +the same In both cases, so are the elevators, conveyors, bolting +chests, etc. But to use the millstone is a debatable question. +After carefully considering the matter I have come to the +conclusion that it has its place, and an important one at that, +under the new regime, viz., that of reducing the finer purified +middlings to flour. The reason for this lies in the peculiar +construction of the wheat berry. If the interior of the berry were +one solid mass of flour, needing only to be broken up to the +requisite fineness, it could be done as well on the rolls. But +instead of this, as is well known, the flour part of the berry is +made up of a large number of granules or cells, the walls of which +are cellular tissue, different from the bran in that it is soft and +white instead of hard and dark colored. It is also fibrous to a +certain extent, and when the fine middlings are passed between the +rolls instead of breaking down and becoming finer, it has a +tendency to cake up and flatten out, rendering the flour soft and +flaky. It does not hurt the color, but it does hurt the strength. +When the millstone is used in place of the roll the flour is of +equally good color, and more round and granular. I know that in +this the advocates of smooth rolls will differ from my conclusions, +but I believe that the final outcome will be the use of millstones +on the finer middlings, and in fact on all the middlings that are +thoroughly freed from the germ.</p> + +<p>It has been said that that which a man gives the most freely and +receives with the worst grace is advice. I will, however, close +with a little of the article which may not be wholly put of place. +If you have a mill do not imagine that the addition of a few pairs +of rolls, a purifier or two, and a little overhauling of +bolting-chests, is going to make it a full-fledged Hungarian roller +mill. If you are going to change an old mill or build a new one, do +not take the counsel or follow the plans of every itinerant miller +or millwright who claims to know all about gradual reduction. No +matter what kind of a mill you want to build, go to some milling +engineer who has a reputation for good work, tell him how large a +mill you want, show him samples of the wheat it must use and the +grades of flour it must make, and have him make a programme for the +mill and plan the machinery to fit it. Then have the mill built to +fit the machinery. When it starts follow the programme, whether it +agrees with your preconceived notions or not, and the mill will, in +ninety-nine cases out of one hundred, do good work.</p> + +<hr> +<p><a name="5"></a></p> + +<h3>MACHINE FOR DOTTING TULLES AND OTHER LIGHT FABRICS.</h3> + +<p>Dotted or chenilled tulles are fabrics extensively used in the +toilet of ladies, and the ornamentation of which has hitherto been +done by the application to the tissue, by hand, either of chenille +or of small circles previously cut out of velvet. This work, which +naturally takes considerable time, greatly increases the cost price +of the article.</p> + +<p>A few trials at doing the work mechanically have been made, but +without any practical outcome. The workwomen who do the dotting are +paid at Lyons at the rate of 80 centimes per 100 dots; so that if +we take tulle with dots counter-simpled 0.04 of an inch, which is +the smallest quincunx used, and suppose that the tissue is 31 +inches wide and that the daily maximum production is one yard, we +find that 400 dots at 80 centimes per 100 = 3 francs and 20 +centimes (about 63 cents), the cost of dotting per yard. It is true +that the workwoman furnishes the velvet herself.</p> + +<p>Mr. C. Ricanet, of Lyons, has recently invented a machine with +which he effects mechanically the different operations of dotting, +not only on tulles but also upon gauzes or any other light tissues +whatever, such as those of cotton, silk, wool, etc. Aided by a +talented mechanic, Mr. Ricanet has succeeded in constructing one of +those masterpieces of wonderfully accurate mechanism of which the +textile industry appears to have the monopoly--at least it is +permissible to judge so from the remarkable inventions of +Vaucanson, Jacquard, Philippe de Girard, Heilmann, and others.</p> + +<p>The object of this new machine, then, which has been doing its +wonderful work for a few days only, is to reproduce artificially +chenille embroidered on light tissues, by mechanically cutting out +and gluing small circles of velvet upon these fabrics.</p> + +<p>For this purpose all kinds of velvet may be employed, and, in +order to facilitate the cutting, they are previously coated on the +reverse side with any glue or gum whatever, which gives the velvet +a stiffness favorable to the action of the punch. To effect the +object desired the apparatus has three successive operations to +perform: first, cutting the circles; second, moistening; and third, +fastening down the dots upon the tissue according to a definite +order and spacing. The machine may be constructed upon any scale +whatever, although at present it is only made for operating on +pieces 31 inches wide, that being the normal width of dotted +tulles. The quincuncial arrangement of the dots is effected by the +punching, moistening, and fastening down of odd and even dots, +combined with the forward movement of the tissue to be +chenilled.</p> + +<p>The principal part of the machine is the cam-shaft, A (Figs. 1, +2, and 3), which revolves in the direction of the arrows and passes +in the center of 80 cam-wheels, 40 of which are odd and 40 even, +alternately opposed to each other. This shaft actuates, through its +two extremities, the different combined motions in view of the +final object to be attained, and also carries the motive pulleys, +PP'. Figs. 1 and 2 show the profile of two of these opposed +cam-wheels--the arrangement by means of which two rows of dots (odd +and even) are laid down upon the tissue during one revolution of +the shaft or drum, A. Each of the wheels carries three cams (Figs. +1 and 3), the first, (<i>a</i>), corresponding to the punching; the +second, (<i>a'</i>), to the moistening, and the third, +(<i>a''</i>), to the gluing down of the dots.</p> + +<p>The annexed figure, one-quarter actual size, shows in section +the details of the cutting mechanism. To each cam-wheel there +corresponds one punch, and the eighty punches are arranged side by +side and parallel upon a shaft, B, a spring, <i>b</i>, holding them +constantly against the circumference of the cam-wheels. In Fig. 2 +only one of these details is shown. The punching arrangement +consists of an ordinary punch, <i>c</i>, of variable diameter, +screwed to the extremity of a tube, <i>d</i>, which is itself +suspended from the end of the lever, <i>p</i>, but which can +receive from it at the desired moment the pressure necessary to +effect the cutting. The vertical position of these multiple tubes +is insured by a guide, <i>e</i>, which is thoroughly indispensable. +Through each of the tubes, <i>d</i>, there passes a plunger +designed for expelling from the punch the piece that has been cut +out of the velvet, and for gluing it down to the fabric. The two +small springs, <i>b'</i> and <i>b''</i>, tend continually to lift +the tubes as well as the plunger. The whole mechanism is affixed to +solid cast-iron frames, and the machine itself may be mounted on +wooden supports or a metal frame.</p> + +<p>The punching is effected on a bronze straight-edge, C, which +slides in a cast-iron channel, D. This presents alternately, in its +movement, entire and punctured spaces, the former for receiving the +blow of the punch and the latter for allowing passage at the +desired moment to the plunger as it goes to fasten the dots upon +the tulle which is passing along underneath the channel, D. The +punching is done primarily and principally by pressure, but, in +order to facilitate the complete detachment of filaments which +might retain the punched-out piece, the punch is likewise given at +the same time a slight rotary motion, thus imitating mechanically +what is performed by hand in the maneuver of all punches. This +rotary motion is communicated to the punches by means of levers +actuated by an eccentric, E, and which move the frame, <i>h</i>, +whose bars engage with the horizontal lever, <i>g</i>, soldered to +the tube, <i>d</i>, thus causing the latter at the very moment the +punch descends to revolve from right to left. The forty punches in +operation cause the frame to return to its initial position through +the action of the springs, <i>b'</i>. We say forty, since the +inventor, in principle, has admitted 80 punches, operating 40 as +odd and 40 as even; obtaining in this way a dotting in a regular +quincunx of one yard, that is to say, 80 dots arranged in two rows +on a fabric 31 inches wide. But it is evident that a much larger +quincunx may be had by putting in play only a half, a third, or a +fourth of the punches, and causing the tulle and velvet to advance +proportionally. For this purpose it is only necessary to unscrew +the punches which are not to act, and to substitute for the ratchet +wheel which controls the unrolling of the I tulle, another having a +number of teeth proportioned to the desired spacing of the +dots.</p> + +<p>The punching having been executed, and the drum, A, continuing +to revolve, the punches rise a little owing to the conformation of +the cam-wheel, and through the action of the springs, <i>b</i>, and +allow the moistener to move forward to dampen the little circles +which remain at the orifice of the punches. The moistener or +dampener is a sort of pad equal in length to the field of action of +the punches, and is affixed to a cross-bar, F, which is connected +at its two extremities with the levers, G, that are actuated by the +cam-wheels, H. These cam-wheels, or eccentrics, H, which are +mounted on the shaft of the drum, A, cause the moistener to move +forward as soon as the punches rise after operating, and, when it +arrives beneath the punches, the larger cams, <i>a</i>, of the +cam-wheels, A, press the latter upon the pad and thus effect the +dampening of the circles of velvet.</p> + +<p>Immediately afterwards, the same eccentrics, H, acting on a +lever, I, uncover the holes in the straight-edge, C, and the +channel, D. The large cams, <i>a"</i>, of the wheel, A, then acting +very powerfully upon the respective punches, cause these latter to +pass through the orifices so that the extremity of each punch comes +within about one twenty-fifth of an inch of the fabric to be +dotted. In this passage of the tube, <i>d</i>, a small rod, +<i>i</i>, connected by a lever with the plunger, <i>f</i>, is made +to abut against the guide, <i>e</i>, thus causing the descent of +the plunger to a sufficient degree to push the velvet "dot" out of +the tube and to glue it upon the fabric. The manner in which these +operations are performed being now well enough understood, let us +for a moment examine the motions of the fabrics to be cut and +dotted--the first being velvet or any other material, even metal +(goldleaf, for example), and the second, the tulle.</p> + +<p>The latter has but one motion, and that is in the direction of +its length, while the velvet has, in addition to this same motion, +another slight one from right to left in the direction of its width +in order to diminish waste as much as possible.</p> + +<p>The tulle to be dotted is first wound around a roller, R, from +whence it passes over the glass guide-roller, R', and between the +channel, D, and the table, T, to the roller, R", which is heated by +steam.</p> + +<p>The hot air which is radiated dries the dots, and from thence +the fabric is taken up by other rollers or by any other method. The +steam roller, R", carries at one of its extremities a ratchet wheel +whose teeth vary in number according to the greater or less +rapidity with which the tulle is unrolled. It is actuated by a +lever which receives its motion from the eccentric, K.</p> + +<p class="ctr"><a href="images/6a.png"><img src= +"images/6a_th.png" alt= +"IMPROVED MACHINE FOR DOTTING TULLAND OTHER LIGHT FABRICS."> +</a></p> + +<p class="ctr">IMPROVED MACHINE FOR DOTTING TULLAND OTHER LIGHT +FABRICS.</p> + +<p>In the table, T, there is a rectangular receptacle, <i>t</i>, +containing rasped or powdered velvet for the purpose of forming a +reverse of the dot. This powder attaches itself to the gum and +imitates on the wrong side of the fabric a dot similar to that on +the upper or right side. The velvet is wound upon the roller, +<i>r</i>, and from thence passes under the guiding roller, +<i>r'</i>, the punches, and the second roller, <i>r"</i>. These two +latter rollers are solidly connected by a straight-edge fixed at +the extremity of the lever, L, whose other end is in continuous +correlation with the eccentric, M, which controls the lateral +displacements; while the eccentric, O, actuates, by means of the +screw, Q, and the ratchet-wheel, S, the longitudinal advance of the +velvet. The eccentric, M, is fixed upon an axle, A', which carries +a wheel, U, having teeth inclined with respect to its axis, and +which derives its motion from the Archimedean screw, N, fixed at +one of the extremities of the cam-shaft, A.</p> + +<p>We have stated above that the maximum daily hand production of +tulle dotted in quincunxes of 0.04 of an inch is about one yard. At +the rate of 30 revolutions per minute, and for the same article as +that just mentioned, this dotting machine is capable of producing, +theoretically, 360 yards per 10 hours; but practically this +production is reduced to about 250 yards, which, however, is +sufficiently satisfactory.</p> + +<hr> +<p><a name="6"></a></p> + +<h2>THE REPRODUCTION AND MULTIPLICATION OF NEGATIVES.</h2> + +<h3>By ERNEST EDWARDS, B.A.</h3> + +<p>A question, relative to the subject of reproducing negatives, +which was put at a meeting of one of your New York societies, +prompts me to make a few remarks on the subject.</p> + +<p>Among the numerous and widely diversified ramifications of our +business (the Heliotype Printing Company) we have very often to +reproduce and multiply negatives in both a direct and reversed +form. Various methods for doing this have been tried, and I may +here say that I am quite well aware of all the methods that have +hitherto been suggested for the purpose, but that which I am to +describe is the one to which preference has been given, and which +is that known as the carbon process.</p> + +<p>A sheet of carbonized paper or "tissue," having been sensitized +by immersion in a bath of bichromate of potash, is dried in the +dark and placed away for future use, although it is undesirable +that it be kept for more than four or five days. This is placed in +a printing frame in contact with the negative and exposed for a few +minutes, after which it is immersed in water, squeegeed down upon a +glass plate, and developed with warm water in the way so well known +to carbon printers. The result is a transparency which, owing to +having received a sufficient exposure, should show every detail of +the negative. The nature of the tissue employed for such a purpose +must be such as to give no strong contrasts, but everything +reproduced with soft and fine gradation of tone.</p> + +<p>The transparency thus obtained forms the <i>cliché</i> by +which the negatives are subsequently made; and a negative of any +size may be obtained by the camera on wet or dry plates. The +transparency must, of course, be pointed to the sky and the light +transmitted through it, no other light being allowed to reach the +lens except that which passes through the carbon transparency. Care +must also be taken that the transparency is <i>uniformly</i> +lighted. If it is not possible to obtain a northern light, which is +best, a reflector of white paper or card may be used which must be +sufficiently large and placed at an angle of about forty-five +degrees to the transparency.</p> + +<p>If the repeated negative is to be of the same size as the +original it may be readily produced by repeating the operation of +printing on carbon tissue, using the transparency in place of the +negative, or using a dry plate in place of the tissue. But on the +whole I have satisfied myself that the best results are to be +obtained by the first method. There is a greater softness in the +latter method, but a greater character and similarity to the +original in the former method. There is no doubt that the use of +the carbon transparency removes the hardness and riffidness of the +outlines peculiar to the older method of a collodion transparency, +while with carbon as the medium it is difficult for any but the +most experienced eye to distinguish the copy from the +original.--<i>Photo Times.</i></p> + +<hr> +<p><a name="7"></a></p> + +<h2>A NEW METHOD OF MAKING GELATINE EMULSION.</h2> + +<p>Since gelatine emulsion first came into use one of the greatest +troubles in connection with the manufacture of it has been that of +washing. According to the first methods the time taken for this +part of the process was, I believe, about twenty-four hours. It was +very much reduced and the ease of manufacture greatly facilitated +by the methods now most generally used, and which were, I believe, +first communicated by Messrs. Wratten and Wainright. I refer to +those of precipitating with alcohol and of straining the emulsion, +when set, through canvas, so as to divide it very finely. When the +latter method is resorted to a comparatively short time is +sufficient to wash it. This method, although a great improvement +upon the older ones, yet leaves much to be desired, especially for +those who are not in the habit of making emulsion regularly, but +only an occasional batch. When the weather is at all warm it takes +a long time for the emulsion to set, unless ice be used, and when +once it is set the washing process is an exceedingly "messy" one +unless the water be cooled with ice; and the amount of water taken +up during washing is often so great that there is considerable +difficulty in getting the emulsion to set on the plates. In fact, +even in cold weather, it is not an easy process to conduct in the +necessary near approach to total darkness.</p> + +<p>Considerable suspicion has of late been thrown upon the +thoroughness of the alcohol method, unless the emulsion has, +previous to precipitation, been freed of the greater part of the +soluble salts by washing; that is to say, it is doubtful whether +the whole of the soluble salts can be eliminated by the process, +and, therefore, unless in exceptionally hot weather, it would seem +best not to trust to it, except as a further security against +soluble bromide and nitrate after washing. Besides this, the +consumption of alcohol is very large. Almost three times the amount +of the emulsion precipitated is required, and this, even when +methylated spirit is used, adds considerably to the expense. With a +view of doing away with the washing altogether, or, rather, of +washing of the silver bromide when not incorporated with the +gelatine, several processes have been invented. By these silver +bromide is obtained in a very fine state of division, ready to mix +with gelatine and water in any proportion.</p> + +<p>The best known of them is Captain Abney's very ingenious +glycerine method, which seems to have been thoroughly successful in +his hands, although it has not been in every one's. The silver +bromide obtained by his process is not highly sensitive, and +requires boiling with gelatine before it is in a fit state to make +a rapid plate.</p> + +<p>We have lately had described in these columns a method of +obtaining bromide in a highly-sensitive state by means of the use +of an acid, whereby, after emulsifying and boiling, the viscosity +of the gelatine was destroyed, and the bromide in time deposited +itself. During the late hot weather, when washing became almost +impossible, I was led to cast about for some method of eliminating +the soluble salts less tedious and "sloppy" than that of washing, +more certain and less expensive than that of precipitating the +whole of gelatine with alcohol, and which would take less time than +the method of obtaining the bromide in a pure form.</p> + +<p>My first idea was to make up the solutions used in emulsifying +in a very concentrated form, and, after emulsifying, boiling, and +allowing to cool, to add to the thin emulsion thus obtained +gelatine to the amount of twenty grains to the ounce, and to +precipitate this with alcohol, the rest of the gelatine required to +make up the bulk being afterwards added, and the whole thoroughly +incorporated by warming and shaking. I was thus successful in +reducing the amount of alcohol required to one-third of what would +be necessary if the whole of the emulsion were precipitated; but +still I found that, if a reliable emulsion were required, the +pellicle as formed had to be washed to free it from the last trace +of soluble salts.</p> + +<p>It now struck me that it might be possible to precipitate the +bromide of silver direct from a very weak solution of gelatine, and +obtain it in such a form that it might be filtered, washed, and in +every way treated as an ordinary precipitate. I tried the following +experiment. I took--</p> + +<pre> + 1. Silver nitrate....................... 200 grains + Water............................... 1½ ounce. + 2. Ammonia bromide...................... 120 grains. + Water................................ 1½ ounce. + Gelatine............................. 12 grains. +</pre> + +<p>I emulsified the two together in the usual way, allowed the +whole to cool, and then poured the thin emulsion into about ten +ounces of alcohol, stirring the while. As I had anticipated, a +flocculent precipitate was formed, which settled to the bottom of +the vessel in a few minutes. This was, in fact, sensitive bromide +of silver mixed with a very small quantity of gelatine (about five +per cent.), and could, I found, be treated in the same manner as a +bromide precipitate from an aqueous solution; it might be washed, +either by decantation or by filtration, easily dried, and doubtless +could, when dry, be kept for an indefinite time, and be at any time +used by mixing with gelatine and water in any proportion thought +fit.</p> + +<p>I found that a less amount of gelatine than four grains to the +ounce was sufficient to carry the bromide down, while five grains +to the ounce carried it down in something which I considered too +near an approach to a plastic mass.</p> + +<p>It will be noticed that in the experiments which I have +described the emulsion had not been boiled, so that the +sensitiveness of the bromide was probably not great. As the +experiment was done in daylight it was of no practical use for +making emulsion; but I have since made several batches in this +manner and have found them most satisfactory.</p> + +<p>When sensitiveness is sought by boiling I rind it necessary to +add a small quantity of gelatine after boiling and before +precipitating, as that which has been kept for some time at a high +temperature seems to have lost the viscosity necessary to carry +down the silver bromide in such a form that it can he easily +separated from the alcohol and water.</p> + +<p>The practical manner of making an emulsion by this method may be +as follows. Make up the following mixtures:</p> + +<pre> + I. + Silver nitrate...........................................400 grains. + Water..................................................... 3 ounces. +<br> + II. +<br> + Ammonia bromide..........................................240 grains. + Gelatine..................................................24 grains + Water..................................................... 3 ounces. + Hydrochloric acid enough to slightly acidify the solution. +<br> + III. + Gelatine................................................. 20 grains. + Water.................................................... ½ ounce. + IV. +<br> + Hard gelatine (say Nelson's X opaque, + or Mr. A. L. Henderson's)................................240 grains. + Soft gelatine (Nelson's No.1)........................... 240 grains. + Water.....................................................24 ounces. +</pre> + +<p>Nos. II., III., and IV. are allowed to stand until the gelatine +is softened. No. I is then warmed in a hock bottle until the +gelatine is just melted, when No. II. is poured into it, a little +at a time, with vigorous shaking, until the whole is emulsified. It +is then transferred to an ordinary jelly can, which is placed in a +saucepan half full of water over a ring Bunsen burner in the dark +room, and boiled for half an hour. It is then allowed to cool to +about 100° Fahr., when No. III. is added. The whole is then +allowed to get quite cool, when it is poured, with stirring, into +about one pint of methylated spirit. If it be wished the +precipitate may now be filtered out and washed at once like an +ordinary filtrate, but I prefer to allow it to settle, which it +will do in about five minutes. The supernatant fluid is then gently +poured off.</p> + +<p>This fluid will have the appearance of still containing a +considerable amount of the silver bromide; but if it be kept and +filtered it will be seen that the quantity is really so small that +it may be disregarded. We all know what an alarming quantity of +silver seems to be going down the sink when we wash vessels to +which a very small quantity of emulsion is adhering. If filtering +be resorted to the liquid which comes through will be quite clear. +This was somewhat unexpected by me, as, if an emulsion containing +the whole of the gelatine be precipitated into alcohol in the usual +way, the alcohol becomes milky with a substance which could not, I +imagine, be filtered from it.</p> + +<p>Two or three ounces of methylated spirit are now added to the +vessel containing the silver bromide, and the latter well mixed +with it. This makes the precipitate "firmer"--if such an expression +be allowable--and this time it will sink to the bottom almost +immediately after the stirring has ceased, and the alcohol may be +poured off.</p> + +<p>I consider that the bromide in this state is practically free +from soluble salts, but it may be washed with one or two changes of +water if desired.</p> + +<p>No. IV. is now gently heated till the gelatine is melted and the +precipitate mixed with it. It must be kept warm for some time, and +shaken vigorously until all granularity has disappeared, This is, +of course, ascertained by placing a drop of the emulsion on a piece +of glass, and examining it. If it be wished to keep the bromide of +silver for future use it may be placed on a piece of muslin +stretched in the drying-box, when it will dry in a very short time; +and, although I cannot speak from experience on this point, it +will, I have no doubt, keep for an indefinite time so long as light +is kept from it.</p> + +<p>If it be desired the ammonio-nitrate method may be used instead +of the boiling one, although in my hands it does not give such +sensitiveness. If it be desired to use this method, solution Nos. +I, II., and IV. are made up exactly as for the boiling method, +except that No. II. is not acidified. Liquid ammonia is then poured +with stirring into the silver solution, until it blackens and again +clears. Emulsification is performed exactly as described above, but +instead of boiling, the emulsion is kept at a temperature of about +100° Fahr. for half an hour, when it is poured into the +alcohol, no addition of gelatine being previously made.</p> + +<p>I think I may claim for the method which I have just described +that it is less troublesome and more certain than either the +ordinary washing method or the usual one of precipitating with +alcohol, while it affords an easy method of making sensitive silver +bromide in such a form that it can be more easily stored and +afterwards manipulated than if it were in the form of pellicle. The +whole of the soluble salts are eliminated, and also any gelatine +which may have been destroyed in the cooking. The amount of alcohol +used is comparatively small; in fact, to prepare silver bromide for +a pint of emulsion very little more than a pint of methylated +spirit is required. Besides this I do not think that I would be +wrong in saying that the chance of green fog is reduced to a +minimum.</p> + +<p>Let me take this opportunity of thanking Captain Abney for his +prompt reply to my question about the connection between the +proportion of bromide to gelatine in emulsions, and the density of +resulting images.--<i>W. K. Burton, in British Journal of +Photography</i>.</p> + +<hr> +<p><a name="15"></a></p> + +<p class="ctr"><img src="images/7a.png" alt= +"Old Wrought Iron Gates, Guildhall."></p> + +<p class="ctr">Old Wrought Iron Gates, Guildhall.</p> + +<hr> +<p><a name="8"></a></p> + +<h2>THE POTTERY AND PORCELAIN INDUSTRIES OF JAPAN.</h2> + +<p>Japanese chronicles claim that the first pottery was made in the +year 660 B.C.; it was not, however, until the Christian era that +the art made any considerable advances. In the year 1223 A.D., +great improvements were made in manufacture and decoration of the +ware. From that date to the sixteenth century the great potteries +of Owari, Hizen, Mino, Kioto, Kaga, and Satsuma were established. +The Rahn-Yaki, or crackled ware, was first made at Kioto, at the +commencement of the sixteenth century. The best old Hizen ware, +that which is still the most admired, was made at Arita Hizen, in +1580 to 1585; the old Satsuma dates from 1592. Consul-General Van +Buren states that porcelain clays are found in nearly all parts of +the country, and the different kinds are usually found in close +proximity, and close to canals and rivers, which is of considerable +advantage, as affording a means of transport. In all cases every +variety of clay used in the manufacture of pottery is found in a +natural state; there is no necessity to manufacture the quartzose +or fusible clays as is done in other parts of the world, and which +adds considerably to the cost of the ware. One of the peculiarities +in the clay found in Japan is that it contains both the fusible and +infusible materials in such proportions as to make a light, +beautiful, translucent, and durable porcelain. At Arita, in Hizen, +there is a clay found which contains 783/4 per cent, of silica, and +l73/4 per cent, of alumina; from this clay is made the delicate, +translucent eggshell ware, without the addition of any other +matter. From an adjoining bluff a clay is taken which has 50 per +cent, of silica, and 38 per cent, of alumina; from this the common +porcelain is made.</p> + +<p>Potter's clay is found in very large quantities in the provinces +of Yamashiro, Hoki, Turoo Iyo, Hizen, Higo, Owari, Mikaera, Idyn, +Musashi, and Mino. In the whole of Japan there are 283 localities +where the clay is deposited; many of these only furnish inferior +clays, but they are all fitted for use in some of the various kinds +of pottery. These clays are thoroughly powdered by means of what is +called "balance pounders," worked in some localities by +water-power, but the work is often done by hand. The powder is then +dried, and stored on boards or in flat boxes. This dough does not +go through the process of fermentation. The shaping is almost +exclusively done on the potter's wheel, which is set on a pivot +working in a porcelain eye. As a rule, the wheel is turned by the +potter himself, but in Hizen it is kept in motion by means of a +band connected with its pivot and another wheel turned by a boy. In +making dishes of other shape than round, a crude mould is sometimes +used. After the clay has been shaped on the wheel, it is set away +for drying, and usually in two or three days it is considered +sufficiently dry for smoothing, which is done on the wheel with a +sharp curved knife. The material is now made into "bisque," or +biscuit, by a preliminary baking in small ovens, when it is ready +for painting, if it is to be painted on the biscuit; if not, it is +ready for the glazing. In either event it will then go to the large +furnace for the final baking. The kilns for this purpose are always +built on hill sides, and are joined together, increasing in size +from the lower to the higher ones, and in number from four to +twenty five; these kilns are so constructed that the draught is +from the lowest one, in addition to which each kiln has its own +firing place. The result of this construction is that the upper +ones are by far the most heated, and the ware is arranged +accordingly; that which requires the least baking, in the lower +kiln, and that which requires the greatest heat, in the upper. +These connecting kilns have the merit of being heat saving, but +they are usually small and badly constructed, and the heat in none +of them is uniform.</p> + +<p>The glaze is made from the silicious clay and potash extracted +from wood ashes. This potash is not a pure white, and this accounts +for the dirty color usually to be observed in unpainted Japanese +ware. In different districts the painting varies. For instance, in +Owari, the greater part of the ware is painted a cobalt blue--the +cobalt ore being found in the bluffs near the clay deposits, and is +used for painting the cheaper wares, and for this purpose German +cobalt is also employed. The painting with cobalt is generally done +on the biscuit before glazing. In several districts a very handsome +ware is made, and painted on the glaze. For this kind of painting +the colors are mixed with a silicate of lead and potash, and baked +the third time in a small furnace at a low temperature. The +coloring oxides in use are those of copper, cobalt, iron, antimony, +manganese, and gold. Japanese porcelain painting may be divided +into two categories, decorative and graphic; the first is used to +improve the vessel upon which it is placed, and this class includes +all the ware except that of the province of Kaga, which would come +under the head of graphic, as it delineates all the trades, +occupations, sports, customs, and costumes of the people, as well +as the scenery, flora, and fauna of the country. "Owari ware" is +made in the province of that name; it is not as translucent, but +stronger and more tenacious than some of the Hizen manufacture.</p> + +<p>The principal potteries are at a village called Sèto, +twelve miles from the sea; in this village there are more than 200 +kilns. The ware is mostly painted a cobalt blue, and is merely of a +decorative kind, consisting of branches of trees, grass, flowers, +birds, and insects, all these being copied by the artist from +nature. All the Owari ware is true hard porcelain, and is strong +and durable. In Hizen, a number of wares are manufactured, the best +known kind being the "Eurari," which is made at Arita, but painted +at Eurari. The colors in use are red, blue, green, and gold; these +are combined in various proportions, but, as a rule, the red +predominates. Generally the surface of the vessel is divided into +medallions of figures, which alternately have red, blue, or white +back-ground, with figures in green or blue and gold.</p> + +<p>The egg-shell porcelain sold at Nagasaki is made in this +province from Arita clay, and this is made from clay with no +admixture of fusible matter except that contained by the clay +naturally. The province of Satsuma is noted for crackled ware. It +is only within a very few years that large vases have been +manufactured, and in earlier days the old ware was confined to +small vessels. The glaze is a silicate of alumina and potash, and +the best ware has a complete network of the finest crackles; the +painting is of birds and flowers, and noted for its delicate lines +of green, red, and gold.</p> + +<p>In Kioto, the ware manufactured is very similar to that produced +in Satsuma, but it is lighter and more porous; the decorations are +also nearly the same, being of birds and flowers. There is a +description of ware made in Kioto, called "Eraku," the whole body +of which is covered with a red oxide of iron, and over this +mythical figures of gold are traced. That produced in Kagja is +<i>faïence</i>, and in the style of painting is unlike any +other in Japan, the predominating color being a light red, used +with green and gold. The designs with which it is profusely +decorated are trees, grasses, flowers, birds, and figures of all +classes of people, with their costumes, occupations, and pastimes. +The "Banko" ware is made at the head of the Owari Bay; it is an +unglazed stone-ware, very light and durable, made on moulds in +irregular shapes, and decorated with figures in relief. On the +island of Awadji, a delicate, creamy, crackled, soft paste +porcelain is made. The figures used in decoration are birds and +flowers, but outlined by heavy, dark lines.</p> + +<p>Consul Van Buren is of opinion that, at no distant day, Japan +will be one of the foremost competitors in the pottery markets of +the world, on account of the great variety and excellence of the +clays, their proximity to the sea, the cheapness of labor, and the +beauty and originality of the decorations. Already this important +industry has been greatly stimulated by the foreign demand, and by +the success of Japanese exhibitors at the Exhibitions of Vienna, +Philadelphia, and Paris.--<i>Journal of the Society of +Arts</i>.</p> + +<hr> +<p>Professor Julius E. Hilgard, for twenty years assistant in +charge of the office, has been placed in temporary charge of the +Coast and Geodetic Survey. It is understood that he will be +appointed superintendent to succeed the late Captain Carlile P. +Patterson.</p> + +<hr> +<p><a name="16"></a></p> + +<h2>THE FRENCH CRYSTAL PALACE.</h2> + +<p>The first idea of the French Crystal Palace was suggested by the +English structure of the same name at Sydenham, about eight miles +from London. Such a structure, as may be readily conceived, +requires a site of vast extent, and one that shall be easy of +access and possess the most agreeable surroundings. To the promoter +of the project, those portions of the park of St. Cloud in the +vicinage of the old chateau appeared to combine within themselves +all the conditions that were desirable, and he, therefore, on the +15th of December, 1879, addressed the Ministers of Public Works and +of Finances asking for the necessary concessions. The extensive +specifications have been finally completed and will probably be +shortly submitted for the approval of the parliament. The moment +has arrived then for the public press to take cognizance of a +project which concerns so great interests.</p> + +<p class="ctr"><a href="images/8a.png"><img src= +"images/8a_th.png" alt= +"THE FRENCH CRYSTAL PALACE--PARK OF ST CLOUD, PARIS."></a></p> + +<p class="ctr">THE FRENCH CRYSTAL PALACE--PARK OF ST CLOUD, +PARIS.</p> + +<p>At present we shall say a few words <i>à propos</i> of +the engraving we present herewith. The French Crystal Palace will +consist of one great nave, two lateral naves, two surrounding +galleries, and a vast rotunda behind. The principal entrance, +located at the head of the avenue leading from the present ruins +(which will, ere long, be transformed into a most interesting +museum), will exhibit a very striking aspect with its monumental +fountain and the dome which it is proposed to erect over the very +entrance itself. The whole structure will cover about nineteen +acres of ground, thus being two and a half times the extent of the +Palace of Industry in the Champs Elysees. The great nave of honor +will be nearly 1,650 ft. in length, 78 ft. in width, and 98 ft. in +height. The dome will measure exactly 328 ft. in height, or 105 ft. +more than the towers of Notre Dame. The structure, with the +exception of basement and foundation, will be of glass and +iron.</p> + +<p>The project which we publish to-day has been studied and gotten +up, according to the general plans and dimensions suggested by the +promoter, by Mr. Dumoulin, the architect. We are informed that the +builder is to be Mr. Alfred Hunnebelle, a contractor well known +from the extensive works that he has executed, and who is president +of the Syndical Chamber of Contractors of Paris.</p> + +<p>Among the annexes of this palace we may note a "Palace of the +Republic," to be built on the ruins and designed for illustrious or +distinguished visitors, such as the President of the Republic, the +Ministers, the Municipal Council of Paris, foreign delegates, etc.; +a farm house for special exhibitions and a field for experiments; +galleries, cottages, etc.</p> + +<p>As for the programme, which embraces six divisions and numerous +subdivisions, we are unable to give it at present for want of +space; we need only say that it satisfies perfectly all the +conditions of so vast an undertaking.</p> + +<p>In the hands of the projector, Mr. Nicole, who is well known +from his long experience in such matters, the exhibition will +undoubtedly prove a success and be instrumental in adding +prosperity to all French industries.</p> + +<hr> +<p>THE GREAT HEAT OF THE SUN.--Prof. S. P. Langley has made the +following calculation: A sunbeam one centimeter in section is found +in the clear sky of the Alleghany Mountains to bring to the earth +in one minute enough heat to warm one gramme of water by 1° C. +It would, therefore, if concentrated upon a film of water 1/500th +of a millimeter thick, 1 millimeter wide, and 10 millimeters long, +raise it 83 1/3° in one second, provided all the heat could be +maintained. And since the specific heat of platinum is only 0.0032 +a strip of platinum of the same dimensions would, on a similar +supposition, be warmed <i>in one second</i> to 2,603° C.--a +temperature sufficient to melt it!</p> + +<hr> +<p><a name="17"></a></p> + +<h2>CHATEAU IN THE AEGEAN SEA.</h2> + +<p>From the site of this building, magnificent views are obtained +over the island-dotted sea and the mainland of Asia Minor: but, +"though every prospect pleases," it is a land of earthquakes, and +unfortunately, the works at the chateau have been suspended, owing +to the dreadful calamity which has recently fallen upon the +district. The building is intended for the residence of an English +lady of exalted rank. It is to be built of local white stone, the +hall, staircase, etc., being lined and paved with marbles. The hall +is a large apartment about 25 ft. high, with paneled ceiling, +having galleries on two sides, giving access to the rooms +surrounding it on first floor, and to the turret staircase leading +to roofs, etc. With the exception of sanitary apparatus, painted +windows, etc. (which will be supplied by English firms), the whole +of the work will be executed by native labor. The architect is Mr. +Edwin T. Hall, London.--<i>Building News</i>.</p> + +<p class="ctr"><a href="images/9a.png"><img src= +"images/9a_th.png" alt= +"SUGGESTIONS IN ARCHITECTURE--A CASTELLATED CHATEAU."></a></p> + +<p class="ctr">SUGGESTIONS IN ARCHITECTURE--A CASTELLATED +CHATEAU.</p> + +<hr> +<p><a name="13"></a></p> + +<h2>ELECTRIC POWER.</h2> + +<p>Just now nothing save electricity is talked about in scientific +circles. During the meeting of the British Association the greatest +possible prominence was given to electrical questions and +propositions The success of the electric light, the introduction of +the Faure battery with a great flourish of trumpets, and the +magnificent display of electrical instruments and machinery at +Paris, have all operated to the same end. The daily press has taken +the subject up, and journals which were nothing hitherto if not +political, now indulge in magnificent rhapsodies concerning the +future of electricity. Even eminent engineers, carried away by the +intoxication of the moment, have not hesitated to say that the +steam engine is doomed, and that its place will be taken by the +electricity engine. In the midst of all this noise and clamor and +blowing of personal trumpets, it is not easy to keep one's head +clear, and mistakes may be made which will cause disappointment to +many and retard the progress of electrical science. We confidently +expect that electricity will prove a potent agent by and by in the +hands of the speculator for extracting gold from the pockets of the +public, and we write now to warn our readers in time, and to +endeavor to clear the air of some of the mists with which it is +obscured. There is, no doubt, a great future before electricity; +but it is equally certain that electricity can never do many things +which the half informed may be readily made to believe it will do. +We propose here to say enough on this point to enlighten our +readers, without troubling them with perplexing problems and +speculations.</p> + +<p>No one at this moment knows what electricity is; but for our +present purpose we may regard it as a fluid, non-elastic, and +without weight, and universally diffused through the universe. To +judge by recently published statements, a large section of the +reading public are taught that this fluid is a source of power, and +that it may be made to do the work of coal. This is a delusion. So +long as electricity remains in what we may call a normal state of +repose, it is inert. Before <i>we can get any work out of +electricity a somewhat greater amount of work must be done upon +it</i>. If this fundamental and most important truth be kept in +view it will not be easy to make a grave mistake in estimating the +value of any of the numerous schemes for making electricity do work +which will ere long be brought before the public. To render our +meaning clearer, we may explain that in producing the electric +light, for instance, a certain quantity of electricity passes in +through one wire to the lamp, and precisely the same quantity +passes out through the other wire, and on to the earth or return +wire completing the circuit. Not only is the quantity the same, the +velocity is also unchanged. But in going through the lamp the +current has done something. It has overcome the resistance of the +carbons, heated them to a dazzling white heat, and so performed +work. In doing this the current of electricity has lost something. +Led from the first lamp to a second, it is found powerless--if the +first lamp be of sufficient size. What is it that the electricity +has lost? It has parted with what electricians would term +"potential," or the capacity for performing work. What this is +precisely, or in what way the presence or absence of potential +modifies the nature of the electric current, no one knows; but it +is known that this potential can only be conferred on electricity +by doing work on the electricity in the first instance. The analogy +between electricity and a liquid like water will now be recognized. +So long as the water is at rest, it is inert. If we pump it up to a +height, we confer on it the equivalent of potential. We can let the +water fall into the buckets of an overshot wheel. Its velocity +leaving the tail race may be identical with that at which it left +the supply trough to descend on the wheel. Its quantity will be the +same. It will be in all respects unchanged, just as the current of +electricity passing through a lamp is unchanged; but it has, +nevertheless, lost something. It has parted with its +potential--capacity for doing work--and it becomes once more inert. +But the duty which it discharged in turning the mill wheel was +somewhat less than the precise equivalent of the work done in +pumping it up to a level with the top of the wheel. In the same way +the electric current never can do work equal in amount to the work +done on it in endowing it with potential.</p> + +<p>It will thus be seen that electricity can only be used as a +means of transmitting power from one place to another, or for +storing power up at one time to be used at a subsequent period; but +it cannot be used to originate power in the way coal can be used. +It possesses no inherent potential. It is incapable of performing +work unless something is done to it first. We have spoken of it as +a fluid, but only for the sake of illustration. As we have said, no +one knows what it is, but the theory which bids fair for acceptance +is that it is a mode of motion of the all-pervading ether. Very +curious and instructive experiments are now being carried out in +Paris by Dr. Bjerkness, of Christiania, in the Norwegian section of +the electrical exhibition. This gentleman submerges thin elastic +diaphragms in water, and causes them to vibrate, or rather pulsate, +by compressed air. He finds that if they pulsate synchronously they +attract each other. If the pulsations are not simultaneous, the +disks repel each other. From this and other results he has +obtained, it may be argued that the ether plays the part of the +water in Dr. Bjerkness' tank, and that when special forms of +vibration are set up in bodies they become competent to attract or +repel other bodies. This being so, it will be seen that the power +of attraction or repulsion of an electrical body depends in the +first instance on the motion set up in the body attracted or +repulsed, and this motion is, of course, some function of the work +originally done on the body. We need not pursue this argument +further. Among the most scientific investigators of the day it is +admitted that the efficiency of electricity as a doer of work, or a +producer of action at a distance, must depend for its value on the +performance of work in some one way or another on the electricity +itself in the first instance. It may be worth while here to dispel +a popular delusion. It is held very generally that electricity can +be made, as, for instance, by the galvanic battery. There is no +reason to believe anything of the kind; but whether it is or is not +true that electricity is actually made by the combustion of zinc in +a galvanic trough, it is quite certain that this electricity, +unless it possesses potential, can do no work, no matter how great +its quantity. Of course, it is to be understood that all electric +currents possess potential. If they did not, their presence would +be unknown; but the potential of a current is in all cases the +result of work done on electricity, either by the oxidation of +zinc, or in some other way. This is a broad principle, but it is +strictly consistent in every respect with the truth. Electricity, +then, is, as we have said, totally different from coal; and it can +never become a substitute for it alone. Water power, air power, or +what we may, for want of a better phrase, call chemical power, +combined with electricity, can be used as a substitute for coal; +but electricity cannot of itself be employed to do work. It is +true, however, that electricity, on which work has already been +done, may be found in nature. Atmospheric electricity, for example, +may perhaps yet be utilized. It is by no means inconceivable that +the electricity contained in a thunder cloud might be employed to +charge a Faure battery; but up to the present no one has +contemplated the obtaining of power from the clouds, and whether it +is or is not practicable to utilize a great natural force in this +way does not affect our statement. The use of electricity must be +confined to its power of transmitting or storing up energy, and +this truth being recognized, it becomes easy to estimate the future +prospects of electricity at something like their proper value.</p> + +<p>It has been proved to a certain extent that electricity can be +used to transmit power to a distance, and that it can be used to +store it up. Thus far the man of pure science. The engineer now +comes on the stage and asks--Can practical difficulties be got +over? Can it be made to pay? In trying to answer these questions we +cannot do better than deal with one or two definite proposals which +have been recently made. That with which we shall first concern +ourselves is that trains should be worked by Faure batteries +instead of by steam. It is suggested that each carriage of a train +should be provided with a dynamo motor, and that batteries enough +should be carried by each to drive the wheels, and so propel the +train. Let us see how such a scheme would comply with working +conditions. Let us take for example a train of fifteen coaches on +the Great Northern Railway, running without a stop to Peterborough +in one hour and forty minutes. The power required would be about +500 horses indicated. To supply this for 100 minutes, even on the +most absurdly favorable hypothesis, no less than 25 tons of Faure +batteries would be required. Adding to these the weight of the +dynamo motors, and that unavoidably added to the coaches, it will +be seen that a weight equal to that of an engine would soon be +reached. The only possible saving would be some 28 to 30 tons of +tender. In return for this all the passengers would have to change +coaches at Peterborough, as the train could not be delayed to +replace the expended with fresh batteries. This is out of the +question. The Faure batteries must all be carried on one vehicle or +engine, which could be changed for another, like a locomotive. Even +then no advantage would be gained. As to cost, it is very unlikely +that the stationary engines which must be provided to drive the +dynamo machines for charging the batteries would be more economical +than locomotive engines; and if we allow that the dynamo machine +only wasted 10 per cent. of the power of the engine, the Faure +batteries 10 per cent. of the power of the dynamo machines, and the +dynamo motors 10 per cent. of the power of the batteries--all +ridiculously favorable assumptions--yet the stationary engines +would be handicapped with a difference in net efficiency between +themselves and the locomotive--admitting the original efficiency +per pound of coal in both to be the same--of some 27 per cent., we +think we may relegate this scheme to the realms of oblivion. +Another idea is that by putting up turbines and dynamo machines the +steam engine might be superseded by water power. Now it so happens +that if all the water power of England were quadrupled it would not +nearly suffice for our wants. It may be found worth while perhaps +to construct steam engines close to coalpits and send out power +from these engines by wire; but the question will be asked, Which +is the cheaper of the two, to send the coal or to send the power? +On the answer to this will depend the decision of the mill owners. +Another favorite scheme is that embodied in the Siemens electrical +railway. We believe that there is a great future in store for +electricity as a worker of tramway traffic; but the traffic on a +great line like the Midland or Great Northern Railway could not be +carried on by it. As Robert Stephenson said of the atmospheric +system, it is not flexible enough. The working of points and +crossings, and the shunting of trains and wagons, would present +unsurmountable difficulties. We have cited proposals enough, we +think, to illustrate our meaning. Sir William Armstrong, Sir +Frederick Bramwell, Dr. Siemens, Sir W. Thomson, and many others +may be excused if they are a little enthusiastic. They are just now +overjoyed with success attained; but when the time comes for sober +reflection they will, no doubt, see good reason to moderate their +views. No one can say, of course, what further discoveries may +bring to light; but recent speakers and writers have found in what +is known already, materials for sketching out a romance of +electricity. It is but romancing to assert that the end of the +steam engine is at hand. Wonderful and mystical as electricity is, +there are some very hard and dry facts about it, and these facts +are all opposed to the theory that it can become man's servant of +all work. Ariel-like, electricity may put a girdle round the earth +in forty minutes; but it shows no great aptitude for superseding +the useful old giant steam, who has toiled for the world so long +and to such good purpose--<i>The Engineer</i>.</p> + +<hr> +<p><a name="14"></a></p> + +<h2>ON A METHOD OF OBTAINING AND MEASURING VERY HIGH VACUA WITH A +MODIFIED FORM OF SPRENGEL-PUMP.</h2> + +<h3>By Ogden N. Rood, Professor of Physics in Columbia +College.</h3> + +<p>In the July number of this Journal for 1880, I gave a short +account of certain changes in the Sprengel-pump by means of which +far better vacua could be obtained than had been previously +possible. For example, the highest vacuum at that time known had +been reached by Mr. Crookes, and was about 1/17,000,000, while with +my arrangement vacua of 1/100,000,000 were easily reached. In a +notice that appeared in <i>Nature</i> for August, 1880, p. 375, it +was stated that my improvements were not new, but had already been +made in England four years previously. I have been unable to obtain +a printed account of the English improvements, and am willing to +assume that they are identical with my own; but on the other hand, +as for four years no particular result seems to have followed their +introduction in England, I am reluctantly forced to the conclusion +that their inventor and his customers, for that period of time, +have remained quite in ignorance of the proper mode of utilizing +them. Since then I have pushed the matter still farther, and have +succeeded in obtaining with my apparatus vacua as high as +1/390,000,000 without finding that the limit of its action had been +reached. The pump is simple in construction, inexpensive, and, as I +have proved by a large number of experiments, certain in action and +easy of use; stopcocks and grease are dispensed with, and when the +presence of a stopcock is really desirable its place is supplied by +a movable column of mercury.</p> + +<p><i>Reservoir</i>.--An ordinary inverted bell-glass with a +diameter of 100 mm. and a total height of 205 mm. forms the +reservoir; its mouth is closed by a well-fitting cork through which +passes the glass tube that forms one termination of the pump. The +cork around tube and up to the edge of the former is painted with a +flexible cement. The tube projects 40 mm. into the mercury and +passes through a little watch-glass-shaped piece of sheet-iron, W, +figure 1, which prevents the small air bubbles that creep upward +along the tube from reaching its open end; the little cup is firmly +cemented in its place. The flow of the mercury is regulated by the +steel rod and cylinder, CR, Figure 1. The bottom of the steel +cylinder is filled out with a circular piece of pure India-rubber, +properly cemented; this soon fits itself to the use required and +answers admirably. The pressure of the cylinder on the end of the +tube is regulated by the lever, S, Figure 1; this is attached to a +circular board which again is firmly fastened over the open end of +the bell-glass. It will be noticed that on turning the milled head, +S, the motion of the steel cylinder is not directly vertical, but +that it tends to describe a circle with c as a center; the +necessary play of the cylinder is, however, so small, that +practically the experimenter does not become aware of this +theoretical defect, so that the arrangement really gives entire +satisfaction, and after it has been in use for a few days +accurately controls the flow of the mercury. The glass cylinder is +held in position, but not supported, by two wooden +<i>adjustable</i> clamps, <i>a a</i>, Figure 2. The weight of the +cylinder and mercury is supported by a shelf, S, Figure 2, on which +rests the cork of the cylinder; in this way all danger of a very +disagreeable accident is avoided.</p> + +<p class="ctr"><img src="images/10a.png" alt= +"MODIFIED FORM OF SPRENGEL PUMP."></p> + +<p class="ctr">MODIFIED FORM OF SPRENGEL PUMP.</p> + +<p><i>Vacuum-bulb</i>.--Leaving the reservoir, the mercury enters +the vacuum-bulb, B, Figure 2, where it parts with most of its air +and moisture; this bulb also serves to catch the air that creeps +into the pump from the reservoir, even when there is no flow of +mercury; its diameter is 27 mm. The shape and inclination of the +tube attached to this bulb is by no means a matter of indifference; +accordingly Figure 3 is a separate drawing of it; the tube should +be so bent that a horizontal line drawn from the proper level of +the mercury in the bulb passes through the point, <i>o</i>, where +the drops of mercury break off. The length of the tube, EC, should +be 150 mm., that of the tube, ED, 45 mm.; the bore of this tube is +about the same as that of the fall-tube.</p> + +<p><i>Fall-tube and bends</i>.--The bore of the fall-tube in the +pump now used by me is 1.78 mm.; its length above the bends (U, +Figure 2) is 310 mm.; below the bends the length is 815 mm. The +bends constitute a fluid valve that prevents the air from returning +into the pump; beside this, the play of the mercury in them greatly +facilitates the passage of the air downward. The top of the mercury +column representing the existing barometric pressure should be +about 25 mm. below the bends when the pump is in action. This is +easily regulated by an adjustable shelf, which is also employed to +fill the bends with mercury when a measurement is taken or when the +pump is at rest. On the shelf is a tube, 160 mm. high and 20 mm. in +diameter, into which the end of the fall-tube dips; its side has a +circular perforation into which fits a small cork with a little +tube bent at right angles. With the hard end of a file and a few +drops of turpentine the perforation can be easily made and shaped +in a few minutes. By revolving the little bent tube through +180° the flow of the mercury can be temporarily suspended when +it is desirable to change the vessel that catches it.</p> + +<p><i>Gauge</i>.--For the purpose of measuring the vacua I have +used an arrangement similar to McLeod's gauge, Figure 4; it has, +however, some peculiarities. The tube destined to contain the +compressed air has a diameter of 1.35 mm. as ascertained by a +compound microscope; it is not fused at its upper extremity, but +closed by a fine glass rod that fits into it as accurately as may +be, the end of the rod being ground flat and true. This rod is +introduced into the tube, and while the latter is gently heated a +very small portion of the cement described below is allowed to +enter by capillary attraction, but not to extend beyond the end of +the rod, the operation being watched by a lens. The rod is used for +the purpose of obtaining the compressed air in the form of a +cylinder, and also to allow cleansing of the tube when necessary. +The capacity of the gauge-sphere was obtained by filling it with +mercury; its external diameter was sixty millimeters; for measuring +very high vacua this is somewhat small and makes the probable +errors rather large; I would advise the use of a gauge-sphere of +about twice as great capacity. The tube, CB, Figure 4, has the same +bore as the measuring tube in order to avoid corrections for +capillarity. The tube of the gauge, CD, is not connected with an +India-rubber tube, as is usual, but dips into mercury contained in +a cylinder 340 mm. high, 58 mm. in diameter, which can be raised +and lowered at pleasure. This is best accomplished by the use of a +set of boxes of various thicknesses, made for the purpose and +supplemented by several sheets of cardboard and even of +writing-paper. These have been found to answer well and enable the +experimenter to graduate with a nicety the pressure to which the +gas is exposed during measurement. By employing a cylinder filled +with mercury instead of the usual caoutchouc tubing small bubbles +of air are prevented from entering the gauge along with the +mercury. An adjustable brace or support is used which prevents +accident to the cylinder when the pump is inclined for the purpose +of pumping out the vacuum-bulb. The maximum pressure that can be +employed in the gauge used by me is 100 mm.</p> + +<p>All the tubing of the pump is supported at a distance of about +55 mm. from the wood-work; this is effected by the use of simple +adjustable supports and adjustable clamps; the latter have proved a +great convenience. The object is to gain the ability to heat with a +Bunsen burner all parts of the pump without burning the wood-work. +Where glass and wood necessarily come in contact the wood is +protected by metal or simply painted with a saturated solution of +alum. The glass portions of the pump I have contrived to anneal +completely by the simple means mentioned below. If the glass is not +annealed it is certain to crack when subjected to heat, thus +causing vexation and loss of time. The mercury was purified by the +same method that was used by W. Siemens (Pogg. Annalen, vol. ex., +p. 20), that is, by a little strong sulphuric acid to which a few +drops of nitric acid had been added; it was dried by pouring it +repeatedly from one hot dry vessel to another, by filtering it +while quite warm, the drying being completed finally by the action +of the pump itself. All the measurements were made by a fine +cathetometer which was constructed for me by William Grunow; see +this Journal, Jan., 1874, p. 23. It was provided with a +well-corrected object-glass having a focal length of 200 mm. and as +used by me gave a magnifying power of 16 diameters.</p> + +<p><i>Manipulation</i>.--The necessary connections are effected +with a cement made by melting Burgundy pitch with three or four per +cent of gutta percha. It is indispensable that the cement when cold +should be so hard as completely to resist taking any impression +from the finger nail, otherwise it is certain to yield gradually +and finally to give rise to leaks. The connecting tubes are +selected so as to fit as closely as possible, and after being put +into position are heated to the proper amount, when the edges are +touched with a fragment of cold cement which enters by capillary +attraction and forms a transparent joint that can from time to time +be examined with a lens for the colors of thin plates, which always +precede a leak. Joints of this kind have been in use by me for two +months at a time without showing a trace of leakage, and the +evidence gathered in another series of unfinished experiments goes +to show that no appreciable amount of vapor is furnished by the +resinous compound, which, I may add, is never used until it has +been repeatedly melted. As drying material I prefer caustic potash +that has been in fusion just before its introduction into the +drying tube; during the process of exhaustion it can from time to +time be heated nearly to the melting point: if actually fused in +the drying tube the latter almost invariably cracks. The pump in +the first instance is to be inclined at an angle of about 10 +degrees, the tube of the gauge being supported by a semicircular +piece of thick pasteboard fitted with two corks into the top of the +cylinder. This seemingly awkward proceeding has in no case been +attended with the slightest accident, and owing to the presence of +the four leveling-screws, the pump when righted returns, as shown +by the telescope of the cathetometer, almost exactly to its +original place. In the inclined position the exhaustion of the +vacuum bulb is accomplished along with that of the rest of the +pump. The exhaustion of the vacuum-bulb when once effected can be +preserved to a great extent for use in future work, merely by +allowing mercury from the reservoir to flow in a rapid stream at +the time that air is allowed to re-enter the pump. During the first +process of exhaustion the tube of the gauge is kept hot by moving +to and fro a Bunsen burner, and is in this way freed from those +portions of air and moisture that are not too firmly attached. +After a time the vacuum-bulb ceases to deliver bubbles of air; it +and the attached tube are now to be heated with a moving Bunsen +burner, when it will be found to furnish for 15 or 20 minutes a +large quantity of bubbles mainly of vapor of water. After then +production ceases the pump is righted and the exhaustion carried +farther. In spite of a couple of careful experiments with the +cathetometer I have not succeeded in measuring the vacuum in the +vacuum bulb, but judge from indications, that is about as high as +that obtained in an ordinary Geissler pump. Meanwhile the various +parts of the pump can be heated with a moving Bunsen burner to +detach air and moisture, the cement being protected by wet +lamp-wicking. In one experiment I measured the amount of air that +was detached from the walls of the pump by heating them for ten +minutes somewhat above l00° C., and found that it was +1/1,000,000 of the air originally present. I have also noticed that +a still larger amount of air is detached by electric discharges. +This coincides with an observation of E. Bessel-Hagen in his +interesting article on a new form of Töpler's mercury-pump +(Annalen der Physik und Chemie, 1881, vol. xii.). Even when potash +is used a small amount of moisture always collects in the bends of +the fall tube; this is readily removed by a Bunsen burner; the +tension of the vapor being greatly increased, it passes far down +the fall-tube in large bubbles and is condensed. Without this +precaution I have found it impossible to obtain a vacuum higher +than 1/25,000,000; in point of fact the bends should always be +heated when a high exhaustion is undertaken even if the pump has +been standing well exhausted for a week; the heat should of course +never be applied at a late stage of the exhaustion. Conversely, I +have often by the aid of heat completely and quickly removed quite +large quantities of the vapor of water that had been purposely +introduced. The exhaustion of the vacuum-bulb is of course somewhat +injured by the act of using the pump and also by standing for +several days, so that it has been usual with me before undertaking +a high exhaustion to incline the pump and re-exhaust for 20 +minutes; I have, however, obtained very high vacua without using +this precaution.</p> + +<p>During the process of exhaustion not more than one-half of the +mercury in the reservoir is allowed to run out, other wise when it +is returned bubbles of air are apt to find their way into the +vacuum-bulb. In order to secure its quiet entrance it is poured +into a silk bag provided with several holes. When the reservoir is +first filled its walls for a day or two appear to furnish air that +enters the vacuum-bulb; this action, however, soon sinks to a +minimum and then the leakage remains quite constant for months +together.</p> + +<p><i>Measurement of the vacuum</i>.--The cylinder into which the +gauge-tube dips is first elevated by a box sufficiently thick +merely to close the gauge, afterwards boxes are placed under it +sufficient to elevate the mercury to the base of the measuring +tube; when the mercury has reached this point, thin boards and +card-boards are added till a suitable pressure is obtained. The +length of the inclosed cylinder of air is then measured with the +cathetometer, also the height of the mercurial "meniscus," and the +difference of the heights of the mercurial columns in A and B, +figure 4. To obtain a second measure an assistant removes some of +the boxes and the cylinder is lowered by hand three or four +centimeters and then replaced in its original position. In +measuring really high vacua, it is well to begin with this process +of lowering and raising the cylinder, and to repeat it five or six +times before taking readings. It seems as though the mercury in the +tube, B, supplies to the glass a coating of air that allows it to +move more freely; at all events it is certain that ordinarily the +readings of B become regular, only after the mercury has been +allowed to play up and down the tube a number of times. This +applies particularly to vacua as high 1/50,000,000 and to pressures +of five millimeters and under. It is advantageous in making +measurements to employ large pressures and small volumes; the +correct working of the gauge can from time to time be tested by +varying the relations of these to each other. This I did quite +elaborately, and proved that such constant errors as exist are +small compared with inevitable accidental errors, as, for example, +that there was no measurable correction for capillarity, that the +calculated volume of the "meniscus" was correct, etc. It is +essential in making a measurement that the temperature of the room +should change as little as possible, and that the temperature of +the mercury in the cylinder should be at least nearly that of the +air near the gauge-sphere. The computation is made as follows</p> + +<pre> + n = height of the cylinder inclosing the air; + c = a factor which, multiplied by n, converts it into cubic + millimeters; + S = cubic contents of the meniscus; + d = difference of level between A and B, fig. 4; + = the pressure the air is under; + N = the cubic contents of the gauge in millimeters; + x = a fraction expressing the degree of exhaustion obtained; then +<br> + x=1/([N (760/d)]/[nc - S]) +</pre> + +<p>It will be noticed that the measurements are independent of the +actual height of the barometer, and if several readings are taken +continuously, the result will not be sensibly affected by a +simultaneous change of the barometer. Almost all the readings were +taken at a temperature of about 20° C., and in the present +state of the work corrections for temperature may be considered a +superfluous refinement.</p> + +<p><i>Gauge correction</i>.--It is necessary to apply to the +results thus obtained a correction which becomes very important +when high vacua are measured. It was found in an early stage of the +experiments that the mercury, in the act of entering the highly +exhausted gauge, gave out invariably a certain amount of air which +of course was measured along with the residuum that properly +belonged there; hence to obtain the true vacuum it is necessary to +subtract the volume of this air from nc. By a series of experiments +I ascertained that the amount of air introduced by the mercury in +the acts of entering and leaving the gauge was sensibly constant +for six of these single operations (or for three of these double +operations), when they followed each other immediately. The +correction accordingly is made as follows: the vacuum is first +measured as described above, then by withdrawing all the boxes +except the lowest, the mercury is allowed to fall so as nearly to +empty the gauge; it is then made again to fill the gauge, and these +operations are repeated until they amount in all to six; finally +the volume and pressure are a second time measured. Assuming the +pressure to remain constant, or that the volumes are reduced to the +same pressure,</p> + +<pre> + v = the original volume; v' = the final volume; + V' = volume of air introduced by the first entry of the mercury; + V = corrected volume; then +<br> + V' = (v'-v)/6 + V = v - [(v'-v)/6] +</pre> + +<p>It will be noticed that it is assumed in this formula that the +same amount of air is introduced into the gauge in the acts of +entry and exit; in the act of entering in point of fact more fresh +mercury is exposed to the action of the vacuum than in the act +exit, which might possibly make the true gauge-correction rather +larger than that given by the formula. It has been found that when +the pump is in constant use the gauge-correction gradually +diminishes from day to day; in other words, the air is gradually +pumped out of the gauge-mercury. Thus on December 21, the amount of +air entering with the mercury corresponded to an exhaustion of</p> + +<pre> + 1/27,308,805 .......Dec. 21. +<br> + 1/38,806,688 ...... Dec. 29. +<br> + 1/78,125,000 .......Jan. 15. +<br> + 1/83,333,333 .......Jan. 23 +<br> + 1/128,834,063 ......Feb. 1. +<br> + 1/226,757,400 ..... Feb. 9. +<br> + 1/232,828,800 ..... Feb. 19. +<br> + 1/388,200,000 ......March 7. +</pre> + +<p>That this diminution is not due to the air being gradually +withdrawn from the walls of the gauge or from the gauge-tube, is +shown by the fact that during its progress the pump was several +times taken to pieces, and the portions in question exposed to the +atmosphere without affecting the nature or extent of the change +that was going on. I also made one experiment which proves that the +gauge-correction does not increase sensibly, when the exhausted +pump and gauge are allowed to stand unused for twenty days.</p> + +<p><i>Rate of the pump's work</i>.--It is quite important to know +the rate of the pump at different degrees of exhaustion, for the +purpose of enabling the experimenter to produce a definite +exhaustion with facility; also if its maximum rate is known and the +minimum rate of leakage, it becomes possible to calculate the +highest vacuum attainable with the instrument. Examples are given +in the tables below; the total capacity was about 100,000 cubic +mm.</p> + +<pre> + Time. Exhaustion. Ratio. +<br> + 1/78,511 + 10 minutes }........ 1:1/3.53 + 1/276,980 + 10 minutes }........ 1:1/6.10 + 1/1,687,140 + 10 minutes }........ 1:1/4.15 + 1/7,002,000 +</pre> + +<p>Upon another occasion the following rates and exhaustions were +obtained:</p> + +<pre> + Time. Exhaustion. Rate. +<br> + 1/7,812,500 + 10 minutes }........ 1:1/3.18 + 1/24,875,620 + 10 minutes }........ 1:1/2.69 + 1/67,024,090 + 10 minutes }........ 1:1/1.22 + 1/81,760,810 + 10 minutes }........ 1:1.67 + 1/136,986,300 + 10 minutes }........ 1:1.23 + 1/170,648,500 +</pre> + +<p>The <i>irregular</i> variations in the rates are due to the mode +in which the flow of the mercury was in each case regulated.</p> + +<p><i>Leakage</i>.--We come now to one of the most important +elements in the production of high vacua. After the air is detached +from the walls of the pump the leakage becomes and remains nearly +constant. I give below a table of leakages, the pump being in each +case in a condition suitable for the production of a very high +vacuum:</p> + +<pre> + Duration of the Leakage per hour in + experiment cubic mm., press., + 760 mm. +<br> + 18½ hours............................ 0.000853 + 27 hours............................ 0.001565 + 26½ hours.............................0.000791 + 20 hours.............................0.000842 + 19 hours.............................0.000951 + 19 hours.............................0.001857 + 7 days..............................0.001700 + 7 days..............................0.001574 +<br> + Average.................... 0.001266 +</pre> + +<p>I endeavored to locate this leakage, and proved that one-quarter +of it is due to air that enters the gauge from the top of its +column of mercury, thus:</p> + +<pre> + Duration of the Gauge-leakage per hour + experiment. in cubic mm., press. + 760 mm. +<br> + 18 hours.................................0.0002299 + 7 days..................................0.0004093 + 7 days..................................0.0003464 +<br> + Average.......................0.0003285 +</pre> + +<p>This renders it very probable that the remaining three quarters +are due to air given off from the mercury at B, Fig. 4, from that +in the bends and at the entrance of the fall-tube, <i>o</i>, Fig. +3.</p> + +<p>Further on some evidence will be given that renders it probable +that the leakage of the pump when in action is about four times as +great as the total leakage in a state of rest.</p> + +<p>The gauge, when arranged for measurement of gauge-leakage, +really constitutes a barometer, and a calculation shows that the +leakage would amount to 2.877 cubic millimeters per year, press. +760 mm. If this air were contained in a cylinder 90 mm. long and 15 +mm. in diameter it would exert a pressure of 0.14 mm. To this I may +add that in one experiment I allowed the gauge for seven days to +remain completely filled with mercury and then measured the leakage +into it. This was such as would in a year amount to 0.488 cubic +millimeter, press. 760 mm., and in a cylinder of the above +dimensions would exert a pressure of 0.0233 mm.</p> + +<p><i>Reliability of the results: highest vacuum.</i></p> + +<p>The following are samples of the results obtained. In one case +sixteen readings were taken in groups of four with the following +result:</p> + +<pre> + Exhaustion. + 1 / 74,219,139 + 1 / 78,533,454 + 1 / 79,017,272 + 1 / 68,503,182 + Mean 1 / 74,853,449 +</pre> + +<p>Calculating the probable error of the mean with reference to the +above four results it is found to be 2.28 per cent of the quantity +involved.</p> + +<p>A higher vacuum measured in the same way gave the following +results:</p> + +<pre> + 1 / 146,198,800 + 1 / 175,131,300 + 1 / 204,081,600 + 1 / 201,207,200 +</pre> + +<p>The mean is 1 / 178,411,934, with a probable error of 5.42 per +cent of the quantity involved. I give now an extreme case; only +five single readings were taken; these corresponded to the +following exhaustions:</p> + +<pre> + 1 / 379,219,500 + 1 / 371,057,265 + 1 / 250,941,040 + 1 / 424,088,232 + 1 / 691,082,540 +</pre> + +<p>The mean value is 1 / 381,100,000, with a probable error of +10.36 per cent of the quantity involved. Upon other occasions I +have obtained exhaustions of 1 / 373,134,000 and 1 / 388,200,000. +Of course in these cases a gauge-correction was applied; the +highest vacuum that I have ever obtained irrespective of a +gauge-correction was 1 / 190,392,150. In these cases and in +general, potash was employed as the drying material; I have found +it practical, however, to attain vacua as high as 1 / 50,000,000 in +the total absence of all such substances. The vapor of water which +collects in bends must be removed from time to time with a Bunsen +burner while the pump is in action.</p> + +<p>It is evident that the final condition of the pump is reached +when as much air leaks in per unit of time as can be removed in the +same interval. The total average leakage per ten minutes in the +pump used by me, when at rest, was 0.000211 cubic millimeter at +press. 760 mm. Let us assume that the leakage when the pump is in +action is four times as great as when at rest; then in each ten +minutes 0.000844 cubic millimeter press., 760 mm., would enter; +this corresponds in the pump used by me to an exhaustion of 1 / +124,000,000; if the rate of the pump is such as to remove one-half +of the air present in ten minutes, then the highest attainable +exhaustion would be 1 / 248,000,000. In the same way it may be +shown that if six minutes are required for the removal of half the +air the highest vacuum would be 1 / 413,000,000 nearly, and rates +even higher than this have been observed in my experiments. An +arrangement of the vacuum-bulb whereby the entering drops of +mercury would be exposed to the vacuum in an isolated condition for +a somewhat longer time would doubtless enable the experimenter to +obtain considerably higher vacua than those above given.</p> + +<p><i>Exhaustion obtained with a plain Sprengel Pump.</i>--I made a +series of experiments with a plain Sprengel pump without stopcocks, +and arranged, as far as possible, like the instrument just +described. The leakage per hour was as follows:</p> + +<pre> + Duration of the Leakage per hour in + experiment. cubic mm. at press. + 760 mm. +<br> + 22 hours 0.04563 + 2 days 0.04520 + 2 days 0.09210 + 4 days 0.06428 + ------- + Mean 0.06180 +</pre> + +<p>Using the same reasoning as above we obtain the following +table</p> + +<pre> + Time necessary for removal Greatest attainable + of half the air. exhaustion. +<br> + 10 minutes 1 / 5,000,000 + 7.5 minutes 1 / 7,000,000 + 6.6 minutes 1 / 12,000,000 +</pre> + +<p>In point of fact the highest exhaustion I ever obtained with +this pump was 1 / 5,000,000; from which I infer that the leakage +during action is considerably greater than four times that of the +pump at rest. The general run of the experiments tends to show that +the leakage of a plain Sprengel pump, without stopcocks or grease, +is, when in action, about 80 times as great as in the form used by +me.</p> + +<p><i>Note on annealing glass tubes.</i>--It is quite necessary to +anneal all those parts of the pump that are to be exposed to heat, +otherwise they soon crack. I found by inclosing the glass in heavy +iron tubes and exposing it for five hours to a temperature somewhat +above that of melting zinc, and then allowing an hour or two for +the cooling process, that the strong polarization figure which it +displays in a polariscope was completely removed, and hence the +glass annealed. A common gas-combustion furnace was used, the +bends, etc, being suitably inclosed in heavy metal and heated over +a common ten-fold Bunsen burner. Thus far no accident has happened +to the annealed glass, even when cold drops of mercury struck in +rapid succession on portions heated considerably above 100° +C.</p> + +<p>I wish, in conclusion, to express my thanks to my assistant, Dr. +Ihlseng, for the labor he has expended in making the large number +of computations necessarily involved in work of this +kind.--<i>Amer. Jour. of Science.</i></p> + +<hr> +<p><a name="9"></a></p> + +<h2>CRYSTALLIZATION TABLE.</h2> + +<p>The following table, prepared by E. Finot and Arm. Bertrand for +the <i>Jour. de Ph. et de Chim.</i>, shows the point at which the +evaporation of certain solutions is to be interrupted in order to +procure a good crop of crystals on cooling. The density is +according to Baumé's scale, the solution warm:</p> + +<pre> + Aluminum sulphate 25 | Nickel acetate 30 + Alum (amm. or pot.) 20 | " ammon. sulphate 18 + Ammonium acetate 14 | " chloride 50 + " arsenate 5 | " sulphate 40 + " benzoate 5 | Oxalic acid 12 + " bichromate 28 | Potass. and sod. tartrate 36 + " bromide 30 | Potassium arsenate 36 + " chloride 12 | " benzoate 2 + " nitrate 29 | " bisulphate 35 + " oxalate 5 | " bromide 40 + " phosphate 35 | " chlorate 22 + " sulphate 28 | " chloride 25 + " sulphocyanide 18 | " chromate 38 + " tartrate 25 | " citrate 36 + Barium ethylsulphate 43 | " ferrocyanide 38 + " formate 32 | " iodide 17 + " hyposulphite 24 | " nitrate 28 + " nitrate 18 | " oxalate 30 + " oxide 12 | " permanganate 25 + Bismuth nitrate 70 | " sulphate 15 + Boric acid 6 | " sulphite 25 + Cadmium bromide 65 | " sulphocyanide 35 + Calcium chloride 40 | " tartrate 48 + " ethylsulphate 36 | Soda 28 + " lactate 8 | Sodium acetate 22 + " nitrate 55 | " ammon. phosp. 17 + Cobalt chloride 41 | " arsenate 36 + " nitrate 50 | " borate 24 + " sulphate 40 | " bromide 55 + Copper acetate 5 | " chlorate 43 + " ammon. sulph. 35 | " chromate 45 + " chloride 45 | " citrate 36 + " nitrate 55 | " ethylsulphate 37 + " sulphate 30 | " hyposulphite 24 + Iron-ammon. oxalate 30 | " nitrate 40 + " ammon. sulphate 31 | " phosphate 20 + " sulphate 31 | " pyrophosphate 18 + " tartrate 40 | " sulphate 30 + Lead acetate 42 | " tungstate 45 + " nitrate 50 | Stroutium bromide 50 + Magnesium chloride 35 | " chlorate 65 + " lactate 6 | " chloride 34 + " nitrate 45 | Tin choride (stannous) 75 + " sulphate 40 | + Manganese chloride 47 | Zinc acetate 20 + " lactate 8 | " ammon. chloride 43 + " sulphate 44 | " nitrate 55 + Mercury cyanide 20 | " sulphate 45 +</pre> + +<hr> +<p><a name="10"></a></p> + +<h2>THE PRINCIPLES OF HOP-ANALYSIS.</h2> + +<h3>By Dr. G. O. CECH</h3> + +<p>[Footnote: 'Zeitschrift fur Analyt. Chemie,' 1881.]</p> + +<p>Hop flowers contain a great variety of different substances +susceptible of extraction with ether, alcohol, and water, and +distinguishable from one another by tests of a more or less complex +character. The substances are: Ethereal oil, chlorophyl, hop +tannin, phlobaphen, a wax-like substance, the sulphate, ammoniate, +phosphate, citrate and malates of potash, arabine, a crystallized +white and an amorphous brown resin, and a bitter principle. That +the characteristic action of the hops is due to such of these +constituents only as are of an organic nature is easy to +understand; but up to the present we are in ignorance whether it is +upon the oil, the wax, the resin, the tannin, the phlobaphen, or +the bitter principle individually, or upon them all collectively, +that the effect of the hops in brewing depends.</p> + +<p>It is the rule to judge the strength and goodness of hops by the +amount of farina--the so-called lupuline; and as this contains the +major portion of the active constituents of the hop, there is no +doubt that approximately the amount of lupuline is a useful +quantitative test. But here we are confronted by the question +whether the lupuline is to be regarded as containing <i>all</i> +that is of any value in the hops and the leaves, the organic +principles in which pass undetected under such a test, as +supererogatory for brewers' purposes? Practical experience +negatives any such conclusion. Consequently, we are justified in +assuming that the concurrent development and the presence of the +several organic principles--the oil, the wax, the bitter, the +tannin, the phlobaphen, in the choicer sorts--are subject, within +certain limits, to variations depending on skilled culture and +careful drying, and that the aggregate of these principles has a +certain attainable maximum in the finer sorts, under the most +favorable conditions of culture, and another, lower maximum in less +perfectly cultivated and wild sorts. The difference in the +proportion of active organic substance in each sort must be +determined by analysis. There then remains to be discovered which +of the aforesaid substances plays the leading role in brewing, and +also whether the presence of chlorophyl and inorganic salts in the +hop extract influences or alters the results.</p> + +<p>That in brewing hops cannot be replaced by lupuline alone, even +when the latter is employed in relatively large quantities is well +known, as also that a considerable portion of the bitter principle +of the hop is found in the floral leaves. Neither can the lupuline +be regarded as the only active beer agent, as both the hop-tannin +and the hop-resin serve to precipitate the albuminous matter, and +clarify and preserve the beer.</p> + +<p>Both chemists and brewers would gladly welcome some method of +testing hops, which should be expeditious, and afford reliable +results in practical hands. To accomplish this account must be +taken of all the active organic constituents of the hops, which can +be extracted either with ether, alcohol, or water containing soda +(for the conversion of the hop tannin in phlobaphen).[1] It should +further be ascertained whether the chlorophyl percentage in the hop +bells, new and old, is or is not the same in cultivated and in wild +hops, and whether the aggregate percentages of organic and +constituent observe the same limits.</p> + +<p>[Footnote 1: See C. Etti, in "Dingler's Polytech. Journ.," 1878, +p. 354.]</p> + +<p>As wild hops nowadays are frequently introduced in brewing, the +proportion of chlorophyl and organic and inorganic constituents in +them should be compared with those of cultivated sorts, taking the +best Bavarian or Bohemian hops as the standard of measurement. The +chlorophyl is of minor importance, as it has little effect on the +general results.</p> + +<p>By a series of comparative analysis of cultivated and wild hops, +in which I would lay especial stress on parity of conditions in +regard of age and vegetation, the extreme limits of variation of +which their active organic principles are susceptible could be +determined.</p> + +<p>There is every reason to suppose that the chlorophyl and +inorganic constituents do not differ materially in the most widely +different sorts of hops. The more important differences lie in the +proportions of hop resin and tannin. When this is decided, the +proportion of tannin or phlobaphen in the hop extract or the beer +can be determined by analysis in the ordinary way. But whenever +some quick and sure hop test shall have been found, <i>appearance +and aroma</i> will still be most important factors in any estimate +of the value of hops. Here a question arises as to whether hops +from a warm or even a steppe climate, like that of South Russia, +contain the same proportion of ethereal oil--that is, of aroma--as +those from a cooler climate, like Bavaria and Bohemia, or like +certain other fruit species of southern growth, they are early in +maturing, prolific, large in size, and abounding in farina, but +<i>deficient in aroma</i>.</p> + +<p>The bearings of certain experimental data on this point I +reserve for consideration upon a future occasion.--<i>The +Analyst</i>.</p> + +<hr> +<p><a name="11"></a></p> + +<h2>WATER GAS.</h2> + +<h3>A DESCRIPTION OF APPARATUS FOR PRODUCING CHEAP GAS, AND SOME +NOTES ON THE ECONOMICAL EFFECT OF USING SUCH GAS WITH GAS MOTORS, +ETC.</h3> + +<p>[Footnote: Abstract of paper read in Section G. British +Association, York]</p> + +<h3>By MR. J. EMERSON DOWSON, C.E., of London.</h3> + +<p>In many countries and for many years past, inventors have sought +some cheap and easy means of decomposing steam in the presence of +incandescent carbon in order to produce a cheap heating gas; and +working with the same object the writer has devised an apparatus +which has been fitted up in the garden of the Industrial +Exhibition, and is there making gas for a 3½ horse power +(nominal) Otto gas engine. The retort or generator consists of a +vertical cylindrical iron casing which incloses a thick lining of +ganister to prevent loss of heat and oxidation of the metal, and at +the bottom of this cylinder is a grate on which a fire is built up. +Under the grate is a closed chamber, and a jet of superheated steam +plays into this and carries with it by induction a continuous +current of air. The pressure of the steam forces the mixture of +steam and air upward through the fire, so that the combustion of +the fuel is maintained while a continuous current of steam is +decomposed, and in this way the working of the generator is +constant, and the gas is produced without fluctuations in quality. +The well-known reactions occur, the steam is decomposed, and the +oxygen from the steam and air combines with the carbon of the fuel +to form carbon dioxide (CO<sub>2</sub>), which is reduced to the +monoxide (CO) on ascending the fuel column. In this way the +resulting gases form a mixture of hydrogen, carbon, monoxide, and +nitrogen, with a small percentage of carbon dioxide which usually +escapes without reduction. The steam should have a pressure of +1½ to 2 atmospheres, and is produced and superheated in a +zigzag coil fed with water from a neighboring boiler. The quantity +of water required is very small, being only about 7 pints for each +1,000 cubic feet of gas, and, except on the first occasion when the +apparatus is started, the coil is heated by some of the gas drawn +from the holder, so that after the gas is lighted under the coil +the superheater requires no attention.</p> + +<p>For boiler and furnace work the gas can be used direct from the +generator; but where uniformity of pressure is essential, as for +gas engines, gas burners, etc., the gas should pass into a holder. +The latter somewhat retards the production, but the steam injector +causes gas to be made so rapidly that a holder is easily filled +against a back pressure of 1 in. to 1½ in. of water, and at +this pressure the generator can pass gas continuously into the +holder, while at the same time it is being drawn off for +consumption.</p> + +<p>The nature of the fuel required depends on the purpose for which +the gas is used. If for heating boilers, furnaces, etc, coke or any +kind of coal maybe used; but for gas engines or any application of +the gas requiring great cleanliness and freedom from sulphur and +ammonia it is best to use anthracite, as this does not yield +condensable vapors, and is very free from impurities. Good +qualities of this fuel contain over 90 per cent of carbon and so +little sulphur that, for some purposes, purification is not +necessary. For gas engines, etc., it is, however, better to pass +the gas through some hydrated oxide of iron to remove the +sulphureted hydrogen. The oxide can be used over and over again +after exposure to the air, and the purifying is thus effected +without smell or appreciable expense. Gas made by this process and +with anthracite coal has no tar and no ammonia, and the small +percentage of carbon dioxide present does not sensibly affect the +heating power. A further advantage of this gas is that it cannot +burn with a smoky flame, and there is no deposition of soot even +when the object to be heated is placed over or in the flame, and +this is of importance for the cylinder and valves of a gas +engine.</p> + +<p>To produce 1,000 cubic feet only 12 lb. of anthracite are +required, allowing 8 to 10 per cent, for impurities and waste; thus +a generator A size, which produces 1,000 cubic feet per hour, needs +only 12 lb. in that time, and this can be added once an hour or at +longer intervals. No skilled labor is necessary, and in practice it +is usual to employ a man who has other work to attend to near the +generator, and to pay him a small addition to his usual wages.</p> + +<p>The comparative explosive force of coal gas and the Dowson gas +calculated in the usual way is as 3.4:1, i. e., coal gas has 3.4 +times more energy than the writer's gas. Messrs. Crossley, of +Manchester, the makers of the Otto gas engines, have made several +careful trials of this gas with some of their 3½ horse power +(nominal) engines, and in one trial they took diagrams every +half-hour for nine consecutive days. These practical trials have +shown that without altering the cylinder of the engine it is +possible to admit enough of the Dowson gas to give the same power +as with ordinary coal gas. It has been seen that the comparative +explosive force of the two gases is as 3.4:1, but as it is well +known the combustion of carbon monoxide proceeds at a comparatively +slow rate, and for this reason, and because of the diluents present +in the cylinder which affect the weaker gas more than coal gas, +experience has shown that it is best to allow five volumes of the +Dowson gas for one volume of coal gas, and then the same uniform +power is obtained as with the latter.</p> + +<p>This gives very important economical results; for if the cost of +the Dowson gas given in the tables as 4¼d., 3-1/3d., and +2¾d. per 1,000 cubic feet, be multiplied by 5 there will be +1s. 9¼d., 1s. 4¾d., and 1s. 2¾d., or a mean of +1s. 5½d. for the equivalent of 1,000 cubic feet of coal gas, +which usually costs from 3s. to 4s., and this represents an actual +saving of about 50 to 60 per cent, in working cost. Another +practical consideration is that coal gas requires 224 lb. to 250 +lb. of coal per 1,000 cubic feet of gas, but the writer requires +only 12 lb. per 1,000 cubic feet, and multiplying this by 5 to give +the equivalent of 1,000 cubic feet of coal gas, for engine work, +there are 60 lb. instead of 224 lb. to 250 lb. This is only 24 to +27 per cent, of the weight of the coal required for coal gas, and +in many outlying districts this will effect an appreciable saving +in the cost of transport.</p> + +<h3>APPENDIX.</h3> + +<pre> + TABLE I. +<br> + _Generator A Size_ (producing 1,000 cubic feet per hour): + Anthracite to make gas at the rate of 1,000 s. d. + cubic feet per hour=l2 lb x 9 working + hours=l08 lb., or say, 1 cwt. at 20s. a + ton.................................... 1 0 + Allowance for wages of attendant......... 1 0 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent. on £l25)= + per working day........................ 0 5 + Interest on capital outlay, ditto........ 0 5 + ______ +<br> + Total........................... 2 10 + cub. ft. +<br> + Gas produced............................. 9.000 + Less gas used for generating and + superheating steam..................... 1,000 + _____ + Total effective gas for 2s. 10d. 8,000 +<br> + Net cost 4¼ d. per 1,000 cubic feet. +<br> + TABLE II. +<br> + _Generator B Size_ (producing 1,500 cubic feet per hour) + Anthracite to make gas at the rate of 1,500 s. d. + cubic feet per hour=18 lb. x 9 working + hours=162 lb., or, say, 1½ cwt. 20s. + a ton.................................. 1 6 + Allowance for wages of attendant......... 1 0 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent, on £140) + =per working day....................... 0 5½ + Interest on capital outlay, ditto........ 0 5½ + ___ ___ + Total........................... 3 5 + cub. ft. + Gas produced............................. 13,500 + Less gas used for generating and + superheating steam..................... 1,200 + ______ + Total effective gas for 3s. 5d.. 12,300 +<br> + Net cost 3 1/3d. per 1,000 cubic feet. +<br> + TABLE III. +<br> + _Generator C Size_ (producing 2,500 cubic feet per hour): + Anthracite to make gas at the rate of 2,500 s. d. + cubic feet per hour=30 lb. x 9 working + hours=270 lb. at 20s. a ton............ 2 4½ + Allowance for wages of attendant....... 1 6 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent, on £160)= + per working day...................... 0 6½ + Interest on capital outlay, ditto...... 0 6½ + _______ + Total......................... 4 11½ +<br> + cub. ft. + Gas produced........................... 22,500 + Less gas used for generating and + superheating steam................... 1,500 + ______ + Total effective gas for 4s. 11½d 21,000 +<br> + Net cost, say, 2¾ d. per 1,000 cubic feet. +</pre> + +<hr> +<p><a name="12"></a></p> + +<h2>ON THE FLUID DENSITY OF CERTAIN METALS.</h2> + +<p>[Footnote: Abstract of paper read before Section C (Chemical +Science), British Association meeting, York.]</p> + +<h3>By PROFESSOR W. CHANDLER ROBERTS, F.R.S., and T. +WRIGHTSON.</h3> + +<p>The authors described their experiments on the fluid density of +metals made in continuation of those submitted to Section B at the +Swansea meeting of the Association. Some time since one of the +authors gave an account of the results of experiments made to +determine the density of metallic silver, and of certain alloys of +silver and copper when in a molten state. The method adopted was +that devised by Mr. R. Mallet, and the details were as follows: A +conical vessel of best thin Lowmoor plate (1 millimeter thick), +about 16 centimeters in height, and having an internal volume of +about 540 cubic centimeters, was weighed, first empty, and +subsequently when filled with distilled water at a known +temperature. The necessary data were thus afforded for accurately +determining its capacity at the temperature of the air. Molten +silver was then poured into it, the temperature at the time of +pouring being ascertained by the calorimetric method. The +precautions, as regards filling, pointed out by Mr. Mallet, were +adopted; and as soon as the metal was quite cold, the cone with its +contents was again weighed. Experiments were also made on the +density of fluid bismuth; and two distinctive determinations gave +the following results:</p> + +<pre> + 10.005 ) + ) mean 10.039. + 10.072 ) +</pre> + +<p>The invention of the oncosimeter, which was described by one of +the authors in the "Journal of the Iron and Steel Institute" (No. +II., 1879, p. 418), appeared to afford an opportunity for resuming +the investigation on a new basis, more especially as the delicacy +of the instrument had already been proved by experiments on a +considerable scale for determining the density of fluid cast iron. +The following is the principle on which this instrument acts:</p> + +<p>If a spherical ball of any metal be plunged below the surface of +a molten bath of the same or another metal, the cold ball will +displace its own volume of molten metal. If the densities of the +cold and molten metal be the same, there will be equilibrium, and +no floating or sinking effect will be exhibited. If the density of +the cold be greater than that of the molten metal, there will be a +sinking effect, and if less a floating effect when first immersed. +As the temperature of the submerged ball rises, the volume of the +displaced liquid will increase or decrease according as the ball +expands or contracts. In order to register these changes the ball +is hung on a spiral spring, and the slightest change in buoyancy +causes an elongation or contraction of this spring which can be +read off on a scale of ounces, and is recorded by a pencil on a +revolving drum. A diagram is thus traced out, the ordinates of +which represent increments of volume, or, in other words, of weight +of fluid displaced--the zero line, or line corresponding to a ball +in a liquid of equal density, being previously traced out by +revolving the drum without attaching the ball of metal itself to +the spring, but with all other auxiliary attachments. By means of a +simple adjustment the ball is kept constantly depressed to the same +extent below the surface of the liquid; and the ordinate of this +pencil line, measuring from the line of equilibrium, thus gives an +exact measure of the floating or sinking effect at every stage of +temperature, from the cold solid to the state when the ball begins +to melt.</p> + +<p>If the weight and specific gravity of the ball be taken when +cold, there are obtained, with the ordinate on the diagram at the +moment of immersion, sufficient data for determining the density of +the fluid metal; for</p> + +<p>W / W<sub>1</sub> = D / D<sub>1</sub></p> + +<p>the volumes being equal. And remembering that</p> + +<p>W (weight of liquid) = W<sub>1</sub> (weight of ball) + x</p> + +<p>(where x is always measured as +<i>ve</i> or -<i>ve</i> floating +effect), there is obtained the equation: <img src= +"images/tex1.png" align="middle" alt= +"D = \frac{D_1 \times (W_1 +x)}{W_1}"></p> + +<p>The results obtained with metallic silver are perhaps the most +interesting, mainly from the fact that the metal melts at a higher +temperature, which was determined with great care by the +illustrious physicist and metallurgist, the late Henri St. Claire +Deville, whose latest experiments led him to fix the melting point +at 940° Cent. The authors of the paper showed that the density +of the fluid metal was 9.51 as compared with 10.57, the density of +the solid metal. Taking their results generally, it is found that +the change of volume of the following metals in passing from the +solid to the liquid state may be thus stated:</p> + +<pre> + Specific Specific + Metal. Gravity, Gravity, Percentage of + Solid. Liquid. Change. +<br> + Bismuth 9.82 10.055 Decrease of volume 2.3 + Copper 8.8 8.217 Increase " 7.1 + Lead 11.4 10.37 " " 9.93 + Tin. 7.5 7.025 " " 6.76 + Zinc 7.2 6.48 " " 11.10 + Silver 10.57 9.51 " " 11.20 + Iron 6.95 6.88 " " 1.02 +</pre> + +<hr> +<p><a name="18"></a></p> + +<h2>HYDROPHOBIA PREVENTED BY VACCINATION.</h2> + +<p>M. Pasteur and other French savants have lately been devoting +special attention to hydrophobia. The great authority on germs has, +in fact, definitely announced that he does not intend to rest until +he has made known the exact nature and life-history of this +terrible disease, and discovered a means of preventing or curing +it. The most curious result yet attained in this direction, +however, has been announced by Professor V. Galtier, of the Lyons +Veterinary School. This inquirer has found, in the first place, +that if the virus of rabies be injected into the veins of a sheep, +the animal does not subsequently exhibit any symptoms of +hydrophobia. This in itself would be a sufficiently curious result +to justify attention, though its importance, except as confirmatory +testimony, becomes less striking when it is remembered that M. +Pasteur has lately shown that the special <i>nidus</i> of the +disease appears to be the nervous tissue, and particularly the +ganglionic centers. But there is this further curious consequence: +sheep who have thus been treated through the blood, and who are +afterwards inoculated in the ordinary way through the cellular +tissue, as if by a bite, are proof against the disease. It is as +though the injection into the veins acted as a vaccine. Twenty +sheep were experimented upon; ten only were treated to the venous +injection, and then all were inoculated through the cellular +tissue. The ten which had been first "vaccinated" continue alive +and well; they have not even shown any adverse symptoms. The other +ten have all died of rabies. It remains to say why M. Galtier +experimented upon sheep, and not upon dogs and cats, which usually +communicate the disease. The incubation of the disease is much more +rapid and less capricious in the sheep than in the dog or in man, +and hence M. Galtier was able to get his results more certainly +within a short period. Having succeeded so far, he is now justified +in undertaking the more protracted series of observations which +experiments upon the canine species will involve; and this he +proposes to do. Experiments of this nature are not without a +serious risk, and admiration is almost equally due to the courage +and the intelligence of the experimentalist. But what will the +anti-vaccinator say?--<i>Pall Mall Gazette</i>.</p> + +<hr> +<p><a name="19"></a></p> + +<h2>ON DIPTERA AS SPREADERS OF DISEASE.</h2> + +<h3>By J.W. SLATER.</h3> + +<p>The two-winged flies, in their behavior to man, stand in a +marked contrast to all the other orders of insects. The +Lepidoptera, the Coleoptera, the Neuroptera, the Hymenoptera no +doubt occasion, in some of their forms at least, much damage to our +crops. But none of them are parasitic in or upon our bodies; none +of them persistently intrude into our dwellings, hover around us in +our walks, and harass us with noise and constant attempts to bite, +or at least to crawl upon us. Even the ants, except in a few +tropical districts, rarely act upon the offensive. The Hemiptera +contain one semi-parasitic species which has attained a "world-wide +circulation," and one degraded, purely parasitic group. But the +Diptera, among which the fleas are now generally included as a +degenerated type, comprise more forms personally annoying to man +than all the remaining insect orders put together. These hostile +species are, further, incalculably numerous, and occur in every +part of the globe. Mosquitoes swarm not merely in the swampy +forests of the Orinoco or the Irrawaddy, but in the Tundras of +Siberia, en the storm-beaten rocks of the Loffodens, and are even +encountered by voyagers in quest of the North Pole. The common +house fly was probably at one time peculiar to the Eastern +Continent, but it followed the footsteps of the Pilgrim Fathers, +and is now as great a nuisance in the United Slates and the +Dominion as in any part of Europe. It is curious, but distressing, +to note the tendency of evils to become international. We have +communicated to America the house-fly and the Hessian fly, the +"cabbage-white," the small pox, and the cholera. She, in return, +has given us the <i>Phylloxera</i>, a few visitations of yellow +fever, the <i>Blatta gigantea</i>, and, climate allowing, may +perhaps throw in the Colorado beetle as a make-weight. In this +department, at least, free trade reigns undisputed. It is a +singular thing that no beautiful, useful, or even harmless species +of bird or insect seems capable of acclimatizing itself as do those +characterized by ugliness and noisomeness.</p> + +<p>But, returning from this digression, we find in the Diptera the +habit of obtrusion and intrusion, of coming in actual contact with +our food and our persons, combined with another propensity--that of +feeding upon carrion, excrement, blood, pus, and morbid matter of +all kinds. This is a combination far more serious than is generally +imagined. If the fly--which may at any moment settle upon our lips, +our eyes, or upon an abraded part of our skin--were cleanly in its +habits, we need feel little annoyance at its visits. Or if it were +the most eager carrion devourer, but did not, after having dined, +think it necessary to seek our company, we might hold it, as is +done too hastily by some naturalists, a valuable scavenger. I fear, +however, that I have already made too great a concession. So long +as very many persons are suffering from disease--so long as many +diseases are capable of being transmitted from the sick to the +healthy--so long must any creature which is in the habit of flying +about, and touching first one person and then another, be a +possible medium of infection and death.</p> + +<p>Let us take the following case, by no means imaginary, but a +generalization from occurrences far too frequent: A healthy man, +sitting in his house or walking in the fields, especially in +countries where the insectivorous birds have been shot down, +suddenly feels a sharp prick on his neck or his cheek. Putting his +hand to the place he perhaps crushes, perhaps merely brushes away, +a fly which has bitten him so as to draw blood. The man thinks +little of so trifling a hurt, but the next morning he finds the +puncture exceedingly painful. An inflamed pimple forms, which +quickly gets worse, while constitutional symptoms of a feverish +kind come on. In alarm he seeks medical advice. The doctor tells +him that it is a malignant pustule, and takes at once the most +active measures. In spite of all possible skill and care the +patient too often succumbs to the bite of a <i>mouche +charbonneuse</i>, or carbuncle-fly. But has any kind of fly the +property of producing malignant pustule by some specific inherent +power of its own? Surely not. The antecedent circumstances are +these: A sheep or heifer is attacked with the disease known in +France as <i>charbon</i>, in Germany as <i>milz-brand</i>, and in +England as <i>splenic fever</i>. Its blood on examination would be +found plentifully peopled with bacteria. If a lancet were plunged +into the body of the animal, and were then used to slightly scratch +or cut the skin of a man, he would be inoculated with "charbon." +The bite of the fly is precisely similar in its action. Its rostrum +has been smeared with the poisoned blood, an infinitesimal particle +of which is sufficient to inclose several of the disease "germs," +and these are then transferred to the blood of the next man or +animal which the fly happens to bite. The disease is reproduced as +simply and certainly as the spores of some species of fern give +rise to their like if scattered upon soil suitable for their +growth. But flies which do not bite may transfer infection. Every +one must know that if blood be spilt upon the ground a crowd of +flies will settle upon and eagerly absorb it. Animals suffering +from splenic fever in the later stages of the disease sometimes +emit bloody urine. Often they are shot or slaughtered by way of +stamping out the plague, and their carcasses are buried deep in the +ground. But some loss of blood is sure to happen, and this will +mostly be left to soak into the ground. Here again the flies will +come, and their feet and mouth will become charged with the +contagion. Such a fly, settling upon another animal or a man, and +selecting--as it will do by preference, if such exist--a wound, or +a place where the skin is broken, will convey the disease.</p> + +<p>Again, M. Pasteur has thoughtfully pointed out that if an animal +has died of splenic fever, and has been carefully buried, the +earth-worms may bring up portions of infectious matter to the +surface, so that sheep grazing, or merely being folded over the +spot in question, may take the plague and die. Hence be wisely +counsels that the bodies of such animals should be buried in sandy +or calcareous soils where earth-worms are not numerous. But it is +perfectly legitimate to go a step farther. If such worm-borings +retain the slightest savor of animal matter, flies will settle upon +them and will convey the infectious dust to the most unexpected +places, giving wings to the plague.</p> + +<p>Now it is very true that no one has seen a fly feasting upon the +blood of a heifer or sheep dying or just dead of splenic fever, has +then watched it settle upon and bite some person, and has traced +the following stages of the disease. But it is positively known +that a person has been bitten by a fly, and has then exhibited all +the symptoms of charbon, the place of the bite being the primary +seat of the infection. We know also, beyond all doubt, the +eagerness with which flies will suck up blood, and we likewise know +the strange persistence of the disease "germs."</p> + +<p>Again, the avidity of flies for purulent matter is not a thing +of mere possibility. In Egypt, where ophthalmia is common, and +where the "plague of flies" seems never to have been removed, it is +reported as almost impossible to keep these insects away from the +eyes of the sufferers. The infection which they thus take up they +convey to the eyes of persons still healthy, and thus the scourge +is continually multiplied.</p> + +<p>A third case which seems established beyond question is the +agency of mosquitoes in spreading elephantiasis. These so-called +sanitary agents suck from the blood of one person the Filariae, the +direct cause of the disease, and transfer them to another. The +manner in which this process is effected will appear simple enough +if we reflect that the mosquito begins operations by injecting a +few drops of fluid into its victim, so as to dilute the blood and +make it easier to be sucked.</p> + +<p>So much being established it becomes in the highest degree +probable that every infectious disease may be, and actually is, at +times propagated by the agency of flies. Attention turned to this +much neglected quarter will very probably go far to explain obscure +phenomena connected with the distribution of epidemics and their +sudden outbreaks in unexpected quarters. I have seen it stated that +in former outbreaks of pestilence flies were remarkably numerous, +and although mediaeval observations on Entomology are not to be +taken without a grain of salt, the tradition is suggestive. Perhaps +the Diptera have their seasons of unusual multiplication and +emigration. A wave of the common flea appears to have passed over +Maidstone in August, 1880.</p> + +<p>We now see the way to some practical conclusions not without +importance. Recognizing a very considerable part of the order of +Diptera, or two-winged flies, as agents in spreading disease, it +surely follows that man should wage war against them in a much more +systematic and consistent manner than at present. The destruction +of the common house-fly by "<i>papier Moure</i>," by decoctions of +quassia, by various traps, and by the so-called "catch 'em alive," +is tried here and there, now and then, by some grocer, +confectioner, or housewife angry at the spoliation and defilement +caused by these little marauders. But there is no concerted +continuous action--which after all would be neither difficult nor +expensive--and consequently no marked success. Experiments with a +view of finding out new modes of fly-killing are few and far +between.</p> + +<p>Every one must occasionally have seen, in autumn, flies as if +cemented to the window-pane, and surrounded with a whitish halo. +That in some seasons numbers of flies thus perish--that the +phenomenon is due to a kind of fungus, the spores of which readily +transfer the disease from one fly to another--we know. But here our +knowledge is at fault. We have not learnt why this fly-epidemic is +more rife in some seasons than others. We are ignorant concerning +the methods of multiplying this fungus at will, and of launching it +against our enemies. We cannot tell whether it is capable of +destroying <i>Stomoxys calcitram</i>, the blowflies, gadflies, +gnats, mosquitoes, etc. Experiment on these points is rendered +difficult by the circumstance that the fungus is rarely procurable +except in autumn, when some of the species we most need to destroy +are not to be found. Another question is whether the fungus, if +largely multiplied and widely spread, might not prove fatal to +other than Dipterous insects, especially to the Hymenoptera, so +many of which, in their character of plant-fertilizers, are highly +useful, or rather essential to man.</p> + +<p>Another fungus, the so-called "green muscardine" (<i>Isaria +destructor</i>), has been found so deadly to insects that Prof. +Metschnikoff, who is experimenting upon it, hopes to extirpate the +<i>Phylloxera</i>, the Colorado beetle, etc., by its agency.</p> + +<p>Coming to better known and still undervalued fly-destroyers, we +have interfered most unwisely with the balance of nature. The +substitution of wire and railings for live fences in so many fields +has greatly lessened the cover both for insectivorous birds and for +spiders. The war waged against the latter in our houses is plainly +carried too far. Whatever may be the case at the Cape, in +Australia, or even in Southern Europe, no British species is +venomous enough to cause danger to human beings. Though cobwebs are +not ornamental, save to the eye of the naturalist, there are parts +of our houses where they might be judiciously tolerated: their +scarcity in large towns, even where their prey abounds, is somewhat +remarkable.</p> + +<p>But perhaps the most effectual phase of man's war against the +flies will be negative rather than positive, turning not so much on +putting to death the mature individuals as in destroying the matter +in which the larvae are nourished. Or if, from other +considerations, we cannot destroy all organic refuse, we may and +should render it unfit for the multiplication of these vermin. We +have, indeed, in most of our large towns and in their suburbs, +abolished cesspools, which are admirable breeding-places for many +kinds of Diptera, and which sometimes presented one wriggling mass +of larvae. We have drained many marshes, ditches, and unclean +pools, rich in decomposing vegetable matter, and have thus notably +checked the propagation of gnats and midges. I know an instance of +a country mansion, situate in one of the best wooded parts of the +home counties, which twenty years ago was almost uninhabitable, +owing to the swarms of gnats which penetrated into every room. But +the present proprietor, being the reverse of pachydermatous, has +substituted covered drains for stagnant ditches, filled up a number +of slimy ponds as neither useful nor ornamental, and now in most +seasons the gnats no longer occasion any annoyance.</p> + +<p>But if we have to some extent done away with cesspools and +ditches, and have reaped very distinct benefit by so doing, there +is still a grievous amount of organic matter allowed to putrefy in +the very heart of our cities. The dust bins--a necessary +accompaniment of the water-carriage system of disposing of +sewage--are theoretically supposed to be receptacles mainly for +organic refuse, such as coal-ashes, broken crockery, and at worst +the sweepings from the floors. In sober fact they are largely mixed +with the rinds, shells, etc., of fruits and vegetables, the bones +and heads of fish, egg-shells, the sweepings out of dog-kennels and +henhouses, forming thus, in short, a mixture of evil odor, and well +adapted for the breeding-place of not a few Diptera.</p> + +<p>The uses to which this "dust" is put when ultimately fetched +away are surprising: without being freed from its organic refuse it +is used to fill up hollows in building-ground, and even for the +repair of roads. A few weeks ago I passed along a road which was +being treated according to the iniquity of Macadam. Over the broken +stones had been shot, to consolidate them, a complex of ashes, +cabbage-leaves, egg and periwinkle shells, straw, potato-parings, a +dead kitten (over which a few carrion-flies were hovering), and +other promiscuous nuisances. The road in question, be it remarked, +is highly "respectable," if not actually fashionable. The houses +facing upon it are severely rated, and are inhabited chiefly by +"carriage people." What, then, may not be expected in lower +districts?</p> + +<p>Much attention has lately been drawn to the fish trade of +London. It has <i>not</i>, however, come out in evidence that the +fish retailers, if they find a quantity of their perishable wares +entering into decomposition, send out late in the evening a +messenger, who, watching his opportunity, throws his burden down in +some plot of building land, or over a fence. When I say that I have +seen in one place, close alongside a public thoroughfare, a heap of +about fifty herrings, in most active putrefaction and buzzing with +flies, and some days afterward, in another place, some twenty +soles, it will be understood that such nuisances can only be +occasioned by dealers. To get rid of, or at least greatly diminish, +carrion-flies, house-flies, and the whole class of winged travelers +in disease, it will be, before all things, essential to abolish +such loathsome malpractices. The dustbins must cease being made the +receptacle for putrescent and putrescible matter, the destruction +of which by fire should be insisted upon.</p> + +<p>The banishment of slaughter-houses to some truly rural +situation, where the blood and offal could be at once utilized, +would be another step toward depriving flies of their pabulum in +the larva state. An equally important movement would be the +substitution of steam or electricity for horsepower in propelling +tram-cars and other passenger carriages, with a view to minimize +the number of horses kept within greater London. Every large stable +is a focus of flies--<i>Journal of Science</i>.</p> + +<hr> +<p><a name="20"></a></p> + +<h2>ON THE RELATIONS OF MINUTE ORGANISMS TO CERTAIN SPECIFIC +DISEASES.</h2> + +<p>At the recent Medical Congress in London, Professor Klebs +undertook to answer the question: "Are there specific organized +causes of disease?"</p> + +<p>A short historical review of the various opinions of mankind as +to the origin of disease led, the speaker thought, to the +presumption that these causes were specific and organized.</p> + +<p>If we now, he said, consider the present state of this question, +the three following points of view present themselves as those from +which the subject may be regarded:</p> + +<p>I.--We have to inquire whether the lower organisms, which are +found in the diseased body, may arise there spontaneously; or +whether even they may be regarded as regular constituents of the +body.</p> + +<p>II.--The morphological relations of these organisms have to be +investigated, and their specific nature in the different morbid +processes has to be determined.</p> + +<p>III.--We have to inquire into their biological relations, their +development inside and outside the body, and the conditions under +which they are able to penetrate into the body, and there to set up +disease.</p> + +<p><i>First</i>.--With regard to the first question, that of the +possibility of spontaneous generation, the speaker gave a decided +negative.</p> + +<p><i>Second and third</i>.--There is in microscopic organisms a +difference of form corresponding, as a rule, to difference of +function. The facts regarding these various lower forms are briefly +reviewed.</p> + +<p>"Three groups of hyphomycetae, algae, and schizomycetae, have +been demonstrated to occur in the animal and human organism in +infective diseases. Their significance increases with the increase +of their capacity for development in the animal body. This depends +partly upon their natural or ordinary conditions of life, but +partly also, and that in a very high degree, upon their power of +adaptation, which, as Darwin has shown, is a property of all living +things, and causes the production of new species with new active +functions.</p> + +<p>"1. The hyphomycetae, on account of their needing an abundant +supply of oxygen, give rise to but few morbid processes, and these +run their course on the surface of the body, and are hence +relatively of less importance. It will be sufficient here to refer +to the forms, achorion, trichophyton, oïdium, aspergillus, and +the diseases produced by them, favus, ringworm, and thrush, to show +this peculiarity. Nevertheless, we see that these organisms also +(as was proved by the older observations of Hannover and Zenker) +may, under certain circumstances, penetrate into the interior of +the organs. Grawitz, moreover, has recently shown that their +faculty of penetrating into the interior of the organism, and there +undergoing further development, depends on their becoming +accustomed to nitrogenous food.</p> + +<p>"2. Only one of the algae, viz., leptothrix, has as yet acquired +any importance as a producer of disease. It gives rise to the +formation of concretions, and that not only in the mouth, but also, +as I have shown, in the salivary ducts and urinary bladder.</p> + +<p>"Another alga, the sarcina of Goodsir, may indeed pass through +the organism, without, however, producing in its passage either +direct or indirect disturbances. It seems more worthy of note that +many schizomycetae, and especially the group of bacilli, are +evidently nearly allied to the algae in their morphological and +vegetative relations--so as to be assigned to this class by several +authors, and especially by Cienkowski.</p> + +<p>"The schizomycetae furnish, without doubt, by far the most +numerous group of infective diseases. We distinguish within this +group two widely different series of forms, which we will speak of +as bacilli and cocco-bacteria respectively. The former, which was +first exhaustively described by Ferdinand Cohn, and the +pathological importance of which, especially in relation to the +splenic disease of cattle, was first shown by Koch, consist of +threads, in the interior of which permanent or resting-spores are +developed. These spores becoming free, are able, under suitable +conditions of life, again to develop into threads. The whole +development of these organisms, and especially the formation of +spores, is completed on the surface of the fluids, and under the +influence of an abundant supply of oxygen.</p> + +<p>"The number of affections in which these organisms have been +found, and which may be to a certain extent produced artificially +by the introduction of these organisms into healthy animal bodies, +has been largely increased since the discovery of Koch, that the +bacteria of splenic fever (anthrax) belong to this group. Under +this head must be placed the bacillus malarise (Klebs and +Tommassi-Crudeli), the bacillus typhi abdominalis (Klebs, Ebert), +the bacillus typhi exanthematici (Klebs, observations not yet +published), the bacillus of hog-cholera (Klein), and, finally the +bacillus leprosus (Neisser). It would exceed the time appointed +were I to attempt to describe these forms more minutely. This may, +perhaps, be better reserved for discussion and demonstration.</p> + +<p>"Alongside of these general infective diseases produced by +bacilli, local affections also occur, which indicate the presence +of these organisms at the point where disease begins. As an example +of these processes, which probably occur in various organs, I would +mention gastritis bacillaris, of which I shall show you +preparations. In this, we can trace the entrance of the bacilli +into the peptic glands, as well as their further distribution in +the walls of the stomach, and in the vascular system.</p> + +<p>"The second group of the pathogenetic schizomycetae I propose to +call, with Billroth, cocco-bacteria, because they consist of +collections of micrococci, which are capable of transforming +themselves into short rods. The former usually form groups united +by zoögloea; by prolongation of the cocci rods are formed, +which sprout out, break up by division into chains, and further +lead again to the formation of resting masses of cocci. I +distinguish, further, in this group, two genera--the microsporina +and the monadina; in the former of which the micrococci are +collected into spherical lumps, in the latter into layers. The one +class is developed in artificial cultivation fluid, the other on +the surface. The former requires a medium poor in oxygen, the +latter a medium rich in oxygen, for their development.</p> + +<p>"Among the affections produced by microsporina, I reckon +especially the septic processes, and also true diphtheria. On the +other hand, to the processes produced by monadina belong especially +a large series of diseases, which according to their clinical and +anatomical features, may be characterized as inflammatory +processes, acute exanthemata, and infective tumors, or +leucocytoses. Of inflammatory processes, those belong here which do +not generally lead to suppuration, such as rheumatic affections, +including the heart, kidney, and liver affections, which accompany +this process, sequelae which, as is well known, lead more +especially to formation of connective tissue, and not to +suppuration. Here, also, belong croupous pneumonia, the allied +disease erysipelas, certain puerperal processes, and finally, +parotitis epidemica, or mumps.</p> + +<p>"Among the acute exanthemata, the following may, up to the +present time, be placed in this group; variola-vaccina, scarlatina, +and measles.</p> + +<p>"The group of infective tumors is represented by tuberculosis, +syphilis, and glanders. Throughout the whole group of +cocco-bacteria the demonstration of organisms in the diseased parts +encounters difficulties which vary considerably in the different +kinds."</p> + +<p>The speaker concluded by describing the methods (now well known) +by which the powers of the different organisms are tested.</p> + +<p>He also referred to Pasteur's, Chauveau's, and Toussaint's +recent experiments.</p> + +<p>His conclusion was that the specific communicable diseases are +produced by specific organisms.</p> + +<hr> +<p><a name="21"></a></p> + +<h2>THE CENTENARY OF THE DISCOVERY OF URANUS.</h2> + +<h3>By W. F. DENNING, F.R.A.S.</h3> + +<p>The year 1781 was signalized by an astronomical discovery of +great importance, and one which marked the epoch as memorable in +the annals of science. A musician at Bath, William Herschel by +name, who had been constructing some excellent telescopes and +making a systematic survey of the heavens, observed an object on +the night of March 13 of that year, which ultimately proved to be a +large planet revolving in an orbit exterior to that of Saturn. The +discovery was as unique as it was significant. Only five planets, +in addition to the Earth, had hitherto been known; they were +observed by the ancients, and by each succeeding generation, but +now a new light burst upon men. The genius of Herschel had singled +out from the host of stars which his telescope revealed an object +the true character of which had evaded human perception for +thousands of years!</p> + +<p class="ctr"><a href="images/14a.png"><img src= +"images/14a_th.png" alt=""></a></p> + +<p class="ctr">FIG. 1.--APPROXIMATE PLACE OF URANUS AMONGST THE +STARS AT ITS DISCOVERY<br> +ON MARCH 13, 1781</p> + +<p>The centenary of this remarkable advance in knowledge naturally +recalls to mind the circumstances of the discovery, and makes us +inquisitive to know what new facts have been gleaned of Herschel's +planet, now that a hundred years have passed away, and we are +enabled to look back and review the vast amount of labor which has +been accomplished in this wide and attractive field of astronomical +research. We may learn what new features have been discerned of the +new body, and what additional discoveries in connection with other +planets unknown in Herschel's day, have been effected by aid of the +powerful telescopes which have been devoted to the work. We do not, +however, intend dealing with the general question of planetary +discovery, for at a glance we are impressed with its magnitude. +While a century ago five planets only were known, we now have some +two hundred and thirty of these bodies, and the stream of discovery +flows on without abatement through each succeeding year. The +detection of Uranus seems, indeed, to have been the prelude to many +similar discoveries, and to have offered the incentive to greater +diligence and energy on the part of observers in various parts of +the world.</p> + +<p class="ctr"><a href="images/14b.png"><img src= +"images/14b_th.png" alt= +"Fig. 2.--ORBITS OF THE URANIAN SATELLITES."></a></p> + +<p class="ctr">Fig. 2.--ORBITS OF THE URANIAN SATELLITES.</p> + +<p>Many great discoveries have resulted from accident; and the +leading facts attending that of Uranus prove that, in a large +measure, the result was brought about in a similar way. Herschel, +as he unwearyingly swept the heavens night after night, was in +quest of sidereal wonders--such as double stars and nebulae--and he +happened to alight upon the new planet in a purely chance way. He +had no expectation of finding such a remarkable object, and indeed, +when he had found it, wholly mistook its character. There could be +no doubt that it was a body wholly dissimilar to the fixed stars, +and it was equally certain that it could not be a nebula. It had a +perceptible disk, for when it had first come under the critical eye +of its discoverer he had noticed immediately that its appearance +differed widely from the multitude of objects which crossed the +field of his telescope. He had been accustomed to see hosts of +stars pass in review, and their aspect was in one respect similar, +namely, they were invariably presented as points of light incapable +of being sensibly magnified, even with the highest powers. True, +there was a great variety of apparent brightness in these objects +and a singular diversity of configuration, but there was no +exception to the invariable feature referred to. The point of light +was constant, and no striking exception was anticipated until one +night--March 13, 1781--Herschel being intently engaged in the +examination of some small stars in the region of Gemini, brought an +object under the range of, his telescope, which his eye at once +selected as one of anomalous character.</p> + +<p>Applying a higher power, he noticed that it exhibited a +planetary disk, but his instrument failed to define it with +sufficient distinctness, and hence he became doubtful as to its +real nature. The object was found to be in motion, and subsequent +observations led him to the assumption that it must be a comet of +rather exceptional type. This appeared to be the best explanation +of the strange body, for history contained many records of curious +comets, some of which were observed as nearly circular patches of +nebulous light, and probably of similar aspect to the object then +visible; and apart from this it must be remembered that the idea of +a large planet exterior to Saturn was a fact of such momentous +import that Herschel, with a due regard to that modesty which +accompanies true genius, refrained from attaching such an +interpretation to his observations. He was content to direct the +notice of astronomers to it as a phenomenon requiring close +attention, and suggested that it might be a comet in consequence of +its motion and the faint and somewhat ill-defined character of its +appearance.</p> + +<p>From the earliest ages five planets only were known, and the +discovery of another large planet beyond the sphere of Saturn must +at once revolutionize existing ideas as to the range of the solar +system, and immediately take rank as a scientific event of equal +interest to the discovery of the moons of Jupiter or the rings of +Saturn, which each in their day impressed men with new ideas of the +celestial mechanism. But the truth could not long be delayed. The +new body being watched and its orbit rigorously computed from a +series of observed positions revealed its true character, and +Herschel was awarded the honor due to the author of a discovery of +such importance. His diligence and pertinacity alone had enabled +him to search out from among the multitude of stars thickly strewn +over the firmament this unknown and well-nigh invisible planet +which, during all the preceding years of the world's history, had +eluded human perception. Men had been all unconscious of its +existence as it had been slowly completing its circuits around the +sun, obedient to the same laws as the other planets of the solar +system, and awaiting the hour when the unfailing eve of Herschel +should introduce it as the faint and far-off planet girding our +system within its expansive folds.</p> + +<p>As soon as the existence of the new orb was confirmed and the +fact rendered indisputable, the question naturally arose whether it +had ever been seen in former years by the authors of star +catalogues, who could hardly have overlooked an object like this +though its planetary nature had manifestly escaped detection. It +was just perceptible to the naked eye, shining like a star of the +sixth magnitude, and ought to have been distinguished by those who +had reviewed the heavens with the purpose of determining and +mapping the positions of the stars. Reference was, therefore, made +to the chief catalogues, when it was found at once that the planet +had been unquestionably observed by Tobias Mayer, Le Monnier, +Bradley, and Flamsteed. It was several times noted by these +observers: by Le Monnier no less than twelve times, and by +Flamsteed on six occasions; and it is remarkable that in every +instance its true character escaped detection. Neither its special +appearance nor its motion attracted attention, so that it was +merely catalogued as an ordinary fixed star. Thus Herschel was not +anticipated in his discovery. It remained for him, in 1781, to note +its exceptional aspect, and to specify it as an object requiring +critical investigation. But the early observations above alluded to +served a useful purpose in testing the accuracy of the computed +orbit, for without waiting many years to compare the theoretical +and observed positions, astronomers had in these old records a +reliable series of points through which the previous course of the +planet could be traced.</p> + +<p>The calculations showed that its mean distance from the sun was +some 1,750,000,000 miles, and that a revolution was completed in +about eighty-four years. It was also found to be a very large +planet, greatly exceeding either Mercury, Venus, the Earth, or +Mars, though considerably inferior to either Jupiter or Saturn.</p> + +<p>Here, then, was a discovery of the utmost importance, and one of +the most salient additions to our knowledge which the telescope had +ever achieved. The new planet was now definitely assigned its +proper place in the solar system, and was regarded as of equal +significance with the old planets. True, the new planet of Herschel +could not be compared as regards its visible aspect with the other +previously known members of our system, but it was nevertheless an +object of equal weight. Its vast distance alone rendered it faint. +It formed one of the constituent parts of the solar system, which, +though separated by immense intervals of space, are yet coherent by +the far-reaching effects of gravitation. There is, indeed, a bond +of harmony between the series of planetary orbits, which exhibit a +marked degree of regularity in their successive distances from the +sun; and though they are not connected by any visible links, they +are firmly held together by unseen influences, and their motions +are subject to certain laws which have been revealed by centuries +of observation.</p> + +<p>The question of suitably naming the new planet soon came to the +fore. Herschel himself proposed to designate it the "Georgium +Sidus," in honor of his patron, George III., just as Galileo had +called the satellites of Jupiter the "Medicean stars," after Cosmo +de' Medici. But La Place proposed that the planet should be named +after its discoverer; and thus it was frequently referred to as +"Herschel," and sometimes as "The Herschelian planet." Astronomers +on the continent objected to this system of personal nomenclature, +and argued that the new body should receive an appellative in +accordance with those adopted for the old planets, which had been +selected from the heathen mythology. Several names were suggested +as suitable (on the basis of this principle), and ultimately the +one advanced by Bode received the most favor, and the planet +thereafter was called "Uranus."</p> + +<p>The varying positions of the new body as observed on successive +nights were determined by comparisons with a group of six small +stars, termed by Herschel [Greek: alpha, beta, gamma, delta, +epsilon] and afterwards formed into a constellation under the +designation of "Britannia," though it does not appear that this +little asterism is acknowledged as one of our constellations. Its +position is about midway between Taurus and Gemini, and the +following are the principal stars computed for 1881.0, as given by +Mr. Marth:</p> + +<pre> + Star. Magnitude. Right Ascension. Declination. + h. m. s. + alpha 9.0 5 42 6.06 23° 35' 6.7" N. + eta 8.7 5 43 17.82 23 26' 7.2 N. + theta 8.8 5 44 0.99 23 53' 30.8 N. + epsilon 8.8 5 45 40.68 23 34' 46.8 N. +</pre> + +<p>The stars are therefore merely telescopic, and are confined to a +small area of space, so that the propriety of adopting the group as +a distinct constellation is very questionable. Their positions +close to Uranus at the time of its discovery, and the fact that the +planet's motion was detected by means of comparisons with them, has +given to these stars an historical interest which in future years +must often attract the student to their reobservation. But it would +be unwise, as forming a bad precedent, to accept a group of stars +of this inferior type as meriting to rank among the old +constellations, when we have numbers of richer groups, situated on +their confines, which first deserve such a distinction. However +special or unique the circumstances connected with certain +telescopic stars may be, and however necessary it may appear to +signalize them by a specific title, we are inclined to question the +adoption of such means as likely to exercise a wrong influence, +inasmuch as it may hereafter originate further innovations of a +similar character, and ultimate complications will be certain to +arise.</p> + +<p>Soon after the discovery of Uranus it was suspected that the +planet was encircled, like Saturn, by a luminous ring, but on +subsequent observation this was not confirmed, and no such +appendage has ever been revealed in the more perfected instruments +of our own times. Indeed, if Uranus displays a peculiarity of +constitution in any way analogous to the ring system of Saturn, it +must be of the most minute character so as to have thus evaded +telescopic scrutiny during a hundred years.</p> + +<p>The discovery soon attracted the notice of royalty, and the +reigning sovereign, George III., anxious to practically express his +appreciation of the valuable labors of Herschel, awarded him a +pension of £200 a year and furnished him with a residence at +Slough, near Windsor, and the means to erect a gigantic telescope +with which he might be enabled to continue his important +researches. This instrument consisted of a reflector on the +"Front-view" construction, with a speculum 4 feet in diameter and +of 40 feet focal length. Upon its completion, Herschel immediately +began to observe the region of the new planet with the idea of +discovering any satellites which might belong to it, for analogy +suggested that it was surrounded by a numerous retinue of such +bodies. He was soon successful, for, on the night of January 11, +1787. he saw two minute objects near the planet, which renewed +observations revealed to be satellites; and he detected two +additional ones in 1790, and two others in 1794, making six in all. +But the observations were of extreme difficulty. The path of the +planet frequently passed near minute stars, and it became hard to +distinguish between them and the suspected satellites. Herschel, +however, considered he had obtained conclusive evidence of the +existence of six satellites with sidereal periods ranging from 5d. +21h. 25m. to 107d. 16h. 39m., and his means of observation being +much superior to those possessed by any of his contemporaries it +was impossible to have corroborative testimony.</p> + +<p>The matter was thus allowed to rest until the middle of the +present century, when Lassell, in the pure sky at Malta, endeavored +to reobserve the satellites with a two-foot reflector. This +instrument was considered superior to Herschel's telescope; and the +atmosphere at this station being decidedly more suitable for such +delicate observations than in England, it was removed there for the +express purpose of dealing successfully with objects of extreme +difficulty. The results were very important. Mr. Lassell became +convinced that Uranus had only four satellites, and that if any +others existed they remained to be discovered. Two of these were +found to be identical with those seen by Herschel in 1787, and now +called Titania and Oberon. The other two, Ariel and Umbriel, could +not be identified with any of those alleged to have been previously +detected by Herschel, so that the inference was that they were new +bodies, and that the priority of discovery was due to Mr. Lassell; +whence it also followed that the older observations were erroneous, +and that in fact Herschel had been entirely mistaken with regard to +the four satellites he believed he had detected subsequently to +1787.</p> + +<p>In November, 1873, a fine twenty-six-inch object glass, by Alvan +Clark, was mounted at the U. S. Naval Observatory at Washington, +and it was soon employed upon the difficult task of solving the +problem as to the exact periods of the Uranian satellites. This was +very satisfactorily effected, and with distinct and conclusive +favor to Mr. Lassell, whose observations were fully corroborated. +Only four satellites could be distinguished by the American +observers, and their periods, as computed from a valuable series of +measures, agreed with those previously derived at Malta. In +Appendix I. to the "Washington Observations" for 1873, Prof. +Newcomb gave a valuable summary of results--the first obtained, be +it noted, with that splendid instrument which soon afterward, in +1877, revealed the satellites of Mars--which included the elements +of the satellites of Uranus as follows:</p> + +<pre> + Mean Longitude. +<br> + Satellite. Epoch 1871. Radius of Period of + Dec. 31, W.M.T. Orbit. Revolution in days. + I. Ariel........ 21.83° 13.78" 2.52038 + II. Umbriel..... 13.52 19.20 4.14418 + III. Titania..... 229.93 31.48 7.70590 + IV. Oberon...... 154.83 42.10 13.43327 +</pre> + +<p>Speaking of the comparative brightness of the satellites, Prof. +Newcomb says:</p> + +<p>"The greater proximity of the inner satellites to the planet +makes it difficult to compare them photometrically with the outer +ones, as actual feebleness of light cannot be distinguished from +difficulty of seeing arising from the proximity of the planet. +However, that Umbriel is intrinsically fainter than Titania is +evinced by the fact that, although the least distance of the latter +is somewhat less than the greatest distance of the former, there is +never any difficulty in seeing it in that position. From their +relative aspects in these respective positions I judge Umbriel to +be about half as bright as Titania. Ariel must be brighter than +Umbriel, because I have never seen the latter unless it was farther +from the planet than the former at its maximum distance.... I think +I may say with considerable certainty that there is no satellite +within 2' of the planet, and outside of Oberon, having one-third +the brilliancy of the latter, and therefore that none of Sir +William Herschel's supposed outer satellites can have any real +existence. The distances of the four known satellites increase in +so regular a way that it can hardly be supposed that any others +exist between them. Of what may be inside of Ariel it is impossible +to speak with certainty, since in the state of atmosphere which +prevails during our winter all the satellites named disappear at +10" from the planet."</p> + +<p>Prof. Newcomb mentions that no systematic search for new +satellites was undertaken because it must have interfered with the +fullness and accuracy of the micrometer measures of the old +satellites, which constituted the main purpose of the observations. +Some faint objects were occasionally glimpsed near the planet, and +their relative places determined, but they were never found to +accompany Uranus. The fact, therefore, that no additional +satellites were discovered is not to be regarded as a strong point +in favor of the theory of their non-existence, because the great +power and excellence of the telescope was expressly directed to the +attainment of other ends; and moreover the season in which the +planet came to opposition was distinctly unfavorable for the +prosecution of a rigorous search for new satellites. There can, +however, be no doubt that the analogies of the planetary systems +interior to Uranus plainly suggest that this planet is attended by +several satellites which the power of our greatest telescopes has +hitherto failed to reveal; and that it is in this direction and +that of Neptune we may anticipate further discoveries in future +years when the conditions are more auspicious and the work is +entered upon with special energy, aided by instruments of even +greater capacity than those which have already so far conduced to +our knowledge of the heavenly bodies.</p> + +<p>Notwithstanding the extreme difficulty with which the Uranian +satellites are observed, the two brighter ones, Titania and Oberon, +discovered by William Herschel in 1787, have been occasionally +detected in telescopes of moderate power, and identified by means +of an ephemeris which has shown that the computed positions +approximately agree with those observed. During the last few years +Mr. Marth has published ephemerides of the satellites of both +Saturn and Uranus, and many amateurs have to acknowledge the +valuable aid rendered by these tables, which supply a ready means +of identifying the satellites, and thus act as an incentive to +observers who are induced to pursue such work for the sake of the +interesting comparisons to be made afterward. In one exceptional +instance the two outer satellites of Uranus appear to have been +glimpsed with an object glass of only 43 inches aperture, and the +facts are given in detail in the "Monthly Notices of the R.A.S.," +April 1876, pp. 294-6. The observations were made in January, +February, and March, 1876, by Mr. J.W. Ward, of Belfast; and the +positions of the satellites, as he estimated them on several +nights, are compared with those computed, the two sets presenting +tolerably good agreement. Indeed the corroborations are such as to +almost wholly negative any skepticism, though such extraordinary +feats should always be received with caution.</p> + +<p>In this particular case the chances of being misled are +manifold; even Herschel himself fell into error in taking minute +stars to be satellites and actually calculating their periods; so +that when we remember the difficulties of the question our doubts +are not altogether dispelled. Extreme acuteness of vision will, in +individual instances, lead to success of abnormal character, and +certainly in Mr. Ward's case the remarkable accordances in the +observed and calculated positions appear to be conclusive evidence +that he was not mistaken.</p> + +<p>It will be readily inferred that the great distance and +consequent feebleness of Uranus must render any markings upon the +disk of the planet beyond the reach of our best telescopes; and +indeed this appears to have been a matter of common experience. +Though the surface has been often scanned for traces of spots, we +seldom find mention that any have been distinguished. Consequently +the period of rotation has yet to be determined. It is true that an +approximate value was assigned by Mr. T.H. Buffham from +observations with a nine-inch reflector in 1870 and 1872. but the +materials on which the computation was based were slender and +necessarily somewhat uncertain, so that his period of about twelve +hours stands greatly in need of confirmation. The bright spots and +zones seen on the disk in the years mentioned appear to have +entirely eluded other observers, though they are probably phenomena +of permanent character and within reach of instruments of moderate +size. Mr. Buffham [1] thus describes them:</p> + +<p>[Footnote 1: "Monthly Notices K. A. S.," January, 1873.]</p> + +<p>"1870, Jan. 25, 11h. to 12h. in clear and tolerably steady air; +power 132 showed that the disk was not uniform. With powers 202 and +3.0, two round, bright spots were perceived, not quite crossing the +center but a little nearer to the eastern side of the planet, the +position angle of a line passing through their centers being about +20º and 200--ellipticity of Uranus seemed obvious, the major +axis lying parallel to the line of the spots.</p> + +<p>"Jan. 27, 10h. to 10½h.; some fog, and definition not +good, but the appearance of the spots was almost exactly the same +as on the 25th."</p> + +<p>On March 19 glimpses were obtained of a light streak and two +spots. On April 1, 4, 6, and 8, a luminous zone was seen on the +disk, and in February and March, 1872, when observations were +resumed, certain regions were noted brighter than others, and +underwent changes indicating the rotation of the planet in a +similar direction to that derived from the results obtained in +1870. Mr. Buffham points out that, if this is admitted, then the +plane of the planet's equator is not coincident with the plane of +the orbits of the satellites. Nor need we be surprised at this +departure from the general rule, where such an anomalous +inclination exists. In singular confirmation of this is Mr. +Lassell's observation of 1862, Jan. 29, where he says: "I received +an impression which I am unable to render certain of an equatorial +dark belt, and of an ellipticity of form."</p> + +<p>Some observations made in 1872-3 with the great six-foot +reflector of Lord Rosse may here be briefly referred to. A number +of measures, both of position and distance, of Oberon and Titania, +were made, [1] and a few of Umbriel and Ariel, but "the shortness +of the time available (40 minutes) each night for the observation +of the planet with the six-foot instrument, the atmospheric +disturbance, so often a source of annoyance in using so large an +aperture, and other unfavorable circumstances, tended to affect the +value of the observations, and to make the two inner satellites +rarely within detection."</p> + +<p>[Footnote 1: "Monthly Notices R. A. S.," March, 1875.]</p> + +<p>On Feb. 10, 1872, Lord Rosse notes that all four satellites were +seen on the same side of the planet. On Jan. 16, 1873, when +definition was good, no traces of any markings were seen. Diameter +of Uranus = 5.29". Power 414 was usually employed, though at times +the inner satellites could be more satisfactorily seen with +625.</p> + +<p>It may be mentioned as an interesting point that, some fifty +years after the first discovery of Uranus by Herschel, it was +accidentally rediscovered by his son, Sir John Herschel, who +recognized it by its disk, and had no idea as to the identity of +the object until an ephemeris was referred to. Sir John mentions +the fact as follows, in a letter to Admiral Smyth, written in 1830, +August 8:</p> + +<p>"I have just completed two twenty-foot reflectors, and have got +some interesting observations of the satellites of Uranus. The +first sweep I made with my new mirror I <i>re-discovered</i> this +planet by its <i>disk</i>, having blundered upon it by the merest +accident for 19 Capricorni."</p> + +<p>In commenting upon the centenary of an important scientific +discovery we are naturally attracted to inquire what progress has +been made in the same field during the comparatively short interval +of one hundred years which has elapsed since it occurred. We have +called it a short interval, because it cannot be considered +otherwise from an astronomical or geological point of view, though, +as far as human life is concerned, it can only be regarded as a +very lengthy period, including several generations within its +limits.</p> + +<p>Since Herschel, in 1781, discovered Uranus, astronomy has +progressed with great rapidity, so that it would be impossible to +enumerate in a brief memoir the many additional discoveries which +have resulted from assiduous observation. A century ago only five +planets were known (excluding the Earth), now we are acquainted +with about two hundred and thirty of these bodies; and one of +these, found in 1846, is a large planet whose orbit lies exterior +to that of Uranus. In fact, the state of astronomical knowledge a +century ago has undergone wonderful changes. It has been rendered +far more complete and comprehensive by the diligence of its +adherents and by the unwearying energy with which both in theory +and practice it has been pursued. A zone of small planets has been +discovered between Mars and Jupiter just where the analogies of the +planetary distances indicated the probable existence of a large +planet. The far-off Neptune was revealed in 1846 by a process of +analytical reasoning as unique as it was triumphant, and which +proved how well the theory of planetary perturbations was +understood. The planet was discovered by calculation, its position +in the heavens assigned, and the telescope was then employed merely +as the instrument of its detection. The number of satellites which +a century ago numbered only ten has now reached twenty, and the +discovery in 1877 of two moons accompanying Mars shows that the +work is being continued with marked success.</p> + +<p>In other departments we also find similar evidence of increasing +knowledge. The periodicity of the sun spots, the existence of +systems of binary stars, meteor showers, and their affinity with +cometary orbits may be mentioned as among the more important, while +a host of new comets, chiefly telescopic, have been detected. Large +numbers of nebulæ and double stars have been catalogued, and +we have evidence every year of the activity with which these +several branches are being followed up.</p> + +<p>In fine, it matters little to what particular department of +astronomical investigation we look for traces of advancement during +the past hundred years, for it is evident throughout them all, and +sufficiently proves that the interest formerly taken in the science +has not only been well sustained but has become more general and +popular, and is extending its attractive features to all classes of +the community.</p> + +<p>In Herschel's day large telescopes were rare. A man devoting +himself to the study of the heavenly bodies as a means of +intellectual recreation was considered a phenomenon, and indeed +that appellation might be fittingly applied to the few isolated +individuals who really occupied themselves in such work. How +different is the case now that the pleasant ways of science have +called so many to her side and so far perfected her means of +research as to make them accessible to all who care to see and +investigate for themselves the unique and wonderful truths so +easily within reach! Large telescopes have become common enough, +and there is no lack of hands and eyes to utilize them, nor of +understanding, ever ready to appreciate, in sincerity and +humbleness, those objects which display in an eminent degree the +all-wise conceptions of a great Creator! It is, therefore, a most +gratifying sign to notice this rapid development of astronomy, and +to see year by year the increasing number of its advocates and the +record of many new facts gleaned by vigorous observation.</p> + +<p>The character of recent discoveries distinctly intimates that, +in future years, some departments of the science will become very +complicated, owing to the necessity of dealing with a large number +of minute bodies, for the tendency of modern researches has been to +reveal objects which by their faintness had hitherto eluded +detection. And when we consider that these bodies are rapidly +increasing year by year, the idea is obviously suggested that, +inasmuch as their numbers are comparatively illimitable, and there +is likely to be no immediate abatement in the enthusiasm of +observers, difficulties will arise in identifying them apart and +forming them into catalogues with their orbital elements attached, +so that the individual members may be redetected at any time.</p> + +<p>In this connection we allude particularly to minor planets, to +telescopic comets, and to meteoric streams, which severally form a +very numerous group of bodies of which the known members are +accumulating to a great extent. As complications arise, some +remedies must be applied to their solution, and one probable effect +will be that astronomers will be induced each one to have a +specialty or branch to which his energies are mainly directed. The +science will become so wide in its application and so intricate in +its details that it will become more than ever necessary for +observers to select or single out definite lines of investigation +and pursue them closely, for success is far more likely to attend +such exertions than those which are not devoted to any special end, +but employed rather in a general survey of phenomena.</p> + +<p>We have already before us some excellent instances in which +individual energies have been aptly utilized in the prosecution of +original work in some specific branch of astronomy, and we are +strongly disposed to recommend such exclusive labors to those who +have the means and the desire to achieve something useful. +Observers who find one subject monotonous and then take up another +for the sake of variation are not likely to get far advanced in +either. In the case of amateurs who use a telescope merely for +amusement, and indiscriminately apply it to nearly every +conspicuous object in the firmament without any particular purpose +other than to satisfy their curiosity, the matter is somewhat +different, and our remarks are not applicable to them. We refer +more pointedly to those who have a regard for the interests of the +science and whose enthusiasm enables them to work habitually and +with some pertinacity.</p> + +<p>History tells us that the Great Alexander wept when he found he +had no other worlds to conquer, and we fear that some astronomers +will lament that they have little prospect of discovering anything +fresh in a sphere to which our giant telescopes have been so often +directed, but this is founded on a palpable misconception. Certain +objects, such as comets for example, do not require great power, +and the revelation of new meteor showers is entirely a question for +the naked eye. In fact, it may be confidently asserted that +observations undertaken with energy and persistency will, if +rightly directed, more than compensate for defects of instrumental +power.</p> + +<p>It is true, however, that in certain quarters we must look to +large instruments alone for new discoveries. It would be useless +searching for an ultra-Neptunian planet, or for additional +satellites to Uranus or Neptune, or for the materials to determine +the rotation periods of these planets with a small telescope. Every +observer will find objects suited to the capacity of his +instrument, and he may not only employ it usefully but possibly +make a discovery of nearly equal import with that which rendered +the name of Herschel famous a century ago.--<i>Popular Science +Review</i>.</p> + +<hr> +<p><a name="22"></a></p> + +<h2>THE VARYING SUSCEPTIBILITY OF PLANTS AND ANIMALS TO POISONS AND +DISEASES.</h2> + +<p>Much attention is being devoted to the causes which determine +the aptitude or immunity with animals for maladies. This is in a +general sense called medical geography, as a physician who has +prescribed for patients in various parts of the world, and +belonging to different races--the white, yellow, and black--has +been able to note the diversities in the same disease, and the +contradictions in the remedies employed.</p> + +<p>The true social peril, hardly discovered before we became aware +how to conjure it, lies in those legions of animalcules or microbes +that surround us and in the middle of which we live. M. Pasteur has +revealed them to us as the factors in infectious diseases. Claude +Bernard has demonstrated the community which exists between animals +and vegetables--phenomena of movement, of sensibility, of +production of heat, of respiration, of digestion even, for there +are the <i>Drosera</i> and kindred carnivorous plants. Iron cures +chlorosis in vegetables as well as in animals, and chloroform and +ether render both insensible. There resemblances are more striking +still between animals. After Baudrimont, insects are, in presence +of alcohols, chloroform, and irrespirable gases, similarly affected +as man. Many maladies, too, are common to man and several species +of animals; and this organic identity is best illustrated in the +relationship between epidemics and epizootias, cancer, asthma, +phthisis, smallpox, rabies, glanders, charbon, etc., afflict alike +man and many species of animals.</p> + +<p>The differences between races are not less remarkable--odor and +taste, for example. According to anthropophagy, negroes are best, +and white people most detestable. Broca remarked, that, in the +dissecting room, the muscles of the negro putrefied less rapidly +than those of whites. It is perhaps to these anatomical differences +that the diverse action of the same poison, in the case of races or +species, may be attributed. On certain rodentia belladonna +exercises no influence; morphine for a horse is a violent +stimulant; a snail remains insensible to digitalis; goats eat +tobacco with impunity; and in the Tarentin the inhabitants rear +only black sheep, because a plant abounds which is noxious for +white sheep.</p> + +<p>The nature of these conditions is a mystery for science. The +<i>Solanæ</i> tribe of plants furnish a principle which, as +its name implies, produces consolation or forgetfulness, by acting +on the tissues of the brain where resides the organ of thought; +now, on the authority of Professor Bouchardat, these opiates have +the less of effect in proportion as the animals possess the less of +intelligence.</p> + +<p>To the same anatomical peculiarities must be ascribed the choice +that disease makes in such or such a race. Glanders, for instance, +so virulent with the horse, the ass, and man, produce in the case +of the dog only a local accident; peripneumonia, so contagious +among horned cattle, is more benign in its action on Dutch than +other breeds of stock; the cattle plague that decimates so many +farms is communicated by cattle to each other from the slightest +contact, while the closest and most constant association is +necessary to communicate the disease to sheep, and even when they +are affected its action is not severe. Further, that plague only +attacks ruminant animals--oxen, goats, sheep, zebras, gazelles, +etc. Ten years ago this plague broke out in the Jardin +d'Acclimatation; not a ruminant escaped, and also one animal not of +that class, a little tenant nearly related to the pig--the +<i>peccari</i>.</p> + +<p>Now, Dr. Condereau has demonstrated recently that the stomach of +the pig has a rudimentary organization recalling that of the +ruminants. Clearly, the stomach of the peccari, and perhaps that of +the pig, present a favorable medium for the parasitical microbe +peculiar to the rinderpest. In the potato disease, again, all the +varieties are not affected with the same degree of violence; it is +more marked in its action on the round yellows than the reds, and +on the latter rather than the pink. But the symptoms even of the +same malady differ, the parasite's attacks on the tissues being +dissimilar. Oak galls are produced from the prickings of insects; +now around the same larva often four varieties of galls are +recognized. In the case of consumption in cattle, the disease +marches slowly; in that of pigs it takes the galloping form, as +with man.</p> + +<p>Each people or nation has its peculiar pathology and also its +peculiar cures. A negro can take a dose of tartar ten times more +excessive than a white; the same dose of brandy given to a black, a +yellow, and a white, will not produce on the three men either +drunkenness at the same moment, or intoxication at all. Mulattoes +can sustain more drastic aperients than other races; the negro does +not suffer from yellow fever, but he readily falls to phthisis; he +will catch the cholera more quickly than a white. Human races, +where they may catch the same intermittent fever at the identical +moment and in the same swamp, will not the less display different +types of fever. Dr. Crevaux has shown that a certain insect with +the North American Indian is not the same as with the negro or the +maroon, and both differ from that peculiar to Europeans.</p> + +<p>M. Pasteur's beautiful experiments have conclusively +demonstrated that fowls do not catch the <i>charbon</i>; now the +vital warmth of birds is from seven to nine degrees higher than in +the case of mammiferous animals; he imagined that if the fowl was +cooled down by baths to the lower temperature, it would be liable +equally to become affected; he tried, and the result proved he was +correct.</p> + +<p>The absence, then, of a certain temperature would be the reason +why birds are exempt. The microbes are the agents of infectious +disease; when these swarm in the blood of an individual they seem +to leave there something pernicious for parasites resembling +themselves, or to bring away with them something necessary to the +life of their successors. A glass of sugar and water, where leaven +has already fermented and yielded alcohol, is incapable of +producing a second crop of leaven; similarly the blood of an +individual, once contaminated, becomes uninhabitable afterward for +like microbes. The individual has acquired immunity. Such is the +principle of vaccination.--<i>Paris Correspondent of the Kansas +City Review</i>.</p> + +<hr> +<p><a name="23"></a></p> + +<h2>KIND TREATMENT OF HORSES.</h2> + +<p>It has been observed by experienced horse trainers that +naturally vicious horses are rare, and that among those that are +properly trained and kindly treated when colts they are the +exception.</p> + +<p>It is superfluous to say that a gentle and docile horse is +always the more valuable, other qualities being equal, and it is +almost obvious that gentle treatment tends to develop this +admirable quality in the horse as well as in the human species, +while harsh treatment has the contrary tendency. Horses have been +trained so as to be entirely governed by the words of his driver, +and they will obey and perform their simple but important duties +with as much alacrity as the child obeys the direction of the +parent.</p> + +<p>It is true that all horses are not equally intelligent and +tractable, but it is probable that there is less difference among +them in this regard than there is among his human masters, since +there are many incitements and ambitions among men that do not +affect animals.</p> + +<p>The horse learns to know and to have confidence in a gentle +driver, and soon discovers how to secure for himself that which he +desires, and to understand his surroundings and his duties. The +tone, volume, and inflection of his master's voice indicate much, +perhaps more than the words that are spoken. Soothing tones rather +than words calm him if excited by fear or anger, and angry and +excited tones tend to excite or anger him. In short, bad masters +make bad horses.</p> + +<hr> +<p>A catalogue, containing brief notices of many important +scientific papers heretofore published in the SUPPLEMENT, may be +had gratis at this office.</p> + +<hr> +<h2>THE SCIENTIFIC AMERICAN SUPPLEMENT.</h2> + +<h3>PUBLISHED WEEKLY.</h3> + +<p><b>Terms of Subscription, $5 a Year.</b></p> + +<p>Sent by mail, postage prepaid, to subscribers in any part of the +United States or Canada. Six dollars a year, sent, prepaid, to any +foreign country.</p> + +<p>All the back numbers of THE SUPPLEMENT, from the commencement, +January 1, 1876, can be had. Price, 10 cents each.</p> + +<p>All the back volumes of THE SUPPLEMENT can likewise be supplied. +Two volumes are issued yearly. 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By the immense circulation thus given, +public attention is directed to the merits of the new patent, and +sales or introduction often easily effected.</p> + +<p>Any person who has made a new discovery or invention can +ascertain, free of charge, whether a patent can probably be +obtained, by writing to MUNN & Co.</p> + +<p>We also send free our Hand Book about the Patent Laws, Patents, +Caveats. Trade Marks, their costs, and how procured, with hints for +procuring advances on inventions. Address</p> + +<p><b>MUNN & CO., 37 Park Row, New York.</b></p> + +<p>Branch Office, cor. F and 7th Sts., Washington, D. 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You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Scientific American Supplement, No. 303 + October 22, 1881 + +Author: Various + +Posting Date: October 10, 2012 [EBook #8296] +Release Date: June, 2005 +First Posted: July 4, 2003 + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPPL., NO. 303 *** + + + + +Produced by Olaf Voss, Don Kretz, Juliet Sutherland, Charles +Franks and the Online Distributed Proofreading Team. + + + + + + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 303 + + + + +NEW YORK, OCTOBER 22, 1881 + +Scientific American Supplement. Vol. XII, No. 303. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + + TABLE OF CONTENTS + +I. ENGINEERING AND MECHANICS.--New Eighty-ton Steam Hammer at the Saint + Chamond Works, France.--7 figures.--Elevation of hammer.--Profile-- + Transverse section.--Profile view of foundation, etc.--Plan of + plant.--General plan of the forging mill.--Details of truss and + support for the cranes. + + Great Steamers.--Comparative details of the Servia, the City of Rome, + the Alaska, and the Great Eastern. + + Improved Road Locomotive.--2 figures.--Side and end views + + American Milling Methods. By ALBERT HOPPIN.--Ten years' progress.--Low + milling.--Half high milling.--High milling.--Important paper read + before the Pennsylvania State Millers' Association. + + Machine for Dotting Tulles and other Light Fabrics.--3 figures. + +II. TECHNOLOGY AND CHEMISTRY.--The Reproduction and Multiplication of + Negatives. By ERNEST EDWARDS. + + A New Method of Making Gelatine Emulsion. By W. K. BURTON. + + The Pottery and Porcelain Industries of Japan. + + Crystallization Table. + + The Principles of Hop Analysis. By Dr. G. O. CECH. + + Water Gas.--A description of apparatus for producing cheap gas, and + some notes on the economical effects of using such gas with gas + motors, etc.--By J. EMERSON DOWSON. + + On the Fluid Density of Certain Metals. By Professors CHANDLER ROBERTS + and T. WRIGLESON. + +III. PHYSICS, ELECTRICITY, ETC.--Electric Power.--The nature and uses of + electricity.--Electricity vs. steam. + + On the Method of Obtaining and Measuring Very High Vacua with a + Modified Form of Sprengel Pump. By Prof OGDEN N. ROOD.--4 figures.-- + Apparatus for obtaining vacua of one four hundred-millionth of an + atmosphere--Construction.--Manipulation.--Calculations.--Results + +IV. ART, ARCHITECTURE, ETC.--Old Wrought Iron Gates, Guildhall. + Worcester, England. 1 figure. + + The French Crystal Palace, Park of St. Cloud, Paris. 1 full page + illustration. + + Suggestions in Architecture. A Castellated Chateau. Perspective and + plan. Chateau in the AEgean Sea. + +V. HYGIENE AND MEDICINE.--Hydrophobia Prevented by Vaccination. + + On Diptera as Spreaders of Disease. By J. W. SLATER. + + On the Relations of Minute Organisms to Certain Specific Diseases. + +VI. ASTRONOMY--The Centenary of the Discovery of Uranus. By F. W. DENNING. + 2 figures. Approximate place of Uranus among the stars at its + discovery, March l3, 1871.--Orbits of the Uranian Satellites. + +VII. BIOLOGY, ETC.--The Varying Susceptibility of Plants and Animals to + Poisons and Disease. + + Kind Treatment of Horses. + + * * * * * + + + + +NEW EIGHTY TON STEAM HAMMER AT THE SAINT CHAMOND WORKS + + +Ever since the improvements that have been introduced into the +manufacture of steel, and especially into the erection of works for its +production, have made it possible to obtain this metal in very large +masses, it has necessarily been preferred to iron for all pieces of +large dimensions, inasmuch as it possesses in the highest degree that +homogeneousness and resistance which are so difficult to obtain in the +latter metal. It has consequently been found necessary to construct +engines sufficiently powerful to effect the forging of enormous +ingots, as well as special furnaces for heating them and apparatus for +manipulating and transporting them. + +The greatest efforts in this direction have been made with a view to +supplying the wants of heavy artillery and of naval constructions; +and to these efforts is metallurgy indebted for the creation of +establishments on a scale that no one would have dared a few years ago +to think of. The forging mill which we are about to describe is one of +those creations which is destined to remain for a long time yet very +rare; and one which is fully able to respond, not only to all present +exigencies, but also, as far as can be foreseen, to all those that may +arise for a long period to come. The mill is constructed as a portion of +the vast works that the Compagnie des Forges et Acieries de la Marine +own at Saint Chamond, and which embrace likewise a powerful steel works +that furnishes, especially, large ingots exceeding 100 tons in weight. + +The mill consists, altogether, of three hammers, located in the same +room, and being of unequal powers in order to respond to different +requirements. The largest of these hammers is of 80 tons weight, and +the other two weigh respectively 35 and 28 tons. Each of them has +a corresponding furnace for heating by gas, as well as cranes for +maneuvering the ingots and the different engines. The general plan view +in Fig. 4 shows the arrangement of the hammers, cranes, and furnaces in +the millhouse. + +[Illustration: FIG. A.--ELEVATION OF A HAMMER. FIG. B.--PROFILE VIEW] + +The gas generators which supply the gas-furnaces are located out of +doors, as are the steam-generators. The ingots are brought from the +steel factory, and the forged pieces are taken away, by special trucks +running on a system of rails. We shall now give the most important +details in regard to the different parts of the works. + +_The Mill-House_--This consists of a central room, 262 feet long, 98 +feet wide, and 68 feet in height, with two lean-to annexes of 16 feet +each, making the total width 100 feet. The structure is wholly of metal, +and is so arranged as to permit of advantage being taken of every foot +of space under cover. For this purpose the system of construction +without tie-beams, known as the "De Dion type," has been adopted. Fig. +1 gives a general view of one of the trusses, and Fig. 5 shows some +further details. The binding-rafters consist of four angle-irons +connected by cross-bars of flat iron. The covering of corrugated +galvanized iron rests directly upon the binding-rafters, the upper parts +of which are covered with wood for the attachment of the corrugated +metal. The spacing of these rafters is calculated according to the +length of the sheets of corrugated iron, thus dispensing with the use of +ordinary rafters, and making a roof which is at once very light and very +durable, and consequently very economical. Rain falling on the roof +flows into leaden gutters, from whence it is carried by leaders into a +subterranean drain. The vertical walls of the structure are likewise of +corrugated iron, and the general aspect of the building is very original +and very satisfactory. + +_The 80 Ton Hammer_--The three hammers, notwithstanding their difference +in power, present similar arrangements, and scarcely vary except in +dimensions. We shall confine ourselves here to a description of the 80 +ton apparatus. This consists, in addition to the hammer, properly so +called, of three cranes of 120 tons each, serving to maneuver the pieces +to be forged, and of a fourth of 75 tons for maneuvering the working +implements. These four cranes are arranged symmetrically around the +hammer, and are supported at their upper extremity by metallic stays. +Besides the foregoing there are three gas furnaces for heating the +ingots. Figs. 1, 2, and 3 show the general arrangement of the apparatus. + +_Foundations of the Hammer and Composition of the Anvil-Bed_--To obtain +a foundation for the hammer an excavation was made to a depth of 26 feet +until a bed of solid rock was reached, and upon this there was then +spread a thick layer of beton, and upon this again there was placed a +bed of dressed stones in the part that was to receive the anvil-stock +and hammer. + +On this base of dressed stones there was placed a bed formed of logs +of heartwood of oak squaring 16 inches by 3 feet in height, standing +upright, joined together very perfectly, and kept in close juxtaposition +by a double band of iron straps joined by bolts. The object of this +wooden bed was to deaden, in a great measure, the effect of the shock +transmitted by the anvil-stock. + +NEW EIGHTY-TON STEAM HAMMER AT THE ST CHAMOND WORKS. + +[Illustration: FIG. 1.--TRANSVERSE SECTION.] + +[Illustration: FIG. 2.--PLAN.] + +[Illustration: FIG. 3.--PROFILE VIEW.] + +[Illustration: FIG. 4.--GENERAL PLAN OF THE FORGING MILL.] + +[Illustration: FIG. 5.--DETAILS OF THE TRUSSAND SUPPORT FOR THE CRANE.] + +_The Anvil-Stock_.--The anvil-stock, which is pyramidal in shape, and +the total weight of which amounts to 500 tons, is composed of superposed +courses, each formed of one or two blocks of cast iron. Each course +and every contact was very carefully planed in order to make sure of +a perfect fitting of the parts; and all the different blocks were +connected by means of mortises, by hot bandaging, and by joints with +key-pieces, in such a way as to effect a perfect solidity of the parts +and to make the whole compact and impossible to get out of shape. + +The anvil-stock was afterwards surrounded by a filling-in of masonry +composed of rag-stones and a mortar made of cement and hydraulic lime. +This masonry also forms the foundation for the standards of the hammer, +and is capped with dressed stone to receive the bed-plates. + +_The Power-Hammer_ (Figs. A and B).--The power-hammer, properly +so-called, consists, in addition to the hammer-head, of two standards to +whose inner sides are bolted guides upon which slides the moving mass. +The bed-plates of cast iron are 28 inches thick, and are independent of +the anvil-stock. They are set into the bed of dressed stone capping the +foundation, and are connected together by bars of iron and affixed to +the masonry by foundation bolts. To these bedplates are affixed the +standards by means of bolts and keys. The two standards are connected +together by iron plates four inches in thickness, which are set into the +metal and bolted to it so as to secure the utmost strength and solidity. +The platform which connects the upper extremities of the standards +supports the steam cylinder and the apparatus for distributing the +steam. The latter consists of a throttle valve, twelve inches in +diameter, and an eduction valve eighteen inches in diameter, the +maneuvering of which is done by means of rods extending down to a +platform upon which the engineman stands. This platform is so situated +that all orders can be distinctly heard by the engineman, and so that +he shall be protected from the heat radiated by the steel that is +being forged. All the maneuvers of the hammers are effected with most +wonderful facility and with the greatest precision. + +The piston is of cast-steel, and the rod is of iron, 12 inches in +diameter. The waste steam is carried out of the mill by a pipe, and, +before being allowed to escape into the atmosphere, is directed into an +expansion pipe which it penetrates from bottom to top. Here a portion of +the water condenses and flows off, and the steam then escapes into +the open air with a greatly diminished pressure. The object of this +arrangement is to diminish to a considerable extent the shocks and +disagreeable noise that would be produced by the direct escape of the +steam at quite a high pressure and also to avoid the fall of condensed +water. + +The following are a few details regarding the construction of the +hammer: + + Total height of foundations........... 26 ft. + From the ground to the platform ...... 28 " + + Platform .............................. 3.25 " + Height of cylinder.................... 21 " + ________ + + Total height...................... 78.25 ft. + + Weight of anvil-stock................ 500 tons. + Weight of bed-plates................. 122 " + Weight of standards.................. 270 " + Weight of platform and cylinder...... 148 " + Piston, valves, engineman's platform, + hammer, etc........................ 160 " + __________ + + Total weight................... 1,200 tons. + + Weight of the hammer.................. 80 tons. + Maximum fall.......................... 25.75 ft. + Distance apart of the standards....... 21.6 " + Width of hammer....................... 6 " + Pressure of steam..................... 16 lb. + Effective pressure to lift 80 tons.... 7 " +_Description of Figures_.--A, the 80-ton hammer; B, B1, B2, cranes; C, +C1, C2, supports of cranes; D, D1, D2, gas furnaces; A1, the 35-ton +hammer; A2, the 28-ton hammer; EE, railways; F, engineman's platform; G, +lever for maneuvering the throttle valve; H, an ingot being forged. + + * * * * * + + + + +GREAT STEAMERS. + + +The _Brooklyn Eagle_ gives a very interesting description of the three +new steamships now almost completed and shortly to be placed in the New +York and Liverpool trade by the Cunard, Inman, and Williams and Guion +lines. The writer has prepared a table comparing the three vessels +with each other and with the Great Eastern, the only ship of greater +dimensions ever built. We give as much of the article as our space will +allow, and regret that we have not the room to give it entire: + + Line. Cunard. Inman. Guion. Admiralty. + Vessel. Servia City of Rome. Alaska. Great[1] + + Length 530 feet. 546 feet. 520 feet. 679 feet. + Breadth 52 feet. 52 ft. 3 in. 50 ft. 6 in. 82 feet. + Depth 44 ft. 9 in. 37 feet. 38 feet. 60 feet. + Gross ton'ge 8,500 8,300 8,000 13,344[2] + Horse pow'r 10,500 10,000 11,000 2,600 + Speed 171/2 knots. 18 knots. 18 knots. 14 knots. + Sal'n pas- 320 and 52 + sengers. 450 300 2d class + Steerage 600 1,500 1,000 + Where Clydeb'nk Barrow in Clyde, + built. Thomson Furness Elder + Date of + sailing. October 22 October 13 November 5 + +[Footnote 1: To be sold at auction soon.] + +[Footnote 2: Net register.] + +In 1870 the total tonnage of British steam shipping was 1,111,375; the +returns for the year 1876 showed an increase to 2,150,302 tons, and from +that time to the present it has been increasing still more rapidly. But, +as can be seen from the above table, not only has the total tonnage +increased to this enormous extent, but an immense advance has been made +in increasing the size of vessels. The reason for this is, that it has +been found that where speed is required, along with large cargo and +passenger accommodation, a vessel of large dimensions is necessary, and +will give what is required with the least proportionate first cost as +well as working cost. Up to the present time the Inman line possessed, +in the City of Berlin, of 5,491 tons, the vessel of largest tonnage in +existence. Now, however, the Berlin is surpassed by the City of Rome by +nearly 3,000 tons, and the latter is less, by 200 tons, than the Servia, +of the Cunard line. It will be observed, too, that while there is not +much difference between the three vessels in point of length, the depth +of the Alaska and the City of Rome, respectively, is only 38 feet and 37 +feet, that of the Servia is nearly 45 feet as compared with that of the +Great Eastern of 60 feet. This makes the Servia, proportionately, the +deepest ship of all. All three vessels are built of steel. This metal +was chosen not only because of its greater strength as against iron, +but also because it is more ductile and the advantage of less weight is +gained, as will be seen when it is mentioned that the Servia, if built +of iron, would have weighed 620 tons more than she does of steel, and +would have entailed the drawback of a corresponding increase in draught +of water. As regards rig, the three vessels have each a different style. +The Cunard Company have adhered to their special rig--three masts, bark +rigged--believing it to be more ship shape than the practice of fitting +up masts according to the length of the ship. On these masts there is a +good spread of canvas to assist in propelling the ship. The City of Rome +is rigged with four masts; and here the handsome full-ship rig of the +Inman line has been adhered to, with the addition of the fore and aft +rigged jigger mast, rendered necessary by the enormous length of the +vessel. It will be seen that the distinctive type of the Inman line +has not been departed from in respect to the old fashioned but still +handsome profile, with clipper bow, figurehead, and bowsprit--which +latter makes the Rome's length over all 600 feet. For the figurehead +has been chosen a full length figure of one of the Roman Caesars, in the +imperial purple. Altogether, the City of Rome is the most imposing and +beautiful sight that can be seen on the water. The Alaska has also four +masts, but only two crossed. + +The length of the City of Rome, as compared with breadth, insures long +and easy lines for the high speed required; and the depth of hold being +only 37 feet, as compared with the beam of 52 feet, insures great +stability and the consequent comfort of the passengers. A point calling +for special notice is the large number of separate compartments formed +by water tight bulkheads, each extending to the main deck. The largest +of these compartments is only about 60 feet long; and, supposing that +from collision or some other cause, one of these was filled with water, +the trim of the vessel would not be materially affected. With a view to +giving still further safety in the event of collision or stranding, the +boilers are arranged in two boiler rooms, entirely separated from each +other by means of a water tight iron bulkhead. This reduces what, in +nearly all full-powered steamships, is a vast single compartment, into +two of moderate size, 60 feet in length; and in the event of either +boiler room being flooded, it still leaves the vessel with half her +boiler power available, giving a speed of from thirteen to fourteen +knots per hour. The vessel's decks are of iron, covered with teak +planking; while the whole of the deck houses, with turtle decks and +other erections on the upper deck, are of iron, to stand the strains +of an Atlantic winter. Steam is supplied by eight cylindrical tubular +boilers, fired from both ends, each of the boilers being 19 feet long +and having 14 feet mean diameter. There are in all forty eight furnaces. +The internal arrangements are of the finest description. There are two +smoking rooms, and in the after deckhouse is a deck saloon for ladies, +which is fitted up in the most elegant manner, and will prevent the +necessity of going below in showery weather. At the sides of the +hurricane deck are carried twelve life boats, one of which is fitted as +a steam launch. The upper saloon or drawing-room is 100 feet long, the +height between decks being 9 feet. The grand dining-saloon is 52 feet +long, 52 feet wide, and 9 feet high, or 17 feet in the way of the large +opening to the drawing-room above. This opening is surmounted by a +skylight, and forms a very effective and elegant relief to the otherwise +flat and heavy ceiling. There are three large and fourteen small dining +tables, the large tables being arranged longitudinally in the central +part of the saloon, and the small tables at right angles on the sides. +Each diner has his own revolving arm chair, and accommodation is +provided for 250 persons at once. A large American organ is fixed at the +fore end of the room, and opening off through double spring doors at the +foot of the grand staircase is a handsome American luncheon bar, with +the usual fittings. On each side of the vessel, from the saloon to the +after end of the engine room, are placed staterooms providing for 300 +passengers. The arrangements for steerage passengers are of a superior +description. The berths are arranged in single tiers or half rooms, not +double, as is usually the custom, each being separated by a passage, +and having a large side light, thus adding greatly to the light, +ventilation, and comfort of the steerage passengers, and necessitating +the advantage of a smaller number of persons in each room. The City +of Rome is the first of the two due here; she sails from Liverpool on +October 13. + +In the Servia the machinery consists of three cylinder compound surface +condensing engines, one cylinder being 72 inches, and two 100 inches in +diameter, with a stroke of piston of 6 feet 6 inches. There are seven +boilers and thirty-nine furnaces. Practically the Servia is a five +decker, as she is built with four decks--of steel, covered with yellow +pine--and a promenade reserved for passengers. There is a music room on +the upper deck, which is 50 feet by 22 feet, and which is handsomely +fitted up with polished wood panelings. For the convenience of the +passengers there are no less than four different entrances from the +upper deck to the cabins. The saloon is 74 feet by 49 feet, with sitting +accommodations for 350 persons, while the clear height under the beams +is 8 feet 6 inches. The sides are all in fancy woods, with beautifully +polished inlaid panels, and all the upholstery of the saloon is of +morocco leather. For two-thirds of its entire length the lower deck is +fitted up with first class staterooms. The ship is divided into nine +water-tight bulkheads, and she is built according to the Admiralty +requirements for war purposes. There are in all twelve boats equipped +as life-boats. The Servia possesses a peculiarity which will add to her +safety, namely, a double bottom, or inner skin. Thus, were she to +ground on rocks, she would be perfectly safe, so long as the inner skin +remained intact. Steam is used for heating the cabins and saloons, and +by this means the temperature can be properly adjusted in all weathers. +In every part of the vessel the most advanced scientific improvements +have been adopted. The Servia leaves Liverpool on October 22. + +The Alaska, whose owners, it is understood, are determined to make her +beat all afloat in speed, does not sail until November 5, and therefore +it is premature to say anything about her interior equipments. She is +the sister of the celebrated Arizona, and was built by the well-known +firm of Elder & Co., on the Clyde. + + * * * * * + + + + +IMPROVED ROAD LOCOMOTIVE. + + +Several attempts have been made to connect the leading wheels of a +traction engine with the driving wheels, so as to make drivers of all of +them, and thus increase the tractive power of the engine, and to afford +greater facilities for getting along soft ground or out of holes. The +wheels with continuous railway and India-rubber tires have been employed +to gain the required adhesion, but these wheels have been too costly, +and the attempts to couple driving and leading wheels have failed. The +arrangement for making the leading wheels into drivers, illustrated +on page 4825, has been recently brought out by the Durham and North +Yorkshire Steam Cultivation Company, Ripon, the design being by Messrs. +Johnson and Phillips. The invention consists in mounting the leading +axle in a ball and long socket, the socket being rotated in fixed +bearings. The ball having but limited range of motion in the socket, is +driven round with it, but is free to move in azimuth for steering. + +This engine has now been in use more than twelve months in traction +and thrashing work, and, we are informed, with complete success. The +illustrations represent a 7-horse power, with a cylinder 8 in. diameter +by 12 in. stroke, and steam jacketed. The shafts and axles are of +Bowling iron. The boiler contains 140 ft. of heating surface, and is +made entirely of Bowling iron, with the longitudinal seams welded. The +gearing is fitted with two speeds arranged to travel at 11/2 and 3 miles +per hour, and the front or hind road wheels can be put out of gear when +not required. The hind driving wheels are 5 ft. 6 in. diameter, and the +front wheels 5 ft.; weight of engine 8 tons.--_The Engineer._ + +[Illustration: IMPROVED ROAD LOCOMOTIVE] + +[Illustration: IMPROVED ROAD LOCOMOTIVE] + + * * * * * + + + + +AMERICAN MILLING METHODS. + +[Footnote 1: A paper read before the meeting of the Pennsylvania State +Millers Association at Pittsburgh, Pa., by Albert Hoppin, Editor of the +_Northwestern Miller_.] + +By ALBERT HOPPIN. + + +To speak of the wonderful strides which the art of milling has taken +during the past decade has become exceedingly trite. This progress, +patent to the most casual observer, is a marked example of the power +inherent in man to overcome natural obstacles. Had the climatic +conditions of the Northwest allowed the raising of as good winter wheat +as that raised in winter wheat sections generally, I doubt if we should +hear so much to-day of new processes and gradual reduction systems. So +long as the great bulk of our supply of breadstuffs came from the winter +wheat fields, progress was very slow; the mills of 1860, and I may even +say of 1870, being but little in advance, so far as processes were +concerned, of those built half a century earlier. The reason for this +lack of progress may be found in the ease with which winter wheat could +be made into good, white, merchantable flour. That this flour was +inferior to the flour turned out by winter wheat mills now is proven by +the old recipe for telling good flour from that which was bad, viz.: To +throw a handful against the side of the barrel, if it stuck there it was +good, the color being of a yellowish cast. What good winter wheat patent +to-day will do this? Still the old time winter wheat flour was the best +there was, and it had no competitor. The settling up of the Northwest +which could not produce winter wheat at all, but which did produce a +most superior article of hard spring wheat, was a new factor in the +milling problem. The first mills built in the spring wheat States tried +to make flour on the old system and made a most lamentable failure of +it. I can remember when the farmer in Wisconsin, who liked a good loaf +of bread, thought it necessary to raise a little patch of winter wheat +for his own use. He oftener failed than succeeded, and most frequently +gave it up as a bad job. Spring wheat was hard, with a very tender, +brittle bran. If ground fine enough to make a good yield a good share +of the bran went into the flour, making it dark and specky. If not +so finely ground the flour was whiter, but the large percentage of +middlings made the yield per bushel ruinously small. These middlings +contained the choicest part of the flour producing part of the berry, +but owing to the dirt, germ, and other impurities mixed with them, it +was impossible to regrind them except for a low grade flour. Merchant +milling of spring wheat was impossible wherever the flour came in +competition with winter wheat flours. At Minneapolis, where the millers +had an almost unlimited water power, and wheat at the lowest price, +merchant milling was almost given up as impracticable. It was certainly +unprofitable. To the apparently insurmountable obstacles in the way of +milling spring wheat successfully, we may ascribe the progress of modern +milling. Had it been as easy to raise good winter wheat in Wisconsin and +Minnesota as in Pennsylvania and Ohio, or as easy to make white flour +from spring as from winter wheat, we should not have heard of purifiers +and roller mills for years to come. + +The first step in advance was the introduction of a machine to purify +middlings. It was found that the flour made from these purified +middlings was whiter than the flour from the first grinding and brought +a better price than even winter wheat flours. Then the aim was to make +as many middlings as possible. To do this and still clean the bran so +as to make a reasonable yield the dress of the burrs was more carefully +attended to, the old fashioned cracks were left out, the faces and +furrows made smooth, true, and uniform, self-adjusting drivers +introduced, and the driving gear better fitted. Spring wheat patents +rapidly rose to the first place in the market, and winter wheat millers +waked up to find their vantage ground occupied by their hitherto +contemned rivals. To their credit it may be said that they have not +been slow in taking up the gauntlet, and through the competition of the +millers of the two climatically divided sections of this country with +each other and among themselves the onward march of milling progress has +been constantly accelerated. Where it will end no man can tell, and +the chief anxiety of every progressive miller, whether he lives in +Pennsylvania or Minnesota, is not to be left behind in the race. + +The millers of the more Eastern winter wheat States have a two-fold +question to solve. First, how to make a flour as good as can be found in +the market, and second, how to meet Western competition, which, through +cheap raw material and discriminating freight rates, is making serious +inroads upon the local markets. Whether the latter trouble can be +remedied by legislature, either State or national, or not, remains to be +proven by actual trial. That you can solve the first part of the problem +satisfactorily to yourselves depends upon your readiness to adopt new +ideas and the means you have at hand to carry them out. It is manifestly +impossible to make as good a flour out of soft starchy wheat as out of +that which is harder and more glutinous. It is equally impossible for +the small mill poorly provided with machinery to cope successfully +with the large merchant mill fully equipped with every appliance that +American ingenuity can suggest and money can buy. I believe, however, +that a mill of moderate size can make flour equally as good as the large +mill, though, perhaps, not as economically in regard to yield and cost +of manufacture. + +The different methods of milling at present in use may be generally +divided into three distinct processes, which, for want of any better +names, I will distinguish as old style, new process, and gradual +reduction. Perhaps the German division of low milling, half high +milling, and high milling is better. Old style milling was that in +general use in this country up to 1870, and which is still followed in +the great majority of small custom or grist mills. It is very simple, +consisting of grinding the wheat as fine as possible at the first +grinding, and separating the meal into flour, superfine or extra, +middlings, shorts, and bran. Given a pair of millstones and reel long +enough, and the wheat could be made into flour by passing through the +two. Because spring wheat was so poorly adapted to this crude process, +it had to be improved and elaborated, resulting in the new process. + +At first this merely consisted of purifying and regrinding the middlings +made in the old way. In its perfected state it may be said to be halfway +between the old style and gradual reduction, and is in use now in many +mills. In it mill stones are used to make the reductions which are only +two in number, in the first of which the aim of the miller is to make as +many middlings as he can while cleaning the bran reasonably well, and +in the second to make the purified middlings into flour. In the most +advanced mills which use the new process, the bran is reground and the +tailings from the coarse middlings, containing germ and large middlings +with pieces of bran attached, are crushed between two rolls. These +can hardly be counted as reductions, as they are simply the finishing +touches, put on to aid in working the stuff up clean and to permit of +a little higher grinding at first. Regarding both old style and new +process milling, you are already posted. Gradual reduction is newer, +much more extensive, and merits a much more thorough explanation. Before +entering upon this I will call your attention to one or two points which +every miller should understand. + +The two essential qualities of a good marketable flour are color and +strength. It should be sharply granular and not feel flat and soft to +the touch. A wheat which has an abundance of starch, but is poor in +gluten, cannot make a strong flour. This is the trouble with all soft +wheats, both winter and spring. A wheat which is rich in gluten is hard, +and in the case of our hard Minnesota wheat has a very tender bran. +It is comparatively easy to make a strong flour, but it requires very +careful milling to make a flour of good color from it. Probably the +wheat which combines the most desirable qualities for flour-making +purposes is the red Mediterranean, which has plenty of gluten and a +tough bran, though claimed by some to have a little too much coloring +matter, while the body of the berry is white. By poor milling a good +wheat can be made into flour deficient both in strength and color, and +by careful milling a wheat naturally deficient in strength may be made +into flour having all the strength there was in the wheat originally and +of good color. Good milling is indispensable, no matter what the quality +of the wheat may be. + +The idea of gradual reduction milling was borrowed by our millers from +the Hungarian mills. There is, however, this difference between the +Hungarian system and gradual reduction, as applied in this country, that +in the former, when fully carried out, the products of the different +breaks are kept separate to the end, and a large number of different +grades of flour made, while in the system, as applied in this country, +the separations are combined at different stages and usually only three +different grades of flour made, viz.: patent, baker's, or as it is +termed in Minnesota, clear flour, and low grade or red dog. In the +largest mills the patent is often subdivided into first and second, and +they may make different grades of baker's flour, these mills approaching +much nearer to the Hungarian system, though modifying it to American +methods and machinery. In mills of from three to five hundred barrels +daily capacity, it is hardly possible or profitable to go to this +subdivision of grades, owing to the excessive amount of machinery +necessary to handling the stuff in its different stages of completion. +The Hungarian system has, therefore, been greatly modified by American +millers and milling engineers to adapt it to the requirements of mills +of average capacity. This modified Hungarian system we call gradual +reduction. It can be profitably employed in any mill large enough to run +at all on merchant work. So far it has not been found practicable to use +it in mills of less than one hundred and twenty-five to one hundred and +fifty barrels capacity in twenty-four hours, and it is better to have +the mill of at least double this capacity. + +Gradual reduction, as its name implies, consists in reducing the +wheat to flour, shorts, and bran, by several successive operations or +reductions technically called breaks, the process going on gradually, +each break leaving the material a little finer than the preceding one. +Usually five reductions or breaks are made, though six or seven may be +used. The larger the number of breaks the more complicated the system +becomes, and it is preferable to keep it as simple as possible, for even +at its simplest it requires a good, wide-awake thinking miller to handle +it successfully. When it is thoroughly and systematically carried out in +the mill it is without question as much in advance of the new process as +that is ahead of the old style of milling. + +In order that I may convey to you as clear an idea of gradual milling +reduction as possible, I will give as fully as possible the programme of +a mill of one hundred and fifty barrels maximum daily capacity designed +to work on mixed hard and soft spring wheat, and which probably will +come much nearer to meeting the conditions under which you have to mill +than any other I have found readily obtainable. I have chosen a mill of +this size, first, because following out the programme of a larger one +would require too much time and too great a repetition of details and +not give you any clearer idea of the main principles involved, and +secondly, because I thought it would come nearer meeting the average +requirements of the members of your association. Your worthy secretary +cautioned me that I must remember that I was going to talk to winter +wheat millers. The main principles and methods of gradual reduction are +the same, whether applied to spring or winter wheat; the details may +have to be varied to suit the varying conditions under which different +mills are operated. For this programme I am indebted to Mr. James Pye, +of Minneapolis, who is rapidly gaining an enviable and well deserved +reputation as a milling engineer, and one who has given much study to +the practical planning and working of gradual reduction mills. + +And right here let me say that no miller should undertake to build +a gradual reduction mill, or to change over his mill to the gradual +reduction system, until he has consulted with some good milling engineer +(the term millwright means very little nowadays), and obtained from him +a programme which shall fit the size of the mill, the stock upon which +it has to work, and the grade of flour which it is to make. This +programme is to the miller what a chart is to the sailor. It shows him +the course he must pursue, how the stuff must be handled, and where it +must go. Without it he will be "going it blind," or at best only feeling +his way in the dark. A gradual reduction mill, to be successful, must +have a well-defined system, and to have this system, the miller must +have a definite plan to work by. But to go on with my programme. + +The wheat is first cleaned as thoroughly as possible to remove all +extraneous impurities. In the cleaning operations care should be taken +to scratch or abrade the bran as little as possible, for this reason: +The outer coating of the bran is hard and more or less friable. Wherever +it is scratched a portion is liable to become finely comminuted in the +subsequent reductions, so finely that it is impossible to separate it +from the flour by bolting, and consequently the grade of the latter is +lowered. The ultimate purpose of the miller being to separate the flour +portion of the berry from dirt, germ, and bran it is important that he +does not at any stage of the process get any dirt or fine bran speck or +dust mixed in with his flour, for if he does he cannot get rid of it +again. So it must be borne in mind that at all stages of flouring, any +abrasion or comminution of the bran is to be avoided as far as possible. + +After the wheat is cleaned, it is by the first break or reduction split +or cut open, in order to liberate the germ and crease impurities. As +whatever of dirt is liberated by this break becomes mixed in with the +flour, it is desirable to keep the amount of the latter as small as +possible. Indeed, in all the reductions the object is to make as little +flour and as many middlings as possible, for the reason that the latter +can be purified, while the former cannot, at least by any means at +present in use. After the first break the cracked wheat goes to a +scalping reel covered with No. 22 wire cloth. The flour, middlings, +etc., go through the cloth, and the cracked wheat goes over the tail of +the reel to the second machine, which breaks it still finer. After this +break the flour and middlings are scalped out on a reel covered with +No. 22 wire cloth. The tailings go to the third machine, and are still +further reduced, then through a reel covered with No. 24 wire cloth. The +tailings go to the fourth machine, which makes them still finer, then +through a fourth scalping reel the same as the third. The tailings from +this reel are mostly bran with some middlings adhering, and go to the +fifth machine, which cleans the bran. From this break the material +passes to a reel covered with bolting cloth varying in fineness from No. +10 at the head to No. 00 at the tail. What goes over the tail of this +reel is sent to the bran bin, and that which goes through next to the +tail of the reel, goes to the shorts bin. The middlings from this reel +go to a middlings purifier, which I will call No. 1, or bran middlings +purifier. The flour which comes from this reel is sent to the chop reel +covered at the head with say No. 9, with about No. 5 in the middle and +No 0 at the tail. You will remember that after each reduction the flour +and middlings were taken out by the scalping reels. This chop, as it is +now called, also goes to the same reel I have just mentioned. The +coarse middlings which go over the tail of this reel go to a middlings +purifier, which I will designate as No. 2. These go through the No. 0 +cloth at the tail of the reel purifier No. 3; those which go through No. +5 cloth got to purifier No. 4; while all that goes through the No. 9 +cloth at the head of the reel is dropped to a second reel clothed with +Nos. 13 to 15 cloth with two feet of No. 10 at the tail. The flour from +this reel goes to the baker's flour packer; that which drops through the +No. 10 is sent to the middlings stone, while that which goes over the +tail of the reel goes to purifier No. 4. We have now disposed of all the +immediate products of the first five breaks, tracing them successively +to the bran and shorts bins, to the baker's flour packer and to the +middlings purifiers, a very small portion going to the middlings stone +without going through the purifiers. + +The middlings are handled as follows in the purifiers. From the No. 1 +machine, which takes the middlings from the fifth break, the tailings go +to the shorts bin, the middlings which are sufficiently well purified go +to the middlings stone, while those from near the tail of the machine +which contain a little germ and bran specks go to the second germ rolls, +these being a pair of smooth rolls which flatten out the germ and crush +the middlings, loosening adhering particles from the bran specks. From +the second germ rolls the material goes to a reel, where it is separated +into flour which goes into the baker's grade, fine middlings which are +returned to the second germ rolls at once, some still coarser which go +to a pair of finely corrugated iron rolls for red dog, and what goes +over the tail of the reel goes to the shorts bin. The No. 2 purifier +takes the coarse middlings from the tail of the first or chop reel as +already stated. The tailings from this machine go to the shorts bin, +some few middlings from next the tail of the machine are returned to the +head of the same machine, while the remainder are sent to the first germ +rolls. The reason for returning is more to enable the miller to keep a +regular feed on the purifiers than otherwise. The No. 3 purifier takes +the middlings from the 0 cloth on the chop reel. From purifier No. 3 +they drop to purifier No. 5. A small portion that are not sufficiently +well purified are returned to the head of No. 3, while those from the +head of the machine, which are well purified, are sent to the middlings +stones. The remainder, which contain a great deal of the germ, are taken +to the first germ rolls, in passing which they are crushed lightly to +flatten the germ without making any more flour than necessary. The No. 4 +purifier takes the middlings from No. 2 and also from No. 5 cloth on +the chop reel and from the No. 10 on the tail of the baker's reel. The +middlings from the head of this machine go to the middlings stones, and +the remainder to purifier No. 6. The tailings from Nos. 3, 4, 5, and 6 +go to the red dog rolls. A small portion not sufficiently well purified +are returned from No. 6 to the head of No. 4, while the cleaned +middlings go to the middlings stones. + +The portions of the material which have not been traced either to the +baker's flour or the bran and shorts bins are the middlings which have +gone to the middlings stones, the germy middlings which have gone to the +first germ rolls, and the tailings from purifiers Nos. 3, 4, 5, and 6, +and some little stuff not quite poor enough for shorts from the reel +following the second germ rolls. Taking these _seriatim_: the middlings +after passing through the middlings stones, go to the first patent reel +covered with eleven feet of No. 13 and four feet of No. 8. The flour +from the head of the reel goes to the patent packer, that from the +remainder of the reel is dropped to another reel, while the tailings go +to the No. 4 purifier. The lower patent reel is clothed with No. 14 and +two feet of No. 10 cloth; from the head of the reel the flour goes to +the patent packer, the remainder that passes through the No. 10 cloth +which will not do to go into the patent, being returned to the middlings +stones, while the tailings are sent to the No. 4 purifier. + +The germ middlings, after being slightly crushed as before stated, are +sent to a reel covered with five feet of No. 13 cloth, five feet of No. +14, and the balance with cloth varying in coarseness from No. 7 to No. +00. The flour from this reel goes into the patent, the tailings to the +red dog rolls, the middlings from next the tail of the reel which still +contain some germ to the second germ rolls, while the middlings which +are free from germ go to the middlings stones. + +The tailings from purifiers 3, 4, 5, and 6, the material from the reel +following the second germ rolls, which is too good for shorts, but not +good enough to be returned into middlings again, and the tailings from +the reel following the first germ rolls are sent to the red dog rolls, +which, as I have stated, are finely corrugated. Following these rolls is +the red dog reel. The flour goes to the red dog bin, the tailings to +the shorts bin, while some stuff intermediate between the two, not fine +enough for the flour but too good for shorts, is returned to the red dog +rolls. + +This finishes the programme. I have not given it as one which is exactly +suited to winter wheat milling. However, as I said before, the general +principles are the same in either winter or wheat gradual reduction +mills, and the various systems of gradual reduction, although they +differ in many points, and although there are probably no two engineers +who would agree as to all the details of a programme, the main ideas +are essentially the same. The system has been well described as one of +gradual and continued purification. In the programme above given the +idea was to fit up a mill which should do a maximum amount of work of +good quality with a minimum amount of expenditure and machinery. In a +larger mill or even in a mill of the same capacity where money was not +an object, the various separations would probably be handled a little +differently, the flour and middlings from the first and fifth breaks +being handled together, and those from the second, third, and fourth +breaks being also handled together. The reason for this separation being +that the flour from the first and fifth breaks contain, the first a +great deal of crease dirt, and the fifth more bran dust than that from +the other breaks, the result being a lower grade of flour. The object +all along being to keep the amount of flour with which dirt can get +mixed as small as possible, and not to lower the grade of any part of +the product by mixing it with that which is inferior, always bearing in +mind that the aim is to make as many middlings as possible, for they can +be purified while the flour can not, and that whenever any dirt is once +eliminated it should be kept out afterwards. This leads me to say that +if a miller thinks the adoption of rolls or reduction machines is all +there is of the system, he is very much mistaken. If anything, more of +the success of the mill depends upon the careful handling of the stuff +after the breaks are made, and here the miller who is in earnest to +master the gradual reduction system will find his greatest opportunities +for study and improvement. A few years back it was an axiom of the trade +that the condition of the millstone was the key to successful +milling. This was true because the subsequent process of bolting was +comparatively simple. Now the mere making of the breaks is a small +matter compared with the complex separations which come after. In +the foregoing programme we had five breaks or successive reductions. +Although this is better than a smaller number, I will here say that +it is not absolutely essential, for very good work is done with four +breaks. The mill for which this programme was made, including the +building, cost about $15,000, and is designed to make about sixty per +cent. of patent, thirty-five per cent. of baker's, and five per cent. +of low grade, results which are in advance of many larger and more +pretentious mills. + +One difficulty in the way of adapting the gradual reduction system to +mills of very small capacity is that the various machines require to be +loaded to a certain degree in order to work at their best. It is only a +matter of short time when our milling inventors will design machinery +especially for small mills; in fact they are now doing it, and every +day brings it more within the power of the small miller to improve his +manner of milling. To show what can be done in this direction I will +briefly describe a mill of about ninety barrels maximum capacity per +twenty-four hours, which is as small as can be profitably worked. I will +premise this description by saying it is designed with a view to the +greatest economy of cost, the best trade of work, and to reduce the +amount of machinery and the handling of the stuff as much as possible. +This latter point is of much importance in any mill, either large or +small, no matter upon what system it is operated, for it takes power to +run elevators and conveyors, and especially in elevating and conveying +middlings, especially those made from winter wheat, their quality is +inured and a loss incurred, by the unavoidable amount of flour made by +the friction of the particles against each other. So much is this the +case that in one of our largest mills it is deemed preferable to move +the middlings from one end of the mill to the other by means of a hopper +bin on a car which runs on a track spiked to the floor, rather than to +employ a conveyor. A mill built as I am going to describe would require +from fifty to sixty horse-power to run it, and including steam power and +building would cost from $10,000 to $12,000, according to location. I +give it as of interest to those among your number who own small mills +and may contemplate improving them. + +The building is four stories high, including basement, and thirty-two +feet square. It would be some better to have it larger, but it is made +this small to show how small a space a mill of this size can be made to +occupy. No story is less than twelve feet high. The machinery Is very +conveniently arranged, and there is plenty of room all around. The +system is a modification of the gradual reduction system, the middlings +being worked upon millstones. The first break is on one pair of 9 x +18 inch corrugated iron rolls, eight corrugations to the inch, the +corrugations running parallel with the axis of the rolls. The second +break on rolls having twelve corrugations to the inch, the third +sixteen, and the fourth twenty to the inch, while the fifth break, where +the bran is finally cleaned, has twenty-four corrugations to the inch. +The basement contains the line shaft and pulleys for driving rolls, +stones, cockle machine, and separator. The only other machinery in the +basement is the cockle machine. The line shaft runs directly through +the center of the basement, the power being from engine or water wheel +outside the building. The first floor has the roller mills in a line +nearly over the line shaft below, the middlings stones, two in number, +at one side opposite the entrance to the mill, the receiving bin at +one side of the entrance in the corner of the mill, and the two flour +packers for the baker's and patent flour in the other corner. This +arrangement leaves over half of the floor area for receiving and packing +purposes. The bolting chests, one with six reel and the other with three +reel begin on the second floor and reach up into the attic. An upright +shaft from the line shaft in the basement geared to a horizontal shaft +running through the attic parallel with the line shaft below, comprise +about all the shafting there is in the mill. There is a short shaft on +the second floor from which the two purifiers on this floor and the two +in the attic are driven, and another short shaft on the first floor to +drive the packers. There are four purifiers, two on the second floor, +and two more directly over them in the attic. The elevator heads are all +directly upon the attic line shaft, and the bolting chests are driven by +uprights dropped from this shaft. The combined smutter and brush machine +is on the third floor at one end of the bolting chests and directly over +the stock hoppers. This comprises all the machinery in the mill. The +programme is about as follows: + +The break reels are clothed as follows: First break No. 20, wire cloth, +second break No. 22, third break No. 24, and fourth break No. 24. The +material passing through these scalping reels, now called chop, goes to +a series of reels, the first clothed with Nos. 6, 4, and 0. The material +passing over the tail is sent to the germ purifier, that passing through +Nos. 4 and 0, to the coarse middlings purifier, and that through the No. +6 goes to the reel below clothed with Nos. 12 and 13. Some nice granular +flour is taken off from this reel; the remainder, which passes over the +tail and through the cutoffs, goes to the next reel below clothed with +Nos. 14, 15, and 9. Some good flour comes from the 14 and 15; that which +passes through the 9 goes at once to the stones without purifying, while +that which passes over the tail is sent to the fine middlings purifiers. + +After the purification, the middlings are ground on stones and bolted +on Nos. 13 and 14 cloth, after having been scalped on No 8. The germ +middlings are crushed on smooth rolls and bolted on Nos. 12 and 13. What +is not crushed fine enough goes with poor tailings to the second germ +rolls, and from these to a reel by themselves or to the fifth reduction +or bran reel. A mill of this kind could be made much more perfect by an +expenditure of two or three thousands dollars more. I have instanced it +to show what can be done with gradual reduction in a very small way. + +In mills of from three hundred to five hundred barrels capacity and +still larger, the programme differs considerably from that I have +sketched, the middlings being graded and handled with little, if any, +returning, and are sized down on the smooth rolls, a much larger +percentage of the work of flouring being done on millstones. For a three +hundred barrel roller mill, the following plant is requisite: five +double corrugated roller mills, five double smooth roller mills, three +pairs of four foot burrs sixteen purifiers, four wire scalping reels, +six feet long, one reel for the fifth break, one reel for low grade +flour, eight chop reels, seven reels for flour from smooth rolls, three +reels for the stone flour, two grading reels, three flour packers, and +necessary cleaning machinery. The reels are eighteen feet thirty-two +inches. The programme is necessarily more complicated. + +When it comes to the machinery to be employed in making the reductions +or breaks, the miller has several styles from which to choose. Which is +best comes under the head of what I don't know, and moreover, of that +which I have found no one else who does know. Each machine has its good +points, and the mill owner must make his own decision as to which is +best suited to his purpose. The main principles involved are to abrade +the bran as little as possible while cleaning it thoroughly, and to make +as little break flour, and as many middlings as possible, the latter to +be made in such shape as to be the most easily purified. Regarding +the difference between spring and winter wheat for gradual reduction +milling, it may be stated something after this manner: Spring wheat +has a thinner and more tender bran, makes more middlings because it is +harder, and for the same reason the flour is more inclined to be coarse +and granular. In milling with winter wheat, especially the better +varieties, there will be more break flour made, the middlings will be +finer with fewer bran specks, and the bran more easily cleaned, because +it will stand harsher treatment. Winter wheat, moreover, requires more +careful handling in making the breaks, not because of the bran, but to +avoid breaking down the middlings, and making too much and too fine and +soft break flour. In order to keep the flour sharp and granular, coarser +cloths are used in bolting, and because the middlings are finer the +bolting is not so free and a larger bolting surface is required. In +milling either spring or winter wheat there should be ample purifying +capacity, it being very unwise to limit the number of machines, so that +any of them will be overtaxed. The day has gone by when one purifier +will take care of all the middlings in the mill. + +There is one point which is of much interest to mill owners who wish to +change their mills over to the gradual reduction process, that is, how +far they can utilize their present plan of milling machinery in making +the change. Of course the cleaning machinery is the same In both cases, +so are the elevators, conveyors, bolting chests, etc. But to use the +millstone is a debatable question. After carefully considering the +matter I have come to the conclusion that it has its place, and an +important one at that, under the new regime, viz., that of reducing +the finer purified middlings to flour. The reason for this lies in the +peculiar construction of the wheat berry. If the interior of the berry +were one solid mass of flour, needing only to be broken up to the +requisite fineness, it could be done as well on the rolls. But instead +of this, as is well known, the flour part of the berry is made up of +a large number of granules or cells, the walls of which are cellular +tissue, different from the bran in that it is soft and white instead of +hard and dark colored. It is also fibrous to a certain extent, and when +the fine middlings are passed between the rolls instead of breaking +down and becoming finer, it has a tendency to cake up and flatten out, +rendering the flour soft and flaky. It does not hurt the color, but it +does hurt the strength. When the millstone is used in place of the roll +the flour is of equally good color, and more round and granular. I +know that in this the advocates of smooth rolls will differ from my +conclusions, but I believe that the final outcome will be the use of +millstones on the finer middlings, and in fact on all the middlings that +are thoroughly freed from the germ. + +It has been said that that which a man gives the most freely and +receives with the worst grace is advice. I will, however, close with a +little of the article which may not be wholly put of place. If you have +a mill do not imagine that the addition of a few pairs of rolls, a +purifier or two, and a little overhauling of bolting-chests, is going to +make it a full-fledged Hungarian roller mill. If you are going to change +an old mill or build a new one, do not take the counsel or follow the +plans of every itinerant miller or millwright who claims to know all +about gradual reduction. No matter what kind of a mill you want to +build, go to some milling engineer who has a reputation for good work, +tell him how large a mill you want, show him samples of the wheat it +must use and the grades of flour it must make, and have him make a +programme for the mill and plan the machinery to fit it. Then have the +mill built to fit the machinery. When it starts follow the programme, +whether it agrees with your preconceived notions or not, and the mill +will, in ninety-nine cases out of one hundred, do good work. + + * * * * * + + +MACHINE FOR DOTTING TULLES AND OTHER LIGHT FABRICS. + +Dotted or chenilled tulles are fabrics extensively used in the toilet +of ladies, and the ornamentation of which has hitherto been done by +the application to the tissue, by hand, either of chenille or of small +circles previously cut out of velvet. This work, which naturally takes +considerable time, greatly increases the cost price of the article. + +A few trials at doing the work mechanically have been made, but without +any practical outcome. The workwomen who do the dotting are paid at +Lyons at the rate of 80 centimes per 100 dots; so that if we take +tulle with dots counter-simpled 0.04 of an inch, which is the smallest +quincunx used, and suppose that the tissue is 31 inches wide and that +the daily maximum production is one yard, we find that 400 dots at 80 +centimes per 100 = 3 francs and 20 centimes (about 63 cents), the cost +of dotting per yard. It is true that the workwoman furnishes the velvet +herself. + +Mr. C. Ricanet, of Lyons, has recently invented a machine with which he +effects mechanically the different operations of dotting, not only on +tulles but also upon gauzes or any other light tissues whatever, such +as those of cotton, silk, wool, etc. Aided by a talented mechanic, Mr. +Ricanet has succeeded in constructing one of those masterpieces of +wonderfully accurate mechanism of which the textile industry appears +to have the monopoly--at least it is permissible to judge so from the +remarkable inventions of Vaucanson, Jacquard, Philippe de Girard, +Heilmann, and others. + +The object of this new machine, then, which has been doing its wonderful +work for a few days only, is to reproduce artificially chenille +embroidered on light tissues, by mechanically cutting out and gluing +small circles of velvet upon these fabrics. + +For this purpose all kinds of velvet may be employed, and, in order to +facilitate the cutting, they are previously coated on the reverse side +with any glue or gum whatever, which gives the velvet a stiffness +favorable to the action of the punch. To effect the object desired the +apparatus has three successive operations to perform: first, cutting the +circles; second, moistening; and third, fastening down the dots upon the +tissue according to a definite order and spacing. The machine may be +constructed upon any scale whatever, although at present it is only made +for operating on pieces 31 inches wide, that being the normal width of +dotted tulles. The quincuncial arrangement of the dots is effected by +the punching, moistening, and fastening down of odd and even dots, +combined with the forward movement of the tissue to be chenilled. + +The principal part of the machine is the cam-shaft, A (Figs. 1, 2, and +3), which revolves in the direction of the arrows and passes in the +center of 80 cam-wheels, 40 of which are odd and 40 even, alternately +opposed to each other. This shaft actuates, through its two extremities, +the different combined motions in view of the final object to be +attained, and also carries the motive pulleys, PP'. Figs. 1 and 2 show +the profile of two of these opposed cam-wheels--the arrangement by means +of which two rows of dots (odd and even) are laid down upon the tissue +during one revolution of the shaft or drum, A. Each of the wheels +carries three cams (Figs. 1 and 3), the first, (_a_), corresponding to +the punching; the second, (_a'_), to the moistening, and the third, +(_a''_), to the gluing down of the dots. + +The annexed figure, one-quarter actual size, shows in section the +details of the cutting mechanism. To each cam-wheel there corresponds +one punch, and the eighty punches are arranged side by side and parallel +upon a shaft, B, a spring, _b_, holding them constantly against the +circumference of the cam-wheels. In Fig. 2 only one of these details is +shown. The punching arrangement consists of an ordinary punch, _c_, of +variable diameter, screwed to the extremity of a tube, _d_, which is +itself suspended from the end of the lever, _p_, but which can receive +from it at the desired moment the pressure necessary to effect the +cutting. The vertical position of these multiple tubes is insured by +a guide, _e_, which is thoroughly indispensable. Through each of the +tubes, _d_, there passes a plunger designed for expelling from the punch +the piece that has been cut out of the velvet, and for gluing it down to +the fabric. The two small springs, _b'_ and _b''_, tend continually to +lift the tubes as well as the plunger. The whole mechanism is affixed to +solid cast-iron frames, and the machine itself may be mounted on wooden +supports or a metal frame. + +The punching is effected on a bronze straight-edge, C, which slides in a +cast-iron channel, D. This presents alternately, in its movement, entire +and punctured spaces, the former for receiving the blow of the punch and +the latter for allowing passage at the desired moment to the plunger +as it goes to fasten the dots upon the tulle which is passing along +underneath the channel, D. The punching is done primarily and +principally by pressure, but, in order to facilitate the complete +detachment of filaments which might retain the punched-out piece, the +punch is likewise given at the same time a slight rotary motion, thus +imitating mechanically what is performed by hand in the maneuver of all +punches. This rotary motion is communicated to the punches by means of +levers actuated by an eccentric, E, and which move the frame, _h_, whose +bars engage with the horizontal lever, _g_, soldered to the tube, _d_, +thus causing the latter at the very moment the punch descends to revolve +from right to left. The forty punches in operation cause the frame to +return to its initial position through the action of the springs, _b'_. +We say forty, since the inventor, in principle, has admitted 80 punches, +operating 40 as odd and 40 as even; obtaining in this way a dotting in +a regular quincunx of one yard, that is to say, 80 dots arranged in two +rows on a fabric 31 inches wide. But it is evident that a much larger +quincunx may be had by putting in play only a half, a third, or a +fourth of the punches, and causing the tulle and velvet to advance +proportionally. For this purpose it is only necessary to unscrew the +punches which are not to act, and to substitute for the ratchet wheel +which controls the unrolling of the I tulle, another having a number of +teeth proportioned to the desired spacing of the dots. + +The punching having been executed, and the drum, A, continuing to +revolve, the punches rise a little owing to the conformation of the +cam-wheel, and through the action of the springs, _b_, and allow the +moistener to move forward to dampen the little circles which remain at +the orifice of the punches. The moistener or dampener is a sort of pad +equal in length to the field of action of the punches, and is affixed +to a cross-bar, F, which is connected at its two extremities with the +levers, G, that are actuated by the cam-wheels, H. These cam-wheels, or +eccentrics, H, which are mounted on the shaft of the drum, A, cause the +moistener to move forward as soon as the punches rise after operating, +and, when it arrives beneath the punches, the larger cams, _a_, of +the cam-wheels, A, press the latter upon the pad and thus effect the +dampening of the circles of velvet. + +Immediately afterwards, the same eccentrics, H, acting on a lever, I, +uncover the holes in the straight-edge, C, and the channel, D. The +large cams, _a"_, of the wheel, A, then acting very powerfully upon the +respective punches, cause these latter to pass through the orifices so +that the extremity of each punch comes within about one twenty-fifth of +an inch of the fabric to be dotted. In this passage of the tube, _d_, a +small rod, _i_, connected by a lever with the plunger, _f_, is made to +abut against the guide, _e_, thus causing the descent of the plunger to +a sufficient degree to push the velvet "dot" out of the tube and to glue +it upon the fabric. The manner in which these operations are performed +being now well enough understood, let us for a moment examine the +motions of the fabrics to be cut and dotted--the first being velvet or +any other material, even metal (goldleaf, for example), and the second, +the tulle. + +The latter has but one motion, and that is in the direction of its +length, while the velvet has, in addition to this same motion, another +slight one from right to left in the direction of its width in order to +diminish waste as much as possible. + +The tulle to be dotted is first wound around a roller, R, from whence it +passes over the glass guide-roller, R', and between the channel, D, and +the table, T, to the roller, R", which is heated by steam. + +The hot air which is radiated dries the dots, and from thence the fabric +is taken up by other rollers or by any other method. The steam roller, +R", carries at one of its extremities a ratchet wheel whose teeth vary +in number according to the greater or less rapidity with which the tulle +is unrolled. It is actuated by a lever which receives its motion from +the eccentric, K. + +[Illustration: IMPROVED MACHINE FOR DOTTING TULLAND OTHER LIGHT +FABRICS.] + +In the table, T, there is a rectangular receptacle, _t_, containing +rasped or powdered velvet for the purpose of forming a reverse of the +dot. This powder attaches itself to the gum and imitates on the wrong +side of the fabric a dot similar to that on the upper or right side. The +velvet is wound upon the roller, _r_, and from thence passes under the +guiding roller, _r'_, the punches, and the second roller, _r"_. These +two latter rollers are solidly connected by a straight-edge fixed at the +extremity of the lever, L, whose other end is in continuous correlation +with the eccentric, M, which controls the lateral displacements; +while the eccentric, O, actuates, by means of the screw, Q, and the +ratchet-wheel, S, the longitudinal advance of the velvet. The eccentric, +M, is fixed upon an axle, A', which carries a wheel, U, having teeth +inclined with respect to its axis, and which derives its motion from the +Archimedean screw, N, fixed at one of the extremities of the cam-shaft, +A. + +We have stated above that the maximum daily hand production of tulle +dotted in quincunxes of 0.04 of an inch is about one yard. At the rate +of 30 revolutions per minute, and for the same article as that just +mentioned, this dotting machine is capable of producing, theoretically, +360 yards per 10 hours; but practically this production is reduced to +about 250 yards, which, however, is sufficiently satisfactory. + + * * * * * + + + + +THE REPRODUCTION AND MULTIPLICATION OF NEGATIVES. + +By ERNEST EDWARDS, B.A. + + +A question, relative to the subject of reproducing negatives, which was +put at a meeting of one of your New York societies, prompts me to make a +few remarks on the subject. + +Among the numerous and widely diversified ramifications of our business +(the Heliotype Printing Company) we have very often to reproduce and +multiply negatives in both a direct and reversed form. Various methods +for doing this have been tried, and I may here say that I am quite well +aware of all the methods that have hitherto been suggested for the +purpose, but that which I am to describe is the one to which preference +has been given, and which is that known as the carbon process. + +A sheet of carbonized paper or "tissue," having been sensitized by +immersion in a bath of bichromate of potash, is dried in the dark and +placed away for future use, although it is undesirable that it be kept +for more than four or five days. This is placed in a printing frame in +contact with the negative and exposed for a few minutes, after which it +is immersed in water, squeegeed down upon a glass plate, and developed +with warm water in the way so well known to carbon printers. The result +is a transparency which, owing to having received a sufficient exposure, +should show every detail of the negative. The nature of the tissue +employed for such a purpose must be such as to give no strong contrasts, +but everything reproduced with soft and fine gradation of tone. + +The transparency thus obtained forms the _cliche_ by which the negatives +are subsequently made; and a negative of any size may be obtained by +the camera on wet or dry plates. The transparency must, of course, be +pointed to the sky and the light transmitted through it, no other light +being allowed to reach the lens except that which passes through the +carbon transparency. Care must also be taken that the transparency is +_uniformly_ lighted. If it is not possible to obtain a northern light, +which is best, a reflector of white paper or card may be used which must +be sufficiently large and placed at an angle of about forty-five degrees +to the transparency. + +If the repeated negative is to be of the same size as the original it +may be readily produced by repeating the operation of printing on carbon +tissue, using the transparency in place of the negative, or using a dry +plate in place of the tissue. But on the whole I have satisfied myself +that the best results are to be obtained by the first method. There is +a greater softness in the latter method, but a greater character and +similarity to the original in the former method. There is no doubt that +the use of the carbon transparency removes the hardness and riffidness +of the outlines peculiar to the older method of a collodion +transparency, while with carbon as the medium it is difficult for +any but the most experienced eye to distinguish the copy from the +original.--_Photo Times._ + + * * * * * + + + + +A NEW METHOD OF MAKING GELATINE EMULSION. + + +Since gelatine emulsion first came into use one of the greatest troubles +in connection with the manufacture of it has been that of washing. +According to the first methods the time taken for this part of the +process was, I believe, about twenty-four hours. It was very much +reduced and the ease of manufacture greatly facilitated by the methods +now most generally used, and which were, I believe, first communicated +by Messrs. Wratten and Wainright. I refer to those of precipitating with +alcohol and of straining the emulsion, when set, through canvas, so +as to divide it very finely. When the latter method is resorted to a +comparatively short time is sufficient to wash it. This method, although +a great improvement upon the older ones, yet leaves much to be desired, +especially for those who are not in the habit of making emulsion +regularly, but only an occasional batch. When the weather is at all warm +it takes a long time for the emulsion to set, unless ice be used, and +when once it is set the washing process is an exceedingly "messy" one +unless the water be cooled with ice; and the amount of water taken up +during washing is often so great that there is considerable difficulty +in getting the emulsion to set on the plates. In fact, even in cold +weather, it is not an easy process to conduct in the necessary near +approach to total darkness. + +Considerable suspicion has of late been thrown upon the thoroughness of +the alcohol method, unless the emulsion has, previous to precipitation, +been freed of the greater part of the soluble salts by washing; that is +to say, it is doubtful whether the whole of the soluble salts can be +eliminated by the process, and, therefore, unless in exceptionally hot +weather, it would seem best not to trust to it, except as a further +security against soluble bromide and nitrate after washing. Besides +this, the consumption of alcohol is very large. Almost three times the +amount of the emulsion precipitated is required, and this, even when +methylated spirit is used, adds considerably to the expense. With a view +of doing away with the washing altogether, or, rather, of washing of +the silver bromide when not incorporated with the gelatine, several +processes have been invented. By these silver bromide is obtained in a +very fine state of division, ready to mix with gelatine and water in any +proportion. + +The best known of them is Captain Abney's very ingenious glycerine +method, which seems to have been thoroughly successful in his hands, +although it has not been in every one's. The silver bromide obtained by +his process is not highly sensitive, and requires boiling with gelatine +before it is in a fit state to make a rapid plate. + +We have lately had described in these columns a method of obtaining +bromide in a highly-sensitive state by means of the use of an acid, +whereby, after emulsifying and boiling, the viscosity of the gelatine +was destroyed, and the bromide in time deposited itself. During the late +hot weather, when washing became almost impossible, I was led to cast +about for some method of eliminating the soluble salts less tedious and +"sloppy" than that of washing, more certain and less expensive than that +of precipitating the whole of gelatine with alcohol, and which would +take less time than the method of obtaining the bromide in a pure form. + +My first idea was to make up the solutions used in emulsifying in a very +concentrated form, and, after emulsifying, boiling, and allowing to +cool, to add to the thin emulsion thus obtained gelatine to the amount +of twenty grains to the ounce, and to precipitate this with alcohol, +the rest of the gelatine required to make up the bulk being afterwards +added, and the whole thoroughly incorporated by warming and shaking. +I was thus successful in reducing the amount of alcohol required to +one-third of what would be necessary if the whole of the emulsion were +precipitated; but still I found that, if a reliable emulsion were +required, the pellicle as formed had to be washed to free it from the +last trace of soluble salts. + +It now struck me that it might be possible to precipitate the bromide of +silver direct from a very weak solution of gelatine, and obtain it in +such a form that it might be filtered, washed, and in every way treated +as an ordinary precipitate. I tried the following experiment. I took-- + + 1. Silver nitrate....................... 200 grains + Water............................... 11/2 ounce. + 2. Ammonia bromide...................... 120 grains. + Water................................ 11/2 ounce. + Gelatine............................. 12 grains. + +I emulsified the two together in the usual way, allowed the whole +to cool, and then poured the thin emulsion into about ten ounces +of alcohol, stirring the while. As I had anticipated, a flocculent +precipitate was formed, which settled to the bottom of the vessel in a +few minutes. This was, in fact, sensitive bromide of silver mixed with +a very small quantity of gelatine (about five per cent.), and could, I +found, be treated in the same manner as a bromide precipitate from +an aqueous solution; it might be washed, either by decantation or by +filtration, easily dried, and doubtless could, when dry, be kept for an +indefinite time, and be at any time used by mixing with gelatine and +water in any proportion thought fit. + +I found that a less amount of gelatine than four grains to the ounce was +sufficient to carry the bromide down, while five grains to the ounce +carried it down in something which I considered too near an approach to +a plastic mass. + +It will be noticed that in the experiments which I have described the +emulsion had not been boiled, so that the sensitiveness of the bromide +was probably not great. As the experiment was done in daylight it was +of no practical use for making emulsion; but I have since made several +batches in this manner and have found them most satisfactory. + +When sensitiveness is sought by boiling I rind it necessary to add a +small quantity of gelatine after boiling and before precipitating, as +that which has been kept for some time at a high temperature seems to +have lost the viscosity necessary to carry down the silver bromide in +such a form that it can he easily separated from the alcohol and water. + +The practical manner of making an emulsion by this method may be as +follows. Make up the following mixtures: + + I. + Silver nitrate...........................................400 grains. + Water..................................................... 3 ounces. + + II. + + Ammonia bromide..........................................240 grains. + Gelatine..................................................24 grains + Water..................................................... 3 ounces. + Hydrochloric acid enough to slightly acidify the solution. + + III. + Gelatine................................................. 20 grains. + Water.................................................... 1/2 ounce. + IV. + + Hard gelatine (say Nelson's X opaque, + or Mr. A. L. Henderson's)................................240 grains. + Soft gelatine (Nelson's No.1)........................... 240 grains. + Water.....................................................24 ounces. + +Nos. II., III., and IV. are allowed to stand until the gelatine is +softened. No. I is then warmed in a hock bottle until the gelatine is +just melted, when No. II. is poured into it, a little at a time, with +vigorous shaking, until the whole is emulsified. It is then transferred +to an ordinary jelly can, which is placed in a saucepan half full of +water over a ring Bunsen burner in the dark room, and boiled for half an +hour. It is then allowed to cool to about 100 deg. Fahr., when No. III. is +added. The whole is then allowed to get quite cool, when it is poured, +with stirring, into about one pint of methylated spirit. If it be wished +the precipitate may now be filtered out and washed at once like an +ordinary filtrate, but I prefer to allow it to settle, which it will do +in about five minutes. The supernatant fluid is then gently poured off. + +This fluid will have the appearance of still containing a considerable +amount of the silver bromide; but if it be kept and filtered it will be +seen that the quantity is really so small that it may be disregarded. We +all know what an alarming quantity of silver seems to be going down the +sink when we wash vessels to which a very small quantity of emulsion is +adhering. If filtering be resorted to the liquid which comes through +will be quite clear. This was somewhat unexpected by me, as, if an +emulsion containing the whole of the gelatine be precipitated into +alcohol in the usual way, the alcohol becomes milky with a substance +which could not, I imagine, be filtered from it. + +Two or three ounces of methylated spirit are now added to the vessel +containing the silver bromide, and the latter well mixed with it. This +makes the precipitate "firmer"--if such an expression be allowable--and +this time it will sink to the bottom almost immediately after the +stirring has ceased, and the alcohol may be poured off. + +I consider that the bromide in this state is practically free from +soluble salts, but it may be washed with one or two changes of water if +desired. + +No. IV. is now gently heated till the gelatine is melted and the +precipitate mixed with it. It must be kept warm for some time, and +shaken vigorously until all granularity has disappeared, This is, of +course, ascertained by placing a drop of the emulsion on a piece of +glass, and examining it. If it be wished to keep the bromide of silver +for future use it may be placed on a piece of muslin stretched in the +drying-box, when it will dry in a very short time; and, although I +cannot speak from experience on this point, it will, I have no doubt, +keep for an indefinite time so long as light is kept from it. + +If it be desired the ammonio-nitrate method may be used instead of the +boiling one, although in my hands it does not give such sensitiveness. +If it be desired to use this method, solution Nos. I, II., and IV. are +made up exactly as for the boiling method, except that No. II. is not +acidified. Liquid ammonia is then poured with stirring into the silver +solution, until it blackens and again clears. Emulsification is +performed exactly as described above, but instead of boiling, the +emulsion is kept at a temperature of about 100 deg. Fahr. for half an hour, +when it is poured into the alcohol, no addition of gelatine being +previously made. + +I think I may claim for the method which I have just described that it +is less troublesome and more certain than either the ordinary washing +method or the usual one of precipitating with alcohol, while it affords +an easy method of making sensitive silver bromide in such a form that it +can be more easily stored and afterwards manipulated than if it were in +the form of pellicle. The whole of the soluble salts are eliminated, +and also any gelatine which may have been destroyed in the cooking. +The amount of alcohol used is comparatively small; in fact, to prepare +silver bromide for a pint of emulsion very little more than a pint of +methylated spirit is required. Besides this I do not think that I would +be wrong in saying that the chance of green fog is reduced to a minimum. + +Let me take this opportunity of thanking Captain Abney for his prompt +reply to my question about the connection between the proportion +of bromide to gelatine in emulsions, and the density of resulting +images.--_W. K. Burton, in British Journal of Photography_. + + * * * * * + +[Illustration: Old Wrought Iron Gates, Guildhall.] + + * * * * * + + + + +THE POTTERY AND PORCELAIN INDUSTRIES OF JAPAN. + + +Japanese chronicles claim that the first pottery was made in the year +660 B.C.; it was not, however, until the Christian era that the art made +any considerable advances. In the year 1223 A.D., great improvements +were made in manufacture and decoration of the ware. From that date to +the sixteenth century the great potteries of Owari, Hizen, Mino, Kioto, +Kaga, and Satsuma were established. The Rahn-Yaki, or crackled ware, was +first made at Kioto, at the commencement of the sixteenth century. The +best old Hizen ware, that which is still the most admired, was made +at Arita Hizen, in 1580 to 1585; the old Satsuma dates from 1592. +Consul-General Van Buren states that porcelain clays are found in nearly +all parts of the country, and the different kinds are usually found +in close proximity, and close to canals and rivers, which is of +considerable advantage, as affording a means of transport. In all cases +every variety of clay used in the manufacture of pottery is found in a +natural state; there is no necessity to manufacture the quartzose or +fusible clays as is done in other parts of the world, and which adds +considerably to the cost of the ware. One of the peculiarities in the +clay found in Japan is that it contains both the fusible and infusible +materials in such proportions as to make a light, beautiful, +translucent, and durable porcelain. At Arita, in Hizen, there is a clay +found which contains 783/4 per cent, of silica, and l73/4 per cent, of +alumina; from this clay is made the delicate, translucent eggshell ware, +without the addition of any other matter. From an adjoining bluff a clay +is taken which has 50 per cent, of silica, and 38 per cent, of alumina; +from this the common porcelain is made. + +Potter's clay is found in very large quantities in the provinces of +Yamashiro, Hoki, Turoo Iyo, Hizen, Higo, Owari, Mikaera, Idyn, Musashi, +and Mino. In the whole of Japan there are 283 localities where the clay +is deposited; many of these only furnish inferior clays, but they are +all fitted for use in some of the various kinds of pottery. These clays +are thoroughly powdered by means of what is called "balance pounders," +worked in some localities by water-power, but the work is often done by +hand. The powder is then dried, and stored on boards or in flat boxes. +This dough does not go through the process of fermentation. The shaping +is almost exclusively done on the potter's wheel, which is set on a +pivot working in a porcelain eye. As a rule, the wheel is turned by the +potter himself, but in Hizen it is kept in motion by means of a band +connected with its pivot and another wheel turned by a boy. In making +dishes of other shape than round, a crude mould is sometimes used. After +the clay has been shaped on the wheel, it is set away for drying, and +usually in two or three days it is considered sufficiently dry for +smoothing, which is done on the wheel with a sharp curved knife. The +material is now made into "bisque," or biscuit, by a preliminary baking +in small ovens, when it is ready for painting, if it is to be painted +on the biscuit; if not, it is ready for the glazing. In either event it +will then go to the large furnace for the final baking. The kilns for +this purpose are always built on hill sides, and are joined together, +increasing in size from the lower to the higher ones, and in number from +four to twenty five; these kilns are so constructed that the draught is +from the lowest one, in addition to which each kiln has its own firing +place. The result of this construction is that the upper ones are by +far the most heated, and the ware is arranged accordingly; that which +requires the least baking, in the lower kiln, and that which requires +the greatest heat, in the upper. These connecting kilns have the merit +of being heat saving, but they are usually small and badly constructed, +and the heat in none of them is uniform. + +The glaze is made from the silicious clay and potash extracted from wood +ashes. This potash is not a pure white, and this accounts for the dirty +color usually to be observed in unpainted Japanese ware. In different +districts the painting varies. For instance, in Owari, the greater part +of the ware is painted a cobalt blue--the cobalt ore being found in the +bluffs near the clay deposits, and is used for painting the cheaper +wares, and for this purpose German cobalt is also employed. The painting +with cobalt is generally done on the biscuit before glazing. In several +districts a very handsome ware is made, and painted on the glaze. For +this kind of painting the colors are mixed with a silicate of lead +and potash, and baked the third time in a small furnace at a low +temperature. The coloring oxides in use are those of copper, cobalt, +iron, antimony, manganese, and gold. Japanese porcelain painting may be +divided into two categories, decorative and graphic; the first is used +to improve the vessel upon which it is placed, and this class includes +all the ware except that of the province of Kaga, which would come under +the head of graphic, as it delineates all the trades, occupations, +sports, customs, and costumes of the people, as well as the scenery, +flora, and fauna of the country. "Owari ware" is made in the province +of that name; it is not as translucent, but stronger and more tenacious +than some of the Hizen manufacture. + +The principal potteries are at a village called Seto, twelve miles from +the sea; in this village there are more than 200 kilns. The ware is +mostly painted a cobalt blue, and is merely of a decorative kind, +consisting of branches of trees, grass, flowers, birds, and insects, all +these being copied by the artist from nature. All the Owari ware is true +hard porcelain, and is strong and durable. In Hizen, a number of wares +are manufactured, the best known kind being the "Eurari," which is made +at Arita, but painted at Eurari. The colors in use are red, blue, green, +and gold; these are combined in various proportions, but, as a rule, the +red predominates. Generally the surface of the vessel is divided into +medallions of figures, which alternately have red, blue, or white +back-ground, with figures in green or blue and gold. + +The egg-shell porcelain sold at Nagasaki is made in this province from +Arita clay, and this is made from clay with no admixture of fusible +matter except that contained by the clay naturally. The province of +Satsuma is noted for crackled ware. It is only within a very few years +that large vases have been manufactured, and in earlier days the old +ware was confined to small vessels. The glaze is a silicate of alumina +and potash, and the best ware has a complete network of the finest +crackles; the painting is of birds and flowers, and noted for its +delicate lines of green, red, and gold. + +In Kioto, the ware manufactured is very similar to that produced in +Satsuma, but it is lighter and more porous; the decorations are also +nearly the same, being of birds and flowers. There is a description of +ware made in Kioto, called "Eraku," the whole body of which is covered +with a red oxide of iron, and over this mythical figures of gold are +traced. That produced in Kagja is _faience_, and in the style of +painting is unlike any other in Japan, the predominating color being +a light red, used with green and gold. The designs with which it is +profusely decorated are trees, grasses, flowers, birds, and figures of +all classes of people, with their costumes, occupations, and pastimes. +The "Banko" ware is made at the head of the Owari Bay; it is an unglazed +stone-ware, very light and durable, made on moulds in irregular shapes, +and decorated with figures in relief. On the island of Awadji, a +delicate, creamy, crackled, soft paste porcelain is made. The figures +used in decoration are birds and flowers, but outlined by heavy, dark +lines. + +Consul Van Buren is of opinion that, at no distant day, Japan will be +one of the foremost competitors in the pottery markets of the world, +on account of the great variety and excellence of the clays, their +proximity to the sea, the cheapness of labor, and the beauty and +originality of the decorations. Already this important industry has been +greatly stimulated by the foreign demand, and by the success of +Japanese exhibitors at the Exhibitions of Vienna, Philadelphia, and +Paris.--_Journal of the Society of Arts_. + + * * * * * + +Professor Julius E. Hilgard, for twenty years assistant in charge of the +office, has been placed in temporary charge of the Coast and Geodetic +Survey. It is understood that he will be appointed superintendent to +succeed the late Captain Carlile P. Patterson. + + * * * * * + + + + +THE FRENCH CRYSTAL PALACE. + + +The first idea of the French Crystal Palace was suggested by the English +structure of the same name at Sydenham, about eight miles from London. +Such a structure, as may be readily conceived, requires a site of vast +extent, and one that shall be easy of access and possess the most +agreeable surroundings. To the promoter of the project, those portions +of the park of St. Cloud in the vicinage of the old chateau appeared to +combine within themselves all the conditions that were desirable, and +he, therefore, on the 15th of December, 1879, addressed the Ministers of +Public Works and of Finances asking for the necessary concessions. The +extensive specifications have been finally completed and will probably +be shortly submitted for the approval of the parliament. The moment has +arrived then for the public press to take cognizance of a project which +concerns so great interests. + +[Illustration: THE FRENCH CRYSTAL PALACE--PARK OF ST CLOUD, PARIS.] + +At present we shall say a few words _a propos_ of the engraving we +present herewith. The French Crystal Palace will consist of one great +nave, two lateral naves, two surrounding galleries, and a vast rotunda +behind. The principal entrance, located at the head of the avenue +leading from the present ruins (which will, ere long, be transformed +into a most interesting museum), will exhibit a very striking aspect +with its monumental fountain and the dome which it is proposed to erect +over the very entrance itself. The whole structure will cover about +nineteen acres of ground, thus being two and a half times the extent of +the Palace of Industry in the Champs Elysees. The great nave of honor +will be nearly 1,650 ft. in length, 78 ft. in width, and 98 ft. in +height. The dome will measure exactly 328 ft. in height, or 105 ft. more +than the towers of Notre Dame. The structure, with the exception of +basement and foundation, will be of glass and iron. + +The project which we publish to-day has been studied and gotten up, +according to the general plans and dimensions suggested by the promoter, +by Mr. Dumoulin, the architect. We are informed that the builder is to +be Mr. Alfred Hunnebelle, a contractor well known from the extensive +works that he has executed, and who is president of the Syndical Chamber +of Contractors of Paris. + +Among the annexes of this palace we may note a "Palace of the Republic," +to be built on the ruins and designed for illustrious or distinguished +visitors, such as the President of the Republic, the Ministers, the +Municipal Council of Paris, foreign delegates, etc.; a farm house for +special exhibitions and a field for experiments; galleries, cottages, +etc. + +As for the programme, which embraces six divisions and numerous +subdivisions, we are unable to give it at present for want of space; we +need only say that it satisfies perfectly all the conditions of so vast +an undertaking. + +In the hands of the projector, Mr. Nicole, who is well known from his +long experience in such matters, the exhibition will undoubtedly prove +a success and be instrumental in adding prosperity to all French +industries. + + * * * * * + +THE GREAT HEAT OF THE SUN.--Prof. S. P. Langley has made the following +calculation: A sunbeam one centimeter in section is found in the clear +sky of the Alleghany Mountains to bring to the earth in one minute +enough heat to warm one gramme of water by 1 deg. C. It would, therefore, +if concentrated upon a film of water 1/500th of a millimeter thick, +1 millimeter wide, and 10 millimeters long, raise it 83 1/3 deg. in one +second, provided all the heat could be maintained. And since the +specific heat of platinum is only 0.0032 a strip of platinum of the same +dimensions would, on a similar supposition, be warmed _in one second_ to +2,603 deg. C.--a temperature sufficient to melt it! + + * * * * * + + + + +CHATEAU IN THE AEGEAN SEA. + + +From the site of this building, magnificent views are obtained over the +island-dotted sea and the mainland of Asia Minor: but, "though every +prospect pleases," it is a land of earthquakes, and unfortunately, the +works at the chateau have been suspended, owing to the dreadful calamity +which has recently fallen upon the district. The building is intended +for the residence of an English lady of exalted rank. It is to be built +of local white stone, the hall, staircase, etc., being lined and paved +with marbles. The hall is a large apartment about 25 ft. high, with +paneled ceiling, having galleries on two sides, giving access to the +rooms surrounding it on first floor, and to the turret staircase leading +to roofs, etc. With the exception of sanitary apparatus, painted +windows, etc. (which will be supplied by English firms), the whole of +the work will be executed by native labor. The architect is Mr. Edwin T. +Hall, London.--_Building News_. + +[Illustration: SUGGESTIONS IN ARCHITECTURE--A CASTELLATED CHATEAU.] + + * * * * * + + + + +ELECTRIC POWER. + + +Just now nothing save electricity is talked about in scientific circles. +During the meeting of the British Association the greatest possible +prominence was given to electrical questions and propositions The +success of the electric light, the introduction of the Faure battery +with a great flourish of trumpets, and the magnificent display of +electrical instruments and machinery at Paris, have all operated to the +same end. The daily press has taken the subject up, and journals which +were nothing hitherto if not political, now indulge in magnificent +rhapsodies concerning the future of electricity. Even eminent engineers, +carried away by the intoxication of the moment, have not hesitated to +say that the steam engine is doomed, and that its place will be taken by +the electricity engine. In the midst of all this noise and clamor and +blowing of personal trumpets, it is not easy to keep one's head clear, +and mistakes may be made which will cause disappointment to many and +retard the progress of electrical science. We confidently expect that +electricity will prove a potent agent by and by in the hands of the +speculator for extracting gold from the pockets of the public, and we +write now to warn our readers in time, and to endeavor to clear the air +of some of the mists with which it is obscured. There is, no doubt, +a great future before electricity; but it is equally certain that +electricity can never do many things which the half informed may be +readily made to believe it will do. We propose here to say enough +on this point to enlighten our readers, without troubling them with +perplexing problems and speculations. + +No one at this moment knows what electricity is; but for our present +purpose we may regard it as a fluid, non-elastic, and without weight, +and universally diffused through the universe. To judge by recently +published statements, a large section of the reading public are taught +that this fluid is a source of power, and that it may be made to do the +work of coal. This is a delusion. So long as electricity remains in what +we may call a normal state of repose, it is inert. Before _we can get +any work out of electricity a somewhat greater amount of work must be +done upon it_. If this fundamental and most important truth be kept in +view it will not be easy to make a grave mistake in estimating the value +of any of the numerous schemes for making electricity do work which will +ere long be brought before the public. To render our meaning clearer, +we may explain that in producing the electric light, for instance, a +certain quantity of electricity passes in through one wire to the lamp, +and precisely the same quantity passes out through the other wire, and +on to the earth or return wire completing the circuit. Not only is the +quantity the same, the velocity is also unchanged. But in going through +the lamp the current has done something. It has overcome the resistance +of the carbons, heated them to a dazzling white heat, and so performed +work. In doing this the current of electricity has lost something. Led +from the first lamp to a second, it is found powerless--if the first +lamp be of sufficient size. What is it that the electricity has lost? +It has parted with what electricians would term "potential," or the +capacity for performing work. What this is precisely, or in what way the +presence or absence of potential modifies the nature of the electric +current, no one knows; but it is known that this potential can only be +conferred on electricity by doing work on the electricity in the first +instance. The analogy between electricity and a liquid like water will +now be recognized. So long as the water is at rest, it is inert. If we +pump it up to a height, we confer on it the equivalent of potential. +We can let the water fall into the buckets of an overshot wheel. Its +velocity leaving the tail race may be identical with that at which it +left the supply trough to descend on the wheel. Its quantity will be +the same. It will be in all respects unchanged, just as the current +of electricity passing through a lamp is unchanged; but it has, +nevertheless, lost something. It has parted with its potential--capacity +for doing work--and it becomes once more inert. But the duty which it +discharged in turning the mill wheel was somewhat less than the precise +equivalent of the work done in pumping it up to a level with the top of +the wheel. In the same way the electric current never can do work equal +in amount to the work done on it in endowing it with potential. + +It will thus be seen that electricity can only be used as a means of +transmitting power from one place to another, or for storing power up +at one time to be used at a subsequent period; but it cannot be used to +originate power in the way coal can be used. It possesses no inherent +potential. It is incapable of performing work unless something is done +to it first. We have spoken of it as a fluid, but only for the sake of +illustration. As we have said, no one knows what it is, but the theory +which bids fair for acceptance is that it is a mode of motion of the +all-pervading ether. Very curious and instructive experiments are now +being carried out in Paris by Dr. Bjerkness, of Christiania, in the +Norwegian section of the electrical exhibition. This gentleman submerges +thin elastic diaphragms in water, and causes them to vibrate, or rather +pulsate, by compressed air. He finds that if they pulsate synchronously +they attract each other. If the pulsations are not simultaneous, the +disks repel each other. From this and other results he has obtained, +it may be argued that the ether plays the part of the water in Dr. +Bjerkness' tank, and that when special forms of vibration are set up +in bodies they become competent to attract or repel other bodies. This +being so, it will be seen that the power of attraction or repulsion of +an electrical body depends in the first instance on the motion set up +in the body attracted or repulsed, and this motion is, of course, some +function of the work originally done on the body. We need not pursue +this argument further. Among the most scientific investigators of the +day it is admitted that the efficiency of electricity as a doer of work, +or a producer of action at a distance, must depend for its value on the +performance of work in some one way or another on the electricity itself +in the first instance. It may be worth while here to dispel a popular +delusion. It is held very generally that electricity can be made, as, +for instance, by the galvanic battery. There is no reason to believe +anything of the kind; but whether it is or is not true that electricity +is actually made by the combustion of zinc in a galvanic trough, it is +quite certain that this electricity, unless it possesses potential, can +do no work, no matter how great its quantity. Of course, it is to be +understood that all electric currents possess potential. If they did +not, their presence would be unknown; but the potential of a current +is in all cases the result of work done on electricity, either by the +oxidation of zinc, or in some other way. This is a broad principle, but +it is strictly consistent in every respect with the truth. Electricity, +then, is, as we have said, totally different from coal; and it can never +become a substitute for it alone. Water power, air power, or what we +may, for want of a better phrase, call chemical power, combined with +electricity, can be used as a substitute for coal; but electricity +cannot of itself be employed to do work. It is true, however, that +electricity, on which work has already been done, may be found in +nature. Atmospheric electricity, for example, may perhaps yet be +utilized. It is by no means inconceivable that the electricity contained +in a thunder cloud might be employed to charge a Faure battery; but up +to the present no one has contemplated the obtaining of power from the +clouds, and whether it is or is not practicable to utilize a great +natural force in this way does not affect our statement. The use of +electricity must be confined to its power of transmitting or storing up +energy, and this truth being recognized, it becomes easy to estimate the +future prospects of electricity at something like their proper value. + +It has been proved to a certain extent that electricity can be used to +transmit power to a distance, and that it can be used to store it up. +Thus far the man of pure science. The engineer now comes on the stage +and asks--Can practical difficulties be got over? Can it be made to pay? +In trying to answer these questions we cannot do better than deal with +one or two definite proposals which have been recently made. That with +which we shall first concern ourselves is that trains should be worked +by Faure batteries instead of by steam. It is suggested that each +carriage of a train should be provided with a dynamo motor, and that +batteries enough should be carried by each to drive the wheels, and so +propel the train. Let us see how such a scheme would comply with working +conditions. Let us take for example a train of fifteen coaches on the +Great Northern Railway, running without a stop to Peterborough in one +hour and forty minutes. The power required would be about 500 horses +indicated. To supply this for 100 minutes, even on the most absurdly +favorable hypothesis, no less than 25 tons of Faure batteries would be +required. Adding to these the weight of the dynamo motors, and that +unavoidably added to the coaches, it will be seen that a weight equal to +that of an engine would soon be reached. The only possible saving would +be some 28 to 30 tons of tender. In return for this all the passengers +would have to change coaches at Peterborough, as the train could not be +delayed to replace the expended with fresh batteries. This is out of +the question. The Faure batteries must all be carried on one vehicle or +engine, which could be changed for another, like a locomotive. Even then +no advantage would be gained. As to cost, it is very unlikely that the +stationary engines which must be provided to drive the dynamo machines +for charging the batteries would be more economical than locomotive +engines; and if we allow that the dynamo machine only wasted 10 per +cent. of the power of the engine, the Faure batteries 10 per cent. of +the power of the dynamo machines, and the dynamo motors 10 per cent. of +the power of the batteries--all ridiculously favorable assumptions--yet +the stationary engines would be handicapped with a difference in net +efficiency between themselves and the locomotive--admitting the original +efficiency per pound of coal in both to be the same--of some 27 per +cent., we think we may relegate this scheme to the realms of oblivion. +Another idea is that by putting up turbines and dynamo machines the +steam engine might be superseded by water power. Now it so happens that +if all the water power of England were quadrupled it would not nearly +suffice for our wants. It may be found worth while perhaps to construct +steam engines close to coalpits and send out power from these engines by +wire; but the question will be asked, Which is the cheaper of the two, +to send the coal or to send the power? On the answer to this will +depend the decision of the mill owners. Another favorite scheme is that +embodied in the Siemens electrical railway. We believe that there is a +great future in store for electricity as a worker of tramway traffic; +but the traffic on a great line like the Midland or Great Northern +Railway could not be carried on by it. As Robert Stephenson said of the +atmospheric system, it is not flexible enough. The working of points +and crossings, and the shunting of trains and wagons, would present +unsurmountable difficulties. We have cited proposals enough, we think, +to illustrate our meaning. Sir William Armstrong, Sir Frederick +Bramwell, Dr. Siemens, Sir W. Thomson, and many others may be excused if +they are a little enthusiastic. They are just now overjoyed with success +attained; but when the time comes for sober reflection they will, no +doubt, see good reason to moderate their views. No one can say, of +course, what further discoveries may bring to light; but recent speakers +and writers have found in what is known already, materials for sketching +out a romance of electricity. It is but romancing to assert that the end +of the steam engine is at hand. Wonderful and mystical as electricity +is, there are some very hard and dry facts about it, and these facts are +all opposed to the theory that it can become man's servant of all work. +Ariel-like, electricity may put a girdle round the earth in forty +minutes; but it shows no great aptitude for superseding the useful old +giant steam, who has toiled for the world so long and to such good +purpose--_The Engineer_. + + * * * * * + + + + +ON A METHOD OF OBTAINING AND MEASURING VERY HIGH VACUA WITH A MODIFIED +FORM OF SPRENGEL-PUMP. + +By Ogden N. Rood, Professor of Physics in Columbia College. + + +In the July number of this Journal for 1880, I gave a short account of +certain changes in the Sprengel-pump by means of which far better vacua +could be obtained than had been previously possible. For example, the +highest vacuum at that time known had been reached by Mr. Crookes, and +was about 1/17,000,000, while with my arrangement vacua of 1/100,000,000 +were easily reached. In a notice that appeared in _Nature_ for August, +1880, p. 375, it was stated that my improvements were not new, but had +already been made in England four years previously. I have been unable +to obtain a printed account of the English improvements, and am willing +to assume that they are identical with my own; but on the other hand, +as for four years no particular result seems to have followed their +introduction in England, I am reluctantly forced to the conclusion that +their inventor and his customers, for that period of time, have remained +quite in ignorance of the proper mode of utilizing them. Since then I +have pushed the matter still farther, and have succeeded in obtaining +with my apparatus vacua as high as 1/390,000,000 without finding +that the limit of its action had been reached. The pump is simple in +construction, inexpensive, and, as I have proved by a large number of +experiments, certain in action and easy of use; stopcocks and grease are +dispensed with, and when the presence of a stopcock is really desirable +its place is supplied by a movable column of mercury. + +_Reservoir_.--An ordinary inverted bell-glass with a diameter of 100 mm. +and a total height of 205 mm. forms the reservoir; its mouth is closed +by a well-fitting cork through which passes the glass tube that forms +one termination of the pump. The cork around tube and up to the edge of +the former is painted with a flexible cement. The tube projects 40 mm. +into the mercury and passes through a little watch-glass-shaped piece of +sheet-iron, W, figure 1, which prevents the small air bubbles that creep +upward along the tube from reaching its open end; the little cup is +firmly cemented in its place. The flow of the mercury is regulated +by the steel rod and cylinder, CR, Figure 1. The bottom of the steel +cylinder is filled out with a circular piece of pure India-rubber, +properly cemented; this soon fits itself to the use required and answers +admirably. The pressure of the cylinder on the end of the tube is +regulated by the lever, S, Figure 1; this is attached to a circular +board which again is firmly fastened over the open end of the +bell-glass. It will be noticed that on turning the milled head, S, the +motion of the steel cylinder is not directly vertical, but that it tends +to describe a circle with c as a center; the necessary play of the +cylinder is, however, so small, that practically the experimenter does +not become aware of this theoretical defect, so that the arrangement +really gives entire satisfaction, and after it has been in use for a few +days accurately controls the flow of the mercury. The glass cylinder is +held in position, but not supported, by two wooden _adjustable_ clamps, +_a a_, Figure 2. The weight of the cylinder and mercury is supported by +a shelf, S, Figure 2, on which rests the cork of the cylinder; in this +way all danger of a very disagreeable accident is avoided. + +[Illustration: MODIFIED FORM OF SPRENGEL PUMP.] + +_Vacuum-bulb_.--Leaving the reservoir, the mercury enters the +vacuum-bulb, B, Figure 2, where it parts with most of its air and +moisture; this bulb also serves to catch the air that creeps into the +pump from the reservoir, even when there is no flow of mercury; its +diameter is 27 mm. The shape and inclination of the tube attached to +this bulb is by no means a matter of indifference; accordingly Figure +3 is a separate drawing of it; the tube should be so bent that a +horizontal line drawn from the proper level of the mercury in the bulb +passes through the point, _o_, where the drops of mercury break off. The +length of the tube, EC, should be 150 mm., that of the tube, ED, 45 mm.; +the bore of this tube is about the same as that of the fall-tube. + +_Fall-tube and bends_.--The bore of the fall-tube in the pump now used +by me is 1.78 mm.; its length above the bends (U, Figure 2) is 310 mm.; +below the bends the length is 815 mm. The bends constitute a fluid valve +that prevents the air from returning into the pump; beside this, the +play of the mercury in them greatly facilitates the passage of the +air downward. The top of the mercury column representing the existing +barometric pressure should be about 25 mm. below the bends when the pump +is in action. This is easily regulated by an adjustable shelf, which is +also employed to fill the bends with mercury when a measurement is taken +or when the pump is at rest. On the shelf is a tube, 160 mm. high and 20 +mm. in diameter, into which the end of the fall-tube dips; its side has +a circular perforation into which fits a small cork with a little tube +bent at right angles. With the hard end of a file and a few drops of +turpentine the perforation can be easily made and shaped in a few +minutes. By revolving the little bent tube through 180 deg. the flow of the +mercury can be temporarily suspended when it is desirable to change the +vessel that catches it. + +_Gauge_.--For the purpose of measuring the vacua I have used an +arrangement similar to McLeod's gauge, Figure 4; it has, however, some +peculiarities. The tube destined to contain the compressed air has a +diameter of 1.35 mm. as ascertained by a compound microscope; it is not +fused at its upper extremity, but closed by a fine glass rod that fits +into it as accurately as may be, the end of the rod being ground flat +and true. This rod is introduced into the tube, and while the latter +is gently heated a very small portion of the cement described below is +allowed to enter by capillary attraction, but not to extend beyond the +end of the rod, the operation being watched by a lens. The rod is +used for the purpose of obtaining the compressed air in the form of a +cylinder, and also to allow cleansing of the tube when necessary. The +capacity of the gauge-sphere was obtained by filling it with mercury; +its external diameter was sixty millimeters; for measuring very high +vacua this is somewhat small and makes the probable errors rather +large; I would advise the use of a gauge-sphere of about twice as great +capacity. The tube, CB, Figure 4, has the same bore as the measuring +tube in order to avoid corrections for capillarity. The tube of the +gauge, CD, is not connected with an India-rubber tube, as is usual, +but dips into mercury contained in a cylinder 340 mm. high, 58 mm. in +diameter, which can be raised and lowered at pleasure. This is best +accomplished by the use of a set of boxes of various thicknesses, made +for the purpose and supplemented by several sheets of cardboard and even +of writing-paper. These have been found to answer well and enable the +experimenter to graduate with a nicety the pressure to which the gas is +exposed during measurement. By employing a cylinder filled with mercury +instead of the usual caoutchouc tubing small bubbles of air are +prevented from entering the gauge along with the mercury. An adjustable +brace or support is used which prevents accident to the cylinder when +the pump is inclined for the purpose of pumping out the vacuum-bulb. The +maximum pressure that can be employed in the gauge used by me is 100 mm. + +All the tubing of the pump is supported at a distance of about 55 mm. +from the wood-work; this is effected by the use of simple adjustable +supports and adjustable clamps; the latter have proved a great +convenience. The object is to gain the ability to heat with a Bunsen +burner all parts of the pump without burning the wood-work. Where glass +and wood necessarily come in contact the wood is protected by metal or +simply painted with a saturated solution of alum. The glass portions +of the pump I have contrived to anneal completely by the simple means +mentioned below. If the glass is not annealed it is certain to crack +when subjected to heat, thus causing vexation and loss of time. The +mercury was purified by the same method that was used by W. Siemens +(Pogg. Annalen, vol. ex., p. 20), that is, by a little strong sulphuric +acid to which a few drops of nitric acid had been added; it was dried by +pouring it repeatedly from one hot dry vessel to another, by filtering +it while quite warm, the drying being completed finally by the action of +the pump itself. All the measurements were made by a fine cathetometer +which was constructed for me by William Grunow; see this Journal, Jan., +1874, p. 23. It was provided with a well-corrected object-glass having a +focal length of 200 mm. and as used by me gave a magnifying power of 16 +diameters. + +_Manipulation_.--The necessary connections are effected with a cement +made by melting Burgundy pitch with three or four per cent of gutta +percha. It is indispensable that the cement when cold should be so hard +as completely to resist taking any impression from the finger nail, +otherwise it is certain to yield gradually and finally to give rise to +leaks. The connecting tubes are selected so as to fit as closely as +possible, and after being put into position are heated to the proper +amount, when the edges are touched with a fragment of cold cement which +enters by capillary attraction and forms a transparent joint that can +from time to time be examined with a lens for the colors of thin plates, +which always precede a leak. Joints of this kind have been in use by me +for two months at a time without showing a trace of leakage, and the +evidence gathered in another series of unfinished experiments goes to +show that no appreciable amount of vapor is furnished by the resinous +compound, which, I may add, is never used until it has been repeatedly +melted. As drying material I prefer caustic potash that has been in +fusion just before its introduction into the drying tube; during the +process of exhaustion it can from time to time be heated nearly to the +melting point: if actually fused in the drying tube the latter almost +invariably cracks. The pump in the first instance is to be inclined at +an angle of about 10 degrees, the tube of the gauge being supported by +a semicircular piece of thick pasteboard fitted with two corks into the +top of the cylinder. This seemingly awkward proceeding has in no case +been attended with the slightest accident, and owing to the presence of +the four leveling-screws, the pump when righted returns, as shown by the +telescope of the cathetometer, almost exactly to its original place. In +the inclined position the exhaustion of the vacuum bulb is accomplished +along with that of the rest of the pump. The exhaustion of the +vacuum-bulb when once effected can be preserved to a great extent for +use in future work, merely by allowing mercury from the reservoir to +flow in a rapid stream at the time that air is allowed to re-enter the +pump. During the first process of exhaustion the tube of the gauge is +kept hot by moving to and fro a Bunsen burner, and is in this way +freed from those portions of air and moisture that are not too firmly +attached. After a time the vacuum-bulb ceases to deliver bubbles of +air; it and the attached tube are now to be heated with a moving Bunsen +burner, when it will be found to furnish for 15 or 20 minutes a large +quantity of bubbles mainly of vapor of water. After then production +ceases the pump is righted and the exhaustion carried farther. In spite +of a couple of careful experiments with the cathetometer I have not +succeeded in measuring the vacuum in the vacuum bulb, but judge from +indications, that is about as high as that obtained in an ordinary +Geissler pump. Meanwhile the various parts of the pump can be heated +with a moving Bunsen burner to detach air and moisture, the cement being +protected by wet lamp-wicking. In one experiment I measured the amount +of air that was detached from the walls of the pump by heating them for +ten minutes somewhat above l00 deg. C., and found that it was 1/1,000,000 +of the air originally present. I have also noticed that a still larger +amount of air is detached by electric discharges. This coincides with an +observation of E. Bessel-Hagen in his interesting article on a new form +of Toepler's mercury-pump (Annalen der Physik und Chemie, 1881, vol. +xii.). Even when potash is used a small amount of moisture always +collects in the bends of the fall tube; this is readily removed by a +Bunsen burner; the tension of the vapor being greatly increased, it +passes far down the fall-tube in large bubbles and is condensed. Without +this precaution I have found it impossible to obtain a vacuum higher +than 1/25,000,000; in point of fact the bends should always be heated +when a high exhaustion is undertaken even if the pump has been standing +well exhausted for a week; the heat should of course never be applied at +a late stage of the exhaustion. Conversely, I have often by the aid of +heat completely and quickly removed quite large quantities of the vapor +of water that had been purposely introduced. The exhaustion of the +vacuum-bulb is of course somewhat injured by the act of using the pump +and also by standing for several days, so that it has been usual with me +before undertaking a high exhaustion to incline the pump and re-exhaust +for 20 minutes; I have, however, obtained very high vacua without using +this precaution. + +During the process of exhaustion not more than one-half of the mercury +in the reservoir is allowed to run out, other wise when it is returned +bubbles of air are apt to find their way into the vacuum-bulb. In order +to secure its quiet entrance it is poured into a silk bag provided with +several holes. When the reservoir is first filled its walls for a day +or two appear to furnish air that enters the vacuum-bulb; this action, +however, soon sinks to a minimum and then the leakage remains quite +constant for months together. + +_Measurement of the vacuum_.--The cylinder into which the gauge-tube +dips is first elevated by a box sufficiently thick merely to close the +gauge, afterwards boxes are placed under it sufficient to elevate the +mercury to the base of the measuring tube; when the mercury has reached +this point, thin boards and card-boards are added till a suitable +pressure is obtained. The length of the inclosed cylinder of air is +then measured with the cathetometer, also the height of the mercurial +"meniscus," and the difference of the heights of the mercurial columns +in A and B, figure 4. To obtain a second measure an assistant removes +some of the boxes and the cylinder is lowered by hand three or four +centimeters and then replaced in its original position. In measuring +really high vacua, it is well to begin with this process of lowering and +raising the cylinder, and to repeat it five or six times before taking +readings. It seems as though the mercury in the tube, B, supplies to the +glass a coating of air that allows it to move more freely; at all events +it is certain that ordinarily the readings of B become regular, only +after the mercury has been allowed to play up and down the tube a number +of times. This applies particularly to vacua as high 1/50,000,000 and to +pressures of five millimeters and under. It is advantageous in making +measurements to employ large pressures and small volumes; the correct +working of the gauge can from time to time be tested by varying the +relations of these to each other. This I did quite elaborately, and +proved that such constant errors as exist are small compared with +inevitable accidental errors, as, for example, that there was no +measurable correction for capillarity, that the calculated volume of the +"meniscus" was correct, etc. It is essential in making a measurement +that the temperature of the room should change as little as possible, +and that the temperature of the mercury in the cylinder should be at +least nearly that of the air near the gauge-sphere. The computation is +made as follows + + n = height of the cylinder inclosing the air; + c = a factor which, multiplied by n, converts it into cubic + millimeters; + S = cubic contents of the meniscus; + d = difference of level between A and B, fig. 4; + = the pressure the air is under; + N = the cubic contents of the gauge in millimeters; + x = a fraction expressing the degree of exhaustion obtained; then + + x=1/([N (760/d)]/[nc - S]) + +It will be noticed that the measurements are independent of the actual +height of the barometer, and if several readings are taken continuously, +the result will not be sensibly affected by a simultaneous change of the +barometer. Almost all the readings were taken at a temperature of about +20 deg. C., and in the present state of the work corrections for temperature +may be considered a superfluous refinement. + +_Gauge correction_.--It is necessary to apply to the results thus +obtained a correction which becomes very important when high vacua are +measured. It was found in an early stage of the experiments that the +mercury, in the act of entering the highly exhausted gauge, gave out +invariably a certain amount of air which of course was measured along +with the residuum that properly belonged there; hence to obtain the true +vacuum it is necessary to subtract the volume of this air from nc. By a +series of experiments I ascertained that the amount of air introduced by +the mercury in the acts of entering and leaving the gauge was sensibly +constant for six of these single operations (or for three of these +double operations), when they followed each other immediately. The +correction accordingly is made as follows: the vacuum is first measured +as described above, then by withdrawing all the boxes except the lowest, +the mercury is allowed to fall so as nearly to empty the gauge; it is +then made again to fill the gauge, and these operations are repeated +until they amount in all to six; finally the volume and pressure are a +second time measured. Assuming the pressure to remain constant, or that +the volumes are reduced to the same pressure, + + v = the original volume; v' = the final volume; + V' = volume of air introduced by the first entry of the mercury; + V = corrected volume; then + + V' = (v'-v)/6 + V = v - [(v'-v)/6] + +It will be noticed that it is assumed in this formula that the same +amount of air is introduced into the gauge in the acts of entry and +exit; in the act of entering in point of fact more fresh mercury is +exposed to the action of the vacuum than in the act exit, which might +possibly make the true gauge-correction rather larger than that given by +the formula. It has been found that when the pump is in constant use the +gauge-correction gradually diminishes from day to day; in other words, +the air is gradually pumped out of the gauge-mercury. Thus on December +21, the amount of air entering with the mercury corresponded to an +exhaustion of + + 1/27,308,805 .......Dec. 21. + + 1/38,806,688 ...... Dec. 29. + + 1/78,125,000 .......Jan. 15. + + 1/83,333,333 .......Jan. 23 + + 1/128,834,063 ......Feb. 1. + + 1/226,757,400 ..... Feb. 9. + + 1/232,828,800 ..... Feb. 19. + + 1/388,200,000 ......March 7. + +That this diminution is not due to the air being gradually withdrawn +from the walls of the gauge or from the gauge-tube, is shown by the fact +that during its progress the pump was several times taken to pieces, and +the portions in question exposed to the atmosphere without affecting +the nature or extent of the change that was going on. I also made one +experiment which proves that the gauge-correction does not increase +sensibly, when the exhausted pump and gauge are allowed to stand unused +for twenty days. + +_Rate of the pump's work_.--It is quite important to know the rate of +the pump at different degrees of exhaustion, for the purpose of enabling +the experimenter to produce a definite exhaustion with facility; also if +its maximum rate is known and the minimum rate of leakage, it becomes +possible to calculate the highest vacuum attainable with the instrument. +Examples are given in the tables below; the total capacity was about +100,000 cubic mm. + + Time. Exhaustion. Ratio. + + 1/78,511 + 10 minutes }........ 1:1/3.53 + 1/276,980 + 10 minutes }........ 1:1/6.10 + 1/1,687,140 + 10 minutes }........ 1:1/4.15 + 1/7,002,000 + +Upon another occasion the following rates and exhaustions were obtained: + + Time. Exhaustion. Rate. + + 1/7,812,500 + 10 minutes }........ 1:1/3.18 + 1/24,875,620 + 10 minutes }........ 1:1/2.69 + 1/67,024,090 + 10 minutes }........ 1:1/1.22 + 1/81,760,810 + 10 minutes }........ 1:1.67 + 1/136,986,300 + 10 minutes }........ 1:1.23 + 1/170,648,500 + +The _irregular_ variations in the rates are due to the mode in which the +flow of the mercury was in each case regulated. + +_Leakage_.--We come now to one of the most important elements in the +production of high vacua. After the air is detached from the walls of +the pump the leakage becomes and remains nearly constant. I give below a +table of leakages, the pump being in each case in a condition suitable +for the production of a very high vacuum: + + Duration of the Leakage per hour in + experiment cubic mm., press., + 760 mm. + + 181/2 hours............................ 0.000853 + 27 hours............................ 0.001565 + 261/2 hours.............................0.000791 + 20 hours.............................0.000842 + 19 hours.............................0.000951 + 19 hours.............................0.001857 + 7 days..............................0.001700 + 7 days..............................0.001574 + + Average.................... 0.001266 + +I endeavored to locate this leakage, and proved that one-quarter of +it is due to air that enters the gauge from the top of its column of +mercury, thus: + + Duration of the Gauge-leakage per hour + experiment. in cubic mm., press. + 760 mm. + + 18 hours.................................0.0002299 + 7 days..................................0.0004093 + 7 days..................................0.0003464 + + Average.......................0.0003285 + +This renders it very probable that the remaining three quarters are due +to air given off from the mercury at B, Fig. 4, from that in the bends +and at the entrance of the fall-tube, _o_, Fig. 3. + +Further on some evidence will be given that renders it probable that the +leakage of the pump when in action is about four times as great as the +total leakage in a state of rest. + +The gauge, when arranged for measurement of gauge-leakage, really +constitutes a barometer, and a calculation shows that the leakage would +amount to 2.877 cubic millimeters per year, press. 760 mm. If this air +were contained in a cylinder 90 mm. long and 15 mm. in diameter it would +exert a pressure of 0.14 mm. To this I may add that in one experiment +I allowed the gauge for seven days to remain completely filled with +mercury and then measured the leakage into it. This was such as would +in a year amount to 0.488 cubic millimeter, press. 760 mm., and in a +cylinder of the above dimensions would exert a pressure of 0.0233 mm. + +_Reliability of the results: highest vacuum._ + +The following are samples of the results obtained. In one case sixteen +readings were taken in groups of four with the following result: + + Exhaustion. + 1 / 74,219,139 + 1 / 78,533,454 + 1 / 79,017,272 + 1 / 68,503,182 + Mean 1 / 74,853,449 + +Calculating the probable error of the mean with reference to the above +four results it is found to be 2.28 per cent of the quantity involved. + +A higher vacuum measured in the same way gave the following results: + + 1 / 146,198,800 + 1 / 175,131,300 + 1 / 204,081,600 + 1 / 201,207,200 + +The mean is 1 / 178,411,934, with a probable error of 5.42 per cent of +the quantity involved. I give now an extreme case; only five single +readings were taken; these corresponded to the following exhaustions: + + 1 / 379,219,500 + 1 / 371,057,265 + 1 / 250,941,040 + 1 / 424,088,232 + 1 / 691,082,540 + +The mean value is 1 / 381,100,000, with a probable error of 10.36 per +cent of the quantity involved. Upon other occasions I have obtained +exhaustions of 1 / 373,134,000 and 1 / 388,200,000. Of course in these +cases a gauge-correction was applied; the highest vacuum that I have +ever obtained irrespective of a gauge-correction was 1 / 190,392,150. In +these cases and in general, potash was employed as the drying material; +I have found it practical, however, to attain vacua as high as 1 / +50,000,000 in the total absence of all such substances. The vapor of +water which collects in bends must be removed from time to time with a +Bunsen burner while the pump is in action. + +It is evident that the final condition of the pump is reached when +as much air leaks in per unit of time as can be removed in the same +interval. The total average leakage per ten minutes in the pump used by +me, when at rest, was 0.000211 cubic millimeter at press. 760 mm. Let +us assume that the leakage when the pump is in action is four times +as great as when at rest; then in each ten minutes 0.000844 cubic +millimeter press., 760 mm., would enter; this corresponds in the pump +used by me to an exhaustion of 1 / 124,000,000; if the rate of the pump +is such as to remove one-half of the air present in ten minutes, then +the highest attainable exhaustion would be 1 / 248,000,000. In the same +way it may be shown that if six minutes are required for the removal of +half the air the highest vacuum would be 1 / 413,000,000 nearly, and +rates even higher than this have been observed in my experiments. An +arrangement of the vacuum-bulb whereby the entering drops of mercury +would be exposed to the vacuum in an isolated condition for a somewhat +longer time would doubtless enable the experimenter to obtain +considerably higher vacua than those above given. + +_Exhaustion obtained with a plain Sprengel Pump._--I made a series of +experiments with a plain Sprengel pump without stopcocks, and arranged, +as far as possible, like the instrument just described. The leakage per +hour was as follows: + + Duration of the Leakage per hour in + experiment. cubic mm. at press. + 760 mm. + + 22 hours 0.04563 + 2 days 0.04520 + 2 days 0.09210 + 4 days 0.06428 + ------- + Mean 0.06180 + +Using the same reasoning as above we obtain the following table + + Time necessary for removal Greatest attainable + of half the air. exhaustion. + + 10 minutes 1 / 5,000,000 + 7.5 minutes 1 / 7,000,000 + 6.6 minutes 1 / 12,000,000 + +In point of fact the highest exhaustion I ever obtained with this pump +was 1 / 5,000,000; from which I infer that the leakage during action +is considerably greater than four times that of the pump at rest. The +general run of the experiments tends to show that the leakage of a plain +Sprengel pump, without stopcocks or grease, is, when in action, about 80 +times as great as in the form used by me. + +_Note on annealing glass tubes._--It is quite necessary to anneal all +those parts of the pump that are to be exposed to heat, otherwise they +soon crack. I found by inclosing the glass in heavy iron tubes and +exposing it for five hours to a temperature somewhat above that of +melting zinc, and then allowing an hour or two for the cooling process, +that the strong polarization figure which it displays in a polariscope +was completely removed, and hence the glass annealed. A common +gas-combustion furnace was used, the bends, etc, being suitably inclosed +in heavy metal and heated over a common ten-fold Bunsen burner. Thus far +no accident has happened to the annealed glass, even when cold drops of +mercury struck in rapid succession on portions heated considerably above +100 deg. C. + +I wish, in conclusion, to express my thanks to my assistant, Dr. +Ihlseng, for the labor he has expended in making the large number of +computations necessarily involved in work of this kind.--_Amer. Jour. of +Science._ + + * * * * * + + + + +CRYSTALLIZATION TABLE. + + +The following table, prepared by E. Finot and Arm. Bertrand for the +_Jour. de Ph. et de Chim._, shows the point at which the evaporation of +certain solutions is to be interrupted in order to procure a good crop +of crystals on cooling. The density is according to Baume's scale, the +solution warm: + + Aluminum sulphate 25 | Nickel acetate 30 + Alum (amm. or pot.) 20 | " ammon. sulphate 18 + Ammonium acetate 14 | " chloride 50 + " arsenate 5 | " sulphate 40 + " benzoate 5 | Oxalic acid 12 + " bichromate 28 | Potass. and sod. tartrate 36 + " bromide 30 | Potassium arsenate 36 + " chloride 12 | " benzoate 2 + " nitrate 29 | " bisulphate 35 + " oxalate 5 | " bromide 40 + " phosphate 35 | " chlorate 22 + " sulphate 28 | " chloride 25 + " sulphocyanide 18 | " chromate 38 + " tartrate 25 | " citrate 36 + Barium ethylsulphate 43 | " ferrocyanide 38 + " formate 32 | " iodide 17 + " hyposulphite 24 | " nitrate 28 + " nitrate 18 | " oxalate 30 + " oxide 12 | " permanganate 25 + Bismuth nitrate 70 | " sulphate 15 + Boric acid 6 | " sulphite 25 + Cadmium bromide 65 | " sulphocyanide 35 + Calcium chloride 40 | " tartrate 48 + " ethylsulphate 36 | Soda 28 + " lactate 8 | Sodium acetate 22 + " nitrate 55 | " ammon. phosp. 17 + Cobalt chloride 41 | " arsenate 36 + " nitrate 50 | " borate 24 + " sulphate 40 | " bromide 55 + Copper acetate 5 | " chlorate 43 + " ammon. sulph. 35 | " chromate 45 + " chloride 45 | " citrate 36 + " nitrate 55 | " ethylsulphate 37 + " sulphate 30 | " hyposulphite 24 + Iron-ammon. oxalate 30 | " nitrate 40 + " ammon. sulphate 31 | " phosphate 20 + " sulphate 31 | " pyrophosphate 18 + " tartrate 40 | " sulphate 30 + Lead acetate 42 | " tungstate 45 + " nitrate 50 | Stroutium bromide 50 + Magnesium chloride 35 | " chlorate 65 + " lactate 6 | " chloride 34 + " nitrate 45 | Tin choride (stannous) 75 + " sulphate 40 | + Manganese chloride 47 | Zinc acetate 20 + " lactate 8 | " ammon. chloride 43 + " sulphate 44 | " nitrate 55 + Mercury cyanide 20 | " sulphate 45 + + * * * * * + + + + +THE PRINCIPLES OF HOP-ANALYSIS. + +By Dr. G. O. CECH + +[Footnote: 'Zeitschrift fur Analyt. Chemie,' 1881.] + + +Hop flowers contain a great variety of different substances susceptible +of extraction with ether, alcohol, and water, and distinguishable from +one another by tests of a more or less complex character. The substances +are: Ethereal oil, chlorophyl, hop tannin, phlobaphen, a wax-like +substance, the sulphate, ammoniate, phosphate, citrate and malates of +potash, arabine, a crystallized white and an amorphous brown resin, and +a bitter principle. That the characteristic action of the hops is due to +such of these constituents only as are of an organic nature is easy to +understand; but up to the present we are in ignorance whether it is upon +the oil, the wax, the resin, the tannin, the phlobaphen, or the bitter +principle individually, or upon them all collectively, that the effect +of the hops in brewing depends. + +It is the rule to judge the strength and goodness of hops by the amount +of farina--the so-called lupuline; and as this contains the major +portion of the active constituents of the hop, there is no doubt that +approximately the amount of lupuline is a useful quantitative test. But +here we are confronted by the question whether the lupuline is to be +regarded as containing _all_ that is of any value in the hops and the +leaves, the organic principles in which pass undetected under such a +test, as supererogatory for brewers' purposes? Practical experience +negatives any such conclusion. Consequently, we are justified in +assuming that the concurrent development and the presence of the several +organic principles--the oil, the wax, the bitter, the tannin, the +phlobaphen, in the choicer sorts--are subject, within certain limits, to +variations depending on skilled culture and careful drying, and that the +aggregate of these principles has a certain attainable maximum in +the finer sorts, under the most favorable conditions of culture, and +another, lower maximum in less perfectly cultivated and wild sorts. The +difference in the proportion of active organic substance in each sort +must be determined by analysis. There then remains to be discovered +which of the aforesaid substances plays the leading role in brewing, and +also whether the presence of chlorophyl and inorganic salts in the hop +extract influences or alters the results. + +That in brewing hops cannot be replaced by lupuline alone, even when the +latter is employed in relatively large quantities is well known, as also +that a considerable portion of the bitter principle of the hop is found +in the floral leaves. Neither can the lupuline be regarded as the only +active beer agent, as both the hop-tannin and the hop-resin serve to +precipitate the albuminous matter, and clarify and preserve the beer. + +Both chemists and brewers would gladly welcome some method of testing +hops, which should be expeditious, and afford reliable results in +practical hands. To accomplish this account must be taken of all the +active organic constituents of the hops, which can be extracted either +with ether, alcohol, or water containing soda (for the conversion of the +hop tannin in phlobaphen).[1] It should further be ascertained whether +the chlorophyl percentage in the hop bells, new and old, is or is not +the same in cultivated and in wild hops, and whether the aggregate +percentages of organic and constituent observe the same limits. + +[Footnote 1: See C. Etti, in "Dingler's Polytech. Journ.," 1878, p. +354.] + +As wild hops nowadays are frequently introduced in brewing, the +proportion of chlorophyl and organic and inorganic constituents in them +should be compared with those of cultivated sorts, taking the best +Bavarian or Bohemian hops as the standard of measurement. The chlorophyl +is of minor importance, as it has little effect on the general results. + +By a series of comparative analysis of cultivated and wild hops, in +which I would lay especial stress on parity of conditions in regard +of age and vegetation, the extreme limits of variation of which their +active organic principles are susceptible could be determined. + +There is every reason to suppose that the chlorophyl and inorganic +constituents do not differ materially in the most widely different sorts +of hops. The more important differences lie in the proportions of hop +resin and tannin. When this is decided, the proportion of tannin or +phlobaphen in the hop extract or the beer can be determined by analysis +in the ordinary way. But whenever some quick and sure hop test shall +have been found, _appearance and aroma_ will still be most important +factors in any estimate of the value of hops. Here a question arises as +to whether hops from a warm or even a steppe climate, like that of +South Russia, contain the same proportion of ethereal oil--that is, of +aroma--as those from a cooler climate, like Bavaria and Bohemia, or +like certain other fruit species of southern growth, they are early +in maturing, prolific, large in size, and abounding in farina, but +_deficient in aroma_. + +The bearings of certain experimental data on this point I reserve for +consideration upon a future occasion.--_The Analyst_. + + * * * * * + + + + +WATER GAS. + +A DESCRIPTION OF APPARATUS FOR PRODUCING CHEAP GAS, AND SOME NOTES ON +THE ECONOMICAL EFFECT OF USING SUCH GAS WITH GAS MOTORS, ETC. + +[Footnote: Abstract of paper read in Section G. British Association, +York] + +By MR. J. EMERSON DOWSON, C.E., of London. + + +In many countries and for many years past, inventors have sought +some cheap and easy means of decomposing steam in the presence of +incandescent carbon in order to produce a cheap heating gas; and working +with the same object the writer has devised an apparatus which has been +fitted up in the garden of the Industrial Exhibition, and is there +making gas for a 31/2 horse power (nominal) Otto gas engine. The retort or +generator consists of a vertical cylindrical iron casing which incloses +a thick lining of ganister to prevent loss of heat and oxidation of the +metal, and at the bottom of this cylinder is a grate on which a fire is +built up. Under the grate is a closed chamber, and a jet of superheated +steam plays into this and carries with it by induction a continuous +current of air. The pressure of the steam forces the mixture of steam +and air upward through the fire, so that the combustion of the fuel is +maintained while a continuous current of steam is decomposed, and in +this way the working of the generator is constant, and the gas is +produced without fluctuations in quality. The well-known reactions +occur, the steam is decomposed, and the oxygen from the steam and air +combines with the carbon of the fuel to form carbon dioxide (CO_2), +which is reduced to the monoxide (CO) on ascending the fuel column. +In this way the resulting gases form a mixture of hydrogen, carbon, +monoxide, and nitrogen, with a small percentage of carbon dioxide which +usually escapes without reduction. The steam should have a pressure of +11/2 to 2 atmospheres, and is produced and superheated in a zigzag coil +fed with water from a neighboring boiler. The quantity of water required +is very small, being only about 7 pints for each 1,000 cubic feet of +gas, and, except on the first occasion when the apparatus is started, +the coil is heated by some of the gas drawn from the holder, so that +after the gas is lighted under the coil the superheater requires no +attention. + +For boiler and furnace work the gas can be used direct from the +generator; but where uniformity of pressure is essential, as for gas +engines, gas burners, etc., the gas should pass into a holder. The +latter somewhat retards the production, but the steam injector causes +gas to be made so rapidly that a holder is easily filled against a back +pressure of 1 in. to 11/2 in. of water, and at this pressure the generator +can pass gas continuously into the holder, while at the same time it is +being drawn off for consumption. + +The nature of the fuel required depends on the purpose for which the gas +is used. If for heating boilers, furnaces, etc, coke or any kind of coal +maybe used; but for gas engines or any application of the gas requiring +great cleanliness and freedom from sulphur and ammonia it is best to use +anthracite, as this does not yield condensable vapors, and is very free +from impurities. Good qualities of this fuel contain over 90 per cent of +carbon and so little sulphur that, for some purposes, purification is +not necessary. For gas engines, etc., it is, however, better to pass +the gas through some hydrated oxide of iron to remove the sulphureted +hydrogen. The oxide can be used over and over again after exposure to +the air, and the purifying is thus effected without smell or appreciable +expense. Gas made by this process and with anthracite coal has no tar +and no ammonia, and the small percentage of carbon dioxide present does +not sensibly affect the heating power. A further advantage of this gas +is that it cannot burn with a smoky flame, and there is no deposition of +soot even when the object to be heated is placed over or in the flame, +and this is of importance for the cylinder and valves of a gas engine. + +To produce 1,000 cubic feet only 12 lb. of anthracite are required, +allowing 8 to 10 per cent, for impurities and waste; thus a generator +A size, which produces 1,000 cubic feet per hour, needs only 12 lb. in +that time, and this can be added once an hour or at longer intervals. No +skilled labor is necessary, and in practice it is usual to employ a man +who has other work to attend to near the generator, and to pay him a +small addition to his usual wages. + +The comparative explosive force of coal gas and the Dowson gas +calculated in the usual way is as 3.4:1, i. e., coal gas has 3.4 times +more energy than the writer's gas. Messrs. Crossley, of Manchester, the +makers of the Otto gas engines, have made several careful trials of this +gas with some of their 31/2 horse power (nominal) engines, and in one +trial they took diagrams every half-hour for nine consecutive days. +These practical trials have shown that without altering the cylinder of +the engine it is possible to admit enough of the Dowson gas to give +the same power as with ordinary coal gas. It has been seen that the +comparative explosive force of the two gases is as 3.4:1, but as it is +well known the combustion of carbon monoxide proceeds at a comparatively +slow rate, and for this reason, and because of the diluents present in +the cylinder which affect the weaker gas more than coal gas, experience +has shown that it is best to allow five volumes of the Dowson gas for +one volume of coal gas, and then the same uniform power is obtained as +with the latter. + +This gives very important economical results; for if the cost of the +Dowson gas given in the tables as 41/4d., 3-1/3d., and 23/4d. per 1,000 +cubic feet, be multiplied by 5 there will be 1s. 91/4d., 1s. 43/4d., and 1s. +23/4d., or a mean of 1s. 51/2d. for the equivalent of 1,000 cubic feet of +coal gas, which usually costs from 3s. to 4s., and this represents an +actual saving of about 50 to 60 per cent, in working cost. Another +practical consideration is that coal gas requires 224 lb. to 250 lb. of +coal per 1,000 cubic feet of gas, but the writer requires only 12 lb. +per 1,000 cubic feet, and multiplying this by 5 to give the equivalent +of 1,000 cubic feet of coal gas, for engine work, there are 60 lb. +instead of 224 lb. to 250 lb. This is only 24 to 27 per cent, of the +weight of the coal required for coal gas, and in many outlying districts +this will effect an appreciable saving in the cost of transport. + + +APPENDIX. + + TABLE I. + + _Generator A Size_ (producing 1,000 cubic feet per hour): + Anthracite to make gas at the rate of 1,000 s. d. + cubic feet per hour=l2 lb x 9 working + hours=l08 lb., or say, 1 cwt. at 20s. a + ton.................................... 1 0 + Allowance for wages of attendant......... 1 0 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent. on Ll25)= + per working day........................ 0 5 + Interest on capital outlay, ditto........ 0 5 + ______ + + Total........................... 2 10 + cub. ft. + + Gas produced............................. 9.000 + Less gas used for generating and + superheating steam..................... 1,000 + _____ + Total effective gas for 2s. 10d. 8,000 + + Net cost 41/4 d. per 1,000 cubic feet. + + TABLE II. + + _Generator B Size_ (producing 1,500 cubic feet per hour) + Anthracite to make gas at the rate of 1,500 s. d. + cubic feet per hour=18 lb. x 9 working + hours=162 lb., or, say, 11/2 cwt. 20s. + a ton.................................. 1 6 + Allowance for wages of attendant......... 1 0 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent, on L140) + =per working day....................... 0 51/2 + Interest on capital outlay, ditto........ 0 51/2 + ___ ___ + Total........................... 3 5 + cub. ft. + Gas produced............................. 13,500 + Less gas used for generating and + superheating steam..................... 1,200 + ______ + Total effective gas for 3s. 5d.. 12,300 + + Net cost 3 1/3d. per 1,000 cubic feet. + + TABLE III. + + _Generator C Size_ (producing 2,500 cubic feet per hour): + Anthracite to make gas at the rate of 2,500 s. d. + cubic feet per hour=30 lb. x 9 working + hours=270 lb. at 20s. a ton............ 2 41/2 + Allowance for wages of attendant....... 1 6 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent, on L160)= + per working day...................... 0 61/2 + Interest on capital outlay, ditto...... 0 61/2 + _______ + Total......................... 4 111/2 + + cub. ft. + Gas produced........................... 22,500 + Less gas used for generating and + superheating steam................... 1,500 + ______ + Total effective gas for 4s. 111/2d 21,000 + + Net cost, say, 23/4 d. per 1,000 cubic feet. + + * * * * * + + + + +ON THE FLUID DENSITY OF CERTAIN METALS. + +[Footnote: Abstract of paper read before Section C (Chemical Science), +British Association meeting, York.] + +By PROFESSOR W. CHANDLER ROBERTS, F.R.S., and T. WRIGHTSON. + + +The authors described their experiments on the fluid density of metals +made in continuation of those submitted to Section B at the Swansea +meeting of the Association. Some time since one of the authors gave an +account of the results of experiments made to determine the density of +metallic silver, and of certain alloys of silver and copper when in a +molten state. The method adopted was that devised by Mr. R. Mallet, and +the details were as follows: A conical vessel of best thin Lowmoor plate +(1 millimeter thick), about 16 centimeters in height, and having an +internal volume of about 540 cubic centimeters, was weighed, first +empty, and subsequently when filled with distilled water at a known +temperature. The necessary data were thus afforded for accurately +determining its capacity at the temperature of the air. Molten silver +was then poured into it, the temperature at the time of pouring being +ascertained by the calorimetric method. The precautions, as regards +filling, pointed out by Mr. Mallet, were adopted; and as soon as the +metal was quite cold, the cone with its contents was again weighed. +Experiments were also made on the density of fluid bismuth; and two +distinctive determinations gave the following results: + + 10.005 ) + ) mean 10.039. + 10.072 ) + +The invention of the oncosimeter, which was described by one of the +authors in the "Journal of the Iron and Steel Institute" (No. II., +1879, p. 418), appeared to afford an opportunity for resuming the +investigation on a new basis, more especially as the delicacy of the +instrument had already been proved by experiments on a considerable +scale for determining the density of fluid cast iron. The following is +the principle on which this instrument acts: + +If a spherical ball of any metal be plunged below the surface of a +molten bath of the same or another metal, the cold ball will displace +its own volume of molten metal. If the densities of the cold and molten +metal be the same, there will be equilibrium, and no floating or sinking +effect will be exhibited. If the density of the cold be greater than +that of the molten metal, there will be a sinking effect, and if less a +floating effect when first immersed. As the temperature of the submerged +ball rises, the volume of the displaced liquid will increase or decrease +according as the ball expands or contracts. In order to register these +changes the ball is hung on a spiral spring, and the slightest change in +buoyancy causes an elongation or contraction of this spring which can +be read off on a scale of ounces, and is recorded by a pencil on a +revolving drum. A diagram is thus traced out, the ordinates of which +represent increments of volume, or, in other words, of weight of fluid +displaced--the zero line, or line corresponding to a ball in a liquid of +equal density, being previously traced out by revolving the drum without +attaching the ball of metal itself to the spring, but with all other +auxiliary attachments. By means of a simple adjustment the ball is kept +constantly depressed to the same extent below the surface of the liquid; +and the ordinate of this pencil line, measuring from the line of +equilibrium, thus gives an exact measure of the floating or sinking +effect at every stage of temperature, from the cold solid to the state +when the ball begins to melt. + +If the weight and specific gravity of the ball be taken when cold, +there are obtained, with the ordinate on the diagram at the moment of +immersion, sufficient data for determining the density of the fluid +metal; for + +W / W1 = D / D1 + +the volumes being equal. And remembering that + +W (weight of liquid) = W1 (weight of ball) + x + +(where x is always measured as +_ve_ or -_ve_ floating effect), there is +obtained the equation: + + D1 x ( W1 + x) + D = --------------- . + W1 + +[TEX: D = \frac{D_1 \times (W_1 +x)}{W_1}] + +The results obtained with metallic silver are perhaps the most +interesting, mainly from the fact that the metal melts at a higher +temperature, which was determined with great care by the illustrious +physicist and metallurgist, the late Henri St. Claire Deville, whose +latest experiments led him to fix the melting point at 940 deg. Cent. The +authors of the paper showed that the density of the fluid metal was 9.51 +as compared with 10.57, the density of the solid metal. Taking their +results generally, it is found that the change of volume of the +following metals in passing from the solid to the liquid state may be +thus stated: + + Specific Specific + Metal. Gravity, Gravity, Percentage of + Solid. Liquid. Change. + + Bismuth 9.82 10.055 Decrease of volume 2.3 + Copper 8.8 8.217 Increase " 7.1 + Lead 11.4 10.37 " " 9.93 + Tin. 7.5 7.025 " " 6.76 + Zinc 7.2 6.48 " " 11.10 + Silver 10.57 9.51 " " 11.20 + Iron 6.95 6.88 " " 1.02 + + * * * * * + + + + +HYDROPHOBIA PREVENTED BY VACCINATION. + + +M. Pasteur and other French savants have lately been devoting special +attention to hydrophobia. The great authority on germs has, in fact, +definitely announced that he does not intend to rest until he has made +known the exact nature and life-history of this terrible disease, and +discovered a means of preventing or curing it. The most curious result +yet attained in this direction, however, has been announced by Professor +V. Galtier, of the Lyons Veterinary School. This inquirer has found, in +the first place, that if the virus of rabies be injected into the veins +of a sheep, the animal does not subsequently exhibit any symptoms of +hydrophobia. This in itself would be a sufficiently curious result +to justify attention, though its importance, except as confirmatory +testimony, becomes less striking when it is remembered that M. Pasteur +has lately shown that the special _nidus_ of the disease appears to be +the nervous tissue, and particularly the ganglionic centers. But there +is this further curious consequence: sheep who have thus been treated +through the blood, and who are afterwards inoculated in the ordinary +way through the cellular tissue, as if by a bite, are proof against +the disease. It is as though the injection into the veins acted as a +vaccine. Twenty sheep were experimented upon; ten only were treated to +the venous injection, and then all were inoculated through the cellular +tissue. The ten which had been first "vaccinated" continue alive and +well; they have not even shown any adverse symptoms. The other ten have +all died of rabies. It remains to say why M. Galtier experimented +upon sheep, and not upon dogs and cats, which usually communicate the +disease. The incubation of the disease is much more rapid and less +capricious in the sheep than in the dog or in man, and hence M. Galtier +was able to get his results more certainly within a short period. Having +succeeded so far, he is now justified in undertaking the more protracted +series of observations which experiments upon the canine species will +involve; and this he proposes to do. Experiments of this nature are not +without a serious risk, and admiration is almost equally due to the +courage and the intelligence of the experimentalist. But what will the +anti-vaccinator say?--_Pall Mall Gazette_. + + * * * * * + + + + +ON DIPTERA AS SPREADERS OF DISEASE. + +By J.W. SLATER. + + +The two-winged flies, in their behavior to man, stand in a marked +contrast to all the other orders of insects. The Lepidoptera, the +Coleoptera, the Neuroptera, the Hymenoptera no doubt occasion, in some +of their forms at least, much damage to our crops. But none of them are +parasitic in or upon our bodies; none of them persistently intrude into +our dwellings, hover around us in our walks, and harass us with noise +and constant attempts to bite, or at least to crawl upon us. Even the +ants, except in a few tropical districts, rarely act upon the offensive. +The Hemiptera contain one semi-parasitic species which has attained a +"world-wide circulation," and one degraded, purely parasitic group. +But the Diptera, among which the fleas are now generally included as a +degenerated type, comprise more forms personally annoying to man than +all the remaining insect orders put together. These hostile species are, +further, incalculably numerous, and occur in every part of the globe. +Mosquitoes swarm not merely in the swampy forests of the Orinoco or the +Irrawaddy, but in the Tundras of Siberia, en the storm-beaten rocks of +the Loffodens, and are even encountered by voyagers in quest of the +North Pole. The common house fly was probably at one time peculiar to +the Eastern Continent, but it followed the footsteps of the Pilgrim +Fathers, and is now as great a nuisance in the United Slates and the +Dominion as in any part of Europe. It is curious, but distressing, to +note the tendency of evils to become international. We have communicated +to America the house-fly and the Hessian fly, the "cabbage-white," +the small pox, and the cholera. She, in return, has given us the +_Phylloxera_, a few visitations of yellow fever, the _Blatta gigantea_, +and, climate allowing, may perhaps throw in the Colorado beetle as a +make-weight. In this department, at least, free trade reigns undisputed. +It is a singular thing that no beautiful, useful, or even harmless +species of bird or insect seems capable of acclimatizing itself as do +those characterized by ugliness and noisomeness. + +But, returning from this digression, we find in the Diptera the habit of +obtrusion and intrusion, of coming in actual contact with our food and +our persons, combined with another propensity--that of feeding upon +carrion, excrement, blood, pus, and morbid matter of all kinds. This +is a combination far more serious than is generally imagined. If the +fly--which may at any moment settle upon our lips, our eyes, or upon +an abraded part of our skin--were cleanly in its habits, we need feel +little annoyance at its visits. Or if it were the most eager carrion +devourer, but did not, after having dined, think it necessary to +seek our company, we might hold it, as is done too hastily by some +naturalists, a valuable scavenger. I fear, however, that I have already +made too great a concession. So long as very many persons are suffering +from disease--so long as many diseases are capable of being transmitted +from the sick to the healthy--so long must any creature which is in the +habit of flying about, and touching first one person and then another, +be a possible medium of infection and death. + +Let us take the following case, by no means imaginary, but a +generalization from occurrences far too frequent: A healthy man, sitting +in his house or walking in the fields, especially in countries where the +insectivorous birds have been shot down, suddenly feels a sharp prick on +his neck or his cheek. Putting his hand to the place he perhaps crushes, +perhaps merely brushes away, a fly which has bitten him so as to draw +blood. The man thinks little of so trifling a hurt, but the next morning +he finds the puncture exceedingly painful. An inflamed pimple forms, +which quickly gets worse, while constitutional symptoms of a feverish +kind come on. In alarm he seeks medical advice. The doctor tells him +that it is a malignant pustule, and takes at once the most active +measures. In spite of all possible skill and care the patient too often +succumbs to the bite of a _mouche charbonneuse_, or carbuncle-fly. But +has any kind of fly the property of producing malignant pustule by +some specific inherent power of its own? Surely not. The antecedent +circumstances are these: A sheep or heifer is attacked with the disease +known in France as _charbon_, in Germany as _milz-brand_, and in England +as _splenic fever_. Its blood on examination would be found plentifully +peopled with bacteria. If a lancet were plunged into the body of the +animal, and were then used to slightly scratch or cut the skin of a man, +he would be inoculated with "charbon." The bite of the fly is precisely +similar in its action. Its rostrum has been smeared with the poisoned +blood, an infinitesimal particle of which is sufficient to inclose +several of the disease "germs," and these are then transferred to the +blood of the next man or animal which the fly happens to bite. The +disease is reproduced as simply and certainly as the spores of some +species of fern give rise to their like if scattered upon soil suitable +for their growth. But flies which do not bite may transfer infection. +Every one must know that if blood be spilt upon the ground a crowd of +flies will settle upon and eagerly absorb it. Animals suffering from +splenic fever in the later stages of the disease sometimes emit bloody +urine. Often they are shot or slaughtered by way of stamping out the +plague, and their carcasses are buried deep in the ground. But some loss +of blood is sure to happen, and this will mostly be left to soak into +the ground. Here again the flies will come, and their feet and mouth +will become charged with the contagion. Such a fly, settling upon +another animal or a man, and selecting--as it will do by preference, if +such exist--a wound, or a place where the skin is broken, will convey +the disease. + +Again, M. Pasteur has thoughtfully pointed out that if an animal has +died of splenic fever, and has been carefully buried, the earth-worms +may bring up portions of infectious matter to the surface, so that sheep +grazing, or merely being folded over the spot in question, may take the +plague and die. Hence be wisely counsels that the bodies of such animals +should be buried in sandy or calcareous soils where earth-worms are not +numerous. But it is perfectly legitimate to go a step farther. If such +worm-borings retain the slightest savor of animal matter, flies will +settle upon them and will convey the infectious dust to the most +unexpected places, giving wings to the plague. + +Now it is very true that no one has seen a fly feasting upon the blood +of a heifer or sheep dying or just dead of splenic fever, has then +watched it settle upon and bite some person, and has traced the +following stages of the disease. But it is positively known that a +person has been bitten by a fly, and has then exhibited all the symptoms +of charbon, the place of the bite being the primary seat of the +infection. We know also, beyond all doubt, the eagerness with which +flies will suck up blood, and we likewise know the strange persistence +of the disease "germs." + +Again, the avidity of flies for purulent matter is not a thing of mere +possibility. In Egypt, where ophthalmia is common, and where the "plague +of flies" seems never to have been removed, it is reported as almost +impossible to keep these insects away from the eyes of the sufferers. +The infection which they thus take up they convey to the eyes of persons +still healthy, and thus the scourge is continually multiplied. + +A third case which seems established beyond question is the agency of +mosquitoes in spreading elephantiasis. These so-called sanitary agents +suck from the blood of one person the Filariae, the direct cause of the +disease, and transfer them to another. The manner in which this process +is effected will appear simple enough if we reflect that the mosquito +begins operations by injecting a few drops of fluid into its victim, so +as to dilute the blood and make it easier to be sucked. + +So much being established it becomes in the highest degree probable that +every infectious disease may be, and actually is, at times propagated +by the agency of flies. Attention turned to this much neglected quarter +will very probably go far to explain obscure phenomena connected with +the distribution of epidemics and their sudden outbreaks in unexpected +quarters. I have seen it stated that in former outbreaks of pestilence +flies were remarkably numerous, and although mediaeval observations on +Entomology are not to be taken without a grain of salt, the tradition +is suggestive. Perhaps the Diptera have their seasons of unusual +multiplication and emigration. A wave of the common flea appears to have +passed over Maidstone in August, 1880. + +We now see the way to some practical conclusions not without importance. +Recognizing a very considerable part of the order of Diptera, or +two-winged flies, as agents in spreading disease, it surely follows +that man should wage war against them in a much more systematic and +consistent manner than at present. The destruction of the common +house-fly by "_papier Moure_," by decoctions of quassia, by various +traps, and by the so-called "catch 'em alive," is tried here and there, +now and then, by some grocer, confectioner, or housewife angry at the +spoliation and defilement caused by these little marauders. But there +is no concerted continuous action--which after all would be neither +difficult nor expensive--and consequently no marked success. Experiments +with a view of finding out new modes of fly-killing are few and far +between. + +Every one must occasionally have seen, in autumn, flies as if cemented +to the window-pane, and surrounded with a whitish halo. That in some +seasons numbers of flies thus perish--that the phenomenon is due to a +kind of fungus, the spores of which readily transfer the disease from +one fly to another--we know. But here our knowledge is at fault. We +have not learnt why this fly-epidemic is more rife in some seasons than +others. We are ignorant concerning the methods of multiplying this +fungus at will, and of launching it against our enemies. We cannot tell +whether it is capable of destroying _Stomoxys calcitram_, the blowflies, +gadflies, gnats, mosquitoes, etc. Experiment on these points is rendered +difficult by the circumstance that the fungus is rarely procurable +except in autumn, when some of the species we most need to destroy are +not to be found. Another question is whether the fungus, if largely +multiplied and widely spread, might not prove fatal to other than +Dipterous insects, especially to the Hymenoptera, so many of which, +in their character of plant-fertilizers, are highly useful, or rather +essential to man. + +Another fungus, the so-called "green muscardine" (_Isaria destructor_), +has been found so deadly to insects that Prof. Metschnikoff, who is +experimenting upon it, hopes to extirpate the _Phylloxera_, the Colorado +beetle, etc., by its agency. + +Coming to better known and still undervalued fly-destroyers, we have +interfered most unwisely with the balance of nature. The substitution of +wire and railings for live fences in so many fields has greatly lessened +the cover both for insectivorous birds and for spiders. The war waged +against the latter in our houses is plainly carried too far. Whatever +may be the case at the Cape, in Australia, or even in Southern Europe, +no British species is venomous enough to cause danger to human beings. +Though cobwebs are not ornamental, save to the eye of the naturalist, +there are parts of our houses where they might be judiciously tolerated: +their scarcity in large towns, even where their prey abounds, is +somewhat remarkable. + +But perhaps the most effectual phase of man's war against the flies will +be negative rather than positive, turning not so much on putting to +death the mature individuals as in destroying the matter in which the +larvae are nourished. Or if, from other considerations, we cannot +destroy all organic refuse, we may and should render it unfit for the +multiplication of these vermin. We have, indeed, in most of our large +towns and in their suburbs, abolished cesspools, which are admirable +breeding-places for many kinds of Diptera, and which sometimes presented +one wriggling mass of larvae. We have drained many marshes, ditches, +and unclean pools, rich in decomposing vegetable matter, and have thus +notably checked the propagation of gnats and midges. I know an instance +of a country mansion, situate in one of the best wooded parts of the +home counties, which twenty years ago was almost uninhabitable, owing to +the swarms of gnats which penetrated into every room. But the present +proprietor, being the reverse of pachydermatous, has substituted covered +drains for stagnant ditches, filled up a number of slimy ponds as +neither useful nor ornamental, and now in most seasons the gnats no +longer occasion any annoyance. + +But if we have to some extent done away with cesspools and ditches, and +have reaped very distinct benefit by so doing, there is still a grievous +amount of organic matter allowed to putrefy in the very heart of our +cities. The dust bins--a necessary accompaniment of the water-carriage +system of disposing of sewage--are theoretically supposed to be +receptacles mainly for organic refuse, such as coal-ashes, broken +crockery, and at worst the sweepings from the floors. In sober fact +they are largely mixed with the rinds, shells, etc., of fruits and +vegetables, the bones and heads of fish, egg-shells, the sweepings out +of dog-kennels and henhouses, forming thus, in short, a mixture of evil +odor, and well adapted for the breeding-place of not a few Diptera. + +The uses to which this "dust" is put when ultimately fetched away are +surprising: without being freed from its organic refuse it is used to +fill up hollows in building-ground, and even for the repair of roads. A +few weeks ago I passed along a road which was being treated according +to the iniquity of Macadam. Over the broken stones had been shot, to +consolidate them, a complex of ashes, cabbage-leaves, egg and periwinkle +shells, straw, potato-parings, a dead kitten (over which a few +carrion-flies were hovering), and other promiscuous nuisances. The road +in question, be it remarked, is highly "respectable," if not actually +fashionable. The houses facing upon it are severely rated, and are +inhabited chiefly by "carriage people." What, then, may not be expected +in lower districts? + +Much attention has lately been drawn to the fish trade of London. It has +_not_, however, come out in evidence that the fish retailers, if they +find a quantity of their perishable wares entering into decomposition, +send out late in the evening a messenger, who, watching his opportunity, +throws his burden down in some plot of building land, or over a fence. +When I say that I have seen in one place, close alongside a public +thoroughfare, a heap of about fifty herrings, in most active +putrefaction and buzzing with flies, and some days afterward, in another +place, some twenty soles, it will be understood that such nuisances +can only be occasioned by dealers. To get rid of, or at least greatly +diminish, carrion-flies, house-flies, and the whole class of winged +travelers in disease, it will be, before all things, essential to +abolish such loathsome malpractices. The dustbins must cease being made +the receptacle for putrescent and putrescible matter, the destruction of +which by fire should be insisted upon. + +The banishment of slaughter-houses to some truly rural situation, where +the blood and offal could be at once utilized, would be another step +toward depriving flies of their pabulum in the larva state. An equally +important movement would be the substitution of steam or electricity for +horsepower in propelling tram-cars and other passenger carriages, with a +view to minimize the number of horses kept within greater London. Every +large stable is a focus of flies--_Journal of Science_. + + * * * * * + + + + +ON THE RELATIONS OF MINUTE ORGANISMS TO CERTAIN SPECIFIC DISEASES. + + +At the recent Medical Congress in London, Professor Klebs undertook to +answer the question: "Are there specific organized causes of disease?" + +A short historical review of the various opinions of mankind as to the +origin of disease led, the speaker thought, to the presumption that +these causes were specific and organized. + +If we now, he said, consider the present state of this question, the +three following points of view present themselves as those from which +the subject may be regarded: + +I.--We have to inquire whether the lower organisms, which are found in +the diseased body, may arise there spontaneously; or whether even they +may be regarded as regular constituents of the body. + +II.--The morphological relations of these organisms have to be +investigated, and their specific nature in the different morbid +processes has to be determined. + +III.--We have to inquire into their biological relations, their +development inside and outside the body, and the conditions under which +they are able to penetrate into the body, and there to set up disease. + +_First_.--With regard to the first question, that of the possibility of +spontaneous generation, the speaker gave a decided negative. + +_Second and third_.--There is in microscopic organisms a difference of +form corresponding, as a rule, to difference of function. The facts +regarding these various lower forms are briefly reviewed. + +"Three groups of hyphomycetae, algae, and schizomycetae, have been +demonstrated to occur in the animal and human organism in infective +diseases. Their significance increases with the increase of their +capacity for development in the animal body. This depends partly upon +their natural or ordinary conditions of life, but partly also, and that +in a very high degree, upon their power of adaptation, which, as Darwin +has shown, is a property of all living things, and causes the production +of new species with new active functions. + +"1. The hyphomycetae, on account of their needing an abundant supply +of oxygen, give rise to but few morbid processes, and these run their +course on the surface of the body, and are hence relatively of less +importance. It will be sufficient here to refer to the forms, achorion, +trichophyton, oidium, aspergillus, and the diseases produced by them, +favus, ringworm, and thrush, to show this peculiarity. Nevertheless, we +see that these organisms also (as was proved by the older observations +of Hannover and Zenker) may, under certain circumstances, penetrate into +the interior of the organs. Grawitz, moreover, has recently shown that +their faculty of penetrating into the interior of the organism, and +there undergoing further development, depends on their becoming +accustomed to nitrogenous food. + +"2. Only one of the algae, viz., leptothrix, has as yet acquired any +importance as a producer of disease. It gives rise to the formation of +concretions, and that not only in the mouth, but also, as I have shown, +in the salivary ducts and urinary bladder. + +"Another alga, the sarcina of Goodsir, may indeed pass through the +organism, without, however, producing in its passage either direct +or indirect disturbances. It seems more worthy of note that many +schizomycetae, and especially the group of bacilli, are evidently nearly +allied to the algae in their morphological and vegetative relations--so +as to be assigned to this class by several authors, and especially by +Cienkowski. + +"The schizomycetae furnish, without doubt, by far the most numerous +group of infective diseases. We distinguish within this group two +widely different series of forms, which we will speak of as bacilli and +cocco-bacteria respectively. The former, which was first exhaustively +described by Ferdinand Cohn, and the pathological importance of which, +especially in relation to the splenic disease of cattle, was first shown +by Koch, consist of threads, in the interior of which permanent or +resting-spores are developed. These spores becoming free, are able, +under suitable conditions of life, again to develop into threads. The +whole development of these organisms, and especially the formation +of spores, is completed on the surface of the fluids, and under the +influence of an abundant supply of oxygen. + +"The number of affections in which these organisms have been found, +and which may be to a certain extent produced artificially by the +introduction of these organisms into healthy animal bodies, has been +largely increased since the discovery of Koch, that the bacteria of +splenic fever (anthrax) belong to this group. Under this head must be +placed the bacillus malarise (Klebs and Tommassi-Crudeli), the bacillus +typhi abdominalis (Klebs, Ebert), the bacillus typhi exanthematici +(Klebs, observations not yet published), the bacillus of hog-cholera +(Klein), and, finally the bacillus leprosus (Neisser). It would exceed +the time appointed were I to attempt to describe these forms more +minutely. This may, perhaps, be better reserved for discussion and +demonstration. + +"Alongside of these general infective diseases produced by bacilli, +local affections also occur, which indicate the presence of these +organisms at the point where disease begins. As an example of these +processes, which probably occur in various organs, I would mention +gastritis bacillaris, of which I shall show you preparations. In this, +we can trace the entrance of the bacilli into the peptic glands, as well +as their further distribution in the walls of the stomach, and in the +vascular system. + +"The second group of the pathogenetic schizomycetae I propose to call, +with Billroth, cocco-bacteria, because they consist of collections of +micrococci, which are capable of transforming themselves into short +rods. The former usually form groups united by zoogloea; by prolongation +of the cocci rods are formed, which sprout out, break up by division +into chains, and further lead again to the formation of resting masses +of cocci. I distinguish, further, in this group, two genera--the +microsporina and the monadina; in the former of which the micrococci are +collected into spherical lumps, in the latter into layers. The one class +is developed in artificial cultivation fluid, the other on the surface. +The former requires a medium poor in oxygen, the latter a medium rich in +oxygen, for their development. + +"Among the affections produced by microsporina, I reckon especially the +septic processes, and also true diphtheria. On the other hand, to the +processes produced by monadina belong especially a large series of +diseases, which according to their clinical and anatomical features, +may be characterized as inflammatory processes, acute exanthemata, and +infective tumors, or leucocytoses. Of inflammatory processes, those +belong here which do not generally lead to suppuration, such as +rheumatic affections, including the heart, kidney, and liver affections, +which accompany this process, sequelae which, as is well known, +lead more especially to formation of connective tissue, and not to +suppuration. Here, also, belong croupous pneumonia, the allied disease +erysipelas, certain puerperal processes, and finally, parotitis +epidemica, or mumps. + +"Among the acute exanthemata, the following may, up to the present time, +be placed in this group; variola-vaccina, scarlatina, and measles. + +"The group of infective tumors is represented by tuberculosis, syphilis, +and glanders. Throughout the whole group of cocco-bacteria the +demonstration of organisms in the diseased parts encounters difficulties +which vary considerably in the different kinds." + +The speaker concluded by describing the methods (now well known) by +which the powers of the different organisms are tested. + +He also referred to Pasteur's, Chauveau's, and Toussaint's recent +experiments. + +His conclusion was that the specific communicable diseases are produced +by specific organisms. + + * * * * * + + + + +THE CENTENARY OF THE DISCOVERY OF URANUS. + +By W. F. DENNING, F.R.A.S. + + +The year 1781 was signalized by an astronomical discovery of great +importance, and one which marked the epoch as memorable in the annals +of science. A musician at Bath, William Herschel by name, who had been +constructing some excellent telescopes and making a systematic survey of +the heavens, observed an object on the night of March 13 of that year, +which ultimately proved to be a large planet revolving in an orbit +exterior to that of Saturn. The discovery was as unique as it was +significant. Only five planets, in addition to the Earth, had hitherto +been known; they were observed by the ancients, and by each succeeding +generation, but now a new light burst upon men. The genius of Herschel +had singled out from the host of stars which his telescope revealed +an object the true character of which had evaded human perception for +thousands of years! + +[Illustration: FIG. 1.--APPROXIMATE PLACE OF URANUS AMONGST THE STARS AT +ITS DISCOVERY ON MARCH 13, 1781] + +The centenary of this remarkable advance in knowledge naturally recalls +to mind the circumstances of the discovery, and makes us inquisitive to +know what new facts have been gleaned of Herschel's planet, now that +a hundred years have passed away, and we are enabled to look back and +review the vast amount of labor which has been accomplished in this wide +and attractive field of astronomical research. We may learn what new +features have been discerned of the new body, and what additional +discoveries in connection with other planets unknown in Herschel's day, +have been effected by aid of the powerful telescopes which have been +devoted to the work. We do not, however, intend dealing with the general +question of planetary discovery, for at a glance we are impressed with +its magnitude. While a century ago five planets only were known, we now +have some two hundred and thirty of these bodies, and the stream of +discovery flows on without abatement through each succeeding year. The +detection of Uranus seems, indeed, to have been the prelude to many +similar discoveries, and to have offered the incentive to greater +diligence and energy on the part of observers in various parts of the +world. + +[Illustration: Fig. 2.--ORBITS OF THE URANIAN SATELLITES.] + +Many great discoveries have resulted from accident; and the leading +facts attending that of Uranus prove that, in a large measure, the +result was brought about in a similar way. Herschel, as he unwearyingly +swept the heavens night after night, was in quest of sidereal +wonders--such as double stars and nebulae--and he happened to alight +upon the new planet in a purely chance way. He had no expectation of +finding such a remarkable object, and indeed, when he had found it, +wholly mistook its character. There could be no doubt that it was a body +wholly dissimilar to the fixed stars, and it was equally certain that it +could not be a nebula. It had a perceptible disk, for when it had first +come under the critical eye of its discoverer he had noticed immediately +that its appearance differed widely from the multitude of objects which +crossed the field of his telescope. He had been accustomed to see hosts +of stars pass in review, and their aspect was in one respect similar, +namely, they were invariably presented as points of light incapable of +being sensibly magnified, even with the highest powers. True, there was +a great variety of apparent brightness in these objects and a singular +diversity of configuration, but there was no exception to the invariable +feature referred to. The point of light was constant, and no striking +exception was anticipated until one night--March 13, 1781--Herschel +being intently engaged in the examination of some small stars in the +region of Gemini, brought an object under the range of, his telescope, +which his eye at once selected as one of anomalous character. + +Applying a higher power, he noticed that it exhibited a planetary disk, +but his instrument failed to define it with sufficient distinctness, and +hence he became doubtful as to its real nature. The object was found to +be in motion, and subsequent observations led him to the assumption that +it must be a comet of rather exceptional type. This appeared to be the +best explanation of the strange body, for history contained many records +of curious comets, some of which were observed as nearly circular +patches of nebulous light, and probably of similar aspect to the object +then visible; and apart from this it must be remembered that the idea of +a large planet exterior to Saturn was a fact of such momentous import +that Herschel, with a due regard to that modesty which accompanies +true genius, refrained from attaching such an interpretation to his +observations. He was content to direct the notice of astronomers to it +as a phenomenon requiring close attention, and suggested that it might +be a comet in consequence of its motion and the faint and somewhat +ill-defined character of its appearance. + +From the earliest ages five planets only were known, and the discovery +of another large planet beyond the sphere of Saturn must at once +revolutionize existing ideas as to the range of the solar system, and +immediately take rank as a scientific event of equal interest to the +discovery of the moons of Jupiter or the rings of Saturn, which each in +their day impressed men with new ideas of the celestial mechanism. But +the truth could not long be delayed. The new body being watched and its +orbit rigorously computed from a series of observed positions revealed +its true character, and Herschel was awarded the honor due to the author +of a discovery of such importance. His diligence and pertinacity alone +had enabled him to search out from among the multitude of stars thickly +strewn over the firmament this unknown and well-nigh invisible planet +which, during all the preceding years of the world's history, had eluded +human perception. Men had been all unconscious of its existence as it +had been slowly completing its circuits around the sun, obedient to the +same laws as the other planets of the solar system, and awaiting the +hour when the unfailing eve of Herschel should introduce it as the faint +and far-off planet girding our system within its expansive folds. + +As soon as the existence of the new orb was confirmed and the fact +rendered indisputable, the question naturally arose whether it had ever +been seen in former years by the authors of star catalogues, who could +hardly have overlooked an object like this though its planetary nature +had manifestly escaped detection. It was just perceptible to the naked +eye, shining like a star of the sixth magnitude, and ought to have been +distinguished by those who had reviewed the heavens with the purpose +of determining and mapping the positions of the stars. Reference was, +therefore, made to the chief catalogues, when it was found at once that +the planet had been unquestionably observed by Tobias Mayer, Le Monnier, +Bradley, and Flamsteed. It was several times noted by these observers: +by Le Monnier no less than twelve times, and by Flamsteed on six +occasions; and it is remarkable that in every instance its true +character escaped detection. Neither its special appearance nor its +motion attracted attention, so that it was merely catalogued as an +ordinary fixed star. Thus Herschel was not anticipated in his discovery. +It remained for him, in 1781, to note its exceptional aspect, and to +specify it as an object requiring critical investigation. But the early +observations above alluded to served a useful purpose in testing the +accuracy of the computed orbit, for without waiting many years to +compare the theoretical and observed positions, astronomers had in these +old records a reliable series of points through which the previous +course of the planet could be traced. + +The calculations showed that its mean distance from the sun was some +1,750,000,000 miles, and that a revolution was completed in about +eighty-four years. It was also found to be a very large planet, greatly +exceeding either Mercury, Venus, the Earth, or Mars, though considerably +inferior to either Jupiter or Saturn. + +Here, then, was a discovery of the utmost importance, and one of the +most salient additions to our knowledge which the telescope had ever +achieved. The new planet was now definitely assigned its proper place in +the solar system, and was regarded as of equal significance with the +old planets. True, the new planet of Herschel could not be compared as +regards its visible aspect with the other previously known members of +our system, but it was nevertheless an object of equal weight. Its vast +distance alone rendered it faint. It formed one of the constituent parts +of the solar system, which, though separated by immense intervals of +space, are yet coherent by the far-reaching effects of gravitation. +There is, indeed, a bond of harmony between the series of planetary +orbits, which exhibit a marked degree of regularity in their successive +distances from the sun; and though they are not connected by any visible +links, they are firmly held together by unseen influences, and their +motions are subject to certain laws which have been revealed by +centuries of observation. + +The question of suitably naming the new planet soon came to the fore. +Herschel himself proposed to designate it the "Georgium Sidus," in honor +of his patron, George III., just as Galileo had called the satellites +of Jupiter the "Medicean stars," after Cosmo de' Medici. But La Place +proposed that the planet should be named after its discoverer; and thus +it was frequently referred to as "Herschel," and sometimes as "The +Herschelian planet." Astronomers on the continent objected to this +system of personal nomenclature, and argued that the new body should +receive an appellative in accordance with those adopted for the old +planets, which had been selected from the heathen mythology. Several +names were suggested as suitable (on the basis of this principle), and +ultimately the one advanced by Bode received the most favor, and the +planet thereafter was called "Uranus." + +The varying positions of the new body as observed on successive nights +were determined by comparisons with a group of six small stars, termed +by Herschel [Greek: alpha, beta, gamma, delta, epsilon] and afterwards +formed into a constellation under the designation of "Britannia," though +it does not appear that this little asterism is acknowledged as one of +our constellations. Its position is about midway between Taurus and +Gemini, and the following are the principal stars computed for 1881.0, +as given by Mr. Marth: + + Star. Magnitude. Right Ascension. Declination. + h. m. s. + alpha 9.0 5 42 6.06 23 deg. 35' 6.7" N. + eta 8.7 5 43 17.82 23 26' 7.2 N. + theta 8.8 5 44 0.99 23 53' 30.8 N. + epsilon 8.8 5 45 40.68 23 34' 46.8 N. + +The stars are therefore merely telescopic, and are confined to a small +area of space, so that the propriety of adopting the group as a distinct +constellation is very questionable. Their positions close to Uranus at +the time of its discovery, and the fact that the planet's motion was +detected by means of comparisons with them, has given to these stars an +historical interest which in future years must often attract the student +to their reobservation. But it would be unwise, as forming a bad +precedent, to accept a group of stars of this inferior type as meriting +to rank among the old constellations, when we have numbers of richer +groups, situated on their confines, which first deserve such a +distinction. However special or unique the circumstances connected with +certain telescopic stars may be, and however necessary it may appear +to signalize them by a specific title, we are inclined to question the +adoption of such means as likely to exercise a wrong influence, +inasmuch as it may hereafter originate further innovations of a similar +character, and ultimate complications will be certain to arise. + +Soon after the discovery of Uranus it was suspected that the planet +was encircled, like Saturn, by a luminous ring, but on subsequent +observation this was not confirmed, and no such appendage has ever been +revealed in the more perfected instruments of our own times. Indeed, if +Uranus displays a peculiarity of constitution in any way analogous to +the ring system of Saturn, it must be of the most minute character so as +to have thus evaded telescopic scrutiny during a hundred years. + +The discovery soon attracted the notice of royalty, and the reigning +sovereign, George III., anxious to practically express his appreciation +of the valuable labors of Herschel, awarded him a pension of L200 a year +and furnished him with a residence at Slough, near Windsor, and the +means to erect a gigantic telescope with which he might be enabled +to continue his important researches. This instrument consisted of a +reflector on the "Front-view" construction, with a speculum 4 feet in +diameter and of 40 feet focal length. Upon its completion, Herschel +immediately began to observe the region of the new planet with the idea +of discovering any satellites which might belong to it, for analogy +suggested that it was surrounded by a numerous retinue of such bodies. +He was soon successful, for, on the night of January 11, 1787. he saw +two minute objects near the planet, which renewed observations revealed +to be satellites; and he detected two additional ones in 1790, and two +others in 1794, making six in all. But the observations were of extreme +difficulty. The path of the planet frequently passed near minute stars, +and it became hard to distinguish between them and the suspected +satellites. Herschel, however, considered he had obtained conclusive +evidence of the existence of six satellites with sidereal periods +ranging from 5d. 21h. 25m. to 107d. 16h. 39m., and his means of +observation being much superior to those possessed by any of his +contemporaries it was impossible to have corroborative testimony. + +The matter was thus allowed to rest until the middle of the present +century, when Lassell, in the pure sky at Malta, endeavored to reobserve +the satellites with a two-foot reflector. This instrument was considered +superior to Herschel's telescope; and the atmosphere at this station +being decidedly more suitable for such delicate observations than +in England, it was removed there for the express purpose of dealing +successfully with objects of extreme difficulty. The results were very +important. Mr. Lassell became convinced that Uranus had only four +satellites, and that if any others existed they remained to be +discovered. Two of these were found to be identical with those seen by +Herschel in 1787, and now called Titania and Oberon. The other two, +Ariel and Umbriel, could not be identified with any of those alleged to +have been previously detected by Herschel, so that the inference was +that they were new bodies, and that the priority of discovery was due to +Mr. Lassell; whence it also followed that the older observations were +erroneous, and that in fact Herschel had been entirely mistaken with +regard to the four satellites he believed he had detected subsequently +to 1787. + +In November, 1873, a fine twenty-six-inch object glass, by Alvan Clark, +was mounted at the U. S. Naval Observatory at Washington, and it was +soon employed upon the difficult task of solving the problem as to the +exact periods of the Uranian satellites. This was very satisfactorily +effected, and with distinct and conclusive favor to Mr. Lassell, whose +observations were fully corroborated. Only four satellites could be +distinguished by the American observers, and their periods, as computed +from a valuable series of measures, agreed with those previously derived +at Malta. In Appendix I. to the "Washington Observations" for 1873, +Prof. Newcomb gave a valuable summary of results--the first obtained, be +it noted, with that splendid instrument which soon afterward, in 1877, +revealed the satellites of Mars--which included the elements of the +satellites of Uranus as follows: + + Mean Longitude. + + Satellite. Epoch 1871. Radius of Period of + Dec. 31, W.M.T. Orbit. Revolution in days. + I. Ariel........ 21.83 deg. 13.78" 2.52038 + II. Umbriel..... 13.52 19.20 4.14418 + III. Titania..... 229.93 31.48 7.70590 + IV. Oberon...... 154.83 42.10 13.43327 + +Speaking of the comparative brightness of the satellites, Prof. Newcomb +says: + +"The greater proximity of the inner satellites to the planet makes it +difficult to compare them photometrically with the outer ones, as actual +feebleness of light cannot be distinguished from difficulty of seeing +arising from the proximity of the planet. However, that Umbriel is +intrinsically fainter than Titania is evinced by the fact that, although +the least distance of the latter is somewhat less than the greatest +distance of the former, there is never any difficulty in seeing it in +that position. From their relative aspects in these respective positions +I judge Umbriel to be about half as bright as Titania. Ariel must be +brighter than Umbriel, because I have never seen the latter unless it +was farther from the planet than the former at its maximum distance.... +I think I may say with considerable certainty that there is no satellite +within 2' of the planet, and outside of Oberon, having one-third the +brilliancy of the latter, and therefore that none of Sir William +Herschel's supposed outer satellites can have any real existence. The +distances of the four known satellites increase in so regular a way that +it can hardly be supposed that any others exist between them. Of what +may be inside of Ariel it is impossible to speak with certainty, since +in the state of atmosphere which prevails during our winter all the +satellites named disappear at 10" from the planet." + +Prof. Newcomb mentions that no systematic search for new satellites +was undertaken because it must have interfered with the fullness and +accuracy of the micrometer measures of the old satellites, which +constituted the main purpose of the observations. Some faint objects +were occasionally glimpsed near the planet, and their relative places +determined, but they were never found to accompany Uranus. The fact, +therefore, that no additional satellites were discovered is not to +be regarded as a strong point in favor of the theory of their +non-existence, because the great power and excellence of the telescope +was expressly directed to the attainment of other ends; and moreover the +season in which the planet came to opposition was distinctly unfavorable +for the prosecution of a rigorous search for new satellites. There +can, however, be no doubt that the analogies of the planetary systems +interior to Uranus plainly suggest that this planet is attended by +several satellites which the power of our greatest telescopes has +hitherto failed to reveal; and that it is in this direction and that of +Neptune we may anticipate further discoveries in future years when the +conditions are more auspicious and the work is entered upon with special +energy, aided by instruments of even greater capacity than those which +have already so far conduced to our knowledge of the heavenly bodies. + +Notwithstanding the extreme difficulty with which the Uranian satellites +are observed, the two brighter ones, Titania and Oberon, discovered by +William Herschel in 1787, have been occasionally detected in telescopes +of moderate power, and identified by means of an ephemeris which has +shown that the computed positions approximately agree with those +observed. During the last few years Mr. Marth has published ephemerides +of the satellites of both Saturn and Uranus, and many amateurs have to +acknowledge the valuable aid rendered by these tables, which supply a +ready means of identifying the satellites, and thus act as an incentive +to observers who are induced to pursue such work for the sake of the +interesting comparisons to be made afterward. In one exceptional +instance the two outer satellites of Uranus appear to have been glimpsed +with an object glass of only 43 inches aperture, and the facts are given +in detail in the "Monthly Notices of the R.A.S.," April 1876, pp. 294-6. +The observations were made in January, February, and March, 1876, by +Mr. J.W. Ward, of Belfast; and the positions of the satellites, as he +estimated them on several nights, are compared with those computed, the +two sets presenting tolerably good agreement. Indeed the corroborations +are such as to almost wholly negative any skepticism, though such +extraordinary feats should always be received with caution. + +In this particular case the chances of being misled are manifold; even +Herschel himself fell into error in taking minute stars to be satellites +and actually calculating their periods; so that when we remember the +difficulties of the question our doubts are not altogether dispelled. +Extreme acuteness of vision will, in individual instances, lead to +success of abnormal character, and certainly in Mr. Ward's case the +remarkable accordances in the observed and calculated positions appear +to be conclusive evidence that he was not mistaken. + +It will be readily inferred that the great distance and consequent +feebleness of Uranus must render any markings upon the disk of the +planet beyond the reach of our best telescopes; and indeed this appears +to have been a matter of common experience. Though the surface has been +often scanned for traces of spots, we seldom find mention that any have +been distinguished. Consequently the period of rotation has yet to be +determined. It is true that an approximate value was assigned by Mr. +T.H. Buffham from observations with a nine-inch reflector in 1870 and +1872. but the materials on which the computation was based were slender +and necessarily somewhat uncertain, so that his period of about twelve +hours stands greatly in need of confirmation. The bright spots and zones +seen on the disk in the years mentioned appear to have entirely eluded +other observers, though they are probably phenomena of permanent +character and within reach of instruments of moderate size. Mr. Buffham +[1] thus describes them: + +[Footnote 1: "Monthly Notices K. A. S.," January, 1873.] + +"1870, Jan. 25, 11h. to 12h. in clear and tolerably steady air; power +132 showed that the disk was not uniform. With powers 202 and 3.0, two +round, bright spots were perceived, not quite crossing the center but a +little nearer to the eastern side of the planet, the position angle of a +line passing through their centers being about 20 deg. and 200--ellipticity +of Uranus seemed obvious, the major axis lying parallel to the line of +the spots. + +"Jan. 27, 10h. to 101/2h.; some fog, and definition not good, but the +appearance of the spots was almost exactly the same as on the 25th." + +On March 19 glimpses were obtained of a light streak and two spots. +On April 1, 4, 6, and 8, a luminous zone was seen on the disk, and +in February and March, 1872, when observations were resumed, certain +regions were noted brighter than others, and underwent changes +indicating the rotation of the planet in a similar direction to that +derived from the results obtained in 1870. Mr. Buffham points out that, +if this is admitted, then the plane of the planet's equator is not +coincident with the plane of the orbits of the satellites. Nor need we +be surprised at this departure from the general rule, where such an +anomalous inclination exists. In singular confirmation of this is Mr. +Lassell's observation of 1862, Jan. 29, where he says: "I received an +impression which I am unable to render certain of an equatorial dark +belt, and of an ellipticity of form." + +Some observations made in 1872-3 with the great six-foot reflector of +Lord Rosse may here be briefly referred to. A number of measures, both +of position and distance, of Oberon and Titania, were made, [1] and a +few of Umbriel and Ariel, but "the shortness of the time available (40 +minutes) each night for the observation of the planet with the six-foot +instrument, the atmospheric disturbance, so often a source of annoyance +in using so large an aperture, and other unfavorable circumstances, +tended to affect the value of the observations, and to make the two +inner satellites rarely within detection." + +[Footnote 1: "Monthly Notices R. A. S.," March, 1875.] + +On Feb. 10, 1872, Lord Rosse notes that all four satellites were seen on +the same side of the planet. On Jan. 16, 1873, when definition was good, +no traces of any markings were seen. Diameter of Uranus = 5.29". Power +414 was usually employed, though at times the inner satellites could be +more satisfactorily seen with 625. + +It may be mentioned as an interesting point that, some fifty years +after the first discovery of Uranus by Herschel, it was accidentally +rediscovered by his son, Sir John Herschel, who recognized it by +its disk, and had no idea as to the identity of the object until an +ephemeris was referred to. Sir John mentions the fact as follows, in a +letter to Admiral Smyth, written in 1830, August 8: + +"I have just completed two twenty-foot reflectors, and have got some +interesting observations of the satellites of Uranus. The first sweep +I made with my new mirror I _re-discovered_ this planet by its _disk_, +having blundered upon it by the merest accident for 19 Capricorni." + +In commenting upon the centenary of an important scientific discovery we +are naturally attracted to inquire what progress has been made in the +same field during the comparatively short interval of one hundred years +which has elapsed since it occurred. We have called it a short interval, +because it cannot be considered otherwise from an astronomical or +geological point of view, though, as far as human life is concerned, +it can only be regarded as a very lengthy period, including several +generations within its limits. + +Since Herschel, in 1781, discovered Uranus, astronomy has progressed +with great rapidity, so that it would be impossible to enumerate in a +brief memoir the many additional discoveries which have resulted from +assiduous observation. A century ago only five planets were known +(excluding the Earth), now we are acquainted with about two hundred and +thirty of these bodies; and one of these, found in 1846, is a large +planet whose orbit lies exterior to that of Uranus. In fact, the state +of astronomical knowledge a century ago has undergone wonderful changes. +It has been rendered far more complete and comprehensive by the +diligence of its adherents and by the unwearying energy with which both +in theory and practice it has been pursued. A zone of small planets has +been discovered between Mars and Jupiter just where the analogies of the +planetary distances indicated the probable existence of a large planet. +The far-off Neptune was revealed in 1846 by a process of analytical +reasoning as unique as it was triumphant, and which proved how well +the theory of planetary perturbations was understood. The planet was +discovered by calculation, its position in the heavens assigned, and the +telescope was then employed merely as the instrument of its detection. +The number of satellites which a century ago numbered only ten has now +reached twenty, and the discovery in 1877 of two moons accompanying Mars +shows that the work is being continued with marked success. + +In other departments we also find similar evidence of increasing +knowledge. The periodicity of the sun spots, the existence of systems of +binary stars, meteor showers, and their affinity with cometary orbits +may be mentioned as among the more important, while a host of new +comets, chiefly telescopic, have been detected. Large numbers of nebulae +and double stars have been catalogued, and we have evidence every year +of the activity with which these several branches are being followed up. + +In fine, it matters little to what particular department of astronomical +investigation we look for traces of advancement during the past hundred +years, for it is evident throughout them all, and sufficiently proves +that the interest formerly taken in the science has not only been well +sustained but has become more general and popular, and is extending its +attractive features to all classes of the community. + +In Herschel's day large telescopes were rare. A man devoting himself to +the study of the heavenly bodies as a means of intellectual recreation +was considered a phenomenon, and indeed that appellation might be +fittingly applied to the few isolated individuals who really occupied +themselves in such work. How different is the case now that the pleasant +ways of science have called so many to her side and so far perfected her +means of research as to make them accessible to all who care to see and +investigate for themselves the unique and wonderful truths so easily +within reach! Large telescopes have become common enough, and there is +no lack of hands and eyes to utilize them, nor of understanding, ever +ready to appreciate, in sincerity and humbleness, those objects which +display in an eminent degree the all-wise conceptions of a great +Creator! It is, therefore, a most gratifying sign to notice this rapid +development of astronomy, and to see year by year the increasing number +of its advocates and the record of many new facts gleaned by vigorous +observation. + +The character of recent discoveries distinctly intimates that, in future +years, some departments of the science will become very complicated, +owing to the necessity of dealing with a large number of minute bodies, +for the tendency of modern researches has been to reveal objects which +by their faintness had hitherto eluded detection. And when we consider +that these bodies are rapidly increasing year by year, the idea is +obviously suggested that, inasmuch as their numbers are comparatively +illimitable, and there is likely to be no immediate abatement in the +enthusiasm of observers, difficulties will arise in identifying them +apart and forming them into catalogues with their orbital elements +attached, so that the individual members may be redetected at any time. + +In this connection we allude particularly to minor planets, to +telescopic comets, and to meteoric streams, which severally form a very +numerous group of bodies of which the known members are accumulating to +a great extent. As complications arise, some remedies must be applied to +their solution, and one probable effect will be that astronomers will be +induced each one to have a specialty or branch to which his energies are +mainly directed. The science will become so wide in its application and +so intricate in its details that it will become more than ever necessary +for observers to select or single out definite lines of investigation +and pursue them closely, for success is far more likely to attend such +exertions than those which are not devoted to any special end, but +employed rather in a general survey of phenomena. + +We have already before us some excellent instances in which individual +energies have been aptly utilized in the prosecution of original work +in some specific branch of astronomy, and we are strongly disposed to +recommend such exclusive labors to those who have the means and the +desire to achieve something useful. Observers who find one subject +monotonous and then take up another for the sake of variation are not +likely to get far advanced in either. In the case of amateurs who use a +telescope merely for amusement, and indiscriminately apply it to nearly +every conspicuous object in the firmament without any particular purpose +other than to satisfy their curiosity, the matter is somewhat different, +and our remarks are not applicable to them. We refer more pointedly +to those who have a regard for the interests of the science and whose +enthusiasm enables them to work habitually and with some pertinacity. + +History tells us that the Great Alexander wept when he found he had no +other worlds to conquer, and we fear that some astronomers will lament +that they have little prospect of discovering anything fresh in a sphere +to which our giant telescopes have been so often directed, but this is +founded on a palpable misconception. Certain objects, such as comets for +example, do not require great power, and the revelation of new meteor +showers is entirely a question for the naked eye. In fact, it may be +confidently asserted that observations undertaken with energy and +persistency will, if rightly directed, more than compensate for defects +of instrumental power. + +It is true, however, that in certain quarters we must look to large +instruments alone for new discoveries. It would be useless searching for +an ultra-Neptunian planet, or for additional satellites to Uranus or +Neptune, or for the materials to determine the rotation periods of these +planets with a small telescope. Every observer will find objects suited +to the capacity of his instrument, and he may not only employ it +usefully but possibly make a discovery of nearly equal import with that +which rendered the name of Herschel famous a century ago.--_Popular +Science Review_. + + * * * * * + + + + +THE VARYING SUSCEPTIBILITY OF PLANTS AND ANIMALS TO POISONS AND +DISEASES. + + +Much attention is being devoted to the causes which determine the +aptitude or immunity with animals for maladies. This is in a general +sense called medical geography, as a physician who has prescribed for +patients in various parts of the world, and belonging to different +races--the white, yellow, and black--has been able to note the +diversities in the same disease, and the contradictions in the remedies +employed. + +The true social peril, hardly discovered before we became aware how +to conjure it, lies in those legions of animalcules or microbes that +surround us and in the middle of which we live. M. Pasteur has revealed +them to us as the factors in infectious diseases. Claude Bernard +has demonstrated the community which exists between animals and +vegetables--phenomena of movement, of sensibility, of production of +heat, of respiration, of digestion even, for there are the _Drosera_ and +kindred carnivorous plants. Iron cures chlorosis in vegetables as well +as in animals, and chloroform and ether render both insensible. There +resemblances are more striking still between animals. After Baudrimont, +insects are, in presence of alcohols, chloroform, and irrespirable +gases, similarly affected as man. Many maladies, too, are common to +man and several species of animals; and this organic identity is best +illustrated in the relationship between epidemics and epizootias, +cancer, asthma, phthisis, smallpox, rabies, glanders, charbon, etc., +afflict alike man and many species of animals. + +The differences between races are not less remarkable--odor and taste, +for example. According to anthropophagy, negroes are best, and white +people most detestable. Broca remarked, that, in the dissecting room, +the muscles of the negro putrefied less rapidly than those of whites. It +is perhaps to these anatomical differences that the diverse action of +the same poison, in the case of races or species, may be attributed. On +certain rodentia belladonna exercises no influence; morphine for a horse +is a violent stimulant; a snail remains insensible to digitalis; goats +eat tobacco with impunity; and in the Tarentin the inhabitants rear only +black sheep, because a plant abounds which is noxious for white sheep. + +The nature of these conditions is a mystery for science. The _Solanae_ +tribe of plants furnish a principle which, as its name implies, produces +consolation or forgetfulness, by acting on the tissues of the brain +where resides the organ of thought; now, on the authority of Professor +Bouchardat, these opiates have the less of effect in proportion as the +animals possess the less of intelligence. + +To the same anatomical peculiarities must be ascribed the choice that +disease makes in such or such a race. Glanders, for instance, so +virulent with the horse, the ass, and man, produce in the case of the +dog only a local accident; peripneumonia, so contagious among horned +cattle, is more benign in its action on Dutch than other breeds of +stock; the cattle plague that decimates so many farms is communicated by +cattle to each other from the slightest contact, while the closest and +most constant association is necessary to communicate the disease +to sheep, and even when they are affected its action is not severe. +Further, that plague only attacks ruminant animals--oxen, goats, sheep, +zebras, gazelles, etc. Ten years ago this plague broke out in the Jardin +d'Acclimatation; not a ruminant escaped, and also one animal not of that +class, a little tenant nearly related to the pig--the _peccari_. + +Now, Dr. Condereau has demonstrated recently that the stomach of the pig +has a rudimentary organization recalling that of the ruminants. Clearly, +the stomach of the peccari, and perhaps that of the pig, present a +favorable medium for the parasitical microbe peculiar to the rinderpest. +In the potato disease, again, all the varieties are not affected with +the same degree of violence; it is more marked in its action on the +round yellows than the reds, and on the latter rather than the pink. But +the symptoms even of the same malady differ, the parasite's attacks on +the tissues being dissimilar. Oak galls are produced from the prickings +of insects; now around the same larva often four varieties of galls are +recognized. In the case of consumption in cattle, the disease marches +slowly; in that of pigs it takes the galloping form, as with man. + +Each people or nation has its peculiar pathology and also its peculiar +cures. A negro can take a dose of tartar ten times more excessive than a +white; the same dose of brandy given to a black, a yellow, and a white, +will not produce on the three men either drunkenness at the same moment, +or intoxication at all. Mulattoes can sustain more drastic aperients +than other races; the negro does not suffer from yellow fever, but he +readily falls to phthisis; he will catch the cholera more quickly than a +white. Human races, where they may catch the same intermittent fever at +the identical moment and in the same swamp, will not the less display +different types of fever. Dr. Crevaux has shown that a certain insect +with the North American Indian is not the same as with the negro or the +maroon, and both differ from that peculiar to Europeans. + +M. Pasteur's beautiful experiments have conclusively demonstrated that +fowls do not catch the _charbon_; now the vital warmth of birds is from +seven to nine degrees higher than in the case of mammiferous animals; +he imagined that if the fowl was cooled down by baths to the lower +temperature, it would be liable equally to become affected; he tried, +and the result proved he was correct. + +The absence, then, of a certain temperature would be the reason why +birds are exempt. The microbes are the agents of infectious disease; +when these swarm in the blood of an individual they seem to leave there +something pernicious for parasites resembling themselves, or to bring +away with them something necessary to the life of their successors. A +glass of sugar and water, where leaven has already fermented and yielded +alcohol, is incapable of producing a second crop of leaven; similarly +the blood of an individual, once contaminated, becomes uninhabitable +afterward for like microbes. The individual has acquired immunity. Such +is the principle of vaccination.--_Paris Correspondent of the Kansas +City Review_. + + * * * * * + + + + +KIND TREATMENT OF HORSES. + + +It has been observed by experienced horse trainers that naturally +vicious horses are rare, and that among those that are properly trained +and kindly treated when colts they are the exception. + +It is superfluous to say that a gentle and docile horse is always the +more valuable, other qualities being equal, and it is almost obvious +that gentle treatment tends to develop this admirable quality in the +horse as well as in the human species, while harsh treatment has the +contrary tendency. Horses have been trained so as to be entirely +governed by the words of his driver, and they will obey and perform +their simple but important duties with as much alacrity as the child +obeys the direction of the parent. + +It is true that all horses are not equally intelligent and tractable, +but it is probable that there is less difference among them in this +regard than there is among his human masters, since there are many +incitements and ambitions among men that do not affect animals. + +The horse learns to know and to have confidence in a gentle driver, and +soon discovers how to secure for himself that which he desires, and +to understand his surroundings and his duties. The tone, volume, and +inflection of his master's voice indicate much, perhaps more than the +words that are spoken. Soothing tones rather than words calm him if +excited by fear or anger, and angry and excited tones tend to excite or +anger him. 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You can also find out about how to make a +donation to Project Gutenberg, and how to get involved. + + +**Welcome To The World of Free Plain Vanilla Electronic Texts** + +**eBooks Readable By Both Humans and By Computers, Since 1971** + +*****These eBooks Were Prepared By Thousands of Volunteers!***** + + +Title: Scientific American Supplement, No. 303 + October 22, 1881 + +Author: Various + +Release Date: June, 2005 [EBook #8296] +[Yes, we are more than one year ahead of schedule] +[This file was first posted on July 4, 2003] + +Edition: 10 + +Language: English + +Character set encoding: ASCII + +*** START OF THE PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN NO. 303 *** + + + + +Olaf Voss, Don Kretz, Juliet Sutherland, Charles Franks +and the Online Distributed Proofreading Team. + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 303 + + + + +NEW YORK, OCTOBER 22, 1881 + +Scientific American Supplement. Vol. XII, No. 303. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + + TABLE OF CONTENTS + +I. ENGINEERING AND MECHANICS.--New Eighty-ton Steam Hammer at the Saint + Chamond Works, France.--7 figures.--Elevation of hammer.--Profile-- + Transverse section.--Profile view of foundation, etc.--Plan of + plant.--General plan of the forging mill.--Details of truss and + support for the cranes. + + Great Steamers.--Comparative details of the Servia, the City of Rome, + the Alaska, and the Great Eastern. + + Improved Road Locomotive.--2 figures.--Side and end views + + American Milling Methods. By ALBERT HOPPIN.--Ten years' progress.--Low + milling.--Half high milling.--High milling.--Important paper read + before the Pennsylvania State Millers' Association. + + Machine for Dotting Tulles and other Light Fabrics.--3 figures. + +II. TECHNOLOGY AND CHEMISTRY.--The Reproduction and Multiplication of + Negatives. By ERNEST EDWARDS. + + A New Method of Making Gelatine Emulsion. By W. K. BURTON. + + The Pottery and Porcelain Industries of Japan. + + Crystallization Table. + + The Principles of Hop Analysis. By Dr. G. O. CECH. + + Water Gas.--A description of apparatus for producing cheap gas, and + some notes on the economical effects of using such gas with gas + motors, etc.--By J. EMERSON DOWSON. + + On the Fluid Density of Certain Metals. By Professors CHANDLER ROBERTS + and T. WRIGLESON. + +III. PHYSICS, ELECTRICITY, ETC.--Electric Power.--The nature and uses of + electricity.--Electricity vs. steam. + + On the Method of Obtaining and Measuring Very High Vacua with a + Modified Form of Sprengel Pump. By Prof OGDEN N. ROOD.--4 figures.-- + Apparatus for obtaining vacua of one four hundred-millionth of an + atmosphere--Construction.--Manipulation.--Calculations.--Results + +IV. ART, ARCHITECTURE, ETC.--Old Wrought Iron Gates, Guildhall. + Worcester, England. 1 figure. + + The French Crystal Palace, Park of St. Cloud, Paris. 1 full page + illustration. + + Suggestions in Architecture. A Castellated Chateau. Perspective and + plan. Chateau in the AEgean Sea. + +V. HYGIENE AND MEDICINE.--Hydrophobia Prevented by Vaccination. + + On Diptera as Spreaders of Disease. By J. W. SLATER. + + On the Relations of Minute Organisms to Certain Specific Diseases. + +VI. ASTRONOMY--The Centenary of the Discovery of Uranus. By F. W. DENNING. + 2 figures. Approximate place of Uranus among the stars at its + discovery, March l3, 1871.--Orbits of the Uranian Satellites. + +VII. BIOLOGY, ETC.--The Varying Susceptibility of Plants and Animals to + Poisons and Disease. + + Kind Treatment of Horses. + + * * * * * + + + + +NEW EIGHTY TON STEAM HAMMER AT THE SAINT CHAMOND WORKS + + +Ever since the improvements that have been introduced into the +manufacture of steel, and especially into the erection of works for its +production, have made it possible to obtain this metal in very large +masses, it has necessarily been preferred to iron for all pieces of +large dimensions, inasmuch as it possesses in the highest degree that +homogeneousness and resistance which are so difficult to obtain in the +latter metal. It has consequently been found necessary to construct +engines sufficiently powerful to effect the forging of enormous +ingots, as well as special furnaces for heating them and apparatus for +manipulating and transporting them. + +The greatest efforts in this direction have been made with a view to +supplying the wants of heavy artillery and of naval constructions; +and to these efforts is metallurgy indebted for the creation of +establishments on a scale that no one would have dared a few years ago +to think of. The forging mill which we are about to describe is one of +those creations which is destined to remain for a long time yet very +rare; and one which is fully able to respond, not only to all present +exigencies, but also, as far as can be foreseen, to all those that may +arise for a long period to come. The mill is constructed as a portion of +the vast works that the Compagnie des Forges et Acieries de la Marine +own at Saint Chamond, and which embrace likewise a powerful steel works +that furnishes, especially, large ingots exceeding 100 tons in weight. + +The mill consists, altogether, of three hammers, located in the same +room, and being of unequal powers in order to respond to different +requirements. The largest of these hammers is of 80 tons weight, and +the other two weigh respectively 35 and 28 tons. Each of them has +a corresponding furnace for heating by gas, as well as cranes for +maneuvering the ingots and the different engines. The general plan view +in Fig. 4 shows the arrangement of the hammers, cranes, and furnaces in +the millhouse. + +[Illustration: FIG. A.--ELEVATION OF A HAMMER. FIG. B.--PROFILE VIEW] + +The gas generators which supply the gas-furnaces are located out of +doors, as are the steam-generators. The ingots are brought from the +steel factory, and the forged pieces are taken away, by special trucks +running on a system of rails. We shall now give the most important +details in regard to the different parts of the works. + +_The Mill-House_--This consists of a central room, 262 feet long, 98 +feet wide, and 68 feet in height, with two lean-to annexes of 16 feet +each, making the total width 100 feet. The structure is wholly of metal, +and is so arranged as to permit of advantage being taken of every foot +of space under cover. For this purpose the system of construction +without tie-beams, known as the "De Dion type," has been adopted. Fig. +1 gives a general view of one of the trusses, and Fig. 5 shows some +further details. The binding-rafters consist of four angle-irons +connected by cross-bars of flat iron. The covering of corrugated +galvanized iron rests directly upon the binding-rafters, the upper parts +of which are covered with wood for the attachment of the corrugated +metal. The spacing of these rafters is calculated according to the +length of the sheets of corrugated iron, thus dispensing with the use of +ordinary rafters, and making a roof which is at once very light and very +durable, and consequently very economical. Rain falling on the roof +flows into leaden gutters, from whence it is carried by leaders into a +subterranean drain. The vertical walls of the structure are likewise of +corrugated iron, and the general aspect of the building is very original +and very satisfactory. + +_The 80 Ton Hammer_--The three hammers, notwithstanding their difference +in power, present similar arrangements, and scarcely vary except in +dimensions. We shall confine ourselves here to a description of the 80 +ton apparatus. This consists, in addition to the hammer, properly so +called, of three cranes of 120 tons each, serving to maneuver the pieces +to be forged, and of a fourth of 75 tons for maneuvering the working +implements. These four cranes are arranged symmetrically around the +hammer, and are supported at their upper extremity by metallic stays. +Besides the foregoing there are three gas furnaces for heating the +ingots. Figs. 1, 2, and 3 show the general arrangement of the apparatus. + +_Foundations of the Hammer and Composition of the Anvil-Bed_--To obtain +a foundation for the hammer an excavation was made to a depth of 26 feet +until a bed of solid rock was reached, and upon this there was then +spread a thick layer of beton, and upon this again there was placed a +bed of dressed stones in the part that was to receive the anvil-stock +and hammer. + +On this base of dressed stones there was placed a bed formed of logs +of heartwood of oak squaring 16 inches by 3 feet in height, standing +upright, joined together very perfectly, and kept in close juxtaposition +by a double band of iron straps joined by bolts. The object of this +wooden bed was to deaden, in a great measure, the effect of the shock +transmitted by the anvil-stock. + +NEW EIGHTY-TON STEAM HAMMER AT THE ST CHAMOND WORKS. + +[Illustration: FIG. 1.--TRANSVERSE SECTION.] + +[Illustration: FIG. 2.--PLAN.] + +[Illustration: FIG. 3.--PROFILE VIEW.] + +[Illustration: FIG. 4.--GENERAL PLAN OF THE FORGING MILL.] + +[Illustration: FIG. 5.--DETAILS OF THE TRUSSAND SUPPORT FOR THE CRANE.] + +_The Anvil-Stock_.--The anvil-stock, which is pyramidal in shape, and +the total weight of which amounts to 500 tons, is composed of superposed +courses, each formed of one or two blocks of cast iron. Each course +and every contact was very carefully planed in order to make sure of +a perfect fitting of the parts; and all the different blocks were +connected by means of mortises, by hot bandaging, and by joints with +key-pieces, in such a way as to effect a perfect solidity of the parts +and to make the whole compact and impossible to get out of shape. + +The anvil-stock was afterwards surrounded by a filling-in of masonry +composed of rag-stones and a mortar made of cement and hydraulic lime. +This masonry also forms the foundation for the standards of the hammer, +and is capped with dressed stone to receive the bed-plates. + +_The Power-Hammer_ (Figs. A and B).--The power-hammer, properly +so-called, consists, in addition to the hammer-head, of two standards to +whose inner sides are bolted guides upon which slides the moving mass. +The bed-plates of cast iron are 28 inches thick, and are independent of +the anvil-stock. They are set into the bed of dressed stone capping the +foundation, and are connected together by bars of iron and affixed to +the masonry by foundation bolts. To these bedplates are affixed the +standards by means of bolts and keys. The two standards are connected +together by iron plates four inches in thickness, which are set into the +metal and bolted to it so as to secure the utmost strength and solidity. +The platform which connects the upper extremities of the standards +supports the steam cylinder and the apparatus for distributing the +steam. The latter consists of a throttle valve, twelve inches in +diameter, and an eduction valve eighteen inches in diameter, the +maneuvering of which is done by means of rods extending down to a +platform upon which the engineman stands. This platform is so situated +that all orders can be distinctly heard by the engineman, and so that +he shall be protected from the heat radiated by the steel that is +being forged. All the maneuvers of the hammers are effected with most +wonderful facility and with the greatest precision. + +The piston is of cast-steel, and the rod is of iron, 12 inches in +diameter. The waste steam is carried out of the mill by a pipe, and, +before being allowed to escape into the atmosphere, is directed into an +expansion pipe which it penetrates from bottom to top. Here a portion of +the water condenses and flows off, and the steam then escapes into +the open air with a greatly diminished pressure. The object of this +arrangement is to diminish to a considerable extent the shocks and +disagreeable noise that would be produced by the direct escape of the +steam at quite a high pressure and also to avoid the fall of condensed +water. + +The following are a few details regarding the construction of the +hammer: + + Total height of foundations........... 26 ft. + From the ground to the platform ...... 28 " + + Platform .............................. 3.25 " + Height of cylinder.................... 21 " + ________ + + Total height...................... 78.25 ft. + + Weight of anvil-stock................ 500 tons. + Weight of bed-plates................. 122 " + Weight of standards.................. 270 " + Weight of platform and cylinder...... 148 " + Piston, valves, engineman's platform, + hammer, etc........................ 160 " + __________ + + Total weight................... 1,200 tons. + + Weight of the hammer.................. 80 tons. + Maximum fall.......................... 25.75 ft. + Distance apart of the standards....... 21.6 " + Width of hammer....................... 6 " + Pressure of steam..................... 16 lb. + Effective pressure to lift 80 tons.... 7 " +_Description of Figures_.--A, the 80-ton hammer; B, B1, B2, cranes; C, +C1, C2, supports of cranes; D, D1, D2, gas furnaces; A1, the 35-ton +hammer; A2, the 28-ton hammer; EE, railways; F, engineman's platform; G, +lever for maneuvering the throttle valve; H, an ingot being forged. + + * * * * * + + + + +GREAT STEAMERS. + + +The _Brooklyn Eagle_ gives a very interesting description of the three +new steamships now almost completed and shortly to be placed in the New +York and Liverpool trade by the Cunard, Inman, and Williams and Guion +lines. The writer has prepared a table comparing the three vessels +with each other and with the Great Eastern, the only ship of greater +dimensions ever built. We give as much of the article as our space will +allow, and regret that we have not the room to give it entire: + + Line. Cunard. Inman. Guion. Admiralty. + Vessel. Servia City of Rome. Alaska. Great[1] + + Length 530 feet. 546 feet. 520 feet. 679 feet. + Breadth 52 feet. 52 ft. 3 in. 50 ft. 6 in. 82 feet. + Depth 44 ft. 9 in. 37 feet. 38 feet. 60 feet. + Gross ton'ge 8,500 8,300 8,000 13,344[2] + Horse pow'r 10,500 10,000 11,000 2,600 + Speed 171/2 knots. 18 knots. 18 knots. 14 knots. + Sal'n pas- 320 and 52 + sengers. 450 300 2d class + Steerage 600 1,500 1,000 + Where Clydeb'nk Barrow in Clyde, + built. Thomson Furness Elder + Date of + sailing. October 22 October 13 November 5 + +[Footnote 1: To be sold at auction soon.] + +[Footnote 2: Net register.] + +In 1870 the total tonnage of British steam shipping was 1,111,375; the +returns for the year 1876 showed an increase to 2,150,302 tons, and from +that time to the present it has been increasing still more rapidly. But, +as can be seen from the above table, not only has the total tonnage +increased to this enormous extent, but an immense advance has been made +in increasing the size of vessels. The reason for this is, that it has +been found that where speed is required, along with large cargo and +passenger accommodation, a vessel of large dimensions is necessary, and +will give what is required with the least proportionate first cost as +well as working cost. Up to the present time the Inman line possessed, +in the City of Berlin, of 5,491 tons, the vessel of largest tonnage in +existence. Now, however, the Berlin is surpassed by the City of Rome by +nearly 3,000 tons, and the latter is less, by 200 tons, than the Servia, +of the Cunard line. It will be observed, too, that while there is not +much difference between the three vessels in point of length, the depth +of the Alaska and the City of Rome, respectively, is only 38 feet and 37 +feet, that of the Servia is nearly 45 feet as compared with that of the +Great Eastern of 60 feet. This makes the Servia, proportionately, the +deepest ship of all. All three vessels are built of steel. This metal +was chosen not only because of its greater strength as against iron, +but also because it is more ductile and the advantage of less weight is +gained, as will be seen when it is mentioned that the Servia, if built +of iron, would have weighed 620 tons more than she does of steel, and +would have entailed the drawback of a corresponding increase in draught +of water. As regards rig, the three vessels have each a different style. +The Cunard Company have adhered to their special rig--three masts, bark +rigged--believing it to be more ship shape than the practice of fitting +up masts according to the length of the ship. On these masts there is a +good spread of canvas to assist in propelling the ship. The City of Rome +is rigged with four masts; and here the handsome full-ship rig of the +Inman line has been adhered to, with the addition of the fore and aft +rigged jigger mast, rendered necessary by the enormous length of the +vessel. It will be seen that the distinctive type of the Inman line +has not been departed from in respect to the old fashioned but still +handsome profile, with clipper bow, figurehead, and bowsprit--which +latter makes the Rome's length over all 600 feet. For the figurehead +has been chosen a full length figure of one of the Roman Caesars, in the +imperial purple. Altogether, the City of Rome is the most imposing and +beautiful sight that can be seen on the water. The Alaska has also four +masts, but only two crossed. + +The length of the City of Rome, as compared with breadth, insures long +and easy lines for the high speed required; and the depth of hold being +only 37 feet, as compared with the beam of 52 feet, insures great +stability and the consequent comfort of the passengers. A point calling +for special notice is the large number of separate compartments formed +by water tight bulkheads, each extending to the main deck. The largest +of these compartments is only about 60 feet long; and, supposing that +from collision or some other cause, one of these was filled with water, +the trim of the vessel would not be materially affected. With a view to +giving still further safety in the event of collision or stranding, the +boilers are arranged in two boiler rooms, entirely separated from each +other by means of a water tight iron bulkhead. This reduces what, in +nearly all full-powered steamships, is a vast single compartment, into +two of moderate size, 60 feet in length; and in the event of either +boiler room being flooded, it still leaves the vessel with half her +boiler power available, giving a speed of from thirteen to fourteen +knots per hour. The vessel's decks are of iron, covered with teak +planking; while the whole of the deck houses, with turtle decks and +other erections on the upper deck, are of iron, to stand the strains +of an Atlantic winter. Steam is supplied by eight cylindrical tubular +boilers, fired from both ends, each of the boilers being 19 feet long +and having 14 feet mean diameter. There are in all forty eight furnaces. +The internal arrangements are of the finest description. There are two +smoking rooms, and in the after deckhouse is a deck saloon for ladies, +which is fitted up in the most elegant manner, and will prevent the +necessity of going below in showery weather. At the sides of the +hurricane deck are carried twelve life boats, one of which is fitted as +a steam launch. The upper saloon or drawing-room is 100 feet long, the +height between decks being 9 feet. The grand dining-saloon is 52 feet +long, 52 feet wide, and 9 feet high, or 17 feet in the way of the large +opening to the drawing-room above. This opening is surmounted by a +skylight, and forms a very effective and elegant relief to the otherwise +flat and heavy ceiling. There are three large and fourteen small dining +tables, the large tables being arranged longitudinally in the central +part of the saloon, and the small tables at right angles on the sides. +Each diner has his own revolving arm chair, and accommodation is +provided for 250 persons at once. A large American organ is fixed at the +fore end of the room, and opening off through double spring doors at the +foot of the grand staircase is a handsome American luncheon bar, with +the usual fittings. On each side of the vessel, from the saloon to the +after end of the engine room, are placed staterooms providing for 300 +passengers. The arrangements for steerage passengers are of a superior +description. The berths are arranged in single tiers or half rooms, not +double, as is usually the custom, each being separated by a passage, +and having a large side light, thus adding greatly to the light, +ventilation, and comfort of the steerage passengers, and necessitating +the advantage of a smaller number of persons in each room. The City +of Rome is the first of the two due here; she sails from Liverpool on +October 13. + +In the Servia the machinery consists of three cylinder compound surface +condensing engines, one cylinder being 72 inches, and two 100 inches in +diameter, with a stroke of piston of 6 feet 6 inches. There are seven +boilers and thirty-nine furnaces. Practically the Servia is a five +decker, as she is built with four decks--of steel, covered with yellow +pine--and a promenade reserved for passengers. There is a music room on +the upper deck, which is 50 feet by 22 feet, and which is handsomely +fitted up with polished wood panelings. For the convenience of the +passengers there are no less than four different entrances from the +upper deck to the cabins. The saloon is 74 feet by 49 feet, with sitting +accommodations for 350 persons, while the clear height under the beams +is 8 feet 6 inches. The sides are all in fancy woods, with beautifully +polished inlaid panels, and all the upholstery of the saloon is of +morocco leather. For two-thirds of its entire length the lower deck is +fitted up with first class staterooms. The ship is divided into nine +water-tight bulkheads, and she is built according to the Admiralty +requirements for war purposes. There are in all twelve boats equipped +as life-boats. The Servia possesses a peculiarity which will add to her +safety, namely, a double bottom, or inner skin. Thus, were she to +ground on rocks, she would be perfectly safe, so long as the inner skin +remained intact. Steam is used for heating the cabins and saloons, and +by this means the temperature can be properly adjusted in all weathers. +In every part of the vessel the most advanced scientific improvements +have been adopted. The Servia leaves Liverpool on October 22. + +The Alaska, whose owners, it is understood, are determined to make her +beat all afloat in speed, does not sail until November 5, and therefore +it is premature to say anything about her interior equipments. She is +the sister of the celebrated Arizona, and was built by the well-known +firm of Elder & Co., on the Clyde. + + * * * * * + + + + +IMPROVED ROAD LOCOMOTIVE. + + +Several attempts have been made to connect the leading wheels of a +traction engine with the driving wheels, so as to make drivers of all of +them, and thus increase the tractive power of the engine, and to afford +greater facilities for getting along soft ground or out of holes. The +wheels with continuous railway and India-rubber tires have been employed +to gain the required adhesion, but these wheels have been too costly, +and the attempts to couple driving and leading wheels have failed. The +arrangement for making the leading wheels into drivers, illustrated +on page 4825, has been recently brought out by the Durham and North +Yorkshire Steam Cultivation Company, Ripon, the design being by Messrs. +Johnson and Phillips. The invention consists in mounting the leading +axle in a ball and long socket, the socket being rotated in fixed +bearings. The ball having but limited range of motion in the socket, is +driven round with it, but is free to move in azimuth for steering. + +This engine has now been in use more than twelve months in traction +and thrashing work, and, we are informed, with complete success. The +illustrations represent a 7-horse power, with a cylinder 8 in. diameter +by 12 in. stroke, and steam jacketed. The shafts and axles are of +Bowling iron. The boiler contains 140 ft. of heating surface, and is +made entirely of Bowling iron, with the longitudinal seams welded. The +gearing is fitted with two speeds arranged to travel at 11/2 and 3 miles +per hour, and the front or hind road wheels can be put out of gear when +not required. The hind driving wheels are 5 ft. 6 in. diameter, and the +front wheels 5 ft.; weight of engine 8 tons.--_The Engineer._ + +[Illustration: IMPROVED ROAD LOCOMOTIVE] + +[Illustration: IMPROVED ROAD LOCOMOTIVE] + + * * * * * + + + + +AMERICAN MILLING METHODS. + +[Footnote 1: A paper read before the meeting of the Pennsylvania State +Millers Association at Pittsburgh, Pa., by Albert Hoppin, Editor of the +_Northwestern Miller_.] + +By ALBERT HOPPIN. + + +To speak of the wonderful strides which the art of milling has taken +during the past decade has become exceedingly trite. This progress, +patent to the most casual observer, is a marked example of the power +inherent in man to overcome natural obstacles. Had the climatic +conditions of the Northwest allowed the raising of as good winter wheat +as that raised in winter wheat sections generally, I doubt if we should +hear so much to-day of new processes and gradual reduction systems. So +long as the great bulk of our supply of breadstuffs came from the winter +wheat fields, progress was very slow; the mills of 1860, and I may even +say of 1870, being but little in advance, so far as processes were +concerned, of those built half a century earlier. The reason for this +lack of progress may be found in the ease with which winter wheat could +be made into good, white, merchantable flour. That this flour was +inferior to the flour turned out by winter wheat mills now is proven by +the old recipe for telling good flour from that which was bad, viz.: To +throw a handful against the side of the barrel, if it stuck there it was +good, the color being of a yellowish cast. What good winter wheat patent +to-day will do this? Still the old time winter wheat flour was the best +there was, and it had no competitor. The settling up of the Northwest +which could not produce winter wheat at all, but which did produce a +most superior article of hard spring wheat, was a new factor in the +milling problem. The first mills built in the spring wheat States tried +to make flour on the old system and made a most lamentable failure of +it. I can remember when the farmer in Wisconsin, who liked a good loaf +of bread, thought it necessary to raise a little patch of winter wheat +for his own use. He oftener failed than succeeded, and most frequently +gave it up as a bad job. Spring wheat was hard, with a very tender, +brittle bran. If ground fine enough to make a good yield a good share +of the bran went into the flour, making it dark and specky. If not +so finely ground the flour was whiter, but the large percentage of +middlings made the yield per bushel ruinously small. These middlings +contained the choicest part of the flour producing part of the berry, +but owing to the dirt, germ, and other impurities mixed with them, it +was impossible to regrind them except for a low grade flour. Merchant +milling of spring wheat was impossible wherever the flour came in +competition with winter wheat flours. At Minneapolis, where the millers +had an almost unlimited water power, and wheat at the lowest price, +merchant milling was almost given up as impracticable. It was certainly +unprofitable. To the apparently insurmountable obstacles in the way of +milling spring wheat successfully, we may ascribe the progress of modern +milling. Had it been as easy to raise good winter wheat in Wisconsin and +Minnesota as in Pennsylvania and Ohio, or as easy to make white flour +from spring as from winter wheat, we should not have heard of purifiers +and roller mills for years to come. + +The first step in advance was the introduction of a machine to purify +middlings. It was found that the flour made from these purified +middlings was whiter than the flour from the first grinding and brought +a better price than even winter wheat flours. Then the aim was to make +as many middlings as possible. To do this and still clean the bran so +as to make a reasonable yield the dress of the burrs was more carefully +attended to, the old fashioned cracks were left out, the faces and +furrows made smooth, true, and uniform, self-adjusting drivers +introduced, and the driving gear better fitted. Spring wheat patents +rapidly rose to the first place in the market, and winter wheat millers +waked up to find their vantage ground occupied by their hitherto +contemned rivals. To their credit it may be said that they have not +been slow in taking up the gauntlet, and through the competition of the +millers of the two climatically divided sections of this country with +each other and among themselves the onward march of milling progress has +been constantly accelerated. Where it will end no man can tell, and +the chief anxiety of every progressive miller, whether he lives in +Pennsylvania or Minnesota, is not to be left behind in the race. + +The millers of the more Eastern winter wheat States have a two-fold +question to solve. First, how to make a flour as good as can be found in +the market, and second, how to meet Western competition, which, through +cheap raw material and discriminating freight rates, is making serious +inroads upon the local markets. Whether the latter trouble can be +remedied by legislature, either State or national, or not, remains to be +proven by actual trial. That you can solve the first part of the problem +satisfactorily to yourselves depends upon your readiness to adopt new +ideas and the means you have at hand to carry them out. It is manifestly +impossible to make as good a flour out of soft starchy wheat as out of +that which is harder and more glutinous. It is equally impossible for +the small mill poorly provided with machinery to cope successfully +with the large merchant mill fully equipped with every appliance that +American ingenuity can suggest and money can buy. I believe, however, +that a mill of moderate size can make flour equally as good as the large +mill, though, perhaps, not as economically in regard to yield and cost +of manufacture. + +The different methods of milling at present in use may be generally +divided into three distinct processes, which, for want of any better +names, I will distinguish as old style, new process, and gradual +reduction. Perhaps the German division of low milling, half high +milling, and high milling is better. Old style milling was that in +general use in this country up to 1870, and which is still followed in +the great majority of small custom or grist mills. It is very simple, +consisting of grinding the wheat as fine as possible at the first +grinding, and separating the meal into flour, superfine or extra, +middlings, shorts, and bran. Given a pair of millstones and reel long +enough, and the wheat could be made into flour by passing through the +two. Because spring wheat was so poorly adapted to this crude process, +it had to be improved and elaborated, resulting in the new process. + +At first this merely consisted of purifying and regrinding the middlings +made in the old way. In its perfected state it may be said to be halfway +between the old style and gradual reduction, and is in use now in many +mills. In it mill stones are used to make the reductions which are only +two in number, in the first of which the aim of the miller is to make as +many middlings as he can while cleaning the bran reasonably well, and +in the second to make the purified middlings into flour. In the most +advanced mills which use the new process, the bran is reground and the +tailings from the coarse middlings, containing germ and large middlings +with pieces of bran attached, are crushed between two rolls. These +can hardly be counted as reductions, as they are simply the finishing +touches, put on to aid in working the stuff up clean and to permit of +a little higher grinding at first. Regarding both old style and new +process milling, you are already posted. Gradual reduction is newer, +much more extensive, and merits a much more thorough explanation. Before +entering upon this I will call your attention to one or two points which +every miller should understand. + +The two essential qualities of a good marketable flour are color and +strength. It should be sharply granular and not feel flat and soft to +the touch. A wheat which has an abundance of starch, but is poor in +gluten, cannot make a strong flour. This is the trouble with all soft +wheats, both winter and spring. A wheat which is rich in gluten is hard, +and in the case of our hard Minnesota wheat has a very tender bran. +It is comparatively easy to make a strong flour, but it requires very +careful milling to make a flour of good color from it. Probably the +wheat which combines the most desirable qualities for flour-making +purposes is the red Mediterranean, which has plenty of gluten and a +tough bran, though claimed by some to have a little too much coloring +matter, while the body of the berry is white. By poor milling a good +wheat can be made into flour deficient both in strength and color, and +by careful milling a wheat naturally deficient in strength may be made +into flour having all the strength there was in the wheat originally and +of good color. Good milling is indispensable, no matter what the quality +of the wheat may be. + +The idea of gradual reduction milling was borrowed by our millers from +the Hungarian mills. There is, however, this difference between the +Hungarian system and gradual reduction, as applied in this country, that +in the former, when fully carried out, the products of the different +breaks are kept separate to the end, and a large number of different +grades of flour made, while in the system, as applied in this country, +the separations are combined at different stages and usually only three +different grades of flour made, viz.: patent, baker's, or as it is +termed in Minnesota, clear flour, and low grade or red dog. In the +largest mills the patent is often subdivided into first and second, and +they may make different grades of baker's flour, these mills approaching +much nearer to the Hungarian system, though modifying it to American +methods and machinery. In mills of from three to five hundred barrels +daily capacity, it is hardly possible or profitable to go to this +subdivision of grades, owing to the excessive amount of machinery +necessary to handling the stuff in its different stages of completion. +The Hungarian system has, therefore, been greatly modified by American +millers and milling engineers to adapt it to the requirements of mills +of average capacity. This modified Hungarian system we call gradual +reduction. It can be profitably employed in any mill large enough to run +at all on merchant work. So far it has not been found practicable to use +it in mills of less than one hundred and twenty-five to one hundred and +fifty barrels capacity in twenty-four hours, and it is better to have +the mill of at least double this capacity. + +Gradual reduction, as its name implies, consists in reducing the +wheat to flour, shorts, and bran, by several successive operations or +reductions technically called breaks, the process going on gradually, +each break leaving the material a little finer than the preceding one. +Usually five reductions or breaks are made, though six or seven may be +used. The larger the number of breaks the more complicated the system +becomes, and it is preferable to keep it as simple as possible, for even +at its simplest it requires a good, wide-awake thinking miller to handle +it successfully. When it is thoroughly and systematically carried out in +the mill it is without question as much in advance of the new process as +that is ahead of the old style of milling. + +In order that I may convey to you as clear an idea of gradual milling +reduction as possible, I will give as fully as possible the programme of +a mill of one hundred and fifty barrels maximum daily capacity designed +to work on mixed hard and soft spring wheat, and which probably will +come much nearer to meeting the conditions under which you have to mill +than any other I have found readily obtainable. I have chosen a mill of +this size, first, because following out the programme of a larger one +would require too much time and too great a repetition of details and +not give you any clearer idea of the main principles involved, and +secondly, because I thought it would come nearer meeting the average +requirements of the members of your association. Your worthy secretary +cautioned me that I must remember that I was going to talk to winter +wheat millers. The main principles and methods of gradual reduction are +the same, whether applied to spring or winter wheat; the details may +have to be varied to suit the varying conditions under which different +mills are operated. For this programme I am indebted to Mr. James Pye, +of Minneapolis, who is rapidly gaining an enviable and well deserved +reputation as a milling engineer, and one who has given much study to +the practical planning and working of gradual reduction mills. + +And right here let me say that no miller should undertake to build +a gradual reduction mill, or to change over his mill to the gradual +reduction system, until he has consulted with some good milling engineer +(the term millwright means very little nowadays), and obtained from him +a programme which shall fit the size of the mill, the stock upon which +it has to work, and the grade of flour which it is to make. This +programme is to the miller what a chart is to the sailor. It shows him +the course he must pursue, how the stuff must be handled, and where it +must go. Without it he will be "going it blind," or at best only feeling +his way in the dark. A gradual reduction mill, to be successful, must +have a well-defined system, and to have this system, the miller must +have a definite plan to work by. But to go on with my programme. + +The wheat is first cleaned as thoroughly as possible to remove all +extraneous impurities. In the cleaning operations care should be taken +to scratch or abrade the bran as little as possible, for this reason: +The outer coating of the bran is hard and more or less friable. Wherever +it is scratched a portion is liable to become finely comminuted in the +subsequent reductions, so finely that it is impossible to separate it +from the flour by bolting, and consequently the grade of the latter is +lowered. The ultimate purpose of the miller being to separate the flour +portion of the berry from dirt, germ, and bran it is important that he +does not at any stage of the process get any dirt or fine bran speck or +dust mixed in with his flour, for if he does he cannot get rid of it +again. So it must be borne in mind that at all stages of flouring, any +abrasion or comminution of the bran is to be avoided as far as possible. + +After the wheat is cleaned, it is by the first break or reduction split +or cut open, in order to liberate the germ and crease impurities. As +whatever of dirt is liberated by this break becomes mixed in with the +flour, it is desirable to keep the amount of the latter as small as +possible. Indeed, in all the reductions the object is to make as little +flour and as many middlings as possible, for the reason that the latter +can be purified, while the former cannot, at least by any means at +present in use. After the first break the cracked wheat goes to a +scalping reel covered with No. 22 wire cloth. The flour, middlings, +etc., go through the cloth, and the cracked wheat goes over the tail of +the reel to the second machine, which breaks it still finer. After this +break the flour and middlings are scalped out on a reel covered with +No. 22 wire cloth. The tailings go to the third machine, and are still +further reduced, then through a reel covered with No. 24 wire cloth. The +tailings go to the fourth machine, which makes them still finer, then +through a fourth scalping reel the same as the third. The tailings from +this reel are mostly bran with some middlings adhering, and go to the +fifth machine, which cleans the bran. From this break the material +passes to a reel covered with bolting cloth varying in fineness from No. +10 at the head to No. 00 at the tail. What goes over the tail of this +reel is sent to the bran bin, and that which goes through next to the +tail of the reel, goes to the shorts bin. The middlings from this reel +go to a middlings purifier, which I will call No. 1, or bran middlings +purifier. The flour which comes from this reel is sent to the chop reel +covered at the head with say No. 9, with about No. 5 in the middle and +No 0 at the tail. You will remember that after each reduction the flour +and middlings were taken out by the scalping reels. This chop, as it is +now called, also goes to the same reel I have just mentioned. The +coarse middlings which go over the tail of this reel go to a middlings +purifier, which I will designate as No. 2. These go through the No. 0 +cloth at the tail of the reel purifier No. 3; those which go through No. +5 cloth got to purifier No. 4; while all that goes through the No. 9 +cloth at the head of the reel is dropped to a second reel clothed with +Nos. 13 to 15 cloth with two feet of No. 10 at the tail. The flour from +this reel goes to the baker's flour packer; that which drops through the +No. 10 is sent to the middlings stone, while that which goes over the +tail of the reel goes to purifier No. 4. We have now disposed of all the +immediate products of the first five breaks, tracing them successively +to the bran and shorts bins, to the baker's flour packer and to the +middlings purifiers, a very small portion going to the middlings stone +without going through the purifiers. + +The middlings are handled as follows in the purifiers. From the No. 1 +machine, which takes the middlings from the fifth break, the tailings go +to the shorts bin, the middlings which are sufficiently well purified go +to the middlings stone, while those from near the tail of the machine +which contain a little germ and bran specks go to the second germ rolls, +these being a pair of smooth rolls which flatten out the germ and crush +the middlings, loosening adhering particles from the bran specks. From +the second germ rolls the material goes to a reel, where it is separated +into flour which goes into the baker's grade, fine middlings which are +returned to the second germ rolls at once, some still coarser which go +to a pair of finely corrugated iron rolls for red dog, and what goes +over the tail of the reel goes to the shorts bin. The No. 2 purifier +takes the coarse middlings from the tail of the first or chop reel as +already stated. The tailings from this machine go to the shorts bin, +some few middlings from next the tail of the machine are returned to the +head of the same machine, while the remainder are sent to the first germ +rolls. The reason for returning is more to enable the miller to keep a +regular feed on the purifiers than otherwise. The No. 3 purifier takes +the middlings from the 0 cloth on the chop reel. From purifier No. 3 +they drop to purifier No. 5. A small portion that are not sufficiently +well purified are returned to the head of No. 3, while those from the +head of the machine, which are well purified, are sent to the middlings +stones. The remainder, which contain a great deal of the germ, are taken +to the first germ rolls, in passing which they are crushed lightly to +flatten the germ without making any more flour than necessary. The No. 4 +purifier takes the middlings from No. 2 and also from No. 5 cloth on +the chop reel and from the No. 10 on the tail of the baker's reel. The +middlings from the head of this machine go to the middlings stones, and +the remainder to purifier No. 6. The tailings from Nos. 3, 4, 5, and 6 +go to the red dog rolls. A small portion not sufficiently well purified +are returned from No. 6 to the head of No. 4, while the cleaned +middlings go to the middlings stones. + +The portions of the material which have not been traced either to the +baker's flour or the bran and shorts bins are the middlings which have +gone to the middlings stones, the germy middlings which have gone to the +first germ rolls, and the tailings from purifiers Nos. 3, 4, 5, and 6, +and some little stuff not quite poor enough for shorts from the reel +following the second germ rolls. Taking these _seriatim_: the middlings +after passing through the middlings stones, go to the first patent reel +covered with eleven feet of No. 13 and four feet of No. 8. The flour +from the head of the reel goes to the patent packer, that from the +remainder of the reel is dropped to another reel, while the tailings go +to the No. 4 purifier. The lower patent reel is clothed with No. 14 and +two feet of No. 10 cloth; from the head of the reel the flour goes to +the patent packer, the remainder that passes through the No. 10 cloth +which will not do to go into the patent, being returned to the middlings +stones, while the tailings are sent to the No. 4 purifier. + +The germ middlings, after being slightly crushed as before stated, are +sent to a reel covered with five feet of No. 13 cloth, five feet of No. +14, and the balance with cloth varying in coarseness from No. 7 to No. +00. The flour from this reel goes into the patent, the tailings to the +red dog rolls, the middlings from next the tail of the reel which still +contain some germ to the second germ rolls, while the middlings which +are free from germ go to the middlings stones. + +The tailings from purifiers 3, 4, 5, and 6, the material from the reel +following the second germ rolls, which is too good for shorts, but not +good enough to be returned into middlings again, and the tailings from +the reel following the first germ rolls are sent to the red dog rolls, +which, as I have stated, are finely corrugated. Following these rolls is +the red dog reel. The flour goes to the red dog bin, the tailings to +the shorts bin, while some stuff intermediate between the two, not fine +enough for the flour but too good for shorts, is returned to the red dog +rolls. + +This finishes the programme. I have not given it as one which is exactly +suited to winter wheat milling. However, as I said before, the general +principles are the same in either winter or wheat gradual reduction +mills, and the various systems of gradual reduction, although they +differ in many points, and although there are probably no two engineers +who would agree as to all the details of a programme, the main ideas +are essentially the same. The system has been well described as one of +gradual and continued purification. In the programme above given the +idea was to fit up a mill which should do a maximum amount of work of +good quality with a minimum amount of expenditure and machinery. In a +larger mill or even in a mill of the same capacity where money was not +an object, the various separations would probably be handled a little +differently, the flour and middlings from the first and fifth breaks +being handled together, and those from the second, third, and fourth +breaks being also handled together. The reason for this separation being +that the flour from the first and fifth breaks contain, the first a +great deal of crease dirt, and the fifth more bran dust than that from +the other breaks, the result being a lower grade of flour. The object +all along being to keep the amount of flour with which dirt can get +mixed as small as possible, and not to lower the grade of any part of +the product by mixing it with that which is inferior, always bearing in +mind that the aim is to make as many middlings as possible, for they can +be purified while the flour can not, and that whenever any dirt is once +eliminated it should be kept out afterwards. This leads me to say that +if a miller thinks the adoption of rolls or reduction machines is all +there is of the system, he is very much mistaken. If anything, more of +the success of the mill depends upon the careful handling of the stuff +after the breaks are made, and here the miller who is in earnest to +master the gradual reduction system will find his greatest opportunities +for study and improvement. A few years back it was an axiom of the trade +that the condition of the millstone was the key to successful +milling. This was true because the subsequent process of bolting was +comparatively simple. Now the mere making of the breaks is a small +matter compared with the complex separations which come after. In +the foregoing programme we had five breaks or successive reductions. +Although this is better than a smaller number, I will here say that +it is not absolutely essential, for very good work is done with four +breaks. The mill for which this programme was made, including the +building, cost about $15,000, and is designed to make about sixty per +cent. of patent, thirty-five per cent. of baker's, and five per cent. +of low grade, results which are in advance of many larger and more +pretentious mills. + +One difficulty in the way of adapting the gradual reduction system to +mills of very small capacity is that the various machines require to be +loaded to a certain degree in order to work at their best. It is only a +matter of short time when our milling inventors will design machinery +especially for small mills; in fact they are now doing it, and every +day brings it more within the power of the small miller to improve his +manner of milling. To show what can be done in this direction I will +briefly describe a mill of about ninety barrels maximum capacity per +twenty-four hours, which is as small as can be profitably worked. I will +premise this description by saying it is designed with a view to the +greatest economy of cost, the best trade of work, and to reduce the +amount of machinery and the handling of the stuff as much as possible. +This latter point is of much importance in any mill, either large or +small, no matter upon what system it is operated, for it takes power to +run elevators and conveyors, and especially in elevating and conveying +middlings, especially those made from winter wheat, their quality is +inured and a loss incurred, by the unavoidable amount of flour made by +the friction of the particles against each other. So much is this the +case that in one of our largest mills it is deemed preferable to move +the middlings from one end of the mill to the other by means of a hopper +bin on a car which runs on a track spiked to the floor, rather than to +employ a conveyor. A mill built as I am going to describe would require +from fifty to sixty horse-power to run it, and including steam power and +building would cost from $10,000 to $12,000, according to location. I +give it as of interest to those among your number who own small mills +and may contemplate improving them. + +The building is four stories high, including basement, and thirty-two +feet square. It would be some better to have it larger, but it is made +this small to show how small a space a mill of this size can be made to +occupy. No story is less than twelve feet high. The machinery Is very +conveniently arranged, and there is plenty of room all around. The +system is a modification of the gradual reduction system, the middlings +being worked upon millstones. The first break is on one pair of 9 x +18 inch corrugated iron rolls, eight corrugations to the inch, the +corrugations running parallel with the axis of the rolls. The second +break on rolls having twelve corrugations to the inch, the third +sixteen, and the fourth twenty to the inch, while the fifth break, where +the bran is finally cleaned, has twenty-four corrugations to the inch. +The basement contains the line shaft and pulleys for driving rolls, +stones, cockle machine, and separator. The only other machinery in the +basement is the cockle machine. The line shaft runs directly through +the center of the basement, the power being from engine or water wheel +outside the building. The first floor has the roller mills in a line +nearly over the line shaft below, the middlings stones, two in number, +at one side opposite the entrance to the mill, the receiving bin at +one side of the entrance in the corner of the mill, and the two flour +packers for the baker's and patent flour in the other corner. This +arrangement leaves over half of the floor area for receiving and packing +purposes. The bolting chests, one with six reel and the other with three +reel begin on the second floor and reach up into the attic. An upright +shaft from the line shaft in the basement geared to a horizontal shaft +running through the attic parallel with the line shaft below, comprise +about all the shafting there is in the mill. There is a short shaft on +the second floor from which the two purifiers on this floor and the two +in the attic are driven, and another short shaft on the first floor to +drive the packers. There are four purifiers, two on the second floor, +and two more directly over them in the attic. The elevator heads are all +directly upon the attic line shaft, and the bolting chests are driven by +uprights dropped from this shaft. The combined smutter and brush machine +is on the third floor at one end of the bolting chests and directly over +the stock hoppers. This comprises all the machinery in the mill. The +programme is about as follows: + +The break reels are clothed as follows: First break No. 20, wire cloth, +second break No. 22, third break No. 24, and fourth break No. 24. The +material passing through these scalping reels, now called chop, goes to +a series of reels, the first clothed with Nos. 6, 4, and 0. The material +passing over the tail is sent to the germ purifier, that passing through +Nos. 4 and 0, to the coarse middlings purifier, and that through the No. +6 goes to the reel below clothed with Nos. 12 and 13. Some nice granular +flour is taken off from this reel; the remainder, which passes over the +tail and through the cutoffs, goes to the next reel below clothed with +Nos. 14, 15, and 9. Some good flour comes from the 14 and 15; that which +passes through the 9 goes at once to the stones without purifying, while +that which passes over the tail is sent to the fine middlings purifiers. + +After the purification, the middlings are ground on stones and bolted +on Nos. 13 and 14 cloth, after having been scalped on No 8. The germ +middlings are crushed on smooth rolls and bolted on Nos. 12 and 13. What +is not crushed fine enough goes with poor tailings to the second germ +rolls, and from these to a reel by themselves or to the fifth reduction +or bran reel. A mill of this kind could be made much more perfect by an +expenditure of two or three thousands dollars more. I have instanced it +to show what can be done with gradual reduction in a very small way. + +In mills of from three hundred to five hundred barrels capacity and +still larger, the programme differs considerably from that I have +sketched, the middlings being graded and handled with little, if any, +returning, and are sized down on the smooth rolls, a much larger +percentage of the work of flouring being done on millstones. For a three +hundred barrel roller mill, the following plant is requisite: five +double corrugated roller mills, five double smooth roller mills, three +pairs of four foot burrs sixteen purifiers, four wire scalping reels, +six feet long, one reel for the fifth break, one reel for low grade +flour, eight chop reels, seven reels for flour from smooth rolls, three +reels for the stone flour, two grading reels, three flour packers, and +necessary cleaning machinery. The reels are eighteen feet thirty-two +inches. The programme is necessarily more complicated. + +When it comes to the machinery to be employed in making the reductions +or breaks, the miller has several styles from which to choose. Which is +best comes under the head of what I don't know, and moreover, of that +which I have found no one else who does know. Each machine has its good +points, and the mill owner must make his own decision as to which is +best suited to his purpose. The main principles involved are to abrade +the bran as little as possible while cleaning it thoroughly, and to make +as little break flour, and as many middlings as possible, the latter to +be made in such shape as to be the most easily purified. Regarding +the difference between spring and winter wheat for gradual reduction +milling, it may be stated something after this manner: Spring wheat +has a thinner and more tender bran, makes more middlings because it is +harder, and for the same reason the flour is more inclined to be coarse +and granular. In milling with winter wheat, especially the better +varieties, there will be more break flour made, the middlings will be +finer with fewer bran specks, and the bran more easily cleaned, because +it will stand harsher treatment. Winter wheat, moreover, requires more +careful handling in making the breaks, not because of the bran, but to +avoid breaking down the middlings, and making too much and too fine and +soft break flour. In order to keep the flour sharp and granular, coarser +cloths are used in bolting, and because the middlings are finer the +bolting is not so free and a larger bolting surface is required. In +milling either spring or winter wheat there should be ample purifying +capacity, it being very unwise to limit the number of machines, so that +any of them will be overtaxed. The day has gone by when one purifier +will take care of all the middlings in the mill. + +There is one point which is of much interest to mill owners who wish to +change their mills over to the gradual reduction process, that is, how +far they can utilize their present plan of milling machinery in making +the change. Of course the cleaning machinery is the same In both cases, +so are the elevators, conveyors, bolting chests, etc. But to use the +millstone is a debatable question. After carefully considering the +matter I have come to the conclusion that it has its place, and an +important one at that, under the new regime, viz., that of reducing +the finer purified middlings to flour. The reason for this lies in the +peculiar construction of the wheat berry. If the interior of the berry +were one solid mass of flour, needing only to be broken up to the +requisite fineness, it could be done as well on the rolls. But instead +of this, as is well known, the flour part of the berry is made up of +a large number of granules or cells, the walls of which are cellular +tissue, different from the bran in that it is soft and white instead of +hard and dark colored. It is also fibrous to a certain extent, and when +the fine middlings are passed between the rolls instead of breaking +down and becoming finer, it has a tendency to cake up and flatten out, +rendering the flour soft and flaky. It does not hurt the color, but it +does hurt the strength. When the millstone is used in place of the roll +the flour is of equally good color, and more round and granular. I +know that in this the advocates of smooth rolls will differ from my +conclusions, but I believe that the final outcome will be the use of +millstones on the finer middlings, and in fact on all the middlings that +are thoroughly freed from the germ. + +It has been said that that which a man gives the most freely and +receives with the worst grace is advice. I will, however, close with a +little of the article which may not be wholly put of place. If you have +a mill do not imagine that the addition of a few pairs of rolls, a +purifier or two, and a little overhauling of bolting-chests, is going to +make it a full-fledged Hungarian roller mill. If you are going to change +an old mill or build a new one, do not take the counsel or follow the +plans of every itinerant miller or millwright who claims to know all +about gradual reduction. No matter what kind of a mill you want to +build, go to some milling engineer who has a reputation for good work, +tell him how large a mill you want, show him samples of the wheat it +must use and the grades of flour it must make, and have him make a +programme for the mill and plan the machinery to fit it. Then have the +mill built to fit the machinery. When it starts follow the programme, +whether it agrees with your preconceived notions or not, and the mill +will, in ninety-nine cases out of one hundred, do good work. + + * * * * * + + +MACHINE FOR DOTTING TULLES AND OTHER LIGHT FABRICS. + +Dotted or chenilled tulles are fabrics extensively used in the toilet +of ladies, and the ornamentation of which has hitherto been done by +the application to the tissue, by hand, either of chenille or of small +circles previously cut out of velvet. This work, which naturally takes +considerable time, greatly increases the cost price of the article. + +A few trials at doing the work mechanically have been made, but without +any practical outcome. The workwomen who do the dotting are paid at +Lyons at the rate of 80 centimes per 100 dots; so that if we take +tulle with dots counter-simpled 0.04 of an inch, which is the smallest +quincunx used, and suppose that the tissue is 31 inches wide and that +the daily maximum production is one yard, we find that 400 dots at 80 +centimes per 100 = 3 francs and 20 centimes (about 63 cents), the cost +of dotting per yard. It is true that the workwoman furnishes the velvet +herself. + +Mr. C. Ricanet, of Lyons, has recently invented a machine with which he +effects mechanically the different operations of dotting, not only on +tulles but also upon gauzes or any other light tissues whatever, such +as those of cotton, silk, wool, etc. Aided by a talented mechanic, Mr. +Ricanet has succeeded in constructing one of those masterpieces of +wonderfully accurate mechanism of which the textile industry appears +to have the monopoly--at least it is permissible to judge so from the +remarkable inventions of Vaucanson, Jacquard, Philippe de Girard, +Heilmann, and others. + +The object of this new machine, then, which has been doing its wonderful +work for a few days only, is to reproduce artificially chenille +embroidered on light tissues, by mechanically cutting out and gluing +small circles of velvet upon these fabrics. + +For this purpose all kinds of velvet may be employed, and, in order to +facilitate the cutting, they are previously coated on the reverse side +with any glue or gum whatever, which gives the velvet a stiffness +favorable to the action of the punch. To effect the object desired the +apparatus has three successive operations to perform: first, cutting the +circles; second, moistening; and third, fastening down the dots upon the +tissue according to a definite order and spacing. The machine may be +constructed upon any scale whatever, although at present it is only made +for operating on pieces 31 inches wide, that being the normal width of +dotted tulles. The quincuncial arrangement of the dots is effected by +the punching, moistening, and fastening down of odd and even dots, +combined with the forward movement of the tissue to be chenilled. + +The principal part of the machine is the cam-shaft, A (Figs. 1, 2, and +3), which revolves in the direction of the arrows and passes in the +center of 80 cam-wheels, 40 of which are odd and 40 even, alternately +opposed to each other. This shaft actuates, through its two extremities, +the different combined motions in view of the final object to be +attained, and also carries the motive pulleys, PP'. Figs. 1 and 2 show +the profile of two of these opposed cam-wheels--the arrangement by means +of which two rows of dots (odd and even) are laid down upon the tissue +during one revolution of the shaft or drum, A. Each of the wheels +carries three cams (Figs. 1 and 3), the first, (_a_), corresponding to +the punching; the second, (_a'_), to the moistening, and the third, +(_a''_), to the gluing down of the dots. + +The annexed figure, one-quarter actual size, shows in section the +details of the cutting mechanism. To each cam-wheel there corresponds +one punch, and the eighty punches are arranged side by side and parallel +upon a shaft, B, a spring, _b_, holding them constantly against the +circumference of the cam-wheels. In Fig. 2 only one of these details is +shown. The punching arrangement consists of an ordinary punch, _c_, of +variable diameter, screwed to the extremity of a tube, _d_, which is +itself suspended from the end of the lever, _p_, but which can receive +from it at the desired moment the pressure necessary to effect the +cutting. The vertical position of these multiple tubes is insured by +a guide, _e_, which is thoroughly indispensable. Through each of the +tubes, _d_, there passes a plunger designed for expelling from the punch +the piece that has been cut out of the velvet, and for gluing it down to +the fabric. The two small springs, _b'_ and _b''_, tend continually to +lift the tubes as well as the plunger. The whole mechanism is affixed to +solid cast-iron frames, and the machine itself may be mounted on wooden +supports or a metal frame. + +The punching is effected on a bronze straight-edge, C, which slides in a +cast-iron channel, D. This presents alternately, in its movement, entire +and punctured spaces, the former for receiving the blow of the punch and +the latter for allowing passage at the desired moment to the plunger +as it goes to fasten the dots upon the tulle which is passing along +underneath the channel, D. The punching is done primarily and +principally by pressure, but, in order to facilitate the complete +detachment of filaments which might retain the punched-out piece, the +punch is likewise given at the same time a slight rotary motion, thus +imitating mechanically what is performed by hand in the maneuver of all +punches. This rotary motion is communicated to the punches by means of +levers actuated by an eccentric, E, and which move the frame, _h_, whose +bars engage with the horizontal lever, _g_, soldered to the tube, _d_, +thus causing the latter at the very moment the punch descends to revolve +from right to left. The forty punches in operation cause the frame to +return to its initial position through the action of the springs, _b'_. +We say forty, since the inventor, in principle, has admitted 80 punches, +operating 40 as odd and 40 as even; obtaining in this way a dotting in +a regular quincunx of one yard, that is to say, 80 dots arranged in two +rows on a fabric 31 inches wide. But it is evident that a much larger +quincunx may be had by putting in play only a half, a third, or a +fourth of the punches, and causing the tulle and velvet to advance +proportionally. For this purpose it is only necessary to unscrew the +punches which are not to act, and to substitute for the ratchet wheel +which controls the unrolling of the I tulle, another having a number of +teeth proportioned to the desired spacing of the dots. + +The punching having been executed, and the drum, A, continuing to +revolve, the punches rise a little owing to the conformation of the +cam-wheel, and through the action of the springs, _b_, and allow the +moistener to move forward to dampen the little circles which remain at +the orifice of the punches. The moistener or dampener is a sort of pad +equal in length to the field of action of the punches, and is affixed +to a cross-bar, F, which is connected at its two extremities with the +levers, G, that are actuated by the cam-wheels, H. These cam-wheels, or +eccentrics, H, which are mounted on the shaft of the drum, A, cause the +moistener to move forward as soon as the punches rise after operating, +and, when it arrives beneath the punches, the larger cams, _a_, of +the cam-wheels, A, press the latter upon the pad and thus effect the +dampening of the circles of velvet. + +Immediately afterwards, the same eccentrics, H, acting on a lever, I, +uncover the holes in the straight-edge, C, and the channel, D. The +large cams, _a"_, of the wheel, A, then acting very powerfully upon the +respective punches, cause these latter to pass through the orifices so +that the extremity of each punch comes within about one twenty-fifth of +an inch of the fabric to be dotted. In this passage of the tube, _d_, a +small rod, _i_, connected by a lever with the plunger, _f_, is made to +abut against the guide, _e_, thus causing the descent of the plunger to +a sufficient degree to push the velvet "dot" out of the tube and to glue +it upon the fabric. The manner in which these operations are performed +being now well enough understood, let us for a moment examine the +motions of the fabrics to be cut and dotted--the first being velvet or +any other material, even metal (goldleaf, for example), and the second, +the tulle. + +The latter has but one motion, and that is in the direction of its +length, while the velvet has, in addition to this same motion, another +slight one from right to left in the direction of its width in order to +diminish waste as much as possible. + +The tulle to be dotted is first wound around a roller, R, from whence it +passes over the glass guide-roller, R', and between the channel, D, and +the table, T, to the roller, R", which is heated by steam. + +The hot air which is radiated dries the dots, and from thence the fabric +is taken up by other rollers or by any other method. The steam roller, +R", carries at one of its extremities a ratchet wheel whose teeth vary +in number according to the greater or less rapidity with which the tulle +is unrolled. It is actuated by a lever which receives its motion from +the eccentric, K. + +[Illustration: IMPROVED MACHINE FOR DOTTING TULLAND OTHER LIGHT +FABRICS.] + +In the table, T, there is a rectangular receptacle, _t_, containing +rasped or powdered velvet for the purpose of forming a reverse of the +dot. This powder attaches itself to the gum and imitates on the wrong +side of the fabric a dot similar to that on the upper or right side. The +velvet is wound upon the roller, _r_, and from thence passes under the +guiding roller, _r'_, the punches, and the second roller, _r"_. These +two latter rollers are solidly connected by a straight-edge fixed at the +extremity of the lever, L, whose other end is in continuous correlation +with the eccentric, M, which controls the lateral displacements; +while the eccentric, O, actuates, by means of the screw, Q, and the +ratchet-wheel, S, the longitudinal advance of the velvet. The eccentric, +M, is fixed upon an axle, A', which carries a wheel, U, having teeth +inclined with respect to its axis, and which derives its motion from the +Archimedean screw, N, fixed at one of the extremities of the cam-shaft, +A. + +We have stated above that the maximum daily hand production of tulle +dotted in quincunxes of 0.04 of an inch is about one yard. At the rate +of 30 revolutions per minute, and for the same article as that just +mentioned, this dotting machine is capable of producing, theoretically, +360 yards per 10 hours; but practically this production is reduced to +about 250 yards, which, however, is sufficiently satisfactory. + + * * * * * + + + + +THE REPRODUCTION AND MULTIPLICATION OF NEGATIVES. + +By ERNEST EDWARDS, B.A. + + +A question, relative to the subject of reproducing negatives, which was +put at a meeting of one of your New York societies, prompts me to make a +few remarks on the subject. + +Among the numerous and widely diversified ramifications of our business +(the Heliotype Printing Company) we have very often to reproduce and +multiply negatives in both a direct and reversed form. Various methods +for doing this have been tried, and I may here say that I am quite well +aware of all the methods that have hitherto been suggested for the +purpose, but that which I am to describe is the one to which preference +has been given, and which is that known as the carbon process. + +A sheet of carbonized paper or "tissue," having been sensitized by +immersion in a bath of bichromate of potash, is dried in the dark and +placed away for future use, although it is undesirable that it be kept +for more than four or five days. This is placed in a printing frame in +contact with the negative and exposed for a few minutes, after which it +is immersed in water, squeegeed down upon a glass plate, and developed +with warm water in the way so well known to carbon printers. The result +is a transparency which, owing to having received a sufficient exposure, +should show every detail of the negative. The nature of the tissue +employed for such a purpose must be such as to give no strong contrasts, +but everything reproduced with soft and fine gradation of tone. + +The transparency thus obtained forms the _cliche_ by which the negatives +are subsequently made; and a negative of any size may be obtained by +the camera on wet or dry plates. The transparency must, of course, be +pointed to the sky and the light transmitted through it, no other light +being allowed to reach the lens except that which passes through the +carbon transparency. Care must also be taken that the transparency is +_uniformly_ lighted. If it is not possible to obtain a northern light, +which is best, a reflector of white paper or card may be used which must +be sufficiently large and placed at an angle of about forty-five degrees +to the transparency. + +If the repeated negative is to be of the same size as the original it +may be readily produced by repeating the operation of printing on carbon +tissue, using the transparency in place of the negative, or using a dry +plate in place of the tissue. But on the whole I have satisfied myself +that the best results are to be obtained by the first method. There is +a greater softness in the latter method, but a greater character and +similarity to the original in the former method. There is no doubt that +the use of the carbon transparency removes the hardness and riffidness +of the outlines peculiar to the older method of a collodion +transparency, while with carbon as the medium it is difficult for +any but the most experienced eye to distinguish the copy from the +original.--_Photo Times._ + + * * * * * + + + + +A NEW METHOD OF MAKING GELATINE EMULSION. + + +Since gelatine emulsion first came into use one of the greatest troubles +in connection with the manufacture of it has been that of washing. +According to the first methods the time taken for this part of the +process was, I believe, about twenty-four hours. It was very much +reduced and the ease of manufacture greatly facilitated by the methods +now most generally used, and which were, I believe, first communicated +by Messrs. Wratten and Wainright. I refer to those of precipitating with +alcohol and of straining the emulsion, when set, through canvas, so +as to divide it very finely. When the latter method is resorted to a +comparatively short time is sufficient to wash it. This method, although +a great improvement upon the older ones, yet leaves much to be desired, +especially for those who are not in the habit of making emulsion +regularly, but only an occasional batch. When the weather is at all warm +it takes a long time for the emulsion to set, unless ice be used, and +when once it is set the washing process is an exceedingly "messy" one +unless the water be cooled with ice; and the amount of water taken up +during washing is often so great that there is considerable difficulty +in getting the emulsion to set on the plates. In fact, even in cold +weather, it is not an easy process to conduct in the necessary near +approach to total darkness. + +Considerable suspicion has of late been thrown upon the thoroughness of +the alcohol method, unless the emulsion has, previous to precipitation, +been freed of the greater part of the soluble salts by washing; that is +to say, it is doubtful whether the whole of the soluble salts can be +eliminated by the process, and, therefore, unless in exceptionally hot +weather, it would seem best not to trust to it, except as a further +security against soluble bromide and nitrate after washing. Besides +this, the consumption of alcohol is very large. Almost three times the +amount of the emulsion precipitated is required, and this, even when +methylated spirit is used, adds considerably to the expense. With a view +of doing away with the washing altogether, or, rather, of washing of +the silver bromide when not incorporated with the gelatine, several +processes have been invented. By these silver bromide is obtained in a +very fine state of division, ready to mix with gelatine and water in any +proportion. + +The best known of them is Captain Abney's very ingenious glycerine +method, which seems to have been thoroughly successful in his hands, +although it has not been in every one's. The silver bromide obtained by +his process is not highly sensitive, and requires boiling with gelatine +before it is in a fit state to make a rapid plate. + +We have lately had described in these columns a method of obtaining +bromide in a highly-sensitive state by means of the use of an acid, +whereby, after emulsifying and boiling, the viscosity of the gelatine +was destroyed, and the bromide in time deposited itself. During the late +hot weather, when washing became almost impossible, I was led to cast +about for some method of eliminating the soluble salts less tedious and +"sloppy" than that of washing, more certain and less expensive than that +of precipitating the whole of gelatine with alcohol, and which would +take less time than the method of obtaining the bromide in a pure form. + +My first idea was to make up the solutions used in emulsifying in a very +concentrated form, and, after emulsifying, boiling, and allowing to +cool, to add to the thin emulsion thus obtained gelatine to the amount +of twenty grains to the ounce, and to precipitate this with alcohol, +the rest of the gelatine required to make up the bulk being afterwards +added, and the whole thoroughly incorporated by warming and shaking. +I was thus successful in reducing the amount of alcohol required to +one-third of what would be necessary if the whole of the emulsion were +precipitated; but still I found that, if a reliable emulsion were +required, the pellicle as formed had to be washed to free it from the +last trace of soluble salts. + +It now struck me that it might be possible to precipitate the bromide of +silver direct from a very weak solution of gelatine, and obtain it in +such a form that it might be filtered, washed, and in every way treated +as an ordinary precipitate. I tried the following experiment. I took-- + + 1. Silver nitrate....................... 200 grains + Water............................... 11/2 ounce. + 2. Ammonia bromide...................... 120 grains. + Water................................ 11/2 ounce. + Gelatine............................. 12 grains. + +I emulsified the two together in the usual way, allowed the whole +to cool, and then poured the thin emulsion into about ten ounces +of alcohol, stirring the while. As I had anticipated, a flocculent +precipitate was formed, which settled to the bottom of the vessel in a +few minutes. This was, in fact, sensitive bromide of silver mixed with +a very small quantity of gelatine (about five per cent.), and could, I +found, be treated in the same manner as a bromide precipitate from +an aqueous solution; it might be washed, either by decantation or by +filtration, easily dried, and doubtless could, when dry, be kept for an +indefinite time, and be at any time used by mixing with gelatine and +water in any proportion thought fit. + +I found that a less amount of gelatine than four grains to the ounce was +sufficient to carry the bromide down, while five grains to the ounce +carried it down in something which I considered too near an approach to +a plastic mass. + +It will be noticed that in the experiments which I have described the +emulsion had not been boiled, so that the sensitiveness of the bromide +was probably not great. As the experiment was done in daylight it was +of no practical use for making emulsion; but I have since made several +batches in this manner and have found them most satisfactory. + +When sensitiveness is sought by boiling I rind it necessary to add a +small quantity of gelatine after boiling and before precipitating, as +that which has been kept for some time at a high temperature seems to +have lost the viscosity necessary to carry down the silver bromide in +such a form that it can he easily separated from the alcohol and water. + +The practical manner of making an emulsion by this method may be as +follows. Make up the following mixtures: + + I. + Silver nitrate...........................................400 grains. + Water..................................................... 3 ounces. + + II. + + Ammonia bromide..........................................240 grains. + Gelatine..................................................24 grains + Water..................................................... 3 ounces. + Hydrochloric acid enough to slightly acidify the solution. + + III. + Gelatine................................................. 20 grains. + Water.................................................... 1/2 ounce. + IV. + + Hard gelatine (say Nelson's X opaque, + or Mr. A. L. Henderson's)................................240 grains. + Soft gelatine (Nelson's No.1)........................... 240 grains. + Water.....................................................24 ounces. + +Nos. II., III., and IV. are allowed to stand until the gelatine is +softened. No. I is then warmed in a hock bottle until the gelatine is +just melted, when No. II. is poured into it, a little at a time, with +vigorous shaking, until the whole is emulsified. It is then transferred +to an ordinary jelly can, which is placed in a saucepan half full of +water over a ring Bunsen burner in the dark room, and boiled for half an +hour. It is then allowed to cool to about 100 deg. Fahr., when No. III. is +added. The whole is then allowed to get quite cool, when it is poured, +with stirring, into about one pint of methylated spirit. If it be wished +the precipitate may now be filtered out and washed at once like an +ordinary filtrate, but I prefer to allow it to settle, which it will do +in about five minutes. The supernatant fluid is then gently poured off. + +This fluid will have the appearance of still containing a considerable +amount of the silver bromide; but if it be kept and filtered it will be +seen that the quantity is really so small that it may be disregarded. We +all know what an alarming quantity of silver seems to be going down the +sink when we wash vessels to which a very small quantity of emulsion is +adhering. If filtering be resorted to the liquid which comes through +will be quite clear. This was somewhat unexpected by me, as, if an +emulsion containing the whole of the gelatine be precipitated into +alcohol in the usual way, the alcohol becomes milky with a substance +which could not, I imagine, be filtered from it. + +Two or three ounces of methylated spirit are now added to the vessel +containing the silver bromide, and the latter well mixed with it. This +makes the precipitate "firmer"--if such an expression be allowable--and +this time it will sink to the bottom almost immediately after the +stirring has ceased, and the alcohol may be poured off. + +I consider that the bromide in this state is practically free from +soluble salts, but it may be washed with one or two changes of water if +desired. + +No. IV. is now gently heated till the gelatine is melted and the +precipitate mixed with it. It must be kept warm for some time, and +shaken vigorously until all granularity has disappeared, This is, of +course, ascertained by placing a drop of the emulsion on a piece of +glass, and examining it. If it be wished to keep the bromide of silver +for future use it may be placed on a piece of muslin stretched in the +drying-box, when it will dry in a very short time; and, although I +cannot speak from experience on this point, it will, I have no doubt, +keep for an indefinite time so long as light is kept from it. + +If it be desired the ammonio-nitrate method may be used instead of the +boiling one, although in my hands it does not give such sensitiveness. +If it be desired to use this method, solution Nos. I, II., and IV. are +made up exactly as for the boiling method, except that No. II. is not +acidified. Liquid ammonia is then poured with stirring into the silver +solution, until it blackens and again clears. Emulsification is +performed exactly as described above, but instead of boiling, the +emulsion is kept at a temperature of about 100 deg. Fahr. for half an hour, +when it is poured into the alcohol, no addition of gelatine being +previously made. + +I think I may claim for the method which I have just described that it +is less troublesome and more certain than either the ordinary washing +method or the usual one of precipitating with alcohol, while it affords +an easy method of making sensitive silver bromide in such a form that it +can be more easily stored and afterwards manipulated than if it were in +the form of pellicle. The whole of the soluble salts are eliminated, +and also any gelatine which may have been destroyed in the cooking. +The amount of alcohol used is comparatively small; in fact, to prepare +silver bromide for a pint of emulsion very little more than a pint of +methylated spirit is required. Besides this I do not think that I would +be wrong in saying that the chance of green fog is reduced to a minimum. + +Let me take this opportunity of thanking Captain Abney for his prompt +reply to my question about the connection between the proportion +of bromide to gelatine in emulsions, and the density of resulting +images.--_W. K. Burton, in British Journal of Photography_. + + * * * * * + +[Illustration: Old Wrought Iron Gates, Guildhall.] + + * * * * * + + + + +THE POTTERY AND PORCELAIN INDUSTRIES OF JAPAN. + + +Japanese chronicles claim that the first pottery was made in the year +660 B.C.; it was not, however, until the Christian era that the art made +any considerable advances. In the year 1223 A.D., great improvements +were made in manufacture and decoration of the ware. From that date to +the sixteenth century the great potteries of Owari, Hizen, Mino, Kioto, +Kaga, and Satsuma were established. The Rahn-Yaki, or crackled ware, was +first made at Kioto, at the commencement of the sixteenth century. The +best old Hizen ware, that which is still the most admired, was made +at Arita Hizen, in 1580 to 1585; the old Satsuma dates from 1592. +Consul-General Van Buren states that porcelain clays are found in nearly +all parts of the country, and the different kinds are usually found +in close proximity, and close to canals and rivers, which is of +considerable advantage, as affording a means of transport. In all cases +every variety of clay used in the manufacture of pottery is found in a +natural state; there is no necessity to manufacture the quartzose or +fusible clays as is done in other parts of the world, and which adds +considerably to the cost of the ware. One of the peculiarities in the +clay found in Japan is that it contains both the fusible and infusible +materials in such proportions as to make a light, beautiful, +translucent, and durable porcelain. At Arita, in Hizen, there is a clay +found which contains 783/4 per cent, of silica, and l73/4 per cent, of +alumina; from this clay is made the delicate, translucent eggshell ware, +without the addition of any other matter. From an adjoining bluff a clay +is taken which has 50 per cent, of silica, and 38 per cent, of alumina; +from this the common porcelain is made. + +Potter's clay is found in very large quantities in the provinces of +Yamashiro, Hoki, Turoo Iyo, Hizen, Higo, Owari, Mikaera, Idyn, Musashi, +and Mino. In the whole of Japan there are 283 localities where the clay +is deposited; many of these only furnish inferior clays, but they are +all fitted for use in some of the various kinds of pottery. These clays +are thoroughly powdered by means of what is called "balance pounders," +worked in some localities by water-power, but the work is often done by +hand. The powder is then dried, and stored on boards or in flat boxes. +This dough does not go through the process of fermentation. The shaping +is almost exclusively done on the potter's wheel, which is set on a +pivot working in a porcelain eye. As a rule, the wheel is turned by the +potter himself, but in Hizen it is kept in motion by means of a band +connected with its pivot and another wheel turned by a boy. In making +dishes of other shape than round, a crude mould is sometimes used. After +the clay has been shaped on the wheel, it is set away for drying, and +usually in two or three days it is considered sufficiently dry for +smoothing, which is done on the wheel with a sharp curved knife. The +material is now made into "bisque," or biscuit, by a preliminary baking +in small ovens, when it is ready for painting, if it is to be painted +on the biscuit; if not, it is ready for the glazing. In either event it +will then go to the large furnace for the final baking. The kilns for +this purpose are always built on hill sides, and are joined together, +increasing in size from the lower to the higher ones, and in number from +four to twenty five; these kilns are so constructed that the draught is +from the lowest one, in addition to which each kiln has its own firing +place. The result of this construction is that the upper ones are by +far the most heated, and the ware is arranged accordingly; that which +requires the least baking, in the lower kiln, and that which requires +the greatest heat, in the upper. These connecting kilns have the merit +of being heat saving, but they are usually small and badly constructed, +and the heat in none of them is uniform. + +The glaze is made from the silicious clay and potash extracted from wood +ashes. This potash is not a pure white, and this accounts for the dirty +color usually to be observed in unpainted Japanese ware. In different +districts the painting varies. For instance, in Owari, the greater part +of the ware is painted a cobalt blue--the cobalt ore being found in the +bluffs near the clay deposits, and is used for painting the cheaper +wares, and for this purpose German cobalt is also employed. The painting +with cobalt is generally done on the biscuit before glazing. In several +districts a very handsome ware is made, and painted on the glaze. For +this kind of painting the colors are mixed with a silicate of lead +and potash, and baked the third time in a small furnace at a low +temperature. The coloring oxides in use are those of copper, cobalt, +iron, antimony, manganese, and gold. Japanese porcelain painting may be +divided into two categories, decorative and graphic; the first is used +to improve the vessel upon which it is placed, and this class includes +all the ware except that of the province of Kaga, which would come under +the head of graphic, as it delineates all the trades, occupations, +sports, customs, and costumes of the people, as well as the scenery, +flora, and fauna of the country. "Owari ware" is made in the province +of that name; it is not as translucent, but stronger and more tenacious +than some of the Hizen manufacture. + +The principal potteries are at a village called Seto, twelve miles from +the sea; in this village there are more than 200 kilns. The ware is +mostly painted a cobalt blue, and is merely of a decorative kind, +consisting of branches of trees, grass, flowers, birds, and insects, all +these being copied by the artist from nature. All the Owari ware is true +hard porcelain, and is strong and durable. In Hizen, a number of wares +are manufactured, the best known kind being the "Eurari," which is made +at Arita, but painted at Eurari. The colors in use are red, blue, green, +and gold; these are combined in various proportions, but, as a rule, the +red predominates. Generally the surface of the vessel is divided into +medallions of figures, which alternately have red, blue, or white +back-ground, with figures in green or blue and gold. + +The egg-shell porcelain sold at Nagasaki is made in this province from +Arita clay, and this is made from clay with no admixture of fusible +matter except that contained by the clay naturally. The province of +Satsuma is noted for crackled ware. It is only within a very few years +that large vases have been manufactured, and in earlier days the old +ware was confined to small vessels. The glaze is a silicate of alumina +and potash, and the best ware has a complete network of the finest +crackles; the painting is of birds and flowers, and noted for its +delicate lines of green, red, and gold. + +In Kioto, the ware manufactured is very similar to that produced in +Satsuma, but it is lighter and more porous; the decorations are also +nearly the same, being of birds and flowers. There is a description of +ware made in Kioto, called "Eraku," the whole body of which is covered +with a red oxide of iron, and over this mythical figures of gold are +traced. That produced in Kagja is _faience_, and in the style of +painting is unlike any other in Japan, the predominating color being +a light red, used with green and gold. The designs with which it is +profusely decorated are trees, grasses, flowers, birds, and figures of +all classes of people, with their costumes, occupations, and pastimes. +The "Banko" ware is made at the head of the Owari Bay; it is an unglazed +stone-ware, very light and durable, made on moulds in irregular shapes, +and decorated with figures in relief. On the island of Awadji, a +delicate, creamy, crackled, soft paste porcelain is made. The figures +used in decoration are birds and flowers, but outlined by heavy, dark +lines. + +Consul Van Buren is of opinion that, at no distant day, Japan will be +one of the foremost competitors in the pottery markets of the world, +on account of the great variety and excellence of the clays, their +proximity to the sea, the cheapness of labor, and the beauty and +originality of the decorations. Already this important industry has been +greatly stimulated by the foreign demand, and by the success of +Japanese exhibitors at the Exhibitions of Vienna, Philadelphia, and +Paris.--_Journal of the Society of Arts_. + + * * * * * + +Professor Julius E. Hilgard, for twenty years assistant in charge of the +office, has been placed in temporary charge of the Coast and Geodetic +Survey. It is understood that he will be appointed superintendent to +succeed the late Captain Carlile P. Patterson. + + * * * * * + + + + +THE FRENCH CRYSTAL PALACE. + + +The first idea of the French Crystal Palace was suggested by the English +structure of the same name at Sydenham, about eight miles from London. +Such a structure, as may be readily conceived, requires a site of vast +extent, and one that shall be easy of access and possess the most +agreeable surroundings. To the promoter of the project, those portions +of the park of St. Cloud in the vicinage of the old chateau appeared to +combine within themselves all the conditions that were desirable, and +he, therefore, on the 15th of December, 1879, addressed the Ministers of +Public Works and of Finances asking for the necessary concessions. The +extensive specifications have been finally completed and will probably +be shortly submitted for the approval of the parliament. The moment has +arrived then for the public press to take cognizance of a project which +concerns so great interests. + +[Illustration: THE FRENCH CRYSTAL PALACE--PARK OF ST CLOUD, PARIS.] + +At present we shall say a few words _a propos_ of the engraving we +present herewith. The French Crystal Palace will consist of one great +nave, two lateral naves, two surrounding galleries, and a vast rotunda +behind. The principal entrance, located at the head of the avenue +leading from the present ruins (which will, ere long, be transformed +into a most interesting museum), will exhibit a very striking aspect +with its monumental fountain and the dome which it is proposed to erect +over the very entrance itself. The whole structure will cover about +nineteen acres of ground, thus being two and a half times the extent of +the Palace of Industry in the Champs Elysees. The great nave of honor +will be nearly 1,650 ft. in length, 78 ft. in width, and 98 ft. in +height. The dome will measure exactly 328 ft. in height, or 105 ft. more +than the towers of Notre Dame. The structure, with the exception of +basement and foundation, will be of glass and iron. + +The project which we publish to-day has been studied and gotten up, +according to the general plans and dimensions suggested by the promoter, +by Mr. Dumoulin, the architect. We are informed that the builder is to +be Mr. Alfred Hunnebelle, a contractor well known from the extensive +works that he has executed, and who is president of the Syndical Chamber +of Contractors of Paris. + +Among the annexes of this palace we may note a "Palace of the Republic," +to be built on the ruins and designed for illustrious or distinguished +visitors, such as the President of the Republic, the Ministers, the +Municipal Council of Paris, foreign delegates, etc.; a farm house for +special exhibitions and a field for experiments; galleries, cottages, +etc. + +As for the programme, which embraces six divisions and numerous +subdivisions, we are unable to give it at present for want of space; we +need only say that it satisfies perfectly all the conditions of so vast +an undertaking. + +In the hands of the projector, Mr. Nicole, who is well known from his +long experience in such matters, the exhibition will undoubtedly prove +a success and be instrumental in adding prosperity to all French +industries. + + * * * * * + +THE GREAT HEAT OF THE SUN.--Prof. S. P. Langley has made the following +calculation: A sunbeam one centimeter in section is found in the clear +sky of the Alleghany Mountains to bring to the earth in one minute +enough heat to warm one gramme of water by 1 deg. C. It would, therefore, +if concentrated upon a film of water 1/500th of a millimeter thick, +1 millimeter wide, and 10 millimeters long, raise it 83 1/3 deg. in one +second, provided all the heat could be maintained. And since the +specific heat of platinum is only 0.0032 a strip of platinum of the same +dimensions would, on a similar supposition, be warmed _in one second_ to +2,603 deg. C.--a temperature sufficient to melt it! + + * * * * * + + + + +CHATEAU IN THE AEGEAN SEA. + + +From the site of this building, magnificent views are obtained over the +island-dotted sea and the mainland of Asia Minor: but, "though every +prospect pleases," it is a land of earthquakes, and unfortunately, the +works at the chateau have been suspended, owing to the dreadful calamity +which has recently fallen upon the district. The building is intended +for the residence of an English lady of exalted rank. It is to be built +of local white stone, the hall, staircase, etc., being lined and paved +with marbles. The hall is a large apartment about 25 ft. high, with +paneled ceiling, having galleries on two sides, giving access to the +rooms surrounding it on first floor, and to the turret staircase leading +to roofs, etc. With the exception of sanitary apparatus, painted +windows, etc. (which will be supplied by English firms), the whole of +the work will be executed by native labor. The architect is Mr. Edwin T. +Hall, London.--_Building News_. + +[Illustration: SUGGESTIONS IN ARCHITECTURE--A CASTELLATED CHATEAU.] + + * * * * * + + + + +ELECTRIC POWER. + + +Just now nothing save electricity is talked about in scientific circles. +During the meeting of the British Association the greatest possible +prominence was given to electrical questions and propositions The +success of the electric light, the introduction of the Faure battery +with a great flourish of trumpets, and the magnificent display of +electrical instruments and machinery at Paris, have all operated to the +same end. The daily press has taken the subject up, and journals which +were nothing hitherto if not political, now indulge in magnificent +rhapsodies concerning the future of electricity. Even eminent engineers, +carried away by the intoxication of the moment, have not hesitated to +say that the steam engine is doomed, and that its place will be taken by +the electricity engine. In the midst of all this noise and clamor and +blowing of personal trumpets, it is not easy to keep one's head clear, +and mistakes may be made which will cause disappointment to many and +retard the progress of electrical science. We confidently expect that +electricity will prove a potent agent by and by in the hands of the +speculator for extracting gold from the pockets of the public, and we +write now to warn our readers in time, and to endeavor to clear the air +of some of the mists with which it is obscured. There is, no doubt, +a great future before electricity; but it is equally certain that +electricity can never do many things which the half informed may be +readily made to believe it will do. We propose here to say enough +on this point to enlighten our readers, without troubling them with +perplexing problems and speculations. + +No one at this moment knows what electricity is; but for our present +purpose we may regard it as a fluid, non-elastic, and without weight, +and universally diffused through the universe. To judge by recently +published statements, a large section of the reading public are taught +that this fluid is a source of power, and that it may be made to do the +work of coal. This is a delusion. So long as electricity remains in what +we may call a normal state of repose, it is inert. Before _we can get +any work out of electricity a somewhat greater amount of work must be +done upon it_. If this fundamental and most important truth be kept in +view it will not be easy to make a grave mistake in estimating the value +of any of the numerous schemes for making electricity do work which will +ere long be brought before the public. To render our meaning clearer, +we may explain that in producing the electric light, for instance, a +certain quantity of electricity passes in through one wire to the lamp, +and precisely the same quantity passes out through the other wire, and +on to the earth or return wire completing the circuit. Not only is the +quantity the same, the velocity is also unchanged. But in going through +the lamp the current has done something. It has overcome the resistance +of the carbons, heated them to a dazzling white heat, and so performed +work. In doing this the current of electricity has lost something. Led +from the first lamp to a second, it is found powerless--if the first +lamp be of sufficient size. What is it that the electricity has lost? +It has parted with what electricians would term "potential," or the +capacity for performing work. What this is precisely, or in what way the +presence or absence of potential modifies the nature of the electric +current, no one knows; but it is known that this potential can only be +conferred on electricity by doing work on the electricity in the first +instance. The analogy between electricity and a liquid like water will +now be recognized. So long as the water is at rest, it is inert. If we +pump it up to a height, we confer on it the equivalent of potential. +We can let the water fall into the buckets of an overshot wheel. Its +velocity leaving the tail race may be identical with that at which it +left the supply trough to descend on the wheel. Its quantity will be +the same. It will be in all respects unchanged, just as the current +of electricity passing through a lamp is unchanged; but it has, +nevertheless, lost something. It has parted with its potential--capacity +for doing work--and it becomes once more inert. But the duty which it +discharged in turning the mill wheel was somewhat less than the precise +equivalent of the work done in pumping it up to a level with the top of +the wheel. In the same way the electric current never can do work equal +in amount to the work done on it in endowing it with potential. + +It will thus be seen that electricity can only be used as a means of +transmitting power from one place to another, or for storing power up +at one time to be used at a subsequent period; but it cannot be used to +originate power in the way coal can be used. It possesses no inherent +potential. It is incapable of performing work unless something is done +to it first. We have spoken of it as a fluid, but only for the sake of +illustration. As we have said, no one knows what it is, but the theory +which bids fair for acceptance is that it is a mode of motion of the +all-pervading ether. Very curious and instructive experiments are now +being carried out in Paris by Dr. Bjerkness, of Christiania, in the +Norwegian section of the electrical exhibition. This gentleman submerges +thin elastic diaphragms in water, and causes them to vibrate, or rather +pulsate, by compressed air. He finds that if they pulsate synchronously +they attract each other. If the pulsations are not simultaneous, the +disks repel each other. From this and other results he has obtained, +it may be argued that the ether plays the part of the water in Dr. +Bjerkness' tank, and that when special forms of vibration are set up +in bodies they become competent to attract or repel other bodies. This +being so, it will be seen that the power of attraction or repulsion of +an electrical body depends in the first instance on the motion set up +in the body attracted or repulsed, and this motion is, of course, some +function of the work originally done on the body. We need not pursue +this argument further. Among the most scientific investigators of the +day it is admitted that the efficiency of electricity as a doer of work, +or a producer of action at a distance, must depend for its value on the +performance of work in some one way or another on the electricity itself +in the first instance. It may be worth while here to dispel a popular +delusion. It is held very generally that electricity can be made, as, +for instance, by the galvanic battery. There is no reason to believe +anything of the kind; but whether it is or is not true that electricity +is actually made by the combustion of zinc in a galvanic trough, it is +quite certain that this electricity, unless it possesses potential, can +do no work, no matter how great its quantity. Of course, it is to be +understood that all electric currents possess potential. If they did +not, their presence would be unknown; but the potential of a current +is in all cases the result of work done on electricity, either by the +oxidation of zinc, or in some other way. This is a broad principle, but +it is strictly consistent in every respect with the truth. Electricity, +then, is, as we have said, totally different from coal; and it can never +become a substitute for it alone. Water power, air power, or what we +may, for want of a better phrase, call chemical power, combined with +electricity, can be used as a substitute for coal; but electricity +cannot of itself be employed to do work. It is true, however, that +electricity, on which work has already been done, may be found in +nature. Atmospheric electricity, for example, may perhaps yet be +utilized. It is by no means inconceivable that the electricity contained +in a thunder cloud might be employed to charge a Faure battery; but up +to the present no one has contemplated the obtaining of power from the +clouds, and whether it is or is not practicable to utilize a great +natural force in this way does not affect our statement. The use of +electricity must be confined to its power of transmitting or storing up +energy, and this truth being recognized, it becomes easy to estimate the +future prospects of electricity at something like their proper value. + +It has been proved to a certain extent that electricity can be used to +transmit power to a distance, and that it can be used to store it up. +Thus far the man of pure science. The engineer now comes on the stage +and asks--Can practical difficulties be got over? Can it be made to pay? +In trying to answer these questions we cannot do better than deal with +one or two definite proposals which have been recently made. That with +which we shall first concern ourselves is that trains should be worked +by Faure batteries instead of by steam. It is suggested that each +carriage of a train should be provided with a dynamo motor, and that +batteries enough should be carried by each to drive the wheels, and so +propel the train. Let us see how such a scheme would comply with working +conditions. Let us take for example a train of fifteen coaches on the +Great Northern Railway, running without a stop to Peterborough in one +hour and forty minutes. The power required would be about 500 horses +indicated. To supply this for 100 minutes, even on the most absurdly +favorable hypothesis, no less than 25 tons of Faure batteries would be +required. Adding to these the weight of the dynamo motors, and that +unavoidably added to the coaches, it will be seen that a weight equal to +that of an engine would soon be reached. The only possible saving would +be some 28 to 30 tons of tender. In return for this all the passengers +would have to change coaches at Peterborough, as the train could not be +delayed to replace the expended with fresh batteries. This is out of +the question. The Faure batteries must all be carried on one vehicle or +engine, which could be changed for another, like a locomotive. Even then +no advantage would be gained. As to cost, it is very unlikely that the +stationary engines which must be provided to drive the dynamo machines +for charging the batteries would be more economical than locomotive +engines; and if we allow that the dynamo machine only wasted 10 per +cent. of the power of the engine, the Faure batteries 10 per cent. of +the power of the dynamo machines, and the dynamo motors 10 per cent. of +the power of the batteries--all ridiculously favorable assumptions--yet +the stationary engines would be handicapped with a difference in net +efficiency between themselves and the locomotive--admitting the original +efficiency per pound of coal in both to be the same--of some 27 per +cent., we think we may relegate this scheme to the realms of oblivion. +Another idea is that by putting up turbines and dynamo machines the +steam engine might be superseded by water power. Now it so happens that +if all the water power of England were quadrupled it would not nearly +suffice for our wants. It may be found worth while perhaps to construct +steam engines close to coalpits and send out power from these engines by +wire; but the question will be asked, Which is the cheaper of the two, +to send the coal or to send the power? On the answer to this will +depend the decision of the mill owners. Another favorite scheme is that +embodied in the Siemens electrical railway. We believe that there is a +great future in store for electricity as a worker of tramway traffic; +but the traffic on a great line like the Midland or Great Northern +Railway could not be carried on by it. As Robert Stephenson said of the +atmospheric system, it is not flexible enough. The working of points +and crossings, and the shunting of trains and wagons, would present +unsurmountable difficulties. We have cited proposals enough, we think, +to illustrate our meaning. Sir William Armstrong, Sir Frederick +Bramwell, Dr. Siemens, Sir W. Thomson, and many others may be excused if +they are a little enthusiastic. They are just now overjoyed with success +attained; but when the time comes for sober reflection they will, no +doubt, see good reason to moderate their views. No one can say, of +course, what further discoveries may bring to light; but recent speakers +and writers have found in what is known already, materials for sketching +out a romance of electricity. It is but romancing to assert that the end +of the steam engine is at hand. Wonderful and mystical as electricity +is, there are some very hard and dry facts about it, and these facts are +all opposed to the theory that it can become man's servant of all work. +Ariel-like, electricity may put a girdle round the earth in forty +minutes; but it shows no great aptitude for superseding the useful old +giant steam, who has toiled for the world so long and to such good +purpose--_The Engineer_. + + * * * * * + + + + +ON A METHOD OF OBTAINING AND MEASURING VERY HIGH VACUA WITH A MODIFIED +FORM OF SPRENGEL-PUMP. + +By Ogden N. Rood, Professor of Physics in Columbia College. + + +In the July number of this Journal for 1880, I gave a short account of +certain changes in the Sprengel-pump by means of which far better vacua +could be obtained than had been previously possible. For example, the +highest vacuum at that time known had been reached by Mr. Crookes, and +was about 1/17,000,000, while with my arrangement vacua of 1/100,000,000 +were easily reached. In a notice that appeared in _Nature_ for August, +1880, p. 375, it was stated that my improvements were not new, but had +already been made in England four years previously. I have been unable +to obtain a printed account of the English improvements, and am willing +to assume that they are identical with my own; but on the other hand, +as for four years no particular result seems to have followed their +introduction in England, I am reluctantly forced to the conclusion that +their inventor and his customers, for that period of time, have remained +quite in ignorance of the proper mode of utilizing them. Since then I +have pushed the matter still farther, and have succeeded in obtaining +with my apparatus vacua as high as 1/390,000,000 without finding +that the limit of its action had been reached. The pump is simple in +construction, inexpensive, and, as I have proved by a large number of +experiments, certain in action and easy of use; stopcocks and grease are +dispensed with, and when the presence of a stopcock is really desirable +its place is supplied by a movable column of mercury. + +_Reservoir_.--An ordinary inverted bell-glass with a diameter of 100 mm. +and a total height of 205 mm. forms the reservoir; its mouth is closed +by a well-fitting cork through which passes the glass tube that forms +one termination of the pump. The cork around tube and up to the edge of +the former is painted with a flexible cement. The tube projects 40 mm. +into the mercury and passes through a little watch-glass-shaped piece of +sheet-iron, W, figure 1, which prevents the small air bubbles that creep +upward along the tube from reaching its open end; the little cup is +firmly cemented in its place. The flow of the mercury is regulated +by the steel rod and cylinder, CR, Figure 1. The bottom of the steel +cylinder is filled out with a circular piece of pure India-rubber, +properly cemented; this soon fits itself to the use required and answers +admirably. The pressure of the cylinder on the end of the tube is +regulated by the lever, S, Figure 1; this is attached to a circular +board which again is firmly fastened over the open end of the +bell-glass. It will be noticed that on turning the milled head, S, the +motion of the steel cylinder is not directly vertical, but that it tends +to describe a circle with c as a center; the necessary play of the +cylinder is, however, so small, that practically the experimenter does +not become aware of this theoretical defect, so that the arrangement +really gives entire satisfaction, and after it has been in use for a few +days accurately controls the flow of the mercury. The glass cylinder is +held in position, but not supported, by two wooden _adjustable_ clamps, +_a a_, Figure 2. The weight of the cylinder and mercury is supported by +a shelf, S, Figure 2, on which rests the cork of the cylinder; in this +way all danger of a very disagreeable accident is avoided. + +[Illustration: MODIFIED FORM OF SPRENGEL PUMP.] + +_Vacuum-bulb_.--Leaving the reservoir, the mercury enters the +vacuum-bulb, B, Figure 2, where it parts with most of its air and +moisture; this bulb also serves to catch the air that creeps into the +pump from the reservoir, even when there is no flow of mercury; its +diameter is 27 mm. The shape and inclination of the tube attached to +this bulb is by no means a matter of indifference; accordingly Figure +3 is a separate drawing of it; the tube should be so bent that a +horizontal line drawn from the proper level of the mercury in the bulb +passes through the point, _o_, where the drops of mercury break off. The +length of the tube, EC, should be 150 mm., that of the tube, ED, 45 mm.; +the bore of this tube is about the same as that of the fall-tube. + +_Fall-tube and bends_.--The bore of the fall-tube in the pump now used +by me is 1.78 mm.; its length above the bends (U, Figure 2) is 310 mm.; +below the bends the length is 815 mm. The bends constitute a fluid valve +that prevents the air from returning into the pump; beside this, the +play of the mercury in them greatly facilitates the passage of the +air downward. The top of the mercury column representing the existing +barometric pressure should be about 25 mm. below the bends when the pump +is in action. This is easily regulated by an adjustable shelf, which is +also employed to fill the bends with mercury when a measurement is taken +or when the pump is at rest. On the shelf is a tube, 160 mm. high and 20 +mm. in diameter, into which the end of the fall-tube dips; its side has +a circular perforation into which fits a small cork with a little tube +bent at right angles. With the hard end of a file and a few drops of +turpentine the perforation can be easily made and shaped in a few +minutes. By revolving the little bent tube through 180 deg. the flow of the +mercury can be temporarily suspended when it is desirable to change the +vessel that catches it. + +_Gauge_.--For the purpose of measuring the vacua I have used an +arrangement similar to McLeod's gauge, Figure 4; it has, however, some +peculiarities. The tube destined to contain the compressed air has a +diameter of 1.35 mm. as ascertained by a compound microscope; it is not +fused at its upper extremity, but closed by a fine glass rod that fits +into it as accurately as may be, the end of the rod being ground flat +and true. This rod is introduced into the tube, and while the latter +is gently heated a very small portion of the cement described below is +allowed to enter by capillary attraction, but not to extend beyond the +end of the rod, the operation being watched by a lens. The rod is +used for the purpose of obtaining the compressed air in the form of a +cylinder, and also to allow cleansing of the tube when necessary. The +capacity of the gauge-sphere was obtained by filling it with mercury; +its external diameter was sixty millimeters; for measuring very high +vacua this is somewhat small and makes the probable errors rather +large; I would advise the use of a gauge-sphere of about twice as great +capacity. The tube, CB, Figure 4, has the same bore as the measuring +tube in order to avoid corrections for capillarity. The tube of the +gauge, CD, is not connected with an India-rubber tube, as is usual, +but dips into mercury contained in a cylinder 340 mm. high, 58 mm. in +diameter, which can be raised and lowered at pleasure. This is best +accomplished by the use of a set of boxes of various thicknesses, made +for the purpose and supplemented by several sheets of cardboard and even +of writing-paper. These have been found to answer well and enable the +experimenter to graduate with a nicety the pressure to which the gas is +exposed during measurement. By employing a cylinder filled with mercury +instead of the usual caoutchouc tubing small bubbles of air are +prevented from entering the gauge along with the mercury. An adjustable +brace or support is used which prevents accident to the cylinder when +the pump is inclined for the purpose of pumping out the vacuum-bulb. The +maximum pressure that can be employed in the gauge used by me is 100 mm. + +All the tubing of the pump is supported at a distance of about 55 mm. +from the wood-work; this is effected by the use of simple adjustable +supports and adjustable clamps; the latter have proved a great +convenience. The object is to gain the ability to heat with a Bunsen +burner all parts of the pump without burning the wood-work. Where glass +and wood necessarily come in contact the wood is protected by metal or +simply painted with a saturated solution of alum. The glass portions +of the pump I have contrived to anneal completely by the simple means +mentioned below. If the glass is not annealed it is certain to crack +when subjected to heat, thus causing vexation and loss of time. The +mercury was purified by the same method that was used by W. Siemens +(Pogg. Annalen, vol. ex., p. 20), that is, by a little strong sulphuric +acid to which a few drops of nitric acid had been added; it was dried by +pouring it repeatedly from one hot dry vessel to another, by filtering +it while quite warm, the drying being completed finally by the action of +the pump itself. All the measurements were made by a fine cathetometer +which was constructed for me by William Grunow; see this Journal, Jan., +1874, p. 23. It was provided with a well-corrected object-glass having a +focal length of 200 mm. and as used by me gave a magnifying power of 16 +diameters. + +_Manipulation_.--The necessary connections are effected with a cement +made by melting Burgundy pitch with three or four per cent of gutta +percha. It is indispensable that the cement when cold should be so hard +as completely to resist taking any impression from the finger nail, +otherwise it is certain to yield gradually and finally to give rise to +leaks. The connecting tubes are selected so as to fit as closely as +possible, and after being put into position are heated to the proper +amount, when the edges are touched with a fragment of cold cement which +enters by capillary attraction and forms a transparent joint that can +from time to time be examined with a lens for the colors of thin plates, +which always precede a leak. Joints of this kind have been in use by me +for two months at a time without showing a trace of leakage, and the +evidence gathered in another series of unfinished experiments goes to +show that no appreciable amount of vapor is furnished by the resinous +compound, which, I may add, is never used until it has been repeatedly +melted. As drying material I prefer caustic potash that has been in +fusion just before its introduction into the drying tube; during the +process of exhaustion it can from time to time be heated nearly to the +melting point: if actually fused in the drying tube the latter almost +invariably cracks. The pump in the first instance is to be inclined at +an angle of about 10 degrees, the tube of the gauge being supported by +a semicircular piece of thick pasteboard fitted with two corks into the +top of the cylinder. This seemingly awkward proceeding has in no case +been attended with the slightest accident, and owing to the presence of +the four leveling-screws, the pump when righted returns, as shown by the +telescope of the cathetometer, almost exactly to its original place. In +the inclined position the exhaustion of the vacuum bulb is accomplished +along with that of the rest of the pump. The exhaustion of the +vacuum-bulb when once effected can be preserved to a great extent for +use in future work, merely by allowing mercury from the reservoir to +flow in a rapid stream at the time that air is allowed to re-enter the +pump. During the first process of exhaustion the tube of the gauge is +kept hot by moving to and fro a Bunsen burner, and is in this way +freed from those portions of air and moisture that are not too firmly +attached. After a time the vacuum-bulb ceases to deliver bubbles of +air; it and the attached tube are now to be heated with a moving Bunsen +burner, when it will be found to furnish for 15 or 20 minutes a large +quantity of bubbles mainly of vapor of water. After then production +ceases the pump is righted and the exhaustion carried farther. In spite +of a couple of careful experiments with the cathetometer I have not +succeeded in measuring the vacuum in the vacuum bulb, but judge from +indications, that is about as high as that obtained in an ordinary +Geissler pump. Meanwhile the various parts of the pump can be heated +with a moving Bunsen burner to detach air and moisture, the cement being +protected by wet lamp-wicking. In one experiment I measured the amount +of air that was detached from the walls of the pump by heating them for +ten minutes somewhat above l00 deg. C., and found that it was 1/1,000,000 +of the air originally present. I have also noticed that a still larger +amount of air is detached by electric discharges. This coincides with an +observation of E. Bessel-Hagen in his interesting article on a new form +of Toepler's mercury-pump (Annalen der Physik und Chemie, 1881, vol. +xii.). Even when potash is used a small amount of moisture always +collects in the bends of the fall tube; this is readily removed by a +Bunsen burner; the tension of the vapor being greatly increased, it +passes far down the fall-tube in large bubbles and is condensed. Without +this precaution I have found it impossible to obtain a vacuum higher +than 1/25,000,000; in point of fact the bends should always be heated +when a high exhaustion is undertaken even if the pump has been standing +well exhausted for a week; the heat should of course never be applied at +a late stage of the exhaustion. Conversely, I have often by the aid of +heat completely and quickly removed quite large quantities of the vapor +of water that had been purposely introduced. The exhaustion of the +vacuum-bulb is of course somewhat injured by the act of using the pump +and also by standing for several days, so that it has been usual with me +before undertaking a high exhaustion to incline the pump and re-exhaust +for 20 minutes; I have, however, obtained very high vacua without using +this precaution. + +During the process of exhaustion not more than one-half of the mercury +in the reservoir is allowed to run out, other wise when it is returned +bubbles of air are apt to find their way into the vacuum-bulb. In order +to secure its quiet entrance it is poured into a silk bag provided with +several holes. When the reservoir is first filled its walls for a day +or two appear to furnish air that enters the vacuum-bulb; this action, +however, soon sinks to a minimum and then the leakage remains quite +constant for months together. + +_Measurement of the vacuum_.--The cylinder into which the gauge-tube +dips is first elevated by a box sufficiently thick merely to close the +gauge, afterwards boxes are placed under it sufficient to elevate the +mercury to the base of the measuring tube; when the mercury has reached +this point, thin boards and card-boards are added till a suitable +pressure is obtained. The length of the inclosed cylinder of air is +then measured with the cathetometer, also the height of the mercurial +"meniscus," and the difference of the heights of the mercurial columns +in A and B, figure 4. To obtain a second measure an assistant removes +some of the boxes and the cylinder is lowered by hand three or four +centimeters and then replaced in its original position. In measuring +really high vacua, it is well to begin with this process of lowering and +raising the cylinder, and to repeat it five or six times before taking +readings. It seems as though the mercury in the tube, B, supplies to the +glass a coating of air that allows it to move more freely; at all events +it is certain that ordinarily the readings of B become regular, only +after the mercury has been allowed to play up and down the tube a number +of times. This applies particularly to vacua as high 1/50,000,000 and to +pressures of five millimeters and under. It is advantageous in making +measurements to employ large pressures and small volumes; the correct +working of the gauge can from time to time be tested by varying the +relations of these to each other. This I did quite elaborately, and +proved that such constant errors as exist are small compared with +inevitable accidental errors, as, for example, that there was no +measurable correction for capillarity, that the calculated volume of the +"meniscus" was correct, etc. It is essential in making a measurement +that the temperature of the room should change as little as possible, +and that the temperature of the mercury in the cylinder should be at +least nearly that of the air near the gauge-sphere. The computation is +made as follows + + n = height of the cylinder inclosing the air; + c = a factor which, multiplied by n, converts it into cubic + millimeters; + S = cubic contents of the meniscus; + d = difference of level between A and B, fig. 4; + = the pressure the air is under; + N = the cubic contents of the gauge in millimeters; + x = a fraction expressing the degree of exhaustion obtained; then + + x=1/([N (760/d)]/[nc - S]) + +It will be noticed that the measurements are independent of the actual +height of the barometer, and if several readings are taken continuously, +the result will not be sensibly affected by a simultaneous change of the +barometer. Almost all the readings were taken at a temperature of about +20 deg. C., and in the present state of the work corrections for temperature +may be considered a superfluous refinement. + +_Gauge correction_.--It is necessary to apply to the results thus +obtained a correction which becomes very important when high vacua are +measured. It was found in an early stage of the experiments that the +mercury, in the act of entering the highly exhausted gauge, gave out +invariably a certain amount of air which of course was measured along +with the residuum that properly belonged there; hence to obtain the true +vacuum it is necessary to subtract the volume of this air from nc. By a +series of experiments I ascertained that the amount of air introduced by +the mercury in the acts of entering and leaving the gauge was sensibly +constant for six of these single operations (or for three of these +double operations), when they followed each other immediately. The +correction accordingly is made as follows: the vacuum is first measured +as described above, then by withdrawing all the boxes except the lowest, +the mercury is allowed to fall so as nearly to empty the gauge; it is +then made again to fill the gauge, and these operations are repeated +until they amount in all to six; finally the volume and pressure are a +second time measured. Assuming the pressure to remain constant, or that +the volumes are reduced to the same pressure, + + v = the original volume; v' = the final volume; + V' = volume of air introduced by the first entry of the mercury; + V = corrected volume; then + + V' = (v'-v)/6 + V = v - [(v'-v)/6] + +It will be noticed that it is assumed in this formula that the same +amount of air is introduced into the gauge in the acts of entry and +exit; in the act of entering in point of fact more fresh mercury is +exposed to the action of the vacuum than in the act exit, which might +possibly make the true gauge-correction rather larger than that given by +the formula. It has been found that when the pump is in constant use the +gauge-correction gradually diminishes from day to day; in other words, +the air is gradually pumped out of the gauge-mercury. Thus on December +21, the amount of air entering with the mercury corresponded to an +exhaustion of + + 1/27,308,805 .......Dec. 21. + + 1/38,806,688 ...... Dec. 29. + + 1/78,125,000 .......Jan. 15. + + 1/83,333,333 .......Jan. 23 + + 1/128,834,063 ......Feb. 1. + + 1/226,757,400 ..... Feb. 9. + + 1/232,828,800 ..... Feb. 19. + + 1/388,200,000 ......March 7. + +That this diminution is not due to the air being gradually withdrawn +from the walls of the gauge or from the gauge-tube, is shown by the fact +that during its progress the pump was several times taken to pieces, and +the portions in question exposed to the atmosphere without affecting +the nature or extent of the change that was going on. I also made one +experiment which proves that the gauge-correction does not increase +sensibly, when the exhausted pump and gauge are allowed to stand unused +for twenty days. + +_Rate of the pump's work_.--It is quite important to know the rate of +the pump at different degrees of exhaustion, for the purpose of enabling +the experimenter to produce a definite exhaustion with facility; also if +its maximum rate is known and the minimum rate of leakage, it becomes +possible to calculate the highest vacuum attainable with the instrument. +Examples are given in the tables below; the total capacity was about +100,000 cubic mm. + + Time. Exhaustion. Ratio. + + 1/78,511 + 10 minutes }........ 1:1/3.53 + 1/276,980 + 10 minutes }........ 1:1/6.10 + 1/1,687,140 + 10 minutes }........ 1:1/4.15 + 1/7,002,000 + +Upon another occasion the following rates and exhaustions were obtained: + + Time. Exhaustion. Rate. + + 1/7,812,500 + 10 minutes }........ 1:1/3.18 + 1/24,875,620 + 10 minutes }........ 1:1/2.69 + 1/67,024,090 + 10 minutes }........ 1:1/1.22 + 1/81,760,810 + 10 minutes }........ 1:1.67 + 1/136,986,300 + 10 minutes }........ 1:1.23 + 1/170,648,500 + +The _irregular_ variations in the rates are due to the mode in which the +flow of the mercury was in each case regulated. + +_Leakage_.--We come now to one of the most important elements in the +production of high vacua. After the air is detached from the walls of +the pump the leakage becomes and remains nearly constant. I give below a +table of leakages, the pump being in each case in a condition suitable +for the production of a very high vacuum: + + Duration of the Leakage per hour in + experiment cubic mm., press., + 760 mm. + + 181/2 hours............................ 0.000853 + 27 hours............................ 0.001565 + 261/2 hours.............................0.000791 + 20 hours.............................0.000842 + 19 hours.............................0.000951 + 19 hours.............................0.001857 + 7 days..............................0.001700 + 7 days..............................0.001574 + + Average.................... 0.001266 + +I endeavored to locate this leakage, and proved that one-quarter of +it is due to air that enters the gauge from the top of its column of +mercury, thus: + + Duration of the Gauge-leakage per hour + experiment. in cubic mm., press. + 760 mm. + + 18 hours.................................0.0002299 + 7 days..................................0.0004093 + 7 days..................................0.0003464 + + Average.......................0.0003285 + +This renders it very probable that the remaining three quarters are due +to air given off from the mercury at B, Fig. 4, from that in the bends +and at the entrance of the fall-tube, _o_, Fig. 3. + +Further on some evidence will be given that renders it probable that the +leakage of the pump when in action is about four times as great as the +total leakage in a state of rest. + +The gauge, when arranged for measurement of gauge-leakage, really +constitutes a barometer, and a calculation shows that the leakage would +amount to 2.877 cubic millimeters per year, press. 760 mm. If this air +were contained in a cylinder 90 mm. long and 15 mm. in diameter it would +exert a pressure of 0.14 mm. To this I may add that in one experiment +I allowed the gauge for seven days to remain completely filled with +mercury and then measured the leakage into it. This was such as would +in a year amount to 0.488 cubic millimeter, press. 760 mm., and in a +cylinder of the above dimensions would exert a pressure of 0.0233 mm. + +_Reliability of the results: highest vacuum._ + +The following are samples of the results obtained. In one case sixteen +readings were taken in groups of four with the following result: + + Exhaustion. + 1 / 74,219,139 + 1 / 78,533,454 + 1 / 79,017,272 + 1 / 68,503,182 + Mean 1 / 74,853,449 + +Calculating the probable error of the mean with reference to the above +four results it is found to be 2.28 per cent of the quantity involved. + +A higher vacuum measured in the same way gave the following results: + + 1 / 146,198,800 + 1 / 175,131,300 + 1 / 204,081,600 + 1 / 201,207,200 + +The mean is 1 / 178,411,934, with a probable error of 5.42 per cent of +the quantity involved. I give now an extreme case; only five single +readings were taken; these corresponded to the following exhaustions: + + 1 / 379,219,500 + 1 / 371,057,265 + 1 / 250,941,040 + 1 / 424,088,232 + 1 / 691,082,540 + +The mean value is 1 / 381,100,000, with a probable error of 10.36 per +cent of the quantity involved. Upon other occasions I have obtained +exhaustions of 1 / 373,134,000 and 1 / 388,200,000. Of course in these +cases a gauge-correction was applied; the highest vacuum that I have +ever obtained irrespective of a gauge-correction was 1 / 190,392,150. In +these cases and in general, potash was employed as the drying material; +I have found it practical, however, to attain vacua as high as 1 / +50,000,000 in the total absence of all such substances. The vapor of +water which collects in bends must be removed from time to time with a +Bunsen burner while the pump is in action. + +It is evident that the final condition of the pump is reached when +as much air leaks in per unit of time as can be removed in the same +interval. The total average leakage per ten minutes in the pump used by +me, when at rest, was 0.000211 cubic millimeter at press. 760 mm. Let +us assume that the leakage when the pump is in action is four times +as great as when at rest; then in each ten minutes 0.000844 cubic +millimeter press., 760 mm., would enter; this corresponds in the pump +used by me to an exhaustion of 1 / 124,000,000; if the rate of the pump +is such as to remove one-half of the air present in ten minutes, then +the highest attainable exhaustion would be 1 / 248,000,000. In the same +way it may be shown that if six minutes are required for the removal of +half the air the highest vacuum would be 1 / 413,000,000 nearly, and +rates even higher than this have been observed in my experiments. An +arrangement of the vacuum-bulb whereby the entering drops of mercury +would be exposed to the vacuum in an isolated condition for a somewhat +longer time would doubtless enable the experimenter to obtain +considerably higher vacua than those above given. + +_Exhaustion obtained with a plain Sprengel Pump._--I made a series of +experiments with a plain Sprengel pump without stopcocks, and arranged, +as far as possible, like the instrument just described. The leakage per +hour was as follows: + + Duration of the Leakage per hour in + experiment. cubic mm. at press. + 760 mm. + + 22 hours 0.04563 + 2 days 0.04520 + 2 days 0.09210 + 4 days 0.06428 + ------- + Mean 0.06180 + +Using the same reasoning as above we obtain the following table + + Time necessary for removal Greatest attainable + of half the air. exhaustion. + + 10 minutes 1 / 5,000,000 + 7.5 minutes 1 / 7,000,000 + 6.6 minutes 1 / 12,000,000 + +In point of fact the highest exhaustion I ever obtained with this pump +was 1 / 5,000,000; from which I infer that the leakage during action +is considerably greater than four times that of the pump at rest. The +general run of the experiments tends to show that the leakage of a plain +Sprengel pump, without stopcocks or grease, is, when in action, about 80 +times as great as in the form used by me. + +_Note on annealing glass tubes._--It is quite necessary to anneal all +those parts of the pump that are to be exposed to heat, otherwise they +soon crack. I found by inclosing the glass in heavy iron tubes and +exposing it for five hours to a temperature somewhat above that of +melting zinc, and then allowing an hour or two for the cooling process, +that the strong polarization figure which it displays in a polariscope +was completely removed, and hence the glass annealed. A common +gas-combustion furnace was used, the bends, etc, being suitably inclosed +in heavy metal and heated over a common ten-fold Bunsen burner. Thus far +no accident has happened to the annealed glass, even when cold drops of +mercury struck in rapid succession on portions heated considerably above +100 deg. C. + +I wish, in conclusion, to express my thanks to my assistant, Dr. +Ihlseng, for the labor he has expended in making the large number of +computations necessarily involved in work of this kind.--_Amer. Jour. of +Science._ + + * * * * * + + + + +CRYSTALLIZATION TABLE. + + +The following table, prepared by E. Finot and Arm. Bertrand for the +_Jour. de Ph. et de Chim._, shows the point at which the evaporation of +certain solutions is to be interrupted in order to procure a good crop +of crystals on cooling. The density is according to Baume's scale, the +solution warm: + + Aluminum sulphate 25 | Nickel acetate 30 + Alum (amm. or pot.) 20 | " ammon. sulphate 18 + Ammonium acetate 14 | " chloride 50 + " arsenate 5 | " sulphate 40 + " benzoate 5 | Oxalic acid 12 + " bichromate 28 | Potass. and sod. tartrate 36 + " bromide 30 | Potassium arsenate 36 + " chloride 12 | " benzoate 2 + " nitrate 29 | " bisulphate 35 + " oxalate 5 | " bromide 40 + " phosphate 35 | " chlorate 22 + " sulphate 28 | " chloride 25 + " sulphocyanide 18 | " chromate 38 + " tartrate 25 | " citrate 36 + Barium ethylsulphate 43 | " ferrocyanide 38 + " formate 32 | " iodide 17 + " hyposulphite 24 | " nitrate 28 + " nitrate 18 | " oxalate 30 + " oxide 12 | " permanganate 25 + Bismuth nitrate 70 | " sulphate 15 + Boric acid 6 | " sulphite 25 + Cadmium bromide 65 | " sulphocyanide 35 + Calcium chloride 40 | " tartrate 48 + " ethylsulphate 36 | Soda 28 + " lactate 8 | Sodium acetate 22 + " nitrate 55 | " ammon. phosp. 17 + Cobalt chloride 41 | " arsenate 36 + " nitrate 50 | " borate 24 + " sulphate 40 | " bromide 55 + Copper acetate 5 | " chlorate 43 + " ammon. sulph. 35 | " chromate 45 + " chloride 45 | " citrate 36 + " nitrate 55 | " ethylsulphate 37 + " sulphate 30 | " hyposulphite 24 + Iron-ammon. oxalate 30 | " nitrate 40 + " ammon. sulphate 31 | " phosphate 20 + " sulphate 31 | " pyrophosphate 18 + " tartrate 40 | " sulphate 30 + Lead acetate 42 | " tungstate 45 + " nitrate 50 | Stroutium bromide 50 + Magnesium chloride 35 | " chlorate 65 + " lactate 6 | " chloride 34 + " nitrate 45 | Tin choride (stannous) 75 + " sulphate 40 | + Manganese chloride 47 | Zinc acetate 20 + " lactate 8 | " ammon. chloride 43 + " sulphate 44 | " nitrate 55 + Mercury cyanide 20 | " sulphate 45 + + * * * * * + + + + +THE PRINCIPLES OF HOP-ANALYSIS. + +By Dr. G. O. CECH + +[Footnote: 'Zeitschrift fur Analyt. Chemie,' 1881.] + + +Hop flowers contain a great variety of different substances susceptible +of extraction with ether, alcohol, and water, and distinguishable from +one another by tests of a more or less complex character. The substances +are: Ethereal oil, chlorophyl, hop tannin, phlobaphen, a wax-like +substance, the sulphate, ammoniate, phosphate, citrate and malates of +potash, arabine, a crystallized white and an amorphous brown resin, and +a bitter principle. That the characteristic action of the hops is due to +such of these constituents only as are of an organic nature is easy to +understand; but up to the present we are in ignorance whether it is upon +the oil, the wax, the resin, the tannin, the phlobaphen, or the bitter +principle individually, or upon them all collectively, that the effect +of the hops in brewing depends. + +It is the rule to judge the strength and goodness of hops by the amount +of farina--the so-called lupuline; and as this contains the major +portion of the active constituents of the hop, there is no doubt that +approximately the amount of lupuline is a useful quantitative test. But +here we are confronted by the question whether the lupuline is to be +regarded as containing _all_ that is of any value in the hops and the +leaves, the organic principles in which pass undetected under such a +test, as supererogatory for brewers' purposes? Practical experience +negatives any such conclusion. Consequently, we are justified in +assuming that the concurrent development and the presence of the several +organic principles--the oil, the wax, the bitter, the tannin, the +phlobaphen, in the choicer sorts--are subject, within certain limits, to +variations depending on skilled culture and careful drying, and that the +aggregate of these principles has a certain attainable maximum in +the finer sorts, under the most favorable conditions of culture, and +another, lower maximum in less perfectly cultivated and wild sorts. The +difference in the proportion of active organic substance in each sort +must be determined by analysis. There then remains to be discovered +which of the aforesaid substances plays the leading role in brewing, and +also whether the presence of chlorophyl and inorganic salts in the hop +extract influences or alters the results. + +That in brewing hops cannot be replaced by lupuline alone, even when the +latter is employed in relatively large quantities is well known, as also +that a considerable portion of the bitter principle of the hop is found +in the floral leaves. Neither can the lupuline be regarded as the only +active beer agent, as both the hop-tannin and the hop-resin serve to +precipitate the albuminous matter, and clarify and preserve the beer. + +Both chemists and brewers would gladly welcome some method of testing +hops, which should be expeditious, and afford reliable results in +practical hands. To accomplish this account must be taken of all the +active organic constituents of the hops, which can be extracted either +with ether, alcohol, or water containing soda (for the conversion of the +hop tannin in phlobaphen).[1] It should further be ascertained whether +the chlorophyl percentage in the hop bells, new and old, is or is not +the same in cultivated and in wild hops, and whether the aggregate +percentages of organic and constituent observe the same limits. + +[Footnote 1: See C. Etti, in "Dingler's Polytech. Journ.," 1878, p. +354.] + +As wild hops nowadays are frequently introduced in brewing, the +proportion of chlorophyl and organic and inorganic constituents in them +should be compared with those of cultivated sorts, taking the best +Bavarian or Bohemian hops as the standard of measurement. The chlorophyl +is of minor importance, as it has little effect on the general results. + +By a series of comparative analysis of cultivated and wild hops, in +which I would lay especial stress on parity of conditions in regard +of age and vegetation, the extreme limits of variation of which their +active organic principles are susceptible could be determined. + +There is every reason to suppose that the chlorophyl and inorganic +constituents do not differ materially in the most widely different sorts +of hops. The more important differences lie in the proportions of hop +resin and tannin. When this is decided, the proportion of tannin or +phlobaphen in the hop extract or the beer can be determined by analysis +in the ordinary way. But whenever some quick and sure hop test shall +have been found, _appearance and aroma_ will still be most important +factors in any estimate of the value of hops. Here a question arises as +to whether hops from a warm or even a steppe climate, like that of +South Russia, contain the same proportion of ethereal oil--that is, of +aroma--as those from a cooler climate, like Bavaria and Bohemia, or +like certain other fruit species of southern growth, they are early +in maturing, prolific, large in size, and abounding in farina, but +_deficient in aroma_. + +The bearings of certain experimental data on this point I reserve for +consideration upon a future occasion.--_The Analyst_. + + * * * * * + + + + +WATER GAS. + +A DESCRIPTION OF APPARATUS FOR PRODUCING CHEAP GAS, AND SOME NOTES ON +THE ECONOMICAL EFFECT OF USING SUCH GAS WITH GAS MOTORS, ETC. + +[Footnote: Abstract of paper read in Section G. British Association, +York] + +By MR. J. EMERSON DOWSON, C.E., of London. + + +In many countries and for many years past, inventors have sought +some cheap and easy means of decomposing steam in the presence of +incandescent carbon in order to produce a cheap heating gas; and working +with the same object the writer has devised an apparatus which has been +fitted up in the garden of the Industrial Exhibition, and is there +making gas for a 31/2 horse power (nominal) Otto gas engine. The retort or +generator consists of a vertical cylindrical iron casing which incloses +a thick lining of ganister to prevent loss of heat and oxidation of the +metal, and at the bottom of this cylinder is a grate on which a fire is +built up. Under the grate is a closed chamber, and a jet of superheated +steam plays into this and carries with it by induction a continuous +current of air. The pressure of the steam forces the mixture of steam +and air upward through the fire, so that the combustion of the fuel is +maintained while a continuous current of steam is decomposed, and in +this way the working of the generator is constant, and the gas is +produced without fluctuations in quality. The well-known reactions +occur, the steam is decomposed, and the oxygen from the steam and air +combines with the carbon of the fuel to form carbon dioxide (CO_2), +which is reduced to the monoxide (CO) on ascending the fuel column. +In this way the resulting gases form a mixture of hydrogen, carbon, +monoxide, and nitrogen, with a small percentage of carbon dioxide which +usually escapes without reduction. The steam should have a pressure of +11/2 to 2 atmospheres, and is produced and superheated in a zigzag coil +fed with water from a neighboring boiler. The quantity of water required +is very small, being only about 7 pints for each 1,000 cubic feet of +gas, and, except on the first occasion when the apparatus is started, +the coil is heated by some of the gas drawn from the holder, so that +after the gas is lighted under the coil the superheater requires no +attention. + +For boiler and furnace work the gas can be used direct from the +generator; but where uniformity of pressure is essential, as for gas +engines, gas burners, etc., the gas should pass into a holder. The +latter somewhat retards the production, but the steam injector causes +gas to be made so rapidly that a holder is easily filled against a back +pressure of 1 in. to 11/2 in. of water, and at this pressure the generator +can pass gas continuously into the holder, while at the same time it is +being drawn off for consumption. + +The nature of the fuel required depends on the purpose for which the gas +is used. If for heating boilers, furnaces, etc, coke or any kind of coal +maybe used; but for gas engines or any application of the gas requiring +great cleanliness and freedom from sulphur and ammonia it is best to use +anthracite, as this does not yield condensable vapors, and is very free +from impurities. Good qualities of this fuel contain over 90 per cent of +carbon and so little sulphur that, for some purposes, purification is +not necessary. For gas engines, etc., it is, however, better to pass +the gas through some hydrated oxide of iron to remove the sulphureted +hydrogen. The oxide can be used over and over again after exposure to +the air, and the purifying is thus effected without smell or appreciable +expense. Gas made by this process and with anthracite coal has no tar +and no ammonia, and the small percentage of carbon dioxide present does +not sensibly affect the heating power. A further advantage of this gas +is that it cannot burn with a smoky flame, and there is no deposition of +soot even when the object to be heated is placed over or in the flame, +and this is of importance for the cylinder and valves of a gas engine. + +To produce 1,000 cubic feet only 12 lb. of anthracite are required, +allowing 8 to 10 per cent, for impurities and waste; thus a generator +A size, which produces 1,000 cubic feet per hour, needs only 12 lb. in +that time, and this can be added once an hour or at longer intervals. No +skilled labor is necessary, and in practice it is usual to employ a man +who has other work to attend to near the generator, and to pay him a +small addition to his usual wages. + +The comparative explosive force of coal gas and the Dowson gas +calculated in the usual way is as 3.4:1, i. e., coal gas has 3.4 times +more energy than the writer's gas. Messrs. Crossley, of Manchester, the +makers of the Otto gas engines, have made several careful trials of this +gas with some of their 31/2 horse power (nominal) engines, and in one +trial they took diagrams every half-hour for nine consecutive days. +These practical trials have shown that without altering the cylinder of +the engine it is possible to admit enough of the Dowson gas to give +the same power as with ordinary coal gas. It has been seen that the +comparative explosive force of the two gases is as 3.4:1, but as it is +well known the combustion of carbon monoxide proceeds at a comparatively +slow rate, and for this reason, and because of the diluents present in +the cylinder which affect the weaker gas more than coal gas, experience +has shown that it is best to allow five volumes of the Dowson gas for +one volume of coal gas, and then the same uniform power is obtained as +with the latter. + +This gives very important economical results; for if the cost of the +Dowson gas given in the tables as 41/4d., 3-1/3d., and 23/4d. per 1,000 +cubic feet, be multiplied by 5 there will be 1s. 91/4d., 1s. 43/4d., and 1s. +23/4d., or a mean of 1s. 51/2d. for the equivalent of 1,000 cubic feet of +coal gas, which usually costs from 3s. to 4s., and this represents an +actual saving of about 50 to 60 per cent, in working cost. Another +practical consideration is that coal gas requires 224 lb. to 250 lb. of +coal per 1,000 cubic feet of gas, but the writer requires only 12 lb. +per 1,000 cubic feet, and multiplying this by 5 to give the equivalent +of 1,000 cubic feet of coal gas, for engine work, there are 60 lb. +instead of 224 lb. to 250 lb. This is only 24 to 27 per cent, of the +weight of the coal required for coal gas, and in many outlying districts +this will effect an appreciable saving in the cost of transport. + + +APPENDIX. + + TABLE I. + + _Generator A Size_ (producing 1,000 cubic feet per hour): + Anthracite to make gas at the rate of 1,000 s. d. + cubic feet per hour=l2 lb x 9 working + hours=l08 lb., or say, 1 cwt. at 20s. a + ton.................................... 1 0 + Allowance for wages of attendant......... 1 0 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent. on Ll25)= + per working day........................ 0 5 + Interest on capital outlay, ditto........ 0 5 + ______ + + Total........................... 2 10 + cub. ft. + + Gas produced............................. 9.000 + Less gas used for generating and + superheating steam..................... 1,000 + _____ + Total effective gas for 2s. 10d. 8,000 + + Net cost 41/4 d. per 1,000 cubic feet. + + TABLE II. + + _Generator B Size_ (producing 1,500 cubic feet per hour) + Anthracite to make gas at the rate of 1,500 s. d. + cubic feet per hour=18 lb. x 9 working + hours=162 lb., or, say, 11/2 cwt. 20s. + a ton.................................. 1 6 + Allowance for wages of attendant......... 1 0 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent, on L140) + =per working day....................... 0 51/2 + Interest on capital outlay, ditto........ 0 51/2 + ___ ___ + Total........................... 3 5 + cub. ft. + Gas produced............................. 13,500 + Less gas used for generating and + superheating steam..................... 1,200 + ______ + Total effective gas for 3s. 5d.. 12,300 + + Net cost 3 1/3d. per 1,000 cubic feet. + + TABLE III. + + _Generator C Size_ (producing 2,500 cubic feet per hour): + Anthracite to make gas at the rate of 2,500 s. d. + cubic feet per hour=30 lb. x 9 working + hours=270 lb. at 20s. a ton............ 2 41/2 + Allowance for wages of attendant....... 1 6 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent, on L160)= + per working day...................... 0 61/2 + Interest on capital outlay, ditto...... 0 61/2 + _______ + Total......................... 4 111/2 + + cub. ft. + Gas produced........................... 22,500 + Less gas used for generating and + superheating steam................... 1,500 + ______ + Total effective gas for 4s. 111/2d 21,000 + + Net cost, say, 23/4 d. per 1,000 cubic feet. + + * * * * * + + + + +ON THE FLUID DENSITY OF CERTAIN METALS. + +[Footnote: Abstract of paper read before Section C (Chemical Science), +British Association meeting, York.] + +By PROFESSOR W. CHANDLER ROBERTS, F.R.S., and T. WRIGHTSON. + + +The authors described their experiments on the fluid density of metals +made in continuation of those submitted to Section B at the Swansea +meeting of the Association. Some time since one of the authors gave an +account of the results of experiments made to determine the density of +metallic silver, and of certain alloys of silver and copper when in a +molten state. The method adopted was that devised by Mr. R. Mallet, and +the details were as follows: A conical vessel of best thin Lowmoor plate +(1 millimeter thick), about 16 centimeters in height, and having an +internal volume of about 540 cubic centimeters, was weighed, first +empty, and subsequently when filled with distilled water at a known +temperature. The necessary data were thus afforded for accurately +determining its capacity at the temperature of the air. Molten silver +was then poured into it, the temperature at the time of pouring being +ascertained by the calorimetric method. The precautions, as regards +filling, pointed out by Mr. Mallet, were adopted; and as soon as the +metal was quite cold, the cone with its contents was again weighed. +Experiments were also made on the density of fluid bismuth; and two +distinctive determinations gave the following results: + + 10.005 ) + ) mean 10.039. + 10.072 ) + +The invention of the oncosimeter, which was described by one of the +authors in the "Journal of the Iron and Steel Institute" (No. II., +1879, p. 418), appeared to afford an opportunity for resuming the +investigation on a new basis, more especially as the delicacy of the +instrument had already been proved by experiments on a considerable +scale for determining the density of fluid cast iron. The following is +the principle on which this instrument acts: + +If a spherical ball of any metal be plunged below the surface of a +molten bath of the same or another metal, the cold ball will displace +its own volume of molten metal. If the densities of the cold and molten +metal be the same, there will be equilibrium, and no floating or sinking +effect will be exhibited. If the density of the cold be greater than +that of the molten metal, there will be a sinking effect, and if less a +floating effect when first immersed. As the temperature of the submerged +ball rises, the volume of the displaced liquid will increase or decrease +according as the ball expands or contracts. In order to register these +changes the ball is hung on a spiral spring, and the slightest change in +buoyancy causes an elongation or contraction of this spring which can +be read off on a scale of ounces, and is recorded by a pencil on a +revolving drum. A diagram is thus traced out, the ordinates of which +represent increments of volume, or, in other words, of weight of fluid +displaced--the zero line, or line corresponding to a ball in a liquid of +equal density, being previously traced out by revolving the drum without +attaching the ball of metal itself to the spring, but with all other +auxiliary attachments. By means of a simple adjustment the ball is kept +constantly depressed to the same extent below the surface of the liquid; +and the ordinate of this pencil line, measuring from the line of +equilibrium, thus gives an exact measure of the floating or sinking +effect at every stage of temperature, from the cold solid to the state +when the ball begins to melt. + +If the weight and specific gravity of the ball be taken when cold, +there are obtained, with the ordinate on the diagram at the moment of +immersion, sufficient data for determining the density of the fluid +metal; for + +W / W1 = D / D1 + +the volumes being equal. And remembering that + +W (weight of liquid) = W1 (weight of ball) + x + +(where x is always measured as +_ve_ or -_ve_ floating effect), there is +obtained the equation: + + D1 x ( W1 + x) + D = --------------- . + W1 + +[TEX: D = \frac{D_1 \times (W_1 +x)}{W_1}] + +The results obtained with metallic silver are perhaps the most +interesting, mainly from the fact that the metal melts at a higher +temperature, which was determined with great care by the illustrious +physicist and metallurgist, the late Henri St. Claire Deville, whose +latest experiments led him to fix the melting point at 940 deg. Cent. The +authors of the paper showed that the density of the fluid metal was 9.51 +as compared with 10.57, the density of the solid metal. Taking their +results generally, it is found that the change of volume of the +following metals in passing from the solid to the liquid state may be +thus stated: + + Specific Specific + Metal. Gravity, Gravity, Percentage of + Solid. Liquid. Change. + + Bismuth 9.82 10.055 Decrease of volume 2.3 + Copper 8.8 8.217 Increase " 7.1 + Lead 11.4 10.37 " " 9.93 + Tin. 7.5 7.025 " " 6.76 + Zinc 7.2 6.48 " " 11.10 + Silver 10.57 9.51 " " 11.20 + Iron 6.95 6.88 " " 1.02 + + * * * * * + + + + +HYDROPHOBIA PREVENTED BY VACCINATION. + + +M. Pasteur and other French savants have lately been devoting special +attention to hydrophobia. The great authority on germs has, in fact, +definitely announced that he does not intend to rest until he has made +known the exact nature and life-history of this terrible disease, and +discovered a means of preventing or curing it. The most curious result +yet attained in this direction, however, has been announced by Professor +V. Galtier, of the Lyons Veterinary School. This inquirer has found, in +the first place, that if the virus of rabies be injected into the veins +of a sheep, the animal does not subsequently exhibit any symptoms of +hydrophobia. This in itself would be a sufficiently curious result +to justify attention, though its importance, except as confirmatory +testimony, becomes less striking when it is remembered that M. Pasteur +has lately shown that the special _nidus_ of the disease appears to be +the nervous tissue, and particularly the ganglionic centers. But there +is this further curious consequence: sheep who have thus been treated +through the blood, and who are afterwards inoculated in the ordinary +way through the cellular tissue, as if by a bite, are proof against +the disease. It is as though the injection into the veins acted as a +vaccine. Twenty sheep were experimented upon; ten only were treated to +the venous injection, and then all were inoculated through the cellular +tissue. The ten which had been first "vaccinated" continue alive and +well; they have not even shown any adverse symptoms. The other ten have +all died of rabies. It remains to say why M. Galtier experimented +upon sheep, and not upon dogs and cats, which usually communicate the +disease. The incubation of the disease is much more rapid and less +capricious in the sheep than in the dog or in man, and hence M. Galtier +was able to get his results more certainly within a short period. Having +succeeded so far, he is now justified in undertaking the more protracted +series of observations which experiments upon the canine species will +involve; and this he proposes to do. Experiments of this nature are not +without a serious risk, and admiration is almost equally due to the +courage and the intelligence of the experimentalist. But what will the +anti-vaccinator say?--_Pall Mall Gazette_. + + * * * * * + + + + +ON DIPTERA AS SPREADERS OF DISEASE. + +By J.W. SLATER. + + +The two-winged flies, in their behavior to man, stand in a marked +contrast to all the other orders of insects. The Lepidoptera, the +Coleoptera, the Neuroptera, the Hymenoptera no doubt occasion, in some +of their forms at least, much damage to our crops. But none of them are +parasitic in or upon our bodies; none of them persistently intrude into +our dwellings, hover around us in our walks, and harass us with noise +and constant attempts to bite, or at least to crawl upon us. Even the +ants, except in a few tropical districts, rarely act upon the offensive. +The Hemiptera contain one semi-parasitic species which has attained a +"world-wide circulation," and one degraded, purely parasitic group. +But the Diptera, among which the fleas are now generally included as a +degenerated type, comprise more forms personally annoying to man than +all the remaining insect orders put together. These hostile species are, +further, incalculably numerous, and occur in every part of the globe. +Mosquitoes swarm not merely in the swampy forests of the Orinoco or the +Irrawaddy, but in the Tundras of Siberia, en the storm-beaten rocks of +the Loffodens, and are even encountered by voyagers in quest of the +North Pole. The common house fly was probably at one time peculiar to +the Eastern Continent, but it followed the footsteps of the Pilgrim +Fathers, and is now as great a nuisance in the United Slates and the +Dominion as in any part of Europe. It is curious, but distressing, to +note the tendency of evils to become international. We have communicated +to America the house-fly and the Hessian fly, the "cabbage-white," +the small pox, and the cholera. She, in return, has given us the +_Phylloxera_, a few visitations of yellow fever, the _Blatta gigantea_, +and, climate allowing, may perhaps throw in the Colorado beetle as a +make-weight. In this department, at least, free trade reigns undisputed. +It is a singular thing that no beautiful, useful, or even harmless +species of bird or insect seems capable of acclimatizing itself as do +those characterized by ugliness and noisomeness. + +But, returning from this digression, we find in the Diptera the habit of +obtrusion and intrusion, of coming in actual contact with our food and +our persons, combined with another propensity--that of feeding upon +carrion, excrement, blood, pus, and morbid matter of all kinds. This +is a combination far more serious than is generally imagined. If the +fly--which may at any moment settle upon our lips, our eyes, or upon +an abraded part of our skin--were cleanly in its habits, we need feel +little annoyance at its visits. Or if it were the most eager carrion +devourer, but did not, after having dined, think it necessary to +seek our company, we might hold it, as is done too hastily by some +naturalists, a valuable scavenger. I fear, however, that I have already +made too great a concession. So long as very many persons are suffering +from disease--so long as many diseases are capable of being transmitted +from the sick to the healthy--so long must any creature which is in the +habit of flying about, and touching first one person and then another, +be a possible medium of infection and death. + +Let us take the following case, by no means imaginary, but a +generalization from occurrences far too frequent: A healthy man, sitting +in his house or walking in the fields, especially in countries where the +insectivorous birds have been shot down, suddenly feels a sharp prick on +his neck or his cheek. Putting his hand to the place he perhaps crushes, +perhaps merely brushes away, a fly which has bitten him so as to draw +blood. The man thinks little of so trifling a hurt, but the next morning +he finds the puncture exceedingly painful. An inflamed pimple forms, +which quickly gets worse, while constitutional symptoms of a feverish +kind come on. In alarm he seeks medical advice. The doctor tells him +that it is a malignant pustule, and takes at once the most active +measures. In spite of all possible skill and care the patient too often +succumbs to the bite of a _mouche charbonneuse_, or carbuncle-fly. But +has any kind of fly the property of producing malignant pustule by +some specific inherent power of its own? Surely not. The antecedent +circumstances are these: A sheep or heifer is attacked with the disease +known in France as _charbon_, in Germany as _milz-brand_, and in England +as _splenic fever_. Its blood on examination would be found plentifully +peopled with bacteria. If a lancet were plunged into the body of the +animal, and were then used to slightly scratch or cut the skin of a man, +he would be inoculated with "charbon." The bite of the fly is precisely +similar in its action. Its rostrum has been smeared with the poisoned +blood, an infinitesimal particle of which is sufficient to inclose +several of the disease "germs," and these are then transferred to the +blood of the next man or animal which the fly happens to bite. The +disease is reproduced as simply and certainly as the spores of some +species of fern give rise to their like if scattered upon soil suitable +for their growth. But flies which do not bite may transfer infection. +Every one must know that if blood be spilt upon the ground a crowd of +flies will settle upon and eagerly absorb it. Animals suffering from +splenic fever in the later stages of the disease sometimes emit bloody +urine. Often they are shot or slaughtered by way of stamping out the +plague, and their carcasses are buried deep in the ground. But some loss +of blood is sure to happen, and this will mostly be left to soak into +the ground. Here again the flies will come, and their feet and mouth +will become charged with the contagion. Such a fly, settling upon +another animal or a man, and selecting--as it will do by preference, if +such exist--a wound, or a place where the skin is broken, will convey +the disease. + +Again, M. Pasteur has thoughtfully pointed out that if an animal has +died of splenic fever, and has been carefully buried, the earth-worms +may bring up portions of infectious matter to the surface, so that sheep +grazing, or merely being folded over the spot in question, may take the +plague and die. Hence be wisely counsels that the bodies of such animals +should be buried in sandy or calcareous soils where earth-worms are not +numerous. But it is perfectly legitimate to go a step farther. If such +worm-borings retain the slightest savor of animal matter, flies will +settle upon them and will convey the infectious dust to the most +unexpected places, giving wings to the plague. + +Now it is very true that no one has seen a fly feasting upon the blood +of a heifer or sheep dying or just dead of splenic fever, has then +watched it settle upon and bite some person, and has traced the +following stages of the disease. But it is positively known that a +person has been bitten by a fly, and has then exhibited all the symptoms +of charbon, the place of the bite being the primary seat of the +infection. We know also, beyond all doubt, the eagerness with which +flies will suck up blood, and we likewise know the strange persistence +of the disease "germs." + +Again, the avidity of flies for purulent matter is not a thing of mere +possibility. In Egypt, where ophthalmia is common, and where the "plague +of flies" seems never to have been removed, it is reported as almost +impossible to keep these insects away from the eyes of the sufferers. +The infection which they thus take up they convey to the eyes of persons +still healthy, and thus the scourge is continually multiplied. + +A third case which seems established beyond question is the agency of +mosquitoes in spreading elephantiasis. These so-called sanitary agents +suck from the blood of one person the Filariae, the direct cause of the +disease, and transfer them to another. The manner in which this process +is effected will appear simple enough if we reflect that the mosquito +begins operations by injecting a few drops of fluid into its victim, so +as to dilute the blood and make it easier to be sucked. + +So much being established it becomes in the highest degree probable that +every infectious disease may be, and actually is, at times propagated +by the agency of flies. Attention turned to this much neglected quarter +will very probably go far to explain obscure phenomena connected with +the distribution of epidemics and their sudden outbreaks in unexpected +quarters. I have seen it stated that in former outbreaks of pestilence +flies were remarkably numerous, and although mediaeval observations on +Entomology are not to be taken without a grain of salt, the tradition +is suggestive. Perhaps the Diptera have their seasons of unusual +multiplication and emigration. A wave of the common flea appears to have +passed over Maidstone in August, 1880. + +We now see the way to some practical conclusions not without importance. +Recognizing a very considerable part of the order of Diptera, or +two-winged flies, as agents in spreading disease, it surely follows +that man should wage war against them in a much more systematic and +consistent manner than at present. The destruction of the common +house-fly by "_papier Moure_," by decoctions of quassia, by various +traps, and by the so-called "catch 'em alive," is tried here and there, +now and then, by some grocer, confectioner, or housewife angry at the +spoliation and defilement caused by these little marauders. But there +is no concerted continuous action--which after all would be neither +difficult nor expensive--and consequently no marked success. Experiments +with a view of finding out new modes of fly-killing are few and far +between. + +Every one must occasionally have seen, in autumn, flies as if cemented +to the window-pane, and surrounded with a whitish halo. That in some +seasons numbers of flies thus perish--that the phenomenon is due to a +kind of fungus, the spores of which readily transfer the disease from +one fly to another--we know. But here our knowledge is at fault. We +have not learnt why this fly-epidemic is more rife in some seasons than +others. We are ignorant concerning the methods of multiplying this +fungus at will, and of launching it against our enemies. We cannot tell +whether it is capable of destroying _Stomoxys calcitram_, the blowflies, +gadflies, gnats, mosquitoes, etc. Experiment on these points is rendered +difficult by the circumstance that the fungus is rarely procurable +except in autumn, when some of the species we most need to destroy are +not to be found. Another question is whether the fungus, if largely +multiplied and widely spread, might not prove fatal to other than +Dipterous insects, especially to the Hymenoptera, so many of which, +in their character of plant-fertilizers, are highly useful, or rather +essential to man. + +Another fungus, the so-called "green muscardine" (_Isaria destructor_), +has been found so deadly to insects that Prof. Metschnikoff, who is +experimenting upon it, hopes to extirpate the _Phylloxera_, the Colorado +beetle, etc., by its agency. + +Coming to better known and still undervalued fly-destroyers, we have +interfered most unwisely with the balance of nature. The substitution of +wire and railings for live fences in so many fields has greatly lessened +the cover both for insectivorous birds and for spiders. The war waged +against the latter in our houses is plainly carried too far. Whatever +may be the case at the Cape, in Australia, or even in Southern Europe, +no British species is venomous enough to cause danger to human beings. +Though cobwebs are not ornamental, save to the eye of the naturalist, +there are parts of our houses where they might be judiciously tolerated: +their scarcity in large towns, even where their prey abounds, is +somewhat remarkable. + +But perhaps the most effectual phase of man's war against the flies will +be negative rather than positive, turning not so much on putting to +death the mature individuals as in destroying the matter in which the +larvae are nourished. Or if, from other considerations, we cannot +destroy all organic refuse, we may and should render it unfit for the +multiplication of these vermin. We have, indeed, in most of our large +towns and in their suburbs, abolished cesspools, which are admirable +breeding-places for many kinds of Diptera, and which sometimes presented +one wriggling mass of larvae. We have drained many marshes, ditches, +and unclean pools, rich in decomposing vegetable matter, and have thus +notably checked the propagation of gnats and midges. I know an instance +of a country mansion, situate in one of the best wooded parts of the +home counties, which twenty years ago was almost uninhabitable, owing to +the swarms of gnats which penetrated into every room. But the present +proprietor, being the reverse of pachydermatous, has substituted covered +drains for stagnant ditches, filled up a number of slimy ponds as +neither useful nor ornamental, and now in most seasons the gnats no +longer occasion any annoyance. + +But if we have to some extent done away with cesspools and ditches, and +have reaped very distinct benefit by so doing, there is still a grievous +amount of organic matter allowed to putrefy in the very heart of our +cities. The dust bins--a necessary accompaniment of the water-carriage +system of disposing of sewage--are theoretically supposed to be +receptacles mainly for organic refuse, such as coal-ashes, broken +crockery, and at worst the sweepings from the floors. In sober fact +they are largely mixed with the rinds, shells, etc., of fruits and +vegetables, the bones and heads of fish, egg-shells, the sweepings out +of dog-kennels and henhouses, forming thus, in short, a mixture of evil +odor, and well adapted for the breeding-place of not a few Diptera. + +The uses to which this "dust" is put when ultimately fetched away are +surprising: without being freed from its organic refuse it is used to +fill up hollows in building-ground, and even for the repair of roads. A +few weeks ago I passed along a road which was being treated according +to the iniquity of Macadam. Over the broken stones had been shot, to +consolidate them, a complex of ashes, cabbage-leaves, egg and periwinkle +shells, straw, potato-parings, a dead kitten (over which a few +carrion-flies were hovering), and other promiscuous nuisances. The road +in question, be it remarked, is highly "respectable," if not actually +fashionable. The houses facing upon it are severely rated, and are +inhabited chiefly by "carriage people." What, then, may not be expected +in lower districts? + +Much attention has lately been drawn to the fish trade of London. It has +_not_, however, come out in evidence that the fish retailers, if they +find a quantity of their perishable wares entering into decomposition, +send out late in the evening a messenger, who, watching his opportunity, +throws his burden down in some plot of building land, or over a fence. +When I say that I have seen in one place, close alongside a public +thoroughfare, a heap of about fifty herrings, in most active +putrefaction and buzzing with flies, and some days afterward, in another +place, some twenty soles, it will be understood that such nuisances +can only be occasioned by dealers. To get rid of, or at least greatly +diminish, carrion-flies, house-flies, and the whole class of winged +travelers in disease, it will be, before all things, essential to +abolish such loathsome malpractices. The dustbins must cease being made +the receptacle for putrescent and putrescible matter, the destruction of +which by fire should be insisted upon. + +The banishment of slaughter-houses to some truly rural situation, where +the blood and offal could be at once utilized, would be another step +toward depriving flies of their pabulum in the larva state. An equally +important movement would be the substitution of steam or electricity for +horsepower in propelling tram-cars and other passenger carriages, with a +view to minimize the number of horses kept within greater London. Every +large stable is a focus of flies--_Journal of Science_. + + * * * * * + + + + +ON THE RELATIONS OF MINUTE ORGANISMS TO CERTAIN SPECIFIC DISEASES. + + +At the recent Medical Congress in London, Professor Klebs undertook to +answer the question: "Are there specific organized causes of disease?" + +A short historical review of the various opinions of mankind as to the +origin of disease led, the speaker thought, to the presumption that +these causes were specific and organized. + +If we now, he said, consider the present state of this question, the +three following points of view present themselves as those from which +the subject may be regarded: + +I.--We have to inquire whether the lower organisms, which are found in +the diseased body, may arise there spontaneously; or whether even they +may be regarded as regular constituents of the body. + +II.--The morphological relations of these organisms have to be +investigated, and their specific nature in the different morbid +processes has to be determined. + +III.--We have to inquire into their biological relations, their +development inside and outside the body, and the conditions under which +they are able to penetrate into the body, and there to set up disease. + +_First_.--With regard to the first question, that of the possibility of +spontaneous generation, the speaker gave a decided negative. + +_Second and third_.--There is in microscopic organisms a difference of +form corresponding, as a rule, to difference of function. The facts +regarding these various lower forms are briefly reviewed. + +"Three groups of hyphomycetae, algae, and schizomycetae, have been +demonstrated to occur in the animal and human organism in infective +diseases. Their significance increases with the increase of their +capacity for development in the animal body. This depends partly upon +their natural or ordinary conditions of life, but partly also, and that +in a very high degree, upon their power of adaptation, which, as Darwin +has shown, is a property of all living things, and causes the production +of new species with new active functions. + +"1. The hyphomycetae, on account of their needing an abundant supply +of oxygen, give rise to but few morbid processes, and these run their +course on the surface of the body, and are hence relatively of less +importance. It will be sufficient here to refer to the forms, achorion, +trichophyton, oidium, aspergillus, and the diseases produced by them, +favus, ringworm, and thrush, to show this peculiarity. Nevertheless, we +see that these organisms also (as was proved by the older observations +of Hannover and Zenker) may, under certain circumstances, penetrate into +the interior of the organs. Grawitz, moreover, has recently shown that +their faculty of penetrating into the interior of the organism, and +there undergoing further development, depends on their becoming +accustomed to nitrogenous food. + +"2. Only one of the algae, viz., leptothrix, has as yet acquired any +importance as a producer of disease. It gives rise to the formation of +concretions, and that not only in the mouth, but also, as I have shown, +in the salivary ducts and urinary bladder. + +"Another alga, the sarcina of Goodsir, may indeed pass through the +organism, without, however, producing in its passage either direct +or indirect disturbances. It seems more worthy of note that many +schizomycetae, and especially the group of bacilli, are evidently nearly +allied to the algae in their morphological and vegetative relations--so +as to be assigned to this class by several authors, and especially by +Cienkowski. + +"The schizomycetae furnish, without doubt, by far the most numerous +group of infective diseases. We distinguish within this group two +widely different series of forms, which we will speak of as bacilli and +cocco-bacteria respectively. The former, which was first exhaustively +described by Ferdinand Cohn, and the pathological importance of which, +especially in relation to the splenic disease of cattle, was first shown +by Koch, consist of threads, in the interior of which permanent or +resting-spores are developed. These spores becoming free, are able, +under suitable conditions of life, again to develop into threads. The +whole development of these organisms, and especially the formation +of spores, is completed on the surface of the fluids, and under the +influence of an abundant supply of oxygen. + +"The number of affections in which these organisms have been found, +and which may be to a certain extent produced artificially by the +introduction of these organisms into healthy animal bodies, has been +largely increased since the discovery of Koch, that the bacteria of +splenic fever (anthrax) belong to this group. Under this head must be +placed the bacillus malarise (Klebs and Tommassi-Crudeli), the bacillus +typhi abdominalis (Klebs, Ebert), the bacillus typhi exanthematici +(Klebs, observations not yet published), the bacillus of hog-cholera +(Klein), and, finally the bacillus leprosus (Neisser). It would exceed +the time appointed were I to attempt to describe these forms more +minutely. This may, perhaps, be better reserved for discussion and +demonstration. + +"Alongside of these general infective diseases produced by bacilli, +local affections also occur, which indicate the presence of these +organisms at the point where disease begins. As an example of these +processes, which probably occur in various organs, I would mention +gastritis bacillaris, of which I shall show you preparations. In this, +we can trace the entrance of the bacilli into the peptic glands, as well +as their further distribution in the walls of the stomach, and in the +vascular system. + +"The second group of the pathogenetic schizomycetae I propose to call, +with Billroth, cocco-bacteria, because they consist of collections of +micrococci, which are capable of transforming themselves into short +rods. The former usually form groups united by zooegloea; by prolongation +of the cocci rods are formed, which sprout out, break up by division +into chains, and further lead again to the formation of resting masses +of cocci. I distinguish, further, in this group, two genera--the +microsporina and the monadina; in the former of which the micrococci are +collected into spherical lumps, in the latter into layers. The one class +is developed in artificial cultivation fluid, the other on the surface. +The former requires a medium poor in oxygen, the latter a medium rich in +oxygen, for their development. + +"Among the affections produced by microsporina, I reckon especially the +septic processes, and also true diphtheria. On the other hand, to the +processes produced by monadina belong especially a large series of +diseases, which according to their clinical and anatomical features, +may be characterized as inflammatory processes, acute exanthemata, and +infective tumors, or leucocytoses. Of inflammatory processes, those +belong here which do not generally lead to suppuration, such as +rheumatic affections, including the heart, kidney, and liver affections, +which accompany this process, sequelae which, as is well known, +lead more especially to formation of connective tissue, and not to +suppuration. Here, also, belong croupous pneumonia, the allied disease +erysipelas, certain puerperal processes, and finally, parotitis +epidemica, or mumps. + +"Among the acute exanthemata, the following may, up to the present time, +be placed in this group; variola-vaccina, scarlatina, and measles. + +"The group of infective tumors is represented by tuberculosis, syphilis, +and glanders. Throughout the whole group of cocco-bacteria the +demonstration of organisms in the diseased parts encounters difficulties +which vary considerably in the different kinds." + +The speaker concluded by describing the methods (now well known) by +which the powers of the different organisms are tested. + +He also referred to Pasteur's, Chauveau's, and Toussaint's recent +experiments. + +His conclusion was that the specific communicable diseases are produced +by specific organisms. + + * * * * * + + + + +THE CENTENARY OF THE DISCOVERY OF URANUS. + +By W. F. DENNING, F.R.A.S. + + +The year 1781 was signalized by an astronomical discovery of great +importance, and one which marked the epoch as memorable in the annals +of science. A musician at Bath, William Herschel by name, who had been +constructing some excellent telescopes and making a systematic survey of +the heavens, observed an object on the night of March 13 of that year, +which ultimately proved to be a large planet revolving in an orbit +exterior to that of Saturn. The discovery was as unique as it was +significant. Only five planets, in addition to the Earth, had hitherto +been known; they were observed by the ancients, and by each succeeding +generation, but now a new light burst upon men. The genius of Herschel +had singled out from the host of stars which his telescope revealed +an object the true character of which had evaded human perception for +thousands of years! + +[Illustration: FIG. 1.--APPROXIMATE PLACE OF URANUS AMONGST THE STARS AT +ITS DISCOVERY ON MARCH 13, 1781] + +The centenary of this remarkable advance in knowledge naturally recalls +to mind the circumstances of the discovery, and makes us inquisitive to +know what new facts have been gleaned of Herschel's planet, now that +a hundred years have passed away, and we are enabled to look back and +review the vast amount of labor which has been accomplished in this wide +and attractive field of astronomical research. We may learn what new +features have been discerned of the new body, and what additional +discoveries in connection with other planets unknown in Herschel's day, +have been effected by aid of the powerful telescopes which have been +devoted to the work. We do not, however, intend dealing with the general +question of planetary discovery, for at a glance we are impressed with +its magnitude. While a century ago five planets only were known, we now +have some two hundred and thirty of these bodies, and the stream of +discovery flows on without abatement through each succeeding year. The +detection of Uranus seems, indeed, to have been the prelude to many +similar discoveries, and to have offered the incentive to greater +diligence and energy on the part of observers in various parts of the +world. + +[Illustration: Fig. 2.--ORBITS OF THE URANIAN SATELLITES.] + +Many great discoveries have resulted from accident; and the leading +facts attending that of Uranus prove that, in a large measure, the +result was brought about in a similar way. Herschel, as he unwearyingly +swept the heavens night after night, was in quest of sidereal +wonders--such as double stars and nebulae--and he happened to alight +upon the new planet in a purely chance way. He had no expectation of +finding such a remarkable object, and indeed, when he had found it, +wholly mistook its character. There could be no doubt that it was a body +wholly dissimilar to the fixed stars, and it was equally certain that it +could not be a nebula. It had a perceptible disk, for when it had first +come under the critical eye of its discoverer he had noticed immediately +that its appearance differed widely from the multitude of objects which +crossed the field of his telescope. He had been accustomed to see hosts +of stars pass in review, and their aspect was in one respect similar, +namely, they were invariably presented as points of light incapable of +being sensibly magnified, even with the highest powers. True, there was +a great variety of apparent brightness in these objects and a singular +diversity of configuration, but there was no exception to the invariable +feature referred to. The point of light was constant, and no striking +exception was anticipated until one night--March 13, 1781--Herschel +being intently engaged in the examination of some small stars in the +region of Gemini, brought an object under the range of, his telescope, +which his eye at once selected as one of anomalous character. + +Applying a higher power, he noticed that it exhibited a planetary disk, +but his instrument failed to define it with sufficient distinctness, and +hence he became doubtful as to its real nature. The object was found to +be in motion, and subsequent observations led him to the assumption that +it must be a comet of rather exceptional type. This appeared to be the +best explanation of the strange body, for history contained many records +of curious comets, some of which were observed as nearly circular +patches of nebulous light, and probably of similar aspect to the object +then visible; and apart from this it must be remembered that the idea of +a large planet exterior to Saturn was a fact of such momentous import +that Herschel, with a due regard to that modesty which accompanies +true genius, refrained from attaching such an interpretation to his +observations. He was content to direct the notice of astronomers to it +as a phenomenon requiring close attention, and suggested that it might +be a comet in consequence of its motion and the faint and somewhat +ill-defined character of its appearance. + +From the earliest ages five planets only were known, and the discovery +of another large planet beyond the sphere of Saturn must at once +revolutionize existing ideas as to the range of the solar system, and +immediately take rank as a scientific event of equal interest to the +discovery of the moons of Jupiter or the rings of Saturn, which each in +their day impressed men with new ideas of the celestial mechanism. But +the truth could not long be delayed. The new body being watched and its +orbit rigorously computed from a series of observed positions revealed +its true character, and Herschel was awarded the honor due to the author +of a discovery of such importance. His diligence and pertinacity alone +had enabled him to search out from among the multitude of stars thickly +strewn over the firmament this unknown and well-nigh invisible planet +which, during all the preceding years of the world's history, had eluded +human perception. Men had been all unconscious of its existence as it +had been slowly completing its circuits around the sun, obedient to the +same laws as the other planets of the solar system, and awaiting the +hour when the unfailing eve of Herschel should introduce it as the faint +and far-off planet girding our system within its expansive folds. + +As soon as the existence of the new orb was confirmed and the fact +rendered indisputable, the question naturally arose whether it had ever +been seen in former years by the authors of star catalogues, who could +hardly have overlooked an object like this though its planetary nature +had manifestly escaped detection. It was just perceptible to the naked +eye, shining like a star of the sixth magnitude, and ought to have been +distinguished by those who had reviewed the heavens with the purpose +of determining and mapping the positions of the stars. Reference was, +therefore, made to the chief catalogues, when it was found at once that +the planet had been unquestionably observed by Tobias Mayer, Le Monnier, +Bradley, and Flamsteed. It was several times noted by these observers: +by Le Monnier no less than twelve times, and by Flamsteed on six +occasions; and it is remarkable that in every instance its true +character escaped detection. Neither its special appearance nor its +motion attracted attention, so that it was merely catalogued as an +ordinary fixed star. Thus Herschel was not anticipated in his discovery. +It remained for him, in 1781, to note its exceptional aspect, and to +specify it as an object requiring critical investigation. But the early +observations above alluded to served a useful purpose in testing the +accuracy of the computed orbit, for without waiting many years to +compare the theoretical and observed positions, astronomers had in these +old records a reliable series of points through which the previous +course of the planet could be traced. + +The calculations showed that its mean distance from the sun was some +1,750,000,000 miles, and that a revolution was completed in about +eighty-four years. It was also found to be a very large planet, greatly +exceeding either Mercury, Venus, the Earth, or Mars, though considerably +inferior to either Jupiter or Saturn. + +Here, then, was a discovery of the utmost importance, and one of the +most salient additions to our knowledge which the telescope had ever +achieved. The new planet was now definitely assigned its proper place in +the solar system, and was regarded as of equal significance with the +old planets. True, the new planet of Herschel could not be compared as +regards its visible aspect with the other previously known members of +our system, but it was nevertheless an object of equal weight. Its vast +distance alone rendered it faint. It formed one of the constituent parts +of the solar system, which, though separated by immense intervals of +space, are yet coherent by the far-reaching effects of gravitation. +There is, indeed, a bond of harmony between the series of planetary +orbits, which exhibit a marked degree of regularity in their successive +distances from the sun; and though they are not connected by any visible +links, they are firmly held together by unseen influences, and their +motions are subject to certain laws which have been revealed by +centuries of observation. + +The question of suitably naming the new planet soon came to the fore. +Herschel himself proposed to designate it the "Georgium Sidus," in honor +of his patron, George III., just as Galileo had called the satellites +of Jupiter the "Medicean stars," after Cosmo de' Medici. But La Place +proposed that the planet should be named after its discoverer; and thus +it was frequently referred to as "Herschel," and sometimes as "The +Herschelian planet." Astronomers on the continent objected to this +system of personal nomenclature, and argued that the new body should +receive an appellative in accordance with those adopted for the old +planets, which had been selected from the heathen mythology. Several +names were suggested as suitable (on the basis of this principle), and +ultimately the one advanced by Bode received the most favor, and the +planet thereafter was called "Uranus." + +The varying positions of the new body as observed on successive nights +were determined by comparisons with a group of six small stars, termed +by Herschel [Greek: alpha, beta, gamma, delta, epsilon] and afterwards +formed into a constellation under the designation of "Britannia," though +it does not appear that this little asterism is acknowledged as one of +our constellations. Its position is about midway between Taurus and +Gemini, and the following are the principal stars computed for 1881.0, +as given by Mr. Marth: + + Star. Magnitude. Right Ascension. Declination. + h. m. s. + alpha 9.0 5 42 6.06 23 deg. 35' 6.7" N. + eta 8.7 5 43 17.82 23 26' 7.2 N. + theta 8.8 5 44 0.99 23 53' 30.8 N. + epsilon 8.8 5 45 40.68 23 34' 46.8 N. + +The stars are therefore merely telescopic, and are confined to a small +area of space, so that the propriety of adopting the group as a distinct +constellation is very questionable. Their positions close to Uranus at +the time of its discovery, and the fact that the planet's motion was +detected by means of comparisons with them, has given to these stars an +historical interest which in future years must often attract the student +to their reobservation. But it would be unwise, as forming a bad +precedent, to accept a group of stars of this inferior type as meriting +to rank among the old constellations, when we have numbers of richer +groups, situated on their confines, which first deserve such a +distinction. However special or unique the circumstances connected with +certain telescopic stars may be, and however necessary it may appear +to signalize them by a specific title, we are inclined to question the +adoption of such means as likely to exercise a wrong influence, +inasmuch as it may hereafter originate further innovations of a similar +character, and ultimate complications will be certain to arise. + +Soon after the discovery of Uranus it was suspected that the planet +was encircled, like Saturn, by a luminous ring, but on subsequent +observation this was not confirmed, and no such appendage has ever been +revealed in the more perfected instruments of our own times. Indeed, if +Uranus displays a peculiarity of constitution in any way analogous to +the ring system of Saturn, it must be of the most minute character so as +to have thus evaded telescopic scrutiny during a hundred years. + +The discovery soon attracted the notice of royalty, and the reigning +sovereign, George III., anxious to practically express his appreciation +of the valuable labors of Herschel, awarded him a pension of L200 a year +and furnished him with a residence at Slough, near Windsor, and the +means to erect a gigantic telescope with which he might be enabled +to continue his important researches. This instrument consisted of a +reflector on the "Front-view" construction, with a speculum 4 feet in +diameter and of 40 feet focal length. Upon its completion, Herschel +immediately began to observe the region of the new planet with the idea +of discovering any satellites which might belong to it, for analogy +suggested that it was surrounded by a numerous retinue of such bodies. +He was soon successful, for, on the night of January 11, 1787. he saw +two minute objects near the planet, which renewed observations revealed +to be satellites; and he detected two additional ones in 1790, and two +others in 1794, making six in all. But the observations were of extreme +difficulty. The path of the planet frequently passed near minute stars, +and it became hard to distinguish between them and the suspected +satellites. Herschel, however, considered he had obtained conclusive +evidence of the existence of six satellites with sidereal periods +ranging from 5d. 21h. 25m. to 107d. 16h. 39m., and his means of +observation being much superior to those possessed by any of his +contemporaries it was impossible to have corroborative testimony. + +The matter was thus allowed to rest until the middle of the present +century, when Lassell, in the pure sky at Malta, endeavored to reobserve +the satellites with a two-foot reflector. This instrument was considered +superior to Herschel's telescope; and the atmosphere at this station +being decidedly more suitable for such delicate observations than +in England, it was removed there for the express purpose of dealing +successfully with objects of extreme difficulty. The results were very +important. Mr. Lassell became convinced that Uranus had only four +satellites, and that if any others existed they remained to be +discovered. Two of these were found to be identical with those seen by +Herschel in 1787, and now called Titania and Oberon. The other two, +Ariel and Umbriel, could not be identified with any of those alleged to +have been previously detected by Herschel, so that the inference was +that they were new bodies, and that the priority of discovery was due to +Mr. Lassell; whence it also followed that the older observations were +erroneous, and that in fact Herschel had been entirely mistaken with +regard to the four satellites he believed he had detected subsequently +to 1787. + +In November, 1873, a fine twenty-six-inch object glass, by Alvan Clark, +was mounted at the U. S. Naval Observatory at Washington, and it was +soon employed upon the difficult task of solving the problem as to the +exact periods of the Uranian satellites. This was very satisfactorily +effected, and with distinct and conclusive favor to Mr. Lassell, whose +observations were fully corroborated. Only four satellites could be +distinguished by the American observers, and their periods, as computed +from a valuable series of measures, agreed with those previously derived +at Malta. In Appendix I. to the "Washington Observations" for 1873, +Prof. Newcomb gave a valuable summary of results--the first obtained, be +it noted, with that splendid instrument which soon afterward, in 1877, +revealed the satellites of Mars--which included the elements of the +satellites of Uranus as follows: + + Mean Longitude. + + Satellite. Epoch 1871. Radius of Period of + Dec. 31, W.M.T. Orbit. Revolution in days. + I. Ariel........ 21.83 deg. 13.78" 2.52038 + II. Umbriel..... 13.52 19.20 4.14418 + III. Titania..... 229.93 31.48 7.70590 + IV. Oberon...... 154.83 42.10 13.43327 + +Speaking of the comparative brightness of the satellites, Prof. Newcomb +says: + +"The greater proximity of the inner satellites to the planet makes it +difficult to compare them photometrically with the outer ones, as actual +feebleness of light cannot be distinguished from difficulty of seeing +arising from the proximity of the planet. However, that Umbriel is +intrinsically fainter than Titania is evinced by the fact that, although +the least distance of the latter is somewhat less than the greatest +distance of the former, there is never any difficulty in seeing it in +that position. From their relative aspects in these respective positions +I judge Umbriel to be about half as bright as Titania. Ariel must be +brighter than Umbriel, because I have never seen the latter unless it +was farther from the planet than the former at its maximum distance.... +I think I may say with considerable certainty that there is no satellite +within 2' of the planet, and outside of Oberon, having one-third the +brilliancy of the latter, and therefore that none of Sir William +Herschel's supposed outer satellites can have any real existence. The +distances of the four known satellites increase in so regular a way that +it can hardly be supposed that any others exist between them. Of what +may be inside of Ariel it is impossible to speak with certainty, since +in the state of atmosphere which prevails during our winter all the +satellites named disappear at 10" from the planet." + +Prof. Newcomb mentions that no systematic search for new satellites +was undertaken because it must have interfered with the fullness and +accuracy of the micrometer measures of the old satellites, which +constituted the main purpose of the observations. Some faint objects +were occasionally glimpsed near the planet, and their relative places +determined, but they were never found to accompany Uranus. The fact, +therefore, that no additional satellites were discovered is not to +be regarded as a strong point in favor of the theory of their +non-existence, because the great power and excellence of the telescope +was expressly directed to the attainment of other ends; and moreover the +season in which the planet came to opposition was distinctly unfavorable +for the prosecution of a rigorous search for new satellites. There +can, however, be no doubt that the analogies of the planetary systems +interior to Uranus plainly suggest that this planet is attended by +several satellites which the power of our greatest telescopes has +hitherto failed to reveal; and that it is in this direction and that of +Neptune we may anticipate further discoveries in future years when the +conditions are more auspicious and the work is entered upon with special +energy, aided by instruments of even greater capacity than those which +have already so far conduced to our knowledge of the heavenly bodies. + +Notwithstanding the extreme difficulty with which the Uranian satellites +are observed, the two brighter ones, Titania and Oberon, discovered by +William Herschel in 1787, have been occasionally detected in telescopes +of moderate power, and identified by means of an ephemeris which has +shown that the computed positions approximately agree with those +observed. During the last few years Mr. Marth has published ephemerides +of the satellites of both Saturn and Uranus, and many amateurs have to +acknowledge the valuable aid rendered by these tables, which supply a +ready means of identifying the satellites, and thus act as an incentive +to observers who are induced to pursue such work for the sake of the +interesting comparisons to be made afterward. In one exceptional +instance the two outer satellites of Uranus appear to have been glimpsed +with an object glass of only 43 inches aperture, and the facts are given +in detail in the "Monthly Notices of the R.A.S.," April 1876, pp. 294-6. +The observations were made in January, February, and March, 1876, by +Mr. J.W. Ward, of Belfast; and the positions of the satellites, as he +estimated them on several nights, are compared with those computed, the +two sets presenting tolerably good agreement. Indeed the corroborations +are such as to almost wholly negative any skepticism, though such +extraordinary feats should always be received with caution. + +In this particular case the chances of being misled are manifold; even +Herschel himself fell into error in taking minute stars to be satellites +and actually calculating their periods; so that when we remember the +difficulties of the question our doubts are not altogether dispelled. +Extreme acuteness of vision will, in individual instances, lead to +success of abnormal character, and certainly in Mr. Ward's case the +remarkable accordances in the observed and calculated positions appear +to be conclusive evidence that he was not mistaken. + +It will be readily inferred that the great distance and consequent +feebleness of Uranus must render any markings upon the disk of the +planet beyond the reach of our best telescopes; and indeed this appears +to have been a matter of common experience. Though the surface has been +often scanned for traces of spots, we seldom find mention that any have +been distinguished. Consequently the period of rotation has yet to be +determined. It is true that an approximate value was assigned by Mr. +T.H. Buffham from observations with a nine-inch reflector in 1870 and +1872. but the materials on which the computation was based were slender +and necessarily somewhat uncertain, so that his period of about twelve +hours stands greatly in need of confirmation. The bright spots and zones +seen on the disk in the years mentioned appear to have entirely eluded +other observers, though they are probably phenomena of permanent +character and within reach of instruments of moderate size. Mr. Buffham +[1] thus describes them: + +[Footnote 1: "Monthly Notices K. A. S.," January, 1873.] + +"1870, Jan. 25, 11h. to 12h. in clear and tolerably steady air; power +132 showed that the disk was not uniform. With powers 202 and 3.0, two +round, bright spots were perceived, not quite crossing the center but a +little nearer to the eastern side of the planet, the position angle of a +line passing through their centers being about 20 and 200--ellipticity +of Uranus seemed obvious, the major axis lying parallel to the line of +the spots. + +"Jan. 27, 10h. to 101/2h.; some fog, and definition not good, but the +appearance of the spots was almost exactly the same as on the 25th." + +On March 19 glimpses were obtained of a light streak and two spots. +On April 1, 4, 6, and 8, a luminous zone was seen on the disk, and +in February and March, 1872, when observations were resumed, certain +regions were noted brighter than others, and underwent changes +indicating the rotation of the planet in a similar direction to that +derived from the results obtained in 1870. Mr. Buffham points out that, +if this is admitted, then the plane of the planet's equator is not +coincident with the plane of the orbits of the satellites. Nor need we +be surprised at this departure from the general rule, where such an +anomalous inclination exists. In singular confirmation of this is Mr. +Lassell's observation of 1862, Jan. 29, where he says: "I received an +impression which I am unable to render certain of an equatorial dark +belt, and of an ellipticity of form." + +Some observations made in 1872-3 with the great six-foot reflector of +Lord Rosse may here be briefly referred to. A number of measures, both +of position and distance, of Oberon and Titania, were made, [1] and a +few of Umbriel and Ariel, but "the shortness of the time available (40 +minutes) each night for the observation of the planet with the six-foot +instrument, the atmospheric disturbance, so often a source of annoyance +in using so large an aperture, and other unfavorable circumstances, +tended to affect the value of the observations, and to make the two +inner satellites rarely within detection." + +[Footnote 1: "Monthly Notices R. A. S.," March, 1875.] + +On Feb. 10, 1872, Lord Rosse notes that all four satellites were seen on +the same side of the planet. On Jan. 16, 1873, when definition was good, +no traces of any markings were seen. Diameter of Uranus = 5.29". Power +414 was usually employed, though at times the inner satellites could be +more satisfactorily seen with 625. + +It may be mentioned as an interesting point that, some fifty years +after the first discovery of Uranus by Herschel, it was accidentally +rediscovered by his son, Sir John Herschel, who recognized it by +its disk, and had no idea as to the identity of the object until an +ephemeris was referred to. Sir John mentions the fact as follows, in a +letter to Admiral Smyth, written in 1830, August 8: + +"I have just completed two twenty-foot reflectors, and have got some +interesting observations of the satellites of Uranus. The first sweep +I made with my new mirror I _re-discovered_ this planet by its _disk_, +having blundered upon it by the merest accident for 19 Capricorni." + +In commenting upon the centenary of an important scientific discovery we +are naturally attracted to inquire what progress has been made in the +same field during the comparatively short interval of one hundred years +which has elapsed since it occurred. We have called it a short interval, +because it cannot be considered otherwise from an astronomical or +geological point of view, though, as far as human life is concerned, +it can only be regarded as a very lengthy period, including several +generations within its limits. + +Since Herschel, in 1781, discovered Uranus, astronomy has progressed +with great rapidity, so that it would be impossible to enumerate in a +brief memoir the many additional discoveries which have resulted from +assiduous observation. A century ago only five planets were known +(excluding the Earth), now we are acquainted with about two hundred and +thirty of these bodies; and one of these, found in 1846, is a large +planet whose orbit lies exterior to that of Uranus. In fact, the state +of astronomical knowledge a century ago has undergone wonderful changes. +It has been rendered far more complete and comprehensive by the +diligence of its adherents and by the unwearying energy with which both +in theory and practice it has been pursued. A zone of small planets has +been discovered between Mars and Jupiter just where the analogies of the +planetary distances indicated the probable existence of a large planet. +The far-off Neptune was revealed in 1846 by a process of analytical +reasoning as unique as it was triumphant, and which proved how well +the theory of planetary perturbations was understood. The planet was +discovered by calculation, its position in the heavens assigned, and the +telescope was then employed merely as the instrument of its detection. +The number of satellites which a century ago numbered only ten has now +reached twenty, and the discovery in 1877 of two moons accompanying Mars +shows that the work is being continued with marked success. + +In other departments we also find similar evidence of increasing +knowledge. The periodicity of the sun spots, the existence of systems of +binary stars, meteor showers, and their affinity with cometary orbits +may be mentioned as among the more important, while a host of new +comets, chiefly telescopic, have been detected. Large numbers of nebulae +and double stars have been catalogued, and we have evidence every year +of the activity with which these several branches are being followed up. + +In fine, it matters little to what particular department of astronomical +investigation we look for traces of advancement during the past hundred +years, for it is evident throughout them all, and sufficiently proves +that the interest formerly taken in the science has not only been well +sustained but has become more general and popular, and is extending its +attractive features to all classes of the community. + +In Herschel's day large telescopes were rare. A man devoting himself to +the study of the heavenly bodies as a means of intellectual recreation +was considered a phenomenon, and indeed that appellation might be +fittingly applied to the few isolated individuals who really occupied +themselves in such work. How different is the case now that the pleasant +ways of science have called so many to her side and so far perfected her +means of research as to make them accessible to all who care to see and +investigate for themselves the unique and wonderful truths so easily +within reach! Large telescopes have become common enough, and there is +no lack of hands and eyes to utilize them, nor of understanding, ever +ready to appreciate, in sincerity and humbleness, those objects which +display in an eminent degree the all-wise conceptions of a great +Creator! It is, therefore, a most gratifying sign to notice this rapid +development of astronomy, and to see year by year the increasing number +of its advocates and the record of many new facts gleaned by vigorous +observation. + +The character of recent discoveries distinctly intimates that, in future +years, some departments of the science will become very complicated, +owing to the necessity of dealing with a large number of minute bodies, +for the tendency of modern researches has been to reveal objects which +by their faintness had hitherto eluded detection. And when we consider +that these bodies are rapidly increasing year by year, the idea is +obviously suggested that, inasmuch as their numbers are comparatively +illimitable, and there is likely to be no immediate abatement in the +enthusiasm of observers, difficulties will arise in identifying them +apart and forming them into catalogues with their orbital elements +attached, so that the individual members may be redetected at any time. + +In this connection we allude particularly to minor planets, to +telescopic comets, and to meteoric streams, which severally form a very +numerous group of bodies of which the known members are accumulating to +a great extent. As complications arise, some remedies must be applied to +their solution, and one probable effect will be that astronomers will be +induced each one to have a specialty or branch to which his energies are +mainly directed. The science will become so wide in its application and +so intricate in its details that it will become more than ever necessary +for observers to select or single out definite lines of investigation +and pursue them closely, for success is far more likely to attend such +exertions than those which are not devoted to any special end, but +employed rather in a general survey of phenomena. + +We have already before us some excellent instances in which individual +energies have been aptly utilized in the prosecution of original work +in some specific branch of astronomy, and we are strongly disposed to +recommend such exclusive labors to those who have the means and the +desire to achieve something useful. Observers who find one subject +monotonous and then take up another for the sake of variation are not +likely to get far advanced in either. In the case of amateurs who use a +telescope merely for amusement, and indiscriminately apply it to nearly +every conspicuous object in the firmament without any particular purpose +other than to satisfy their curiosity, the matter is somewhat different, +and our remarks are not applicable to them. We refer more pointedly +to those who have a regard for the interests of the science and whose +enthusiasm enables them to work habitually and with some pertinacity. + +History tells us that the Great Alexander wept when he found he had no +other worlds to conquer, and we fear that some astronomers will lament +that they have little prospect of discovering anything fresh in a sphere +to which our giant telescopes have been so often directed, but this is +founded on a palpable misconception. Certain objects, such as comets for +example, do not require great power, and the revelation of new meteor +showers is entirely a question for the naked eye. In fact, it may be +confidently asserted that observations undertaken with energy and +persistency will, if rightly directed, more than compensate for defects +of instrumental power. + +It is true, however, that in certain quarters we must look to large +instruments alone for new discoveries. It would be useless searching for +an ultra-Neptunian planet, or for additional satellites to Uranus or +Neptune, or for the materials to determine the rotation periods of these +planets with a small telescope. Every observer will find objects suited +to the capacity of his instrument, and he may not only employ it +usefully but possibly make a discovery of nearly equal import with that +which rendered the name of Herschel famous a century ago.--_Popular +Science Review_. + + * * * * * + + + + +THE VARYING SUSCEPTIBILITY OF PLANTS AND ANIMALS TO POISONS AND +DISEASES. + + +Much attention is being devoted to the causes which determine the +aptitude or immunity with animals for maladies. This is in a general +sense called medical geography, as a physician who has prescribed for +patients in various parts of the world, and belonging to different +races--the white, yellow, and black--has been able to note the +diversities in the same disease, and the contradictions in the remedies +employed. + +The true social peril, hardly discovered before we became aware how +to conjure it, lies in those legions of animalcules or microbes that +surround us and in the middle of which we live. M. Pasteur has revealed +them to us as the factors in infectious diseases. Claude Bernard +has demonstrated the community which exists between animals and +vegetables--phenomena of movement, of sensibility, of production of +heat, of respiration, of digestion even, for there are the _Drosera_ and +kindred carnivorous plants. Iron cures chlorosis in vegetables as well +as in animals, and chloroform and ether render both insensible. There +resemblances are more striking still between animals. After Baudrimont, +insects are, in presence of alcohols, chloroform, and irrespirable +gases, similarly affected as man. Many maladies, too, are common to +man and several species of animals; and this organic identity is best +illustrated in the relationship between epidemics and epizootias, +cancer, asthma, phthisis, smallpox, rabies, glanders, charbon, etc., +afflict alike man and many species of animals. + +The differences between races are not less remarkable--odor and taste, +for example. According to anthropophagy, negroes are best, and white +people most detestable. Broca remarked, that, in the dissecting room, +the muscles of the negro putrefied less rapidly than those of whites. It +is perhaps to these anatomical differences that the diverse action of +the same poison, in the case of races or species, may be attributed. On +certain rodentia belladonna exercises no influence; morphine for a horse +is a violent stimulant; a snail remains insensible to digitalis; goats +eat tobacco with impunity; and in the Tarentin the inhabitants rear only +black sheep, because a plant abounds which is noxious for white sheep. + +The nature of these conditions is a mystery for science. The _Solanae_ +tribe of plants furnish a principle which, as its name implies, produces +consolation or forgetfulness, by acting on the tissues of the brain +where resides the organ of thought; now, on the authority of Professor +Bouchardat, these opiates have the less of effect in proportion as the +animals possess the less of intelligence. + +To the same anatomical peculiarities must be ascribed the choice that +disease makes in such or such a race. Glanders, for instance, so +virulent with the horse, the ass, and man, produce in the case of the +dog only a local accident; peripneumonia, so contagious among horned +cattle, is more benign in its action on Dutch than other breeds of +stock; the cattle plague that decimates so many farms is communicated by +cattle to each other from the slightest contact, while the closest and +most constant association is necessary to communicate the disease +to sheep, and even when they are affected its action is not severe. +Further, that plague only attacks ruminant animals--oxen, goats, sheep, +zebras, gazelles, etc. Ten years ago this plague broke out in the Jardin +d'Acclimatation; not a ruminant escaped, and also one animal not of that +class, a little tenant nearly related to the pig--the _peccari_. + +Now, Dr. Condereau has demonstrated recently that the stomach of the pig +has a rudimentary organization recalling that of the ruminants. Clearly, +the stomach of the peccari, and perhaps that of the pig, present a +favorable medium for the parasitical microbe peculiar to the rinderpest. +In the potato disease, again, all the varieties are not affected with +the same degree of violence; it is more marked in its action on the +round yellows than the reds, and on the latter rather than the pink. But +the symptoms even of the same malady differ, the parasite's attacks on +the tissues being dissimilar. Oak galls are produced from the prickings +of insects; now around the same larva often four varieties of galls are +recognized. In the case of consumption in cattle, the disease marches +slowly; in that of pigs it takes the galloping form, as with man. + +Each people or nation has its peculiar pathology and also its peculiar +cures. A negro can take a dose of tartar ten times more excessive than a +white; the same dose of brandy given to a black, a yellow, and a white, +will not produce on the three men either drunkenness at the same moment, +or intoxication at all. Mulattoes can sustain more drastic aperients +than other races; the negro does not suffer from yellow fever, but he +readily falls to phthisis; he will catch the cholera more quickly than a +white. Human races, where they may catch the same intermittent fever at +the identical moment and in the same swamp, will not the less display +different types of fever. Dr. Crevaux has shown that a certain insect +with the North American Indian is not the same as with the negro or the +maroon, and both differ from that peculiar to Europeans. + +M. Pasteur's beautiful experiments have conclusively demonstrated that +fowls do not catch the _charbon_; now the vital warmth of birds is from +seven to nine degrees higher than in the case of mammiferous animals; +he imagined that if the fowl was cooled down by baths to the lower +temperature, it would be liable equally to become affected; he tried, +and the result proved he was correct. + +The absence, then, of a certain temperature would be the reason why +birds are exempt. The microbes are the agents of infectious disease; +when these swarm in the blood of an individual they seem to leave there +something pernicious for parasites resembling themselves, or to bring +away with them something necessary to the life of their successors. A +glass of sugar and water, where leaven has already fermented and yielded +alcohol, is incapable of producing a second crop of leaven; similarly +the blood of an individual, once contaminated, becomes uninhabitable +afterward for like microbes. The individual has acquired immunity. Such +is the principle of vaccination.--_Paris Correspondent of the Kansas +City Review_. + + * * * * * + + + + +KIND TREATMENT OF HORSES. + + +It has been observed by experienced horse trainers that naturally +vicious horses are rare, and that among those that are properly trained +and kindly treated when colts they are the exception. + +It is superfluous to say that a gentle and docile horse is always the +more valuable, other qualities being equal, and it is almost obvious +that gentle treatment tends to develop this admirable quality in the +horse as well as in the human species, while harsh treatment has the +contrary tendency. Horses have been trained so as to be entirely +governed by the words of his driver, and they will obey and perform +their simple but important duties with as much alacrity as the child +obeys the direction of the parent. + +It is true that all horses are not equally intelligent and tractable, +but it is probable that there is less difference among them in this +regard than there is among his human masters, since there are many +incitements and ambitions among men that do not affect animals. + +The horse learns to know and to have confidence in a gentle driver, and +soon discovers how to secure for himself that which he desires, and +to understand his surroundings and his duties. The tone, volume, and +inflection of his master's voice indicate much, perhaps more than the +words that are spoken. Soothing tones rather than words calm him if +excited by fear or anger, and angry and excited tones tend to excite or +anger him. In short, bad masters make bad horses. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. Six dollars a year, sent, prepaid, to any foreign +country. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. Price, 10 cents each. + +All the back volumes of THE SUPPLEMENT can likewise be supplied. Two +volumes are issued yearly. 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Do not change or edit the +header without written permission. + +Please read the "legal small print," and other information about the +eBook and Project Gutenberg at the bottom of this file. Included is +important information about your specific rights and restrictions in +how the file may be used. You can also find out about how to make a +donation to Project Gutenberg, and how to get involved. + + +**Welcome To The World of Free Plain Vanilla Electronic Texts** + +**eBooks Readable By Both Humans and By Computers, Since 1971** + +*****These eBooks Were Prepared By Thousands of Volunteers!***** + + +Title: Scientific American Supplement, No. 303 + October 22, 1881 + +Author: Various + +Release Date: June, 2005 [EBook #8296] +[Yes, we are more than one year ahead of schedule] +[This file was first posted on July 4, 2003] + +Edition: 10 + +Language: English + +Character set encoding: ISO-Latin-1 + +*** START OF THE PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN NO. 303 *** + + + + +Olaf Voss, Don Kretz, Juliet Sutherland, Charles Franks +and the Online Distributed Proofreading Team. + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 303 + + + + +NEW YORK, OCTOBER 22, 1881 + +Scientific American Supplement. Vol. XII, No. 303. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + + TABLE OF CONTENTS + +I. ENGINEERING AND MECHANICS.--New Eighty-ton Steam Hammer at the Saint + Chamond Works, France.--7 figures.--Elevation of hammer.--Profile-- + Transverse section.--Profile view of foundation, etc.--Plan of + plant.--General plan of the forging mill.--Details of truss and + support for the cranes. + + Great Steamers.--Comparative details of the Servia, the City of Rome, + the Alaska, and the Great Eastern. + + Improved Road Locomotive.--2 figures.--Side and end views + + American Milling Methods. By ALBERT HOPPIN.--Ten years' progress.--Low + milling.--Half high milling.--High milling.--Important paper read + before the Pennsylvania State Millers' Association. + + Machine for Dotting Tulles and other Light Fabrics.--3 figures. + +II. TECHNOLOGY AND CHEMISTRY.--The Reproduction and Multiplication of + Negatives. By ERNEST EDWARDS. + + A New Method of Making Gelatine Emulsion. By W. K. BURTON. + + The Pottery and Porcelain Industries of Japan. + + Crystallization Table. + + The Principles of Hop Analysis. By Dr. G. O. CECH. + + Water Gas.--A description of apparatus for producing cheap gas, and + some notes on the economical effects of using such gas with gas + motors, etc.--By J. EMERSON DOWSON. + + On the Fluid Density of Certain Metals. By Professors CHANDLER ROBERTS + and T. WRIGLESON. + +III. PHYSICS, ELECTRICITY, ETC.--Electric Power.--The nature and uses of + electricity.--Electricity vs. steam. + + On the Method of Obtaining and Measuring Very High Vacua with a + Modified Form of Sprengel Pump. By Prof OGDEN N. ROOD.--4 figures.-- + Apparatus for obtaining vacua of one four hundred-millionth of an + atmosphere--Construction.--Manipulation.--Calculations.--Results + +IV. ART, ARCHITECTURE, ETC.--Old Wrought Iron Gates, Guildhall. + Worcester, England. 1 figure. + + The French Crystal Palace, Park of St. Cloud, Paris. 1 full page + illustration. + + Suggestions in Architecture. A Castellated Chateau. Perspective and + plan. Chateau in the Ægean Sea. + +V. HYGIENE AND MEDICINE.--Hydrophobia Prevented by Vaccination. + + On Diptera as Spreaders of Disease. By J. W. SLATER. + + On the Relations of Minute Organisms to Certain Specific Diseases. + +VI. ASTRONOMY--The Centenary of the Discovery of Uranus. By F. W. DENNING. + 2 figures. Approximate place of Uranus among the stars at its + discovery, March l3, 1871.--Orbits of the Uranian Satellites. + +VII. BIOLOGY, ETC.--The Varying Susceptibility of Plants and Animals to + Poisons and Disease. + + Kind Treatment of Horses. + + * * * * * + + + + +NEW EIGHTY TON STEAM HAMMER AT THE SAINT CHAMOND WORKS + + +Ever since the improvements that have been introduced into the +manufacture of steel, and especially into the erection of works for its +production, have made it possible to obtain this metal in very large +masses, it has necessarily been preferred to iron for all pieces of +large dimensions, inasmuch as it possesses in the highest degree that +homogeneousness and resistance which are so difficult to obtain in the +latter metal. It has consequently been found necessary to construct +engines sufficiently powerful to effect the forging of enormous +ingots, as well as special furnaces for heating them and apparatus for +manipulating and transporting them. + +The greatest efforts in this direction have been made with a view to +supplying the wants of heavy artillery and of naval constructions; +and to these efforts is metallurgy indebted for the creation of +establishments on a scale that no one would have dared a few years ago +to think of. The forging mill which we are about to describe is one of +those creations which is destined to remain for a long time yet very +rare; and one which is fully able to respond, not only to all present +exigencies, but also, as far as can be foreseen, to all those that may +arise for a long period to come. The mill is constructed as a portion of +the vast works that the Compagnie des Forges et Aciéries de la Marine +own at Saint Chamond, and which embrace likewise a powerful steel works +that furnishes, especially, large ingots exceeding 100 tons in weight. + +The mill consists, altogether, of three hammers, located in the same +room, and being of unequal powers in order to respond to different +requirements. The largest of these hammers is of 80 tons weight, and +the other two weigh respectively 35 and 28 tons. Each of them has +a corresponding furnace for heating by gas, as well as cranes for +maneuvering the ingots and the different engines. The general plan view +in Fig. 4 shows the arrangement of the hammers, cranes, and furnaces in +the millhouse. + +[Illustration: FIG. A.--ELEVATION OF A HAMMER. FIG. B.--PROFILE VIEW] + +The gas generators which supply the gas-furnaces are located out of +doors, as are the steam-generators. The ingots are brought from the +steel factory, and the forged pieces are taken away, by special trucks +running on a system of rails. We shall now give the most important +details in regard to the different parts of the works. + +_The Mill-House_--This consists of a central room, 262 feet long, 98 +feet wide, and 68 feet in height, with two lean-to annexes of 16 feet +each, making the total width 100 feet. The structure is wholly of metal, +and is so arranged as to permit of advantage being taken of every foot +of space under cover. For this purpose the system of construction +without tie-beams, known as the "De Dion type," has been adopted. Fig. +1 gives a general view of one of the trusses, and Fig. 5 shows some +further details. The binding-rafters consist of four angle-irons +connected by cross-bars of flat iron. The covering of corrugated +galvanized iron rests directly upon the binding-rafters, the upper parts +of which are covered with wood for the attachment of the corrugated +metal. The spacing of these rafters is calculated according to the +length of the sheets of corrugated iron, thus dispensing with the use of +ordinary rafters, and making a roof which is at once very light and very +durable, and consequently very economical. Rain falling on the roof +flows into leaden gutters, from whence it is carried by leaders into a +subterranean drain. The vertical walls of the structure are likewise of +corrugated iron, and the general aspect of the building is very original +and very satisfactory. + +_The 80 Ton Hammer_--The three hammers, notwithstanding their difference +in power, present similar arrangements, and scarcely vary except in +dimensions. We shall confine ourselves here to a description of the 80 +ton apparatus. This consists, in addition to the hammer, properly so +called, of three cranes of 120 tons each, serving to maneuver the pieces +to be forged, and of a fourth of 75 tons for maneuvering the working +implements. These four cranes are arranged symmetrically around the +hammer, and are supported at their upper extremity by metallic stays. +Besides the foregoing there are three gas furnaces for heating the +ingots. Figs. 1, 2, and 3 show the general arrangement of the apparatus. + +_Foundations of the Hammer and Composition of the Anvil-Bed_--To obtain +a foundation for the hammer an excavation was made to a depth of 26 feet +until a bed of solid rock was reached, and upon this there was then +spread a thick layer of beton, and upon this again there was placed a +bed of dressed stones in the part that was to receive the anvil-stock +and hammer. + +On this base of dressed stones there was placed a bed formed of logs +of heartwood of oak squaring 16 inches by 3 feet in height, standing +upright, joined together very perfectly, and kept in close juxtaposition +by a double band of iron straps joined by bolts. The object of this +wooden bed was to deaden, in a great measure, the effect of the shock +transmitted by the anvil-stock. + +NEW EIGHTY-TON STEAM HAMMER AT THE ST CHAMOND WORKS. + +[Illustration: FIG. 1.--TRANSVERSE SECTION.] + +[Illustration: FIG. 2.--PLAN.] + +[Illustration: FIG. 3.--PROFILE VIEW.] + +[Illustration: FIG. 4.--GENERAL PLAN OF THE FORGING MILL.] + +[Illustration: FIG. 5.--DETAILS OF THE TRUSSAND SUPPORT FOR THE CRANE.] + +_The Anvil-Stock_.--The anvil-stock, which is pyramidal in shape, and +the total weight of which amounts to 500 tons, is composed of superposed +courses, each formed of one or two blocks of cast iron. Each course +and every contact was very carefully planed in order to make sure of +a perfect fitting of the parts; and all the different blocks were +connected by means of mortises, by hot bandaging, and by joints with +key-pieces, in such a way as to effect a perfect solidity of the parts +and to make the whole compact and impossible to get out of shape. + +The anvil-stock was afterwards surrounded by a filling-in of masonry +composed of rag-stones and a mortar made of cement and hydraulic lime. +This masonry also forms the foundation for the standards of the hammer, +and is capped with dressed stone to receive the bed-plates. + +_The Power-Hammer_ (Figs. A and B).--The power-hammer, properly +so-called, consists, in addition to the hammer-head, of two standards to +whose inner sides are bolted guides upon which slides the moving mass. +The bed-plates of cast iron are 28 inches thick, and are independent of +the anvil-stock. They are set into the bed of dressed stone capping the +foundation, and are connected together by bars of iron and affixed to +the masonry by foundation bolts. To these bedplates are affixed the +standards by means of bolts and keys. The two standards are connected +together by iron plates four inches in thickness, which are set into the +metal and bolted to it so as to secure the utmost strength and solidity. +The platform which connects the upper extremities of the standards +supports the steam cylinder and the apparatus for distributing the +steam. The latter consists of a throttle valve, twelve inches in +diameter, and an eduction valve eighteen inches in diameter, the +maneuvering of which is done by means of rods extending down to a +platform upon which the engineman stands. This platform is so situated +that all orders can be distinctly heard by the engineman, and so that +he shall be protected from the heat radiated by the steel that is +being forged. All the maneuvers of the hammers are effected with most +wonderful facility and with the greatest precision. + +The piston is of cast-steel, and the rod is of iron, 12 inches in +diameter. The waste steam is carried out of the mill by a pipe, and, +before being allowed to escape into the atmosphere, is directed into an +expansion pipe which it penetrates from bottom to top. Here a portion of +the water condenses and flows off, and the steam then escapes into +the open air with a greatly diminished pressure. The object of this +arrangement is to diminish to a considerable extent the shocks and +disagreeable noise that would be produced by the direct escape of the +steam at quite a high pressure and also to avoid the fall of condensed +water. + +The following are a few details regarding the construction of the +hammer: + + Total height of foundations........... 26 ft. + From the ground to the platform ...... 28 " + + Platform .............................. 3.25 " + Height of cylinder.................... 21 " + ________ + + Total height...................... 78.25 ft. + + Weight of anvil-stock................ 500 tons. + Weight of bed-plates................. 122 " + Weight of standards.................. 270 " + Weight of platform and cylinder...... 148 " + Piston, valves, engineman's platform, + hammer, etc........................ 160 " + __________ + + Total weight................... 1,200 tons. + + Weight of the hammer.................. 80 tons. + Maximum fall.......................... 25.75 ft. + Distance apart of the standards....... 21.6 " + Width of hammer....................... 6 " + Pressure of steam..................... 16 lb. + Effective pressure to lift 80 tons.... 7 " +_Description of Figures_.--A, the 80-ton hammer; B, B1, B2, cranes; C, +C1, C2, supports of cranes; D, D1, D2, gas furnaces; A1, the 35-ton +hammer; A2, the 28-ton hammer; EE, railways; F, engineman's platform; G, +lever for maneuvering the throttle valve; H, an ingot being forged. + + * * * * * + + + + +GREAT STEAMERS. + + +The _Brooklyn Eagle_ gives a very interesting description of the three +new steamships now almost completed and shortly to be placed in the New +York and Liverpool trade by the Cunard, Inman, and Williams and Guion +lines. The writer has prepared a table comparing the three vessels +with each other and with the Great Eastern, the only ship of greater +dimensions ever built. We give as much of the article as our space will +allow, and regret that we have not the room to give it entire: + + Line. Cunard. Inman. Guion. Admiralty. + Vessel. Servia City of Rome. Alaska. Great[1] + + Length 530 feet. 546 feet. 520 feet. 679 feet. + Breadth 52 feet. 52 ft. 3 in. 50 ft. 6 in. 82 feet. + Depth 44 ft. 9 in. 37 feet. 38 feet. 60 feet. + Gross ton'ge 8,500 8,300 8,000 13,344[2] + Horse pow'r 10,500 10,000 11,000 2,600 + Speed 17½ knots. 18 knots. 18 knots. 14 knots. + Sal'n pas- 320 and 52 + sengers. 450 300 2d class + Steerage 600 1,500 1,000 + Where Clydeb'nk Barrow in Clyde, + built. Thomson Furness Elder + Date of + sailing. October 22 October 13 November 5 + +[Footnote 1: To be sold at auction soon.] + +[Footnote 2: Net register.] + +In 1870 the total tonnage of British steam shipping was 1,111,375; the +returns for the year 1876 showed an increase to 2,150,302 tons, and from +that time to the present it has been increasing still more rapidly. But, +as can be seen from the above table, not only has the total tonnage +increased to this enormous extent, but an immense advance has been made +in increasing the size of vessels. The reason for this is, that it has +been found that where speed is required, along with large cargo and +passenger accommodation, a vessel of large dimensions is necessary, and +will give what is required with the least proportionate first cost as +well as working cost. Up to the present time the Inman line possessed, +in the City of Berlin, of 5,491 tons, the vessel of largest tonnage in +existence. Now, however, the Berlin is surpassed by the City of Rome by +nearly 3,000 tons, and the latter is less, by 200 tons, than the Servia, +of the Cunard line. It will be observed, too, that while there is not +much difference between the three vessels in point of length, the depth +of the Alaska and the City of Rome, respectively, is only 38 feet and 37 +feet, that of the Servia is nearly 45 feet as compared with that of the +Great Eastern of 60 feet. This makes the Servia, proportionately, the +deepest ship of all. All three vessels are built of steel. This metal +was chosen not only because of its greater strength as against iron, +but also because it is more ductile and the advantage of less weight is +gained, as will be seen when it is mentioned that the Servia, if built +of iron, would have weighed 620 tons more than she does of steel, and +would have entailed the drawback of a corresponding increase in draught +of water. As regards rig, the three vessels have each a different style. +The Cunard Company have adhered to their special rig--three masts, bark +rigged--believing it to be more ship shape than the practice of fitting +up masts according to the length of the ship. On these masts there is a +good spread of canvas to assist in propelling the ship. The City of Rome +is rigged with four masts; and here the handsome full-ship rig of the +Inman line has been adhered to, with the addition of the fore and aft +rigged jigger mast, rendered necessary by the enormous length of the +vessel. It will be seen that the distinctive type of the Inman line +has not been departed from in respect to the old fashioned but still +handsome profile, with clipper bow, figurehead, and bowsprit--which +latter makes the Rome's length over all 600 feet. For the figurehead +has been chosen a full length figure of one of the Roman Cæsars, in the +imperial purple. Altogether, the City of Rome is the most imposing and +beautiful sight that can be seen on the water. The Alaska has also four +masts, but only two crossed. + +The length of the City of Rome, as compared with breadth, insures long +and easy lines for the high speed required; and the depth of hold being +only 37 feet, as compared with the beam of 52 feet, insures great +stability and the consequent comfort of the passengers. A point calling +for special notice is the large number of separate compartments formed +by water tight bulkheads, each extending to the main deck. The largest +of these compartments is only about 60 feet long; and, supposing that +from collision or some other cause, one of these was filled with water, +the trim of the vessel would not be materially affected. With a view to +giving still further safety in the event of collision or stranding, the +boilers are arranged in two boiler rooms, entirely separated from each +other by means of a water tight iron bulkhead. This reduces what, in +nearly all full-powered steamships, is a vast single compartment, into +two of moderate size, 60 feet in length; and in the event of either +boiler room being flooded, it still leaves the vessel with half her +boiler power available, giving a speed of from thirteen to fourteen +knots per hour. The vessel's decks are of iron, covered with teak +planking; while the whole of the deck houses, with turtle decks and +other erections on the upper deck, are of iron, to stand the strains +of an Atlantic winter. Steam is supplied by eight cylindrical tubular +boilers, fired from both ends, each of the boilers being 19 feet long +and having 14 feet mean diameter. There are in all forty eight furnaces. +The internal arrangements are of the finest description. There are two +smoking rooms, and in the after deckhouse is a deck saloon for ladies, +which is fitted up in the most elegant manner, and will prevent the +necessity of going below in showery weather. At the sides of the +hurricane deck are carried twelve life boats, one of which is fitted as +a steam launch. The upper saloon or drawing-room is 100 feet long, the +height between decks being 9 feet. The grand dining-saloon is 52 feet +long, 52 feet wide, and 9 feet high, or 17 feet in the way of the large +opening to the drawing-room above. This opening is surmounted by a +skylight, and forms a very effective and elegant relief to the otherwise +flat and heavy ceiling. There are three large and fourteen small dining +tables, the large tables being arranged longitudinally in the central +part of the saloon, and the small tables at right angles on the sides. +Each diner has his own revolving arm chair, and accommodation is +provided for 250 persons at once. A large American organ is fixed at the +fore end of the room, and opening off through double spring doors at the +foot of the grand staircase is a handsome American luncheon bar, with +the usual fittings. On each side of the vessel, from the saloon to the +after end of the engine room, are placed staterooms providing for 300 +passengers. The arrangements for steerage passengers are of a superior +description. The berths are arranged in single tiers or half rooms, not +double, as is usually the custom, each being separated by a passage, +and having a large side light, thus adding greatly to the light, +ventilation, and comfort of the steerage passengers, and necessitating +the advantage of a smaller number of persons in each room. The City +of Rome is the first of the two due here; she sails from Liverpool on +October 13. + +In the Servia the machinery consists of three cylinder compound surface +condensing engines, one cylinder being 72 inches, and two 100 inches in +diameter, with a stroke of piston of 6 feet 6 inches. There are seven +boilers and thirty-nine furnaces. Practically the Servia is a five +decker, as she is built with four decks--of steel, covered with yellow +pine--and a promenade reserved for passengers. There is a music room on +the upper deck, which is 50 feet by 22 feet, and which is handsomely +fitted up with polished wood panelings. For the convenience of the +passengers there are no less than four different entrances from the +upper deck to the cabins. The saloon is 74 feet by 49 feet, with sitting +accommodations for 350 persons, while the clear height under the beams +is 8 feet 6 inches. The sides are all in fancy woods, with beautifully +polished inlaid panels, and all the upholstery of the saloon is of +morocco leather. For two-thirds of its entire length the lower deck is +fitted up with first class staterooms. The ship is divided into nine +water-tight bulkheads, and she is built according to the Admiralty +requirements for war purposes. There are in all twelve boats equipped +as life-boats. The Servia possesses a peculiarity which will add to her +safety, namely, a double bottom, or inner skin. Thus, were she to +ground on rocks, she would be perfectly safe, so long as the inner skin +remained intact. Steam is used for heating the cabins and saloons, and +by this means the temperature can be properly adjusted in all weathers. +In every part of the vessel the most advanced scientific improvements +have been adopted. The Servia leaves Liverpool on October 22. + +The Alaska, whose owners, it is understood, are determined to make her +beat all afloat in speed, does not sail until November 5, and therefore +it is premature to say anything about her interior equipments. She is +the sister of the celebrated Arizona, and was built by the well-known +firm of Elder & Co., on the Clyde. + + * * * * * + + + + +IMPROVED ROAD LOCOMOTIVE. + + +Several attempts have been made to connect the leading wheels of a +traction engine with the driving wheels, so as to make drivers of all of +them, and thus increase the tractive power of the engine, and to afford +greater facilities for getting along soft ground or out of holes. The +wheels with continuous railway and India-rubber tires have been employed +to gain the required adhesion, but these wheels have been too costly, +and the attempts to couple driving and leading wheels have failed. The +arrangement for making the leading wheels into drivers, illustrated +on page 4825, has been recently brought out by the Durham and North +Yorkshire Steam Cultivation Company, Ripon, the design being by Messrs. +Johnson and Phillips. The invention consists in mounting the leading +axle in a ball and long socket, the socket being rotated in fixed +bearings. The ball having but limited range of motion in the socket, is +driven round with it, but is free to move in azimuth for steering. + +This engine has now been in use more than twelve months in traction +and thrashing work, and, we are informed, with complete success. The +illustrations represent a 7-horse power, with a cylinder 8 in. diameter +by 12 in. stroke, and steam jacketed. The shafts and axles are of +Bowling iron. The boiler contains 140 ft. of heating surface, and is +made entirely of Bowling iron, with the longitudinal seams welded. The +gearing is fitted with two speeds arranged to travel at 1½ and 3 miles +per hour, and the front or hind road wheels can be put out of gear when +not required. The hind driving wheels are 5 ft. 6 in. diameter, and the +front wheels 5 ft.; weight of engine 8 tons.--_The Engineer._ + +[Illustration: IMPROVED ROAD LOCOMOTIVE] + +[Illustration: IMPROVED ROAD LOCOMOTIVE] + + * * * * * + + + + +AMERICAN MILLING METHODS. + +[Footnote 1: A paper read before the meeting of the Pennsylvania State +Millers Association at Pittsburgh, Pa., by Albert Hoppin, Editor of the +_Northwestern Miller_.] + +By ALBERT HOPPIN. + + +To speak of the wonderful strides which the art of milling has taken +during the past decade has become exceedingly trite. This progress, +patent to the most casual observer, is a marked example of the power +inherent in man to overcome natural obstacles. Had the climatic +conditions of the Northwest allowed the raising of as good winter wheat +as that raised in winter wheat sections generally, I doubt if we should +hear so much to-day of new processes and gradual reduction systems. So +long as the great bulk of our supply of breadstuffs came from the winter +wheat fields, progress was very slow; the mills of 1860, and I may even +say of 1870, being but little in advance, so far as processes were +concerned, of those built half a century earlier. The reason for this +lack of progress may be found in the ease with which winter wheat could +be made into good, white, merchantable flour. That this flour was +inferior to the flour turned out by winter wheat mills now is proven by +the old recipe for telling good flour from that which was bad, viz.: To +throw a handful against the side of the barrel, if it stuck there it was +good, the color being of a yellowish cast. What good winter wheat patent +to-day will do this? Still the old time winter wheat flour was the best +there was, and it had no competitor. The settling up of the Northwest +which could not produce winter wheat at all, but which did produce a +most superior article of hard spring wheat, was a new factor in the +milling problem. The first mills built in the spring wheat States tried +to make flour on the old system and made a most lamentable failure of +it. I can remember when the farmer in Wisconsin, who liked a good loaf +of bread, thought it necessary to raise a little patch of winter wheat +for his own use. He oftener failed than succeeded, and most frequently +gave it up as a bad job. Spring wheat was hard, with a very tender, +brittle bran. If ground fine enough to make a good yield a good share +of the bran went into the flour, making it dark and specky. If not +so finely ground the flour was whiter, but the large percentage of +middlings made the yield per bushel ruinously small. These middlings +contained the choicest part of the flour producing part of the berry, +but owing to the dirt, germ, and other impurities mixed with them, it +was impossible to regrind them except for a low grade flour. Merchant +milling of spring wheat was impossible wherever the flour came in +competition with winter wheat flours. At Minneapolis, where the millers +had an almost unlimited water power, and wheat at the lowest price, +merchant milling was almost given up as impracticable. It was certainly +unprofitable. To the apparently insurmountable obstacles in the way of +milling spring wheat successfully, we may ascribe the progress of modern +milling. Had it been as easy to raise good winter wheat in Wisconsin and +Minnesota as in Pennsylvania and Ohio, or as easy to make white flour +from spring as from winter wheat, we should not have heard of purifiers +and roller mills for years to come. + +The first step in advance was the introduction of a machine to purify +middlings. It was found that the flour made from these purified +middlings was whiter than the flour from the first grinding and brought +a better price than even winter wheat flours. Then the aim was to make +as many middlings as possible. To do this and still clean the bran so +as to make a reasonable yield the dress of the burrs was more carefully +attended to, the old fashioned cracks were left out, the faces and +furrows made smooth, true, and uniform, self-adjusting drivers +introduced, and the driving gear better fitted. Spring wheat patents +rapidly rose to the first place in the market, and winter wheat millers +waked up to find their vantage ground occupied by their hitherto +contemned rivals. To their credit it may be said that they have not +been slow in taking up the gauntlet, and through the competition of the +millers of the two climatically divided sections of this country with +each other and among themselves the onward march of milling progress has +been constantly accelerated. Where it will end no man can tell, and +the chief anxiety of every progressive miller, whether he lives in +Pennsylvania or Minnesota, is not to be left behind in the race. + +The millers of the more Eastern winter wheat States have a two-fold +question to solve. First, how to make a flour as good as can be found in +the market, and second, how to meet Western competition, which, through +cheap raw material and discriminating freight rates, is making serious +inroads upon the local markets. Whether the latter trouble can be +remedied by legislature, either State or national, or not, remains to be +proven by actual trial. That you can solve the first part of the problem +satisfactorily to yourselves depends upon your readiness to adopt new +ideas and the means you have at hand to carry them out. It is manifestly +impossible to make as good a flour out of soft starchy wheat as out of +that which is harder and more glutinous. It is equally impossible for +the small mill poorly provided with machinery to cope successfully +with the large merchant mill fully equipped with every appliance that +American ingenuity can suggest and money can buy. I believe, however, +that a mill of moderate size can make flour equally as good as the large +mill, though, perhaps, not as economically in regard to yield and cost +of manufacture. + +The different methods of milling at present in use may be generally +divided into three distinct processes, which, for want of any better +names, I will distinguish as old style, new process, and gradual +reduction. Perhaps the German division of low milling, half high +milling, and high milling is better. Old style milling was that in +general use in this country up to 1870, and which is still followed in +the great majority of small custom or grist mills. It is very simple, +consisting of grinding the wheat as fine as possible at the first +grinding, and separating the meal into flour, superfine or extra, +middlings, shorts, and bran. Given a pair of millstones and reel long +enough, and the wheat could be made into flour by passing through the +two. Because spring wheat was so poorly adapted to this crude process, +it had to be improved and elaborated, resulting in the new process. + +At first this merely consisted of purifying and regrinding the middlings +made in the old way. In its perfected state it may be said to be halfway +between the old style and gradual reduction, and is in use now in many +mills. In it mill stones are used to make the reductions which are only +two in number, in the first of which the aim of the miller is to make as +many middlings as he can while cleaning the bran reasonably well, and +in the second to make the purified middlings into flour. In the most +advanced mills which use the new process, the bran is reground and the +tailings from the coarse middlings, containing germ and large middlings +with pieces of bran attached, are crushed between two rolls. These +can hardly be counted as reductions, as they are simply the finishing +touches, put on to aid in working the stuff up clean and to permit of +a little higher grinding at first. Regarding both old style and new +process milling, you are already posted. Gradual reduction is newer, +much more extensive, and merits a much more thorough explanation. Before +entering upon this I will call your attention to one or two points which +every miller should understand. + +The two essential qualities of a good marketable flour are color and +strength. It should be sharply granular and not feel flat and soft to +the touch. A wheat which has an abundance of starch, but is poor in +gluten, cannot make a strong flour. This is the trouble with all soft +wheats, both winter and spring. A wheat which is rich in gluten is hard, +and in the case of our hard Minnesota wheat has a very tender bran. +It is comparatively easy to make a strong flour, but it requires very +careful milling to make a flour of good color from it. Probably the +wheat which combines the most desirable qualities for flour-making +purposes is the red Mediterranean, which has plenty of gluten and a +tough bran, though claimed by some to have a little too much coloring +matter, while the body of the berry is white. By poor milling a good +wheat can be made into flour deficient both in strength and color, and +by careful milling a wheat naturally deficient in strength may be made +into flour having all the strength there was in the wheat originally and +of good color. Good milling is indispensable, no matter what the quality +of the wheat may be. + +The idea of gradual reduction milling was borrowed by our millers from +the Hungarian mills. There is, however, this difference between the +Hungarian system and gradual reduction, as applied in this country, that +in the former, when fully carried out, the products of the different +breaks are kept separate to the end, and a large number of different +grades of flour made, while in the system, as applied in this country, +the separations are combined at different stages and usually only three +different grades of flour made, viz.: patent, baker's, or as it is +termed in Minnesota, clear flour, and low grade or red dog. In the +largest mills the patent is often subdivided into first and second, and +they may make different grades of baker's flour, these mills approaching +much nearer to the Hungarian system, though modifying it to American +methods and machinery. In mills of from three to five hundred barrels +daily capacity, it is hardly possible or profitable to go to this +subdivision of grades, owing to the excessive amount of machinery +necessary to handling the stuff in its different stages of completion. +The Hungarian system has, therefore, been greatly modified by American +millers and milling engineers to adapt it to the requirements of mills +of average capacity. This modified Hungarian system we call gradual +reduction. It can be profitably employed in any mill large enough to run +at all on merchant work. So far it has not been found practicable to use +it in mills of less than one hundred and twenty-five to one hundred and +fifty barrels capacity in twenty-four hours, and it is better to have +the mill of at least double this capacity. + +Gradual reduction, as its name implies, consists in reducing the +wheat to flour, shorts, and bran, by several successive operations or +reductions technically called breaks, the process going on gradually, +each break leaving the material a little finer than the preceding one. +Usually five reductions or breaks are made, though six or seven may be +used. The larger the number of breaks the more complicated the system +becomes, and it is preferable to keep it as simple as possible, for even +at its simplest it requires a good, wide-awake thinking miller to handle +it successfully. When it is thoroughly and systematically carried out in +the mill it is without question as much in advance of the new process as +that is ahead of the old style of milling. + +In order that I may convey to you as clear an idea of gradual milling +reduction as possible, I will give as fully as possible the programme of +a mill of one hundred and fifty barrels maximum daily capacity designed +to work on mixed hard and soft spring wheat, and which probably will +come much nearer to meeting the conditions under which you have to mill +than any other I have found readily obtainable. I have chosen a mill of +this size, first, because following out the programme of a larger one +would require too much time and too great a repetition of details and +not give you any clearer idea of the main principles involved, and +secondly, because I thought it would come nearer meeting the average +requirements of the members of your association. Your worthy secretary +cautioned me that I must remember that I was going to talk to winter +wheat millers. The main principles and methods of gradual reduction are +the same, whether applied to spring or winter wheat; the details may +have to be varied to suit the varying conditions under which different +mills are operated. For this programme I am indebted to Mr. James Pye, +of Minneapolis, who is rapidly gaining an enviable and well deserved +reputation as a milling engineer, and one who has given much study to +the practical planning and working of gradual reduction mills. + +And right here let me say that no miller should undertake to build +a gradual reduction mill, or to change over his mill to the gradual +reduction system, until he has consulted with some good milling engineer +(the term millwright means very little nowadays), and obtained from him +a programme which shall fit the size of the mill, the stock upon which +it has to work, and the grade of flour which it is to make. This +programme is to the miller what a chart is to the sailor. It shows him +the course he must pursue, how the stuff must be handled, and where it +must go. Without it he will be "going it blind," or at best only feeling +his way in the dark. A gradual reduction mill, to be successful, must +have a well-defined system, and to have this system, the miller must +have a definite plan to work by. But to go on with my programme. + +The wheat is first cleaned as thoroughly as possible to remove all +extraneous impurities. In the cleaning operations care should be taken +to scratch or abrade the bran as little as possible, for this reason: +The outer coating of the bran is hard and more or less friable. Wherever +it is scratched a portion is liable to become finely comminuted in the +subsequent reductions, so finely that it is impossible to separate it +from the flour by bolting, and consequently the grade of the latter is +lowered. The ultimate purpose of the miller being to separate the flour +portion of the berry from dirt, germ, and bran it is important that he +does not at any stage of the process get any dirt or fine bran speck or +dust mixed in with his flour, for if he does he cannot get rid of it +again. So it must be borne in mind that at all stages of flouring, any +abrasion or comminution of the bran is to be avoided as far as possible. + +After the wheat is cleaned, it is by the first break or reduction split +or cut open, in order to liberate the germ and crease impurities. As +whatever of dirt is liberated by this break becomes mixed in with the +flour, it is desirable to keep the amount of the latter as small as +possible. Indeed, in all the reductions the object is to make as little +flour and as many middlings as possible, for the reason that the latter +can be purified, while the former cannot, at least by any means at +present in use. After the first break the cracked wheat goes to a +scalping reel covered with No. 22 wire cloth. The flour, middlings, +etc., go through the cloth, and the cracked wheat goes over the tail of +the reel to the second machine, which breaks it still finer. After this +break the flour and middlings are scalped out on a reel covered with +No. 22 wire cloth. The tailings go to the third machine, and are still +further reduced, then through a reel covered with No. 24 wire cloth. The +tailings go to the fourth machine, which makes them still finer, then +through a fourth scalping reel the same as the third. The tailings from +this reel are mostly bran with some middlings adhering, and go to the +fifth machine, which cleans the bran. From this break the material +passes to a reel covered with bolting cloth varying in fineness from No. +10 at the head to No. 00 at the tail. What goes over the tail of this +reel is sent to the bran bin, and that which goes through next to the +tail of the reel, goes to the shorts bin. The middlings from this reel +go to a middlings purifier, which I will call No. 1, or bran middlings +purifier. The flour which comes from this reel is sent to the chop reel +covered at the head with say No. 9, with about No. 5 in the middle and +No 0 at the tail. You will remember that after each reduction the flour +and middlings were taken out by the scalping reels. This chop, as it is +now called, also goes to the same reel I have just mentioned. The +coarse middlings which go over the tail of this reel go to a middlings +purifier, which I will designate as No. 2. These go through the No. 0 +cloth at the tail of the reel purifier No. 3; those which go through No. +5 cloth got to purifier No. 4; while all that goes through the No. 9 +cloth at the head of the reel is dropped to a second reel clothed with +Nos. 13 to 15 cloth with two feet of No. 10 at the tail. The flour from +this reel goes to the baker's flour packer; that which drops through the +No. 10 is sent to the middlings stone, while that which goes over the +tail of the reel goes to purifier No. 4. We have now disposed of all the +immediate products of the first five breaks, tracing them successively +to the bran and shorts bins, to the baker's flour packer and to the +middlings purifiers, a very small portion going to the middlings stone +without going through the purifiers. + +The middlings are handled as follows in the purifiers. From the No. 1 +machine, which takes the middlings from the fifth break, the tailings go +to the shorts bin, the middlings which are sufficiently well purified go +to the middlings stone, while those from near the tail of the machine +which contain a little germ and bran specks go to the second germ rolls, +these being a pair of smooth rolls which flatten out the germ and crush +the middlings, loosening adhering particles from the bran specks. From +the second germ rolls the material goes to a reel, where it is separated +into flour which goes into the baker's grade, fine middlings which are +returned to the second germ rolls at once, some still coarser which go +to a pair of finely corrugated iron rolls for red dog, and what goes +over the tail of the reel goes to the shorts bin. The No. 2 purifier +takes the coarse middlings from the tail of the first or chop reel as +already stated. The tailings from this machine go to the shorts bin, +some few middlings from next the tail of the machine are returned to the +head of the same machine, while the remainder are sent to the first germ +rolls. The reason for returning is more to enable the miller to keep a +regular feed on the purifiers than otherwise. The No. 3 purifier takes +the middlings from the 0 cloth on the chop reel. From purifier No. 3 +they drop to purifier No. 5. A small portion that are not sufficiently +well purified are returned to the head of No. 3, while those from the +head of the machine, which are well purified, are sent to the middlings +stones. The remainder, which contain a great deal of the germ, are taken +to the first germ rolls, in passing which they are crushed lightly to +flatten the germ without making any more flour than necessary. The No. 4 +purifier takes the middlings from No. 2 and also from No. 5 cloth on +the chop reel and from the No. 10 on the tail of the baker's reel. The +middlings from the head of this machine go to the middlings stones, and +the remainder to purifier No. 6. The tailings from Nos. 3, 4, 5, and 6 +go to the red dog rolls. A small portion not sufficiently well purified +are returned from No. 6 to the head of No. 4, while the cleaned +middlings go to the middlings stones. + +The portions of the material which have not been traced either to the +baker's flour or the bran and shorts bins are the middlings which have +gone to the middlings stones, the germy middlings which have gone to the +first germ rolls, and the tailings from purifiers Nos. 3, 4, 5, and 6, +and some little stuff not quite poor enough for shorts from the reel +following the second germ rolls. Taking these _seriatim_: the middlings +after passing through the middlings stones, go to the first patent reel +covered with eleven feet of No. 13 and four feet of No. 8. The flour +from the head of the reel goes to the patent packer, that from the +remainder of the reel is dropped to another reel, while the tailings go +to the No. 4 purifier. The lower patent reel is clothed with No. 14 and +two feet of No. 10 cloth; from the head of the reel the flour goes to +the patent packer, the remainder that passes through the No. 10 cloth +which will not do to go into the patent, being returned to the middlings +stones, while the tailings are sent to the No. 4 purifier. + +The germ middlings, after being slightly crushed as before stated, are +sent to a reel covered with five feet of No. 13 cloth, five feet of No. +14, and the balance with cloth varying in coarseness from No. 7 to No. +00. The flour from this reel goes into the patent, the tailings to the +red dog rolls, the middlings from next the tail of the reel which still +contain some germ to the second germ rolls, while the middlings which +are free from germ go to the middlings stones. + +The tailings from purifiers 3, 4, 5, and 6, the material from the reel +following the second germ rolls, which is too good for shorts, but not +good enough to be returned into middlings again, and the tailings from +the reel following the first germ rolls are sent to the red dog rolls, +which, as I have stated, are finely corrugated. Following these rolls is +the red dog reel. The flour goes to the red dog bin, the tailings to +the shorts bin, while some stuff intermediate between the two, not fine +enough for the flour but too good for shorts, is returned to the red dog +rolls. + +This finishes the programme. I have not given it as one which is exactly +suited to winter wheat milling. However, as I said before, the general +principles are the same in either winter or wheat gradual reduction +mills, and the various systems of gradual reduction, although they +differ in many points, and although there are probably no two engineers +who would agree as to all the details of a programme, the main ideas +are essentially the same. The system has been well described as one of +gradual and continued purification. In the programme above given the +idea was to fit up a mill which should do a maximum amount of work of +good quality with a minimum amount of expenditure and machinery. In a +larger mill or even in a mill of the same capacity where money was not +an object, the various separations would probably be handled a little +differently, the flour and middlings from the first and fifth breaks +being handled together, and those from the second, third, and fourth +breaks being also handled together. The reason for this separation being +that the flour from the first and fifth breaks contain, the first a +great deal of crease dirt, and the fifth more bran dust than that from +the other breaks, the result being a lower grade of flour. The object +all along being to keep the amount of flour with which dirt can get +mixed as small as possible, and not to lower the grade of any part of +the product by mixing it with that which is inferior, always bearing in +mind that the aim is to make as many middlings as possible, for they can +be purified while the flour can not, and that whenever any dirt is once +eliminated it should be kept out afterwards. This leads me to say that +if a miller thinks the adoption of rolls or reduction machines is all +there is of the system, he is very much mistaken. If anything, more of +the success of the mill depends upon the careful handling of the stuff +after the breaks are made, and here the miller who is in earnest to +master the gradual reduction system will find his greatest opportunities +for study and improvement. A few years back it was an axiom of the trade +that the condition of the millstone was the key to successful +milling. This was true because the subsequent process of bolting was +comparatively simple. Now the mere making of the breaks is a small +matter compared with the complex separations which come after. In +the foregoing programme we had five breaks or successive reductions. +Although this is better than a smaller number, I will here say that +it is not absolutely essential, for very good work is done with four +breaks. The mill for which this programme was made, including the +building, cost about $15,000, and is designed to make about sixty per +cent. of patent, thirty-five per cent. of baker's, and five per cent. +of low grade, results which are in advance of many larger and more +pretentious mills. + +One difficulty in the way of adapting the gradual reduction system to +mills of very small capacity is that the various machines require to be +loaded to a certain degree in order to work at their best. It is only a +matter of short time when our milling inventors will design machinery +especially for small mills; in fact they are now doing it, and every +day brings it more within the power of the small miller to improve his +manner of milling. To show what can be done in this direction I will +briefly describe a mill of about ninety barrels maximum capacity per +twenty-four hours, which is as small as can be profitably worked. I will +premise this description by saying it is designed with a view to the +greatest economy of cost, the best trade of work, and to reduce the +amount of machinery and the handling of the stuff as much as possible. +This latter point is of much importance in any mill, either large or +small, no matter upon what system it is operated, for it takes power to +run elevators and conveyors, and especially in elevating and conveying +middlings, especially those made from winter wheat, their quality is +inured and a loss incurred, by the unavoidable amount of flour made by +the friction of the particles against each other. So much is this the +case that in one of our largest mills it is deemed preferable to move +the middlings from one end of the mill to the other by means of a hopper +bin on a car which runs on a track spiked to the floor, rather than to +employ a conveyor. A mill built as I am going to describe would require +from fifty to sixty horse-power to run it, and including steam power and +building would cost from $10,000 to $12,000, according to location. I +give it as of interest to those among your number who own small mills +and may contemplate improving them. + +The building is four stories high, including basement, and thirty-two +feet square. It would be some better to have it larger, but it is made +this small to show how small a space a mill of this size can be made to +occupy. No story is less than twelve feet high. The machinery Is very +conveniently arranged, and there is plenty of room all around. The +system is a modification of the gradual reduction system, the middlings +being worked upon millstones. The first break is on one pair of 9 x +18 inch corrugated iron rolls, eight corrugations to the inch, the +corrugations running parallel with the axis of the rolls. The second +break on rolls having twelve corrugations to the inch, the third +sixteen, and the fourth twenty to the inch, while the fifth break, where +the bran is finally cleaned, has twenty-four corrugations to the inch. +The basement contains the line shaft and pulleys for driving rolls, +stones, cockle machine, and separator. The only other machinery in the +basement is the cockle machine. The line shaft runs directly through +the center of the basement, the power being from engine or water wheel +outside the building. The first floor has the roller mills in a line +nearly over the line shaft below, the middlings stones, two in number, +at one side opposite the entrance to the mill, the receiving bin at +one side of the entrance in the corner of the mill, and the two flour +packers for the baker's and patent flour in the other corner. This +arrangement leaves over half of the floor area for receiving and packing +purposes. The bolting chests, one with six reel and the other with three +reel begin on the second floor and reach up into the attic. An upright +shaft from the line shaft in the basement geared to a horizontal shaft +running through the attic parallel with the line shaft below, comprise +about all the shafting there is in the mill. There is a short shaft on +the second floor from which the two purifiers on this floor and the two +in the attic are driven, and another short shaft on the first floor to +drive the packers. There are four purifiers, two on the second floor, +and two more directly over them in the attic. The elevator heads are all +directly upon the attic line shaft, and the bolting chests are driven by +uprights dropped from this shaft. The combined smutter and brush machine +is on the third floor at one end of the bolting chests and directly over +the stock hoppers. This comprises all the machinery in the mill. The +programme is about as follows: + +The break reels are clothed as follows: First break No. 20, wire cloth, +second break No. 22, third break No. 24, and fourth break No. 24. The +material passing through these scalping reels, now called chop, goes to +a series of reels, the first clothed with Nos. 6, 4, and 0. The material +passing over the tail is sent to the germ purifier, that passing through +Nos. 4 and 0, to the coarse middlings purifier, and that through the No. +6 goes to the reel below clothed with Nos. 12 and 13. Some nice granular +flour is taken off from this reel; the remainder, which passes over the +tail and through the cutoffs, goes to the next reel below clothed with +Nos. 14, 15, and 9. Some good flour comes from the 14 and 15; that which +passes through the 9 goes at once to the stones without purifying, while +that which passes over the tail is sent to the fine middlings purifiers. + +After the purification, the middlings are ground on stones and bolted +on Nos. 13 and 14 cloth, after having been scalped on No 8. The germ +middlings are crushed on smooth rolls and bolted on Nos. 12 and 13. What +is not crushed fine enough goes with poor tailings to the second germ +rolls, and from these to a reel by themselves or to the fifth reduction +or bran reel. A mill of this kind could be made much more perfect by an +expenditure of two or three thousands dollars more. I have instanced it +to show what can be done with gradual reduction in a very small way. + +In mills of from three hundred to five hundred barrels capacity and +still larger, the programme differs considerably from that I have +sketched, the middlings being graded and handled with little, if any, +returning, and are sized down on the smooth rolls, a much larger +percentage of the work of flouring being done on millstones. For a three +hundred barrel roller mill, the following plant is requisite: five +double corrugated roller mills, five double smooth roller mills, three +pairs of four foot burrs sixteen purifiers, four wire scalping reels, +six feet long, one reel for the fifth break, one reel for low grade +flour, eight chop reels, seven reels for flour from smooth rolls, three +reels for the stone flour, two grading reels, three flour packers, and +necessary cleaning machinery. The reels are eighteen feet thirty-two +inches. The programme is necessarily more complicated. + +When it comes to the machinery to be employed in making the reductions +or breaks, the miller has several styles from which to choose. Which is +best comes under the head of what I don't know, and moreover, of that +which I have found no one else who does know. Each machine has its good +points, and the mill owner must make his own decision as to which is +best suited to his purpose. The main principles involved are to abrade +the bran as little as possible while cleaning it thoroughly, and to make +as little break flour, and as many middlings as possible, the latter to +be made in such shape as to be the most easily purified. Regarding +the difference between spring and winter wheat for gradual reduction +milling, it may be stated something after this manner: Spring wheat +has a thinner and more tender bran, makes more middlings because it is +harder, and for the same reason the flour is more inclined to be coarse +and granular. In milling with winter wheat, especially the better +varieties, there will be more break flour made, the middlings will be +finer with fewer bran specks, and the bran more easily cleaned, because +it will stand harsher treatment. Winter wheat, moreover, requires more +careful handling in making the breaks, not because of the bran, but to +avoid breaking down the middlings, and making too much and too fine and +soft break flour. In order to keep the flour sharp and granular, coarser +cloths are used in bolting, and because the middlings are finer the +bolting is not so free and a larger bolting surface is required. In +milling either spring or winter wheat there should be ample purifying +capacity, it being very unwise to limit the number of machines, so that +any of them will be overtaxed. The day has gone by when one purifier +will take care of all the middlings in the mill. + +There is one point which is of much interest to mill owners who wish to +change their mills over to the gradual reduction process, that is, how +far they can utilize their present plan of milling machinery in making +the change. Of course the cleaning machinery is the same In both cases, +so are the elevators, conveyors, bolting chests, etc. But to use the +millstone is a debatable question. After carefully considering the +matter I have come to the conclusion that it has its place, and an +important one at that, under the new regime, viz., that of reducing +the finer purified middlings to flour. The reason for this lies in the +peculiar construction of the wheat berry. If the interior of the berry +were one solid mass of flour, needing only to be broken up to the +requisite fineness, it could be done as well on the rolls. But instead +of this, as is well known, the flour part of the berry is made up of +a large number of granules or cells, the walls of which are cellular +tissue, different from the bran in that it is soft and white instead of +hard and dark colored. It is also fibrous to a certain extent, and when +the fine middlings are passed between the rolls instead of breaking +down and becoming finer, it has a tendency to cake up and flatten out, +rendering the flour soft and flaky. It does not hurt the color, but it +does hurt the strength. When the millstone is used in place of the roll +the flour is of equally good color, and more round and granular. I +know that in this the advocates of smooth rolls will differ from my +conclusions, but I believe that the final outcome will be the use of +millstones on the finer middlings, and in fact on all the middlings that +are thoroughly freed from the germ. + +It has been said that that which a man gives the most freely and +receives with the worst grace is advice. I will, however, close with a +little of the article which may not be wholly put of place. If you have +a mill do not imagine that the addition of a few pairs of rolls, a +purifier or two, and a little overhauling of bolting-chests, is going to +make it a full-fledged Hungarian roller mill. If you are going to change +an old mill or build a new one, do not take the counsel or follow the +plans of every itinerant miller or millwright who claims to know all +about gradual reduction. No matter what kind of a mill you want to +build, go to some milling engineer who has a reputation for good work, +tell him how large a mill you want, show him samples of the wheat it +must use and the grades of flour it must make, and have him make a +programme for the mill and plan the machinery to fit it. Then have the +mill built to fit the machinery. When it starts follow the programme, +whether it agrees with your preconceived notions or not, and the mill +will, in ninety-nine cases out of one hundred, do good work. + + * * * * * + + +MACHINE FOR DOTTING TULLES AND OTHER LIGHT FABRICS. + +Dotted or chenilled tulles are fabrics extensively used in the toilet +of ladies, and the ornamentation of which has hitherto been done by +the application to the tissue, by hand, either of chenille or of small +circles previously cut out of velvet. This work, which naturally takes +considerable time, greatly increases the cost price of the article. + +A few trials at doing the work mechanically have been made, but without +any practical outcome. The workwomen who do the dotting are paid at +Lyons at the rate of 80 centimes per 100 dots; so that if we take +tulle with dots counter-simpled 0.04 of an inch, which is the smallest +quincunx used, and suppose that the tissue is 31 inches wide and that +the daily maximum production is one yard, we find that 400 dots at 80 +centimes per 100 = 3 francs and 20 centimes (about 63 cents), the cost +of dotting per yard. It is true that the workwoman furnishes the velvet +herself. + +Mr. C. Ricanet, of Lyons, has recently invented a machine with which he +effects mechanically the different operations of dotting, not only on +tulles but also upon gauzes or any other light tissues whatever, such +as those of cotton, silk, wool, etc. Aided by a talented mechanic, Mr. +Ricanet has succeeded in constructing one of those masterpieces of +wonderfully accurate mechanism of which the textile industry appears +to have the monopoly--at least it is permissible to judge so from the +remarkable inventions of Vaucanson, Jacquard, Philippe de Girard, +Heilmann, and others. + +The object of this new machine, then, which has been doing its wonderful +work for a few days only, is to reproduce artificially chenille +embroidered on light tissues, by mechanically cutting out and gluing +small circles of velvet upon these fabrics. + +For this purpose all kinds of velvet may be employed, and, in order to +facilitate the cutting, they are previously coated on the reverse side +with any glue or gum whatever, which gives the velvet a stiffness +favorable to the action of the punch. To effect the object desired the +apparatus has three successive operations to perform: first, cutting the +circles; second, moistening; and third, fastening down the dots upon the +tissue according to a definite order and spacing. The machine may be +constructed upon any scale whatever, although at present it is only made +for operating on pieces 31 inches wide, that being the normal width of +dotted tulles. The quincuncial arrangement of the dots is effected by +the punching, moistening, and fastening down of odd and even dots, +combined with the forward movement of the tissue to be chenilled. + +The principal part of the machine is the cam-shaft, A (Figs. 1, 2, and +3), which revolves in the direction of the arrows and passes in the +center of 80 cam-wheels, 40 of which are odd and 40 even, alternately +opposed to each other. This shaft actuates, through its two extremities, +the different combined motions in view of the final object to be +attained, and also carries the motive pulleys, PP'. Figs. 1 and 2 show +the profile of two of these opposed cam-wheels--the arrangement by means +of which two rows of dots (odd and even) are laid down upon the tissue +during one revolution of the shaft or drum, A. Each of the wheels +carries three cams (Figs. 1 and 3), the first, (_a_), corresponding to +the punching; the second, (_a'_), to the moistening, and the third, +(_a''_), to the gluing down of the dots. + +The annexed figure, one-quarter actual size, shows in section the +details of the cutting mechanism. To each cam-wheel there corresponds +one punch, and the eighty punches are arranged side by side and parallel +upon a shaft, B, a spring, _b_, holding them constantly against the +circumference of the cam-wheels. In Fig. 2 only one of these details is +shown. The punching arrangement consists of an ordinary punch, _c_, of +variable diameter, screwed to the extremity of a tube, _d_, which is +itself suspended from the end of the lever, _p_, but which can receive +from it at the desired moment the pressure necessary to effect the +cutting. The vertical position of these multiple tubes is insured by +a guide, _e_, which is thoroughly indispensable. Through each of the +tubes, _d_, there passes a plunger designed for expelling from the punch +the piece that has been cut out of the velvet, and for gluing it down to +the fabric. The two small springs, _b'_ and _b''_, tend continually to +lift the tubes as well as the plunger. The whole mechanism is affixed to +solid cast-iron frames, and the machine itself may be mounted on wooden +supports or a metal frame. + +The punching is effected on a bronze straight-edge, C, which slides in a +cast-iron channel, D. This presents alternately, in its movement, entire +and punctured spaces, the former for receiving the blow of the punch and +the latter for allowing passage at the desired moment to the plunger +as it goes to fasten the dots upon the tulle which is passing along +underneath the channel, D. The punching is done primarily and +principally by pressure, but, in order to facilitate the complete +detachment of filaments which might retain the punched-out piece, the +punch is likewise given at the same time a slight rotary motion, thus +imitating mechanically what is performed by hand in the maneuver of all +punches. This rotary motion is communicated to the punches by means of +levers actuated by an eccentric, E, and which move the frame, _h_, whose +bars engage with the horizontal lever, _g_, soldered to the tube, _d_, +thus causing the latter at the very moment the punch descends to revolve +from right to left. The forty punches in operation cause the frame to +return to its initial position through the action of the springs, _b'_. +We say forty, since the inventor, in principle, has admitted 80 punches, +operating 40 as odd and 40 as even; obtaining in this way a dotting in +a regular quincunx of one yard, that is to say, 80 dots arranged in two +rows on a fabric 31 inches wide. But it is evident that a much larger +quincunx may be had by putting in play only a half, a third, or a +fourth of the punches, and causing the tulle and velvet to advance +proportionally. For this purpose it is only necessary to unscrew the +punches which are not to act, and to substitute for the ratchet wheel +which controls the unrolling of the I tulle, another having a number of +teeth proportioned to the desired spacing of the dots. + +The punching having been executed, and the drum, A, continuing to +revolve, the punches rise a little owing to the conformation of the +cam-wheel, and through the action of the springs, _b_, and allow the +moistener to move forward to dampen the little circles which remain at +the orifice of the punches. The moistener or dampener is a sort of pad +equal in length to the field of action of the punches, and is affixed +to a cross-bar, F, which is connected at its two extremities with the +levers, G, that are actuated by the cam-wheels, H. These cam-wheels, or +eccentrics, H, which are mounted on the shaft of the drum, A, cause the +moistener to move forward as soon as the punches rise after operating, +and, when it arrives beneath the punches, the larger cams, _a_, of +the cam-wheels, A, press the latter upon the pad and thus effect the +dampening of the circles of velvet. + +Immediately afterwards, the same eccentrics, H, acting on a lever, I, +uncover the holes in the straight-edge, C, and the channel, D. The +large cams, _a"_, of the wheel, A, then acting very powerfully upon the +respective punches, cause these latter to pass through the orifices so +that the extremity of each punch comes within about one twenty-fifth of +an inch of the fabric to be dotted. In this passage of the tube, _d_, a +small rod, _i_, connected by a lever with the plunger, _f_, is made to +abut against the guide, _e_, thus causing the descent of the plunger to +a sufficient degree to push the velvet "dot" out of the tube and to glue +it upon the fabric. The manner in which these operations are performed +being now well enough understood, let us for a moment examine the +motions of the fabrics to be cut and dotted--the first being velvet or +any other material, even metal (goldleaf, for example), and the second, +the tulle. + +The latter has but one motion, and that is in the direction of its +length, while the velvet has, in addition to this same motion, another +slight one from right to left in the direction of its width in order to +diminish waste as much as possible. + +The tulle to be dotted is first wound around a roller, R, from whence it +passes over the glass guide-roller, R', and between the channel, D, and +the table, T, to the roller, R", which is heated by steam. + +The hot air which is radiated dries the dots, and from thence the fabric +is taken up by other rollers or by any other method. The steam roller, +R", carries at one of its extremities a ratchet wheel whose teeth vary +in number according to the greater or less rapidity with which the tulle +is unrolled. It is actuated by a lever which receives its motion from +the eccentric, K. + +[Illustration: IMPROVED MACHINE FOR DOTTING TULLAND OTHER LIGHT +FABRICS.] + +In the table, T, there is a rectangular receptacle, _t_, containing +rasped or powdered velvet for the purpose of forming a reverse of the +dot. This powder attaches itself to the gum and imitates on the wrong +side of the fabric a dot similar to that on the upper or right side. The +velvet is wound upon the roller, _r_, and from thence passes under the +guiding roller, _r'_, the punches, and the second roller, _r"_. These +two latter rollers are solidly connected by a straight-edge fixed at the +extremity of the lever, L, whose other end is in continuous correlation +with the eccentric, M, which controls the lateral displacements; +while the eccentric, O, actuates, by means of the screw, Q, and the +ratchet-wheel, S, the longitudinal advance of the velvet. The eccentric, +M, is fixed upon an axle, A', which carries a wheel, U, having teeth +inclined with respect to its axis, and which derives its motion from the +Archimedean screw, N, fixed at one of the extremities of the cam-shaft, +A. + +We have stated above that the maximum daily hand production of tulle +dotted in quincunxes of 0.04 of an inch is about one yard. At the rate +of 30 revolutions per minute, and for the same article as that just +mentioned, this dotting machine is capable of producing, theoretically, +360 yards per 10 hours; but practically this production is reduced to +about 250 yards, which, however, is sufficiently satisfactory. + + * * * * * + + + + +THE REPRODUCTION AND MULTIPLICATION OF NEGATIVES. + +By ERNEST EDWARDS, B.A. + + +A question, relative to the subject of reproducing negatives, which was +put at a meeting of one of your New York societies, prompts me to make a +few remarks on the subject. + +Among the numerous and widely diversified ramifications of our business +(the Heliotype Printing Company) we have very often to reproduce and +multiply negatives in both a direct and reversed form. Various methods +for doing this have been tried, and I may here say that I am quite well +aware of all the methods that have hitherto been suggested for the +purpose, but that which I am to describe is the one to which preference +has been given, and which is that known as the carbon process. + +A sheet of carbonized paper or "tissue," having been sensitized by +immersion in a bath of bichromate of potash, is dried in the dark and +placed away for future use, although it is undesirable that it be kept +for more than four or five days. This is placed in a printing frame in +contact with the negative and exposed for a few minutes, after which it +is immersed in water, squeegeed down upon a glass plate, and developed +with warm water in the way so well known to carbon printers. The result +is a transparency which, owing to having received a sufficient exposure, +should show every detail of the negative. The nature of the tissue +employed for such a purpose must be such as to give no strong contrasts, +but everything reproduced with soft and fine gradation of tone. + +The transparency thus obtained forms the _cliché_ by which the negatives +are subsequently made; and a negative of any size may be obtained by +the camera on wet or dry plates. The transparency must, of course, be +pointed to the sky and the light transmitted through it, no other light +being allowed to reach the lens except that which passes through the +carbon transparency. Care must also be taken that the transparency is +_uniformly_ lighted. If it is not possible to obtain a northern light, +which is best, a reflector of white paper or card may be used which must +be sufficiently large and placed at an angle of about forty-five degrees +to the transparency. + +If the repeated negative is to be of the same size as the original it +may be readily produced by repeating the operation of printing on carbon +tissue, using the transparency in place of the negative, or using a dry +plate in place of the tissue. But on the whole I have satisfied myself +that the best results are to be obtained by the first method. There is +a greater softness in the latter method, but a greater character and +similarity to the original in the former method. There is no doubt that +the use of the carbon transparency removes the hardness and riffidness +of the outlines peculiar to the older method of a collodion +transparency, while with carbon as the medium it is difficult for +any but the most experienced eye to distinguish the copy from the +original.--_Photo Times._ + + * * * * * + + + + +A NEW METHOD OF MAKING GELATINE EMULSION. + + +Since gelatine emulsion first came into use one of the greatest troubles +in connection with the manufacture of it has been that of washing. +According to the first methods the time taken for this part of the +process was, I believe, about twenty-four hours. It was very much +reduced and the ease of manufacture greatly facilitated by the methods +now most generally used, and which were, I believe, first communicated +by Messrs. Wratten and Wainright. I refer to those of precipitating with +alcohol and of straining the emulsion, when set, through canvas, so +as to divide it very finely. When the latter method is resorted to a +comparatively short time is sufficient to wash it. This method, although +a great improvement upon the older ones, yet leaves much to be desired, +especially for those who are not in the habit of making emulsion +regularly, but only an occasional batch. When the weather is at all warm +it takes a long time for the emulsion to set, unless ice be used, and +when once it is set the washing process is an exceedingly "messy" one +unless the water be cooled with ice; and the amount of water taken up +during washing is often so great that there is considerable difficulty +in getting the emulsion to set on the plates. In fact, even in cold +weather, it is not an easy process to conduct in the necessary near +approach to total darkness. + +Considerable suspicion has of late been thrown upon the thoroughness of +the alcohol method, unless the emulsion has, previous to precipitation, +been freed of the greater part of the soluble salts by washing; that is +to say, it is doubtful whether the whole of the soluble salts can be +eliminated by the process, and, therefore, unless in exceptionally hot +weather, it would seem best not to trust to it, except as a further +security against soluble bromide and nitrate after washing. Besides +this, the consumption of alcohol is very large. Almost three times the +amount of the emulsion precipitated is required, and this, even when +methylated spirit is used, adds considerably to the expense. With a view +of doing away with the washing altogether, or, rather, of washing of +the silver bromide when not incorporated with the gelatine, several +processes have been invented. By these silver bromide is obtained in a +very fine state of division, ready to mix with gelatine and water in any +proportion. + +The best known of them is Captain Abney's very ingenious glycerine +method, which seems to have been thoroughly successful in his hands, +although it has not been in every one's. The silver bromide obtained by +his process is not highly sensitive, and requires boiling with gelatine +before it is in a fit state to make a rapid plate. + +We have lately had described in these columns a method of obtaining +bromide in a highly-sensitive state by means of the use of an acid, +whereby, after emulsifying and boiling, the viscosity of the gelatine +was destroyed, and the bromide in time deposited itself. During the late +hot weather, when washing became almost impossible, I was led to cast +about for some method of eliminating the soluble salts less tedious and +"sloppy" than that of washing, more certain and less expensive than that +of precipitating the whole of gelatine with alcohol, and which would +take less time than the method of obtaining the bromide in a pure form. + +My first idea was to make up the solutions used in emulsifying in a very +concentrated form, and, after emulsifying, boiling, and allowing to +cool, to add to the thin emulsion thus obtained gelatine to the amount +of twenty grains to the ounce, and to precipitate this with alcohol, +the rest of the gelatine required to make up the bulk being afterwards +added, and the whole thoroughly incorporated by warming and shaking. +I was thus successful in reducing the amount of alcohol required to +one-third of what would be necessary if the whole of the emulsion were +precipitated; but still I found that, if a reliable emulsion were +required, the pellicle as formed had to be washed to free it from the +last trace of soluble salts. + +It now struck me that it might be possible to precipitate the bromide of +silver direct from a very weak solution of gelatine, and obtain it in +such a form that it might be filtered, washed, and in every way treated +as an ordinary precipitate. I tried the following experiment. I took-- + + 1. Silver nitrate....................... 200 grains + Water............................... 1½ ounce. + 2. Ammonia bromide...................... 120 grains. + Water................................ 1½ ounce. + Gelatine............................. 12 grains. + +I emulsified the two together in the usual way, allowed the whole +to cool, and then poured the thin emulsion into about ten ounces +of alcohol, stirring the while. As I had anticipated, a flocculent +precipitate was formed, which settled to the bottom of the vessel in a +few minutes. This was, in fact, sensitive bromide of silver mixed with +a very small quantity of gelatine (about five per cent.), and could, I +found, be treated in the same manner as a bromide precipitate from +an aqueous solution; it might be washed, either by decantation or by +filtration, easily dried, and doubtless could, when dry, be kept for an +indefinite time, and be at any time used by mixing with gelatine and +water in any proportion thought fit. + +I found that a less amount of gelatine than four grains to the ounce was +sufficient to carry the bromide down, while five grains to the ounce +carried it down in something which I considered too near an approach to +a plastic mass. + +It will be noticed that in the experiments which I have described the +emulsion had not been boiled, so that the sensitiveness of the bromide +was probably not great. As the experiment was done in daylight it was +of no practical use for making emulsion; but I have since made several +batches in this manner and have found them most satisfactory. + +When sensitiveness is sought by boiling I rind it necessary to add a +small quantity of gelatine after boiling and before precipitating, as +that which has been kept for some time at a high temperature seems to +have lost the viscosity necessary to carry down the silver bromide in +such a form that it can he easily separated from the alcohol and water. + +The practical manner of making an emulsion by this method may be as +follows. Make up the following mixtures: + + I. + Silver nitrate...........................................400 grains. + Water..................................................... 3 ounces. + + II. + + Ammonia bromide..........................................240 grains. + Gelatine..................................................24 grains + Water..................................................... 3 ounces. + Hydrochloric acid enough to slightly acidify the solution. + + III. + Gelatine................................................. 20 grains. + Water.................................................... ½ ounce. + IV. + + Hard gelatine (say Nelson's X opaque, + or Mr. A. L. Henderson's)................................240 grains. + Soft gelatine (Nelson's No.1)........................... 240 grains. + Water.....................................................24 ounces. + +Nos. II., III., and IV. are allowed to stand until the gelatine is +softened. No. I is then warmed in a hock bottle until the gelatine is +just melted, when No. II. is poured into it, a little at a time, with +vigorous shaking, until the whole is emulsified. It is then transferred +to an ordinary jelly can, which is placed in a saucepan half full of +water over a ring Bunsen burner in the dark room, and boiled for half an +hour. It is then allowed to cool to about 100° Fahr., when No. III. is +added. The whole is then allowed to get quite cool, when it is poured, +with stirring, into about one pint of methylated spirit. If it be wished +the precipitate may now be filtered out and washed at once like an +ordinary filtrate, but I prefer to allow it to settle, which it will do +in about five minutes. The supernatant fluid is then gently poured off. + +This fluid will have the appearance of still containing a considerable +amount of the silver bromide; but if it be kept and filtered it will be +seen that the quantity is really so small that it may be disregarded. We +all know what an alarming quantity of silver seems to be going down the +sink when we wash vessels to which a very small quantity of emulsion is +adhering. If filtering be resorted to the liquid which comes through +will be quite clear. This was somewhat unexpected by me, as, if an +emulsion containing the whole of the gelatine be precipitated into +alcohol in the usual way, the alcohol becomes milky with a substance +which could not, I imagine, be filtered from it. + +Two or three ounces of methylated spirit are now added to the vessel +containing the silver bromide, and the latter well mixed with it. This +makes the precipitate "firmer"--if such an expression be allowable--and +this time it will sink to the bottom almost immediately after the +stirring has ceased, and the alcohol may be poured off. + +I consider that the bromide in this state is practically free from +soluble salts, but it may be washed with one or two changes of water if +desired. + +No. IV. is now gently heated till the gelatine is melted and the +precipitate mixed with it. It must be kept warm for some time, and +shaken vigorously until all granularity has disappeared, This is, of +course, ascertained by placing a drop of the emulsion on a piece of +glass, and examining it. If it be wished to keep the bromide of silver +for future use it may be placed on a piece of muslin stretched in the +drying-box, when it will dry in a very short time; and, although I +cannot speak from experience on this point, it will, I have no doubt, +keep for an indefinite time so long as light is kept from it. + +If it be desired the ammonio-nitrate method may be used instead of the +boiling one, although in my hands it does not give such sensitiveness. +If it be desired to use this method, solution Nos. I, II., and IV. are +made up exactly as for the boiling method, except that No. II. is not +acidified. Liquid ammonia is then poured with stirring into the silver +solution, until it blackens and again clears. Emulsification is +performed exactly as described above, but instead of boiling, the +emulsion is kept at a temperature of about 100° Fahr. for half an hour, +when it is poured into the alcohol, no addition of gelatine being +previously made. + +I think I may claim for the method which I have just described that it +is less troublesome and more certain than either the ordinary washing +method or the usual one of precipitating with alcohol, while it affords +an easy method of making sensitive silver bromide in such a form that it +can be more easily stored and afterwards manipulated than if it were in +the form of pellicle. The whole of the soluble salts are eliminated, +and also any gelatine which may have been destroyed in the cooking. +The amount of alcohol used is comparatively small; in fact, to prepare +silver bromide for a pint of emulsion very little more than a pint of +methylated spirit is required. Besides this I do not think that I would +be wrong in saying that the chance of green fog is reduced to a minimum. + +Let me take this opportunity of thanking Captain Abney for his prompt +reply to my question about the connection between the proportion +of bromide to gelatine in emulsions, and the density of resulting +images.--_W. K. Burton, in British Journal of Photography_. + + * * * * * + +[Illustration: Old Wrought Iron Gates, Guildhall.] + + * * * * * + + + + +THE POTTERY AND PORCELAIN INDUSTRIES OF JAPAN. + + +Japanese chronicles claim that the first pottery was made in the year +660 B.C.; it was not, however, until the Christian era that the art made +any considerable advances. In the year 1223 A.D., great improvements +were made in manufacture and decoration of the ware. From that date to +the sixteenth century the great potteries of Owari, Hizen, Mino, Kioto, +Kaga, and Satsuma were established. The Rahn-Yaki, or crackled ware, was +first made at Kioto, at the commencement of the sixteenth century. The +best old Hizen ware, that which is still the most admired, was made +at Arita Hizen, in 1580 to 1585; the old Satsuma dates from 1592. +Consul-General Van Buren states that porcelain clays are found in nearly +all parts of the country, and the different kinds are usually found +in close proximity, and close to canals and rivers, which is of +considerable advantage, as affording a means of transport. In all cases +every variety of clay used in the manufacture of pottery is found in a +natural state; there is no necessity to manufacture the quartzose or +fusible clays as is done in other parts of the world, and which adds +considerably to the cost of the ware. One of the peculiarities in the +clay found in Japan is that it contains both the fusible and infusible +materials in such proportions as to make a light, beautiful, +translucent, and durable porcelain. At Arita, in Hizen, there is a clay +found which contains 783/4 per cent, of silica, and l73/4 per cent, of +alumina; from this clay is made the delicate, translucent eggshell ware, +without the addition of any other matter. From an adjoining bluff a clay +is taken which has 50 per cent, of silica, and 38 per cent, of alumina; +from this the common porcelain is made. + +Potter's clay is found in very large quantities in the provinces of +Yamashiro, Hoki, Turoo Iyo, Hizen, Higo, Owari, Mikaera, Idyn, Musashi, +and Mino. In the whole of Japan there are 283 localities where the clay +is deposited; many of these only furnish inferior clays, but they are +all fitted for use in some of the various kinds of pottery. These clays +are thoroughly powdered by means of what is called "balance pounders," +worked in some localities by water-power, but the work is often done by +hand. The powder is then dried, and stored on boards or in flat boxes. +This dough does not go through the process of fermentation. The shaping +is almost exclusively done on the potter's wheel, which is set on a +pivot working in a porcelain eye. As a rule, the wheel is turned by the +potter himself, but in Hizen it is kept in motion by means of a band +connected with its pivot and another wheel turned by a boy. In making +dishes of other shape than round, a crude mould is sometimes used. After +the clay has been shaped on the wheel, it is set away for drying, and +usually in two or three days it is considered sufficiently dry for +smoothing, which is done on the wheel with a sharp curved knife. The +material is now made into "bisque," or biscuit, by a preliminary baking +in small ovens, when it is ready for painting, if it is to be painted +on the biscuit; if not, it is ready for the glazing. In either event it +will then go to the large furnace for the final baking. The kilns for +this purpose are always built on hill sides, and are joined together, +increasing in size from the lower to the higher ones, and in number from +four to twenty five; these kilns are so constructed that the draught is +from the lowest one, in addition to which each kiln has its own firing +place. The result of this construction is that the upper ones are by +far the most heated, and the ware is arranged accordingly; that which +requires the least baking, in the lower kiln, and that which requires +the greatest heat, in the upper. These connecting kilns have the merit +of being heat saving, but they are usually small and badly constructed, +and the heat in none of them is uniform. + +The glaze is made from the silicious clay and potash extracted from wood +ashes. This potash is not a pure white, and this accounts for the dirty +color usually to be observed in unpainted Japanese ware. In different +districts the painting varies. For instance, in Owari, the greater part +of the ware is painted a cobalt blue--the cobalt ore being found in the +bluffs near the clay deposits, and is used for painting the cheaper +wares, and for this purpose German cobalt is also employed. The painting +with cobalt is generally done on the biscuit before glazing. In several +districts a very handsome ware is made, and painted on the glaze. For +this kind of painting the colors are mixed with a silicate of lead +and potash, and baked the third time in a small furnace at a low +temperature. The coloring oxides in use are those of copper, cobalt, +iron, antimony, manganese, and gold. Japanese porcelain painting may be +divided into two categories, decorative and graphic; the first is used +to improve the vessel upon which it is placed, and this class includes +all the ware except that of the province of Kaga, which would come under +the head of graphic, as it delineates all the trades, occupations, +sports, customs, and costumes of the people, as well as the scenery, +flora, and fauna of the country. "Owari ware" is made in the province +of that name; it is not as translucent, but stronger and more tenacious +than some of the Hizen manufacture. + +The principal potteries are at a village called Sèto, twelve miles from +the sea; in this village there are more than 200 kilns. The ware is +mostly painted a cobalt blue, and is merely of a decorative kind, +consisting of branches of trees, grass, flowers, birds, and insects, all +these being copied by the artist from nature. All the Owari ware is true +hard porcelain, and is strong and durable. In Hizen, a number of wares +are manufactured, the best known kind being the "Eurari," which is made +at Arita, but painted at Eurari. The colors in use are red, blue, green, +and gold; these are combined in various proportions, but, as a rule, the +red predominates. Generally the surface of the vessel is divided into +medallions of figures, which alternately have red, blue, or white +back-ground, with figures in green or blue and gold. + +The egg-shell porcelain sold at Nagasaki is made in this province from +Arita clay, and this is made from clay with no admixture of fusible +matter except that contained by the clay naturally. The province of +Satsuma is noted for crackled ware. It is only within a very few years +that large vases have been manufactured, and in earlier days the old +ware was confined to small vessels. The glaze is a silicate of alumina +and potash, and the best ware has a complete network of the finest +crackles; the painting is of birds and flowers, and noted for its +delicate lines of green, red, and gold. + +In Kioto, the ware manufactured is very similar to that produced in +Satsuma, but it is lighter and more porous; the decorations are also +nearly the same, being of birds and flowers. There is a description of +ware made in Kioto, called "Eraku," the whole body of which is covered +with a red oxide of iron, and over this mythical figures of gold are +traced. That produced in Kagja is _faïence_, and in the style of +painting is unlike any other in Japan, the predominating color being +a light red, used with green and gold. The designs with which it is +profusely decorated are trees, grasses, flowers, birds, and figures of +all classes of people, with their costumes, occupations, and pastimes. +The "Banko" ware is made at the head of the Owari Bay; it is an unglazed +stone-ware, very light and durable, made on moulds in irregular shapes, +and decorated with figures in relief. On the island of Awadji, a +delicate, creamy, crackled, soft paste porcelain is made. The figures +used in decoration are birds and flowers, but outlined by heavy, dark +lines. + +Consul Van Buren is of opinion that, at no distant day, Japan will be +one of the foremost competitors in the pottery markets of the world, +on account of the great variety and excellence of the clays, their +proximity to the sea, the cheapness of labor, and the beauty and +originality of the decorations. Already this important industry has been +greatly stimulated by the foreign demand, and by the success of +Japanese exhibitors at the Exhibitions of Vienna, Philadelphia, and +Paris.--_Journal of the Society of Arts_. + + * * * * * + +Professor Julius E. Hilgard, for twenty years assistant in charge of the +office, has been placed in temporary charge of the Coast and Geodetic +Survey. It is understood that he will be appointed superintendent to +succeed the late Captain Carlile P. Patterson. + + * * * * * + + + + +THE FRENCH CRYSTAL PALACE. + + +The first idea of the French Crystal Palace was suggested by the English +structure of the same name at Sydenham, about eight miles from London. +Such a structure, as may be readily conceived, requires a site of vast +extent, and one that shall be easy of access and possess the most +agreeable surroundings. To the promoter of the project, those portions +of the park of St. Cloud in the vicinage of the old chateau appeared to +combine within themselves all the conditions that were desirable, and +he, therefore, on the 15th of December, 1879, addressed the Ministers of +Public Works and of Finances asking for the necessary concessions. The +extensive specifications have been finally completed and will probably +be shortly submitted for the approval of the parliament. The moment has +arrived then for the public press to take cognizance of a project which +concerns so great interests. + +[Illustration: THE FRENCH CRYSTAL PALACE--PARK OF ST CLOUD, PARIS.] + +At present we shall say a few words _à propos_ of the engraving we +present herewith. The French Crystal Palace will consist of one great +nave, two lateral naves, two surrounding galleries, and a vast rotunda +behind. The principal entrance, located at the head of the avenue +leading from the present ruins (which will, ere long, be transformed +into a most interesting museum), will exhibit a very striking aspect +with its monumental fountain and the dome which it is proposed to erect +over the very entrance itself. The whole structure will cover about +nineteen acres of ground, thus being two and a half times the extent of +the Palace of Industry in the Champs Elysees. The great nave of honor +will be nearly 1,650 ft. in length, 78 ft. in width, and 98 ft. in +height. The dome will measure exactly 328 ft. in height, or 105 ft. more +than the towers of Notre Dame. The structure, with the exception of +basement and foundation, will be of glass and iron. + +The project which we publish to-day has been studied and gotten up, +according to the general plans and dimensions suggested by the promoter, +by Mr. Dumoulin, the architect. We are informed that the builder is to +be Mr. Alfred Hunnebelle, a contractor well known from the extensive +works that he has executed, and who is president of the Syndical Chamber +of Contractors of Paris. + +Among the annexes of this palace we may note a "Palace of the Republic," +to be built on the ruins and designed for illustrious or distinguished +visitors, such as the President of the Republic, the Ministers, the +Municipal Council of Paris, foreign delegates, etc.; a farm house for +special exhibitions and a field for experiments; galleries, cottages, +etc. + +As for the programme, which embraces six divisions and numerous +subdivisions, we are unable to give it at present for want of space; we +need only say that it satisfies perfectly all the conditions of so vast +an undertaking. + +In the hands of the projector, Mr. Nicole, who is well known from his +long experience in such matters, the exhibition will undoubtedly prove +a success and be instrumental in adding prosperity to all French +industries. + + * * * * * + +THE GREAT HEAT OF THE SUN.--Prof. S. P. Langley has made the following +calculation: A sunbeam one centimeter in section is found in the clear +sky of the Alleghany Mountains to bring to the earth in one minute +enough heat to warm one gramme of water by 1° C. It would, therefore, +if concentrated upon a film of water 1/500th of a millimeter thick, +1 millimeter wide, and 10 millimeters long, raise it 83 1/3° in one +second, provided all the heat could be maintained. And since the +specific heat of platinum is only 0.0032 a strip of platinum of the same +dimensions would, on a similar supposition, be warmed _in one second_ to +2,603° C.--a temperature sufficient to melt it! + + * * * * * + + + + +CHATEAU IN THE AEGEAN SEA. + + +From the site of this building, magnificent views are obtained over the +island-dotted sea and the mainland of Asia Minor: but, "though every +prospect pleases," it is a land of earthquakes, and unfortunately, the +works at the chateau have been suspended, owing to the dreadful calamity +which has recently fallen upon the district. The building is intended +for the residence of an English lady of exalted rank. It is to be built +of local white stone, the hall, staircase, etc., being lined and paved +with marbles. The hall is a large apartment about 25 ft. high, with +paneled ceiling, having galleries on two sides, giving access to the +rooms surrounding it on first floor, and to the turret staircase leading +to roofs, etc. With the exception of sanitary apparatus, painted +windows, etc. (which will be supplied by English firms), the whole of +the work will be executed by native labor. The architect is Mr. Edwin T. +Hall, London.--_Building News_. + +[Illustration: SUGGESTIONS IN ARCHITECTURE--A CASTELLATED CHATEAU.] + + * * * * * + + + + +ELECTRIC POWER. + + +Just now nothing save electricity is talked about in scientific circles. +During the meeting of the British Association the greatest possible +prominence was given to electrical questions and propositions The +success of the electric light, the introduction of the Faure battery +with a great flourish of trumpets, and the magnificent display of +electrical instruments and machinery at Paris, have all operated to the +same end. The daily press has taken the subject up, and journals which +were nothing hitherto if not political, now indulge in magnificent +rhapsodies concerning the future of electricity. Even eminent engineers, +carried away by the intoxication of the moment, have not hesitated to +say that the steam engine is doomed, and that its place will be taken by +the electricity engine. In the midst of all this noise and clamor and +blowing of personal trumpets, it is not easy to keep one's head clear, +and mistakes may be made which will cause disappointment to many and +retard the progress of electrical science. We confidently expect that +electricity will prove a potent agent by and by in the hands of the +speculator for extracting gold from the pockets of the public, and we +write now to warn our readers in time, and to endeavor to clear the air +of some of the mists with which it is obscured. There is, no doubt, +a great future before electricity; but it is equally certain that +electricity can never do many things which the half informed may be +readily made to believe it will do. We propose here to say enough +on this point to enlighten our readers, without troubling them with +perplexing problems and speculations. + +No one at this moment knows what electricity is; but for our present +purpose we may regard it as a fluid, non-elastic, and without weight, +and universally diffused through the universe. To judge by recently +published statements, a large section of the reading public are taught +that this fluid is a source of power, and that it may be made to do the +work of coal. This is a delusion. So long as electricity remains in what +we may call a normal state of repose, it is inert. Before _we can get +any work out of electricity a somewhat greater amount of work must be +done upon it_. If this fundamental and most important truth be kept in +view it will not be easy to make a grave mistake in estimating the value +of any of the numerous schemes for making electricity do work which will +ere long be brought before the public. To render our meaning clearer, +we may explain that in producing the electric light, for instance, a +certain quantity of electricity passes in through one wire to the lamp, +and precisely the same quantity passes out through the other wire, and +on to the earth or return wire completing the circuit. Not only is the +quantity the same, the velocity is also unchanged. But in going through +the lamp the current has done something. It has overcome the resistance +of the carbons, heated them to a dazzling white heat, and so performed +work. In doing this the current of electricity has lost something. Led +from the first lamp to a second, it is found powerless--if the first +lamp be of sufficient size. What is it that the electricity has lost? +It has parted with what electricians would term "potential," or the +capacity for performing work. What this is precisely, or in what way the +presence or absence of potential modifies the nature of the electric +current, no one knows; but it is known that this potential can only be +conferred on electricity by doing work on the electricity in the first +instance. The analogy between electricity and a liquid like water will +now be recognized. So long as the water is at rest, it is inert. If we +pump it up to a height, we confer on it the equivalent of potential. +We can let the water fall into the buckets of an overshot wheel. Its +velocity leaving the tail race may be identical with that at which it +left the supply trough to descend on the wheel. Its quantity will be +the same. It will be in all respects unchanged, just as the current +of electricity passing through a lamp is unchanged; but it has, +nevertheless, lost something. It has parted with its potential--capacity +for doing work--and it becomes once more inert. But the duty which it +discharged in turning the mill wheel was somewhat less than the precise +equivalent of the work done in pumping it up to a level with the top of +the wheel. In the same way the electric current never can do work equal +in amount to the work done on it in endowing it with potential. + +It will thus be seen that electricity can only be used as a means of +transmitting power from one place to another, or for storing power up +at one time to be used at a subsequent period; but it cannot be used to +originate power in the way coal can be used. It possesses no inherent +potential. It is incapable of performing work unless something is done +to it first. We have spoken of it as a fluid, but only for the sake of +illustration. As we have said, no one knows what it is, but the theory +which bids fair for acceptance is that it is a mode of motion of the +all-pervading ether. Very curious and instructive experiments are now +being carried out in Paris by Dr. Bjerkness, of Christiania, in the +Norwegian section of the electrical exhibition. This gentleman submerges +thin elastic diaphragms in water, and causes them to vibrate, or rather +pulsate, by compressed air. He finds that if they pulsate synchronously +they attract each other. If the pulsations are not simultaneous, the +disks repel each other. From this and other results he has obtained, +it may be argued that the ether plays the part of the water in Dr. +Bjerkness' tank, and that when special forms of vibration are set up +in bodies they become competent to attract or repel other bodies. This +being so, it will be seen that the power of attraction or repulsion of +an electrical body depends in the first instance on the motion set up +in the body attracted or repulsed, and this motion is, of course, some +function of the work originally done on the body. We need not pursue +this argument further. Among the most scientific investigators of the +day it is admitted that the efficiency of electricity as a doer of work, +or a producer of action at a distance, must depend for its value on the +performance of work in some one way or another on the electricity itself +in the first instance. It may be worth while here to dispel a popular +delusion. It is held very generally that electricity can be made, as, +for instance, by the galvanic battery. There is no reason to believe +anything of the kind; but whether it is or is not true that electricity +is actually made by the combustion of zinc in a galvanic trough, it is +quite certain that this electricity, unless it possesses potential, can +do no work, no matter how great its quantity. Of course, it is to be +understood that all electric currents possess potential. If they did +not, their presence would be unknown; but the potential of a current +is in all cases the result of work done on electricity, either by the +oxidation of zinc, or in some other way. This is a broad principle, but +it is strictly consistent in every respect with the truth. Electricity, +then, is, as we have said, totally different from coal; and it can never +become a substitute for it alone. Water power, air power, or what we +may, for want of a better phrase, call chemical power, combined with +electricity, can be used as a substitute for coal; but electricity +cannot of itself be employed to do work. It is true, however, that +electricity, on which work has already been done, may be found in +nature. Atmospheric electricity, for example, may perhaps yet be +utilized. It is by no means inconceivable that the electricity contained +in a thunder cloud might be employed to charge a Faure battery; but up +to the present no one has contemplated the obtaining of power from the +clouds, and whether it is or is not practicable to utilize a great +natural force in this way does not affect our statement. The use of +electricity must be confined to its power of transmitting or storing up +energy, and this truth being recognized, it becomes easy to estimate the +future prospects of electricity at something like their proper value. + +It has been proved to a certain extent that electricity can be used to +transmit power to a distance, and that it can be used to store it up. +Thus far the man of pure science. The engineer now comes on the stage +and asks--Can practical difficulties be got over? Can it be made to pay? +In trying to answer these questions we cannot do better than deal with +one or two definite proposals which have been recently made. That with +which we shall first concern ourselves is that trains should be worked +by Faure batteries instead of by steam. It is suggested that each +carriage of a train should be provided with a dynamo motor, and that +batteries enough should be carried by each to drive the wheels, and so +propel the train. Let us see how such a scheme would comply with working +conditions. Let us take for example a train of fifteen coaches on the +Great Northern Railway, running without a stop to Peterborough in one +hour and forty minutes. The power required would be about 500 horses +indicated. To supply this for 100 minutes, even on the most absurdly +favorable hypothesis, no less than 25 tons of Faure batteries would be +required. Adding to these the weight of the dynamo motors, and that +unavoidably added to the coaches, it will be seen that a weight equal to +that of an engine would soon be reached. The only possible saving would +be some 28 to 30 tons of tender. In return for this all the passengers +would have to change coaches at Peterborough, as the train could not be +delayed to replace the expended with fresh batteries. This is out of +the question. The Faure batteries must all be carried on one vehicle or +engine, which could be changed for another, like a locomotive. Even then +no advantage would be gained. As to cost, it is very unlikely that the +stationary engines which must be provided to drive the dynamo machines +for charging the batteries would be more economical than locomotive +engines; and if we allow that the dynamo machine only wasted 10 per +cent. of the power of the engine, the Faure batteries 10 per cent. of +the power of the dynamo machines, and the dynamo motors 10 per cent. of +the power of the batteries--all ridiculously favorable assumptions--yet +the stationary engines would be handicapped with a difference in net +efficiency between themselves and the locomotive--admitting the original +efficiency per pound of coal in both to be the same--of some 27 per +cent., we think we may relegate this scheme to the realms of oblivion. +Another idea is that by putting up turbines and dynamo machines the +steam engine might be superseded by water power. Now it so happens that +if all the water power of England were quadrupled it would not nearly +suffice for our wants. It may be found worth while perhaps to construct +steam engines close to coalpits and send out power from these engines by +wire; but the question will be asked, Which is the cheaper of the two, +to send the coal or to send the power? On the answer to this will +depend the decision of the mill owners. Another favorite scheme is that +embodied in the Siemens electrical railway. We believe that there is a +great future in store for electricity as a worker of tramway traffic; +but the traffic on a great line like the Midland or Great Northern +Railway could not be carried on by it. As Robert Stephenson said of the +atmospheric system, it is not flexible enough. The working of points +and crossings, and the shunting of trains and wagons, would present +unsurmountable difficulties. We have cited proposals enough, we think, +to illustrate our meaning. Sir William Armstrong, Sir Frederick +Bramwell, Dr. Siemens, Sir W. Thomson, and many others may be excused if +they are a little enthusiastic. They are just now overjoyed with success +attained; but when the time comes for sober reflection they will, no +doubt, see good reason to moderate their views. No one can say, of +course, what further discoveries may bring to light; but recent speakers +and writers have found in what is known already, materials for sketching +out a romance of electricity. It is but romancing to assert that the end +of the steam engine is at hand. Wonderful and mystical as electricity +is, there are some very hard and dry facts about it, and these facts are +all opposed to the theory that it can become man's servant of all work. +Ariel-like, electricity may put a girdle round the earth in forty +minutes; but it shows no great aptitude for superseding the useful old +giant steam, who has toiled for the world so long and to such good +purpose--_The Engineer_. + + * * * * * + + + + +ON A METHOD OF OBTAINING AND MEASURING VERY HIGH VACUA WITH A MODIFIED +FORM OF SPRENGEL-PUMP. + +By Ogden N. Rood, Professor of Physics in Columbia College. + + +In the July number of this Journal for 1880, I gave a short account of +certain changes in the Sprengel-pump by means of which far better vacua +could be obtained than had been previously possible. For example, the +highest vacuum at that time known had been reached by Mr. Crookes, and +was about 1/17,000,000, while with my arrangement vacua of 1/100,000,000 +were easily reached. In a notice that appeared in _Nature_ for August, +1880, p. 375, it was stated that my improvements were not new, but had +already been made in England four years previously. I have been unable +to obtain a printed account of the English improvements, and am willing +to assume that they are identical with my own; but on the other hand, +as for four years no particular result seems to have followed their +introduction in England, I am reluctantly forced to the conclusion that +their inventor and his customers, for that period of time, have remained +quite in ignorance of the proper mode of utilizing them. Since then I +have pushed the matter still farther, and have succeeded in obtaining +with my apparatus vacua as high as 1/390,000,000 without finding +that the limit of its action had been reached. The pump is simple in +construction, inexpensive, and, as I have proved by a large number of +experiments, certain in action and easy of use; stopcocks and grease are +dispensed with, and when the presence of a stopcock is really desirable +its place is supplied by a movable column of mercury. + +_Reservoir_.--An ordinary inverted bell-glass with a diameter of 100 mm. +and a total height of 205 mm. forms the reservoir; its mouth is closed +by a well-fitting cork through which passes the glass tube that forms +one termination of the pump. The cork around tube and up to the edge of +the former is painted with a flexible cement. The tube projects 40 mm. +into the mercury and passes through a little watch-glass-shaped piece of +sheet-iron, W, figure 1, which prevents the small air bubbles that creep +upward along the tube from reaching its open end; the little cup is +firmly cemented in its place. The flow of the mercury is regulated +by the steel rod and cylinder, CR, Figure 1. The bottom of the steel +cylinder is filled out with a circular piece of pure India-rubber, +properly cemented; this soon fits itself to the use required and answers +admirably. The pressure of the cylinder on the end of the tube is +regulated by the lever, S, Figure 1; this is attached to a circular +board which again is firmly fastened over the open end of the +bell-glass. It will be noticed that on turning the milled head, S, the +motion of the steel cylinder is not directly vertical, but that it tends +to describe a circle with c as a center; the necessary play of the +cylinder is, however, so small, that practically the experimenter does +not become aware of this theoretical defect, so that the arrangement +really gives entire satisfaction, and after it has been in use for a few +days accurately controls the flow of the mercury. The glass cylinder is +held in position, but not supported, by two wooden _adjustable_ clamps, +_a a_, Figure 2. The weight of the cylinder and mercury is supported by +a shelf, S, Figure 2, on which rests the cork of the cylinder; in this +way all danger of a very disagreeable accident is avoided. + +[Illustration: MODIFIED FORM OF SPRENGEL PUMP.] + +_Vacuum-bulb_.--Leaving the reservoir, the mercury enters the +vacuum-bulb, B, Figure 2, where it parts with most of its air and +moisture; this bulb also serves to catch the air that creeps into the +pump from the reservoir, even when there is no flow of mercury; its +diameter is 27 mm. The shape and inclination of the tube attached to +this bulb is by no means a matter of indifference; accordingly Figure +3 is a separate drawing of it; the tube should be so bent that a +horizontal line drawn from the proper level of the mercury in the bulb +passes through the point, _o_, where the drops of mercury break off. The +length of the tube, EC, should be 150 mm., that of the tube, ED, 45 mm.; +the bore of this tube is about the same as that of the fall-tube. + +_Fall-tube and bends_.--The bore of the fall-tube in the pump now used +by me is 1.78 mm.; its length above the bends (U, Figure 2) is 310 mm.; +below the bends the length is 815 mm. The bends constitute a fluid valve +that prevents the air from returning into the pump; beside this, the +play of the mercury in them greatly facilitates the passage of the +air downward. The top of the mercury column representing the existing +barometric pressure should be about 25 mm. below the bends when the pump +is in action. This is easily regulated by an adjustable shelf, which is +also employed to fill the bends with mercury when a measurement is taken +or when the pump is at rest. On the shelf is a tube, 160 mm. high and 20 +mm. in diameter, into which the end of the fall-tube dips; its side has +a circular perforation into which fits a small cork with a little tube +bent at right angles. With the hard end of a file and a few drops of +turpentine the perforation can be easily made and shaped in a few +minutes. By revolving the little bent tube through 180° the flow of the +mercury can be temporarily suspended when it is desirable to change the +vessel that catches it. + +_Gauge_.--For the purpose of measuring the vacua I have used an +arrangement similar to McLeod's gauge, Figure 4; it has, however, some +peculiarities. The tube destined to contain the compressed air has a +diameter of 1.35 mm. as ascertained by a compound microscope; it is not +fused at its upper extremity, but closed by a fine glass rod that fits +into it as accurately as may be, the end of the rod being ground flat +and true. This rod is introduced into the tube, and while the latter +is gently heated a very small portion of the cement described below is +allowed to enter by capillary attraction, but not to extend beyond the +end of the rod, the operation being watched by a lens. The rod is +used for the purpose of obtaining the compressed air in the form of a +cylinder, and also to allow cleansing of the tube when necessary. The +capacity of the gauge-sphere was obtained by filling it with mercury; +its external diameter was sixty millimeters; for measuring very high +vacua this is somewhat small and makes the probable errors rather +large; I would advise the use of a gauge-sphere of about twice as great +capacity. The tube, CB, Figure 4, has the same bore as the measuring +tube in order to avoid corrections for capillarity. The tube of the +gauge, CD, is not connected with an India-rubber tube, as is usual, +but dips into mercury contained in a cylinder 340 mm. high, 58 mm. in +diameter, which can be raised and lowered at pleasure. This is best +accomplished by the use of a set of boxes of various thicknesses, made +for the purpose and supplemented by several sheets of cardboard and even +of writing-paper. These have been found to answer well and enable the +experimenter to graduate with a nicety the pressure to which the gas is +exposed during measurement. By employing a cylinder filled with mercury +instead of the usual caoutchouc tubing small bubbles of air are +prevented from entering the gauge along with the mercury. An adjustable +brace or support is used which prevents accident to the cylinder when +the pump is inclined for the purpose of pumping out the vacuum-bulb. The +maximum pressure that can be employed in the gauge used by me is 100 mm. + +All the tubing of the pump is supported at a distance of about 55 mm. +from the wood-work; this is effected by the use of simple adjustable +supports and adjustable clamps; the latter have proved a great +convenience. The object is to gain the ability to heat with a Bunsen +burner all parts of the pump without burning the wood-work. Where glass +and wood necessarily come in contact the wood is protected by metal or +simply painted with a saturated solution of alum. The glass portions +of the pump I have contrived to anneal completely by the simple means +mentioned below. If the glass is not annealed it is certain to crack +when subjected to heat, thus causing vexation and loss of time. The +mercury was purified by the same method that was used by W. Siemens +(Pogg. Annalen, vol. ex., p. 20), that is, by a little strong sulphuric +acid to which a few drops of nitric acid had been added; it was dried by +pouring it repeatedly from one hot dry vessel to another, by filtering +it while quite warm, the drying being completed finally by the action of +the pump itself. All the measurements were made by a fine cathetometer +which was constructed for me by William Grunow; see this Journal, Jan., +1874, p. 23. It was provided with a well-corrected object-glass having a +focal length of 200 mm. and as used by me gave a magnifying power of 16 +diameters. + +_Manipulation_.--The necessary connections are effected with a cement +made by melting Burgundy pitch with three or four per cent of gutta +percha. It is indispensable that the cement when cold should be so hard +as completely to resist taking any impression from the finger nail, +otherwise it is certain to yield gradually and finally to give rise to +leaks. The connecting tubes are selected so as to fit as closely as +possible, and after being put into position are heated to the proper +amount, when the edges are touched with a fragment of cold cement which +enters by capillary attraction and forms a transparent joint that can +from time to time be examined with a lens for the colors of thin plates, +which always precede a leak. Joints of this kind have been in use by me +for two months at a time without showing a trace of leakage, and the +evidence gathered in another series of unfinished experiments goes to +show that no appreciable amount of vapor is furnished by the resinous +compound, which, I may add, is never used until it has been repeatedly +melted. As drying material I prefer caustic potash that has been in +fusion just before its introduction into the drying tube; during the +process of exhaustion it can from time to time be heated nearly to the +melting point: if actually fused in the drying tube the latter almost +invariably cracks. The pump in the first instance is to be inclined at +an angle of about 10 degrees, the tube of the gauge being supported by +a semicircular piece of thick pasteboard fitted with two corks into the +top of the cylinder. This seemingly awkward proceeding has in no case +been attended with the slightest accident, and owing to the presence of +the four leveling-screws, the pump when righted returns, as shown by the +telescope of the cathetometer, almost exactly to its original place. In +the inclined position the exhaustion of the vacuum bulb is accomplished +along with that of the rest of the pump. The exhaustion of the +vacuum-bulb when once effected can be preserved to a great extent for +use in future work, merely by allowing mercury from the reservoir to +flow in a rapid stream at the time that air is allowed to re-enter the +pump. During the first process of exhaustion the tube of the gauge is +kept hot by moving to and fro a Bunsen burner, and is in this way +freed from those portions of air and moisture that are not too firmly +attached. After a time the vacuum-bulb ceases to deliver bubbles of +air; it and the attached tube are now to be heated with a moving Bunsen +burner, when it will be found to furnish for 15 or 20 minutes a large +quantity of bubbles mainly of vapor of water. After then production +ceases the pump is righted and the exhaustion carried farther. In spite +of a couple of careful experiments with the cathetometer I have not +succeeded in measuring the vacuum in the vacuum bulb, but judge from +indications, that is about as high as that obtained in an ordinary +Geissler pump. Meanwhile the various parts of the pump can be heated +with a moving Bunsen burner to detach air and moisture, the cement being +protected by wet lamp-wicking. In one experiment I measured the amount +of air that was detached from the walls of the pump by heating them for +ten minutes somewhat above l00° C., and found that it was 1/1,000,000 +of the air originally present. I have also noticed that a still larger +amount of air is detached by electric discharges. This coincides with an +observation of E. Bessel-Hagen in his interesting article on a new form +of Töpler's mercury-pump (Annalen der Physik und Chemie, 1881, vol. +xii.). Even when potash is used a small amount of moisture always +collects in the bends of the fall tube; this is readily removed by a +Bunsen burner; the tension of the vapor being greatly increased, it +passes far down the fall-tube in large bubbles and is condensed. Without +this precaution I have found it impossible to obtain a vacuum higher +than 1/25,000,000; in point of fact the bends should always be heated +when a high exhaustion is undertaken even if the pump has been standing +well exhausted for a week; the heat should of course never be applied at +a late stage of the exhaustion. Conversely, I have often by the aid of +heat completely and quickly removed quite large quantities of the vapor +of water that had been purposely introduced. The exhaustion of the +vacuum-bulb is of course somewhat injured by the act of using the pump +and also by standing for several days, so that it has been usual with me +before undertaking a high exhaustion to incline the pump and re-exhaust +for 20 minutes; I have, however, obtained very high vacua without using +this precaution. + +During the process of exhaustion not more than one-half of the mercury +in the reservoir is allowed to run out, other wise when it is returned +bubbles of air are apt to find their way into the vacuum-bulb. In order +to secure its quiet entrance it is poured into a silk bag provided with +several holes. When the reservoir is first filled its walls for a day +or two appear to furnish air that enters the vacuum-bulb; this action, +however, soon sinks to a minimum and then the leakage remains quite +constant for months together. + +_Measurement of the vacuum_.--The cylinder into which the gauge-tube +dips is first elevated by a box sufficiently thick merely to close the +gauge, afterwards boxes are placed under it sufficient to elevate the +mercury to the base of the measuring tube; when the mercury has reached +this point, thin boards and card-boards are added till a suitable +pressure is obtained. The length of the inclosed cylinder of air is +then measured with the cathetometer, also the height of the mercurial +"meniscus," and the difference of the heights of the mercurial columns +in A and B, figure 4. To obtain a second measure an assistant removes +some of the boxes and the cylinder is lowered by hand three or four +centimeters and then replaced in its original position. In measuring +really high vacua, it is well to begin with this process of lowering and +raising the cylinder, and to repeat it five or six times before taking +readings. It seems as though the mercury in the tube, B, supplies to the +glass a coating of air that allows it to move more freely; at all events +it is certain that ordinarily the readings of B become regular, only +after the mercury has been allowed to play up and down the tube a number +of times. This applies particularly to vacua as high 1/50,000,000 and to +pressures of five millimeters and under. It is advantageous in making +measurements to employ large pressures and small volumes; the correct +working of the gauge can from time to time be tested by varying the +relations of these to each other. This I did quite elaborately, and +proved that such constant errors as exist are small compared with +inevitable accidental errors, as, for example, that there was no +measurable correction for capillarity, that the calculated volume of the +"meniscus" was correct, etc. It is essential in making a measurement +that the temperature of the room should change as little as possible, +and that the temperature of the mercury in the cylinder should be at +least nearly that of the air near the gauge-sphere. The computation is +made as follows + + n = height of the cylinder inclosing the air; + c = a factor which, multiplied by n, converts it into cubic + millimeters; + S = cubic contents of the meniscus; + d = difference of level between A and B, fig. 4; + = the pressure the air is under; + N = the cubic contents of the gauge in millimeters; + x = a fraction expressing the degree of exhaustion obtained; then + + x=1/([N (760/d)]/[nc - S]) + +It will be noticed that the measurements are independent of the actual +height of the barometer, and if several readings are taken continuously, +the result will not be sensibly affected by a simultaneous change of the +barometer. Almost all the readings were taken at a temperature of about +20° C., and in the present state of the work corrections for temperature +may be considered a superfluous refinement. + +_Gauge correction_.--It is necessary to apply to the results thus +obtained a correction which becomes very important when high vacua are +measured. It was found in an early stage of the experiments that the +mercury, in the act of entering the highly exhausted gauge, gave out +invariably a certain amount of air which of course was measured along +with the residuum that properly belonged there; hence to obtain the true +vacuum it is necessary to subtract the volume of this air from nc. By a +series of experiments I ascertained that the amount of air introduced by +the mercury in the acts of entering and leaving the gauge was sensibly +constant for six of these single operations (or for three of these +double operations), when they followed each other immediately. The +correction accordingly is made as follows: the vacuum is first measured +as described above, then by withdrawing all the boxes except the lowest, +the mercury is allowed to fall so as nearly to empty the gauge; it is +then made again to fill the gauge, and these operations are repeated +until they amount in all to six; finally the volume and pressure are a +second time measured. Assuming the pressure to remain constant, or that +the volumes are reduced to the same pressure, + + v = the original volume; v' = the final volume; + V' = volume of air introduced by the first entry of the mercury; + V = corrected volume; then + + V' = (v'-v)/6 + V = v - [(v'-v)/6] + +It will be noticed that it is assumed in this formula that the same +amount of air is introduced into the gauge in the acts of entry and +exit; in the act of entering in point of fact more fresh mercury is +exposed to the action of the vacuum than in the act exit, which might +possibly make the true gauge-correction rather larger than that given by +the formula. It has been found that when the pump is in constant use the +gauge-correction gradually diminishes from day to day; in other words, +the air is gradually pumped out of the gauge-mercury. Thus on December +21, the amount of air entering with the mercury corresponded to an +exhaustion of + + 1/27,308,805 .......Dec. 21. + + 1/38,806,688 ...... Dec. 29. + + 1/78,125,000 .......Jan. 15. + + 1/83,333,333 .......Jan. 23 + + 1/128,834,063 ......Feb. 1. + + 1/226,757,400 ..... Feb. 9. + + 1/232,828,800 ..... Feb. 19. + + 1/388,200,000 ......March 7. + +That this diminution is not due to the air being gradually withdrawn +from the walls of the gauge or from the gauge-tube, is shown by the fact +that during its progress the pump was several times taken to pieces, and +the portions in question exposed to the atmosphere without affecting +the nature or extent of the change that was going on. I also made one +experiment which proves that the gauge-correction does not increase +sensibly, when the exhausted pump and gauge are allowed to stand unused +for twenty days. + +_Rate of the pump's work_.--It is quite important to know the rate of +the pump at different degrees of exhaustion, for the purpose of enabling +the experimenter to produce a definite exhaustion with facility; also if +its maximum rate is known and the minimum rate of leakage, it becomes +possible to calculate the highest vacuum attainable with the instrument. +Examples are given in the tables below; the total capacity was about +100,000 cubic mm. + + Time. Exhaustion. Ratio. + + 1/78,511 + 10 minutes }........ 1:1/3.53 + 1/276,980 + 10 minutes }........ 1:1/6.10 + 1/1,687,140 + 10 minutes }........ 1:1/4.15 + 1/7,002,000 + +Upon another occasion the following rates and exhaustions were obtained: + + Time. Exhaustion. Rate. + + 1/7,812,500 + 10 minutes }........ 1:1/3.18 + 1/24,875,620 + 10 minutes }........ 1:1/2.69 + 1/67,024,090 + 10 minutes }........ 1:1/1.22 + 1/81,760,810 + 10 minutes }........ 1:1.67 + 1/136,986,300 + 10 minutes }........ 1:1.23 + 1/170,648,500 + +The _irregular_ variations in the rates are due to the mode in which the +flow of the mercury was in each case regulated. + +_Leakage_.--We come now to one of the most important elements in the +production of high vacua. After the air is detached from the walls of +the pump the leakage becomes and remains nearly constant. I give below a +table of leakages, the pump being in each case in a condition suitable +for the production of a very high vacuum: + + Duration of the Leakage per hour in + experiment cubic mm., press., + 760 mm. + + 18½ hours............................ 0.000853 + 27 hours............................ 0.001565 + 26½ hours.............................0.000791 + 20 hours.............................0.000842 + 19 hours.............................0.000951 + 19 hours.............................0.001857 + 7 days..............................0.001700 + 7 days..............................0.001574 + + Average.................... 0.001266 + +I endeavored to locate this leakage, and proved that one-quarter of +it is due to air that enters the gauge from the top of its column of +mercury, thus: + + Duration of the Gauge-leakage per hour + experiment. in cubic mm., press. + 760 mm. + + 18 hours.................................0.0002299 + 7 days..................................0.0004093 + 7 days..................................0.0003464 + + Average.......................0.0003285 + +This renders it very probable that the remaining three quarters are due +to air given off from the mercury at B, Fig. 4, from that in the bends +and at the entrance of the fall-tube, _o_, Fig. 3. + +Further on some evidence will be given that renders it probable that the +leakage of the pump when in action is about four times as great as the +total leakage in a state of rest. + +The gauge, when arranged for measurement of gauge-leakage, really +constitutes a barometer, and a calculation shows that the leakage would +amount to 2.877 cubic millimeters per year, press. 760 mm. If this air +were contained in a cylinder 90 mm. long and 15 mm. in diameter it would +exert a pressure of 0.14 mm. To this I may add that in one experiment +I allowed the gauge for seven days to remain completely filled with +mercury and then measured the leakage into it. This was such as would +in a year amount to 0.488 cubic millimeter, press. 760 mm., and in a +cylinder of the above dimensions would exert a pressure of 0.0233 mm. + +_Reliability of the results: highest vacuum._ + +The following are samples of the results obtained. In one case sixteen +readings were taken in groups of four with the following result: + + Exhaustion. + 1 / 74,219,139 + 1 / 78,533,454 + 1 / 79,017,272 + 1 / 68,503,182 + Mean 1 / 74,853,449 + +Calculating the probable error of the mean with reference to the above +four results it is found to be 2.28 per cent of the quantity involved. + +A higher vacuum measured in the same way gave the following results: + + 1 / 146,198,800 + 1 / 175,131,300 + 1 / 204,081,600 + 1 / 201,207,200 + +The mean is 1 / 178,411,934, with a probable error of 5.42 per cent of +the quantity involved. I give now an extreme case; only five single +readings were taken; these corresponded to the following exhaustions: + + 1 / 379,219,500 + 1 / 371,057,265 + 1 / 250,941,040 + 1 / 424,088,232 + 1 / 691,082,540 + +The mean value is 1 / 381,100,000, with a probable error of 10.36 per +cent of the quantity involved. Upon other occasions I have obtained +exhaustions of 1 / 373,134,000 and 1 / 388,200,000. Of course in these +cases a gauge-correction was applied; the highest vacuum that I have +ever obtained irrespective of a gauge-correction was 1 / 190,392,150. In +these cases and in general, potash was employed as the drying material; +I have found it practical, however, to attain vacua as high as 1 / +50,000,000 in the total absence of all such substances. The vapor of +water which collects in bends must be removed from time to time with a +Bunsen burner while the pump is in action. + +It is evident that the final condition of the pump is reached when +as much air leaks in per unit of time as can be removed in the same +interval. The total average leakage per ten minutes in the pump used by +me, when at rest, was 0.000211 cubic millimeter at press. 760 mm. Let +us assume that the leakage when the pump is in action is four times +as great as when at rest; then in each ten minutes 0.000844 cubic +millimeter press., 760 mm., would enter; this corresponds in the pump +used by me to an exhaustion of 1 / 124,000,000; if the rate of the pump +is such as to remove one-half of the air present in ten minutes, then +the highest attainable exhaustion would be 1 / 248,000,000. In the same +way it may be shown that if six minutes are required for the removal of +half the air the highest vacuum would be 1 / 413,000,000 nearly, and +rates even higher than this have been observed in my experiments. An +arrangement of the vacuum-bulb whereby the entering drops of mercury +would be exposed to the vacuum in an isolated condition for a somewhat +longer time would doubtless enable the experimenter to obtain +considerably higher vacua than those above given. + +_Exhaustion obtained with a plain Sprengel Pump._--I made a series of +experiments with a plain Sprengel pump without stopcocks, and arranged, +as far as possible, like the instrument just described. The leakage per +hour was as follows: + + Duration of the Leakage per hour in + experiment. cubic mm. at press. + 760 mm. + + 22 hours 0.04563 + 2 days 0.04520 + 2 days 0.09210 + 4 days 0.06428 + ------- + Mean 0.06180 + +Using the same reasoning as above we obtain the following table + + Time necessary for removal Greatest attainable + of half the air. exhaustion. + + 10 minutes 1 / 5,000,000 + 7.5 minutes 1 / 7,000,000 + 6.6 minutes 1 / 12,000,000 + +In point of fact the highest exhaustion I ever obtained with this pump +was 1 / 5,000,000; from which I infer that the leakage during action +is considerably greater than four times that of the pump at rest. The +general run of the experiments tends to show that the leakage of a plain +Sprengel pump, without stopcocks or grease, is, when in action, about 80 +times as great as in the form used by me. + +_Note on annealing glass tubes._--It is quite necessary to anneal all +those parts of the pump that are to be exposed to heat, otherwise they +soon crack. I found by inclosing the glass in heavy iron tubes and +exposing it for five hours to a temperature somewhat above that of +melting zinc, and then allowing an hour or two for the cooling process, +that the strong polarization figure which it displays in a polariscope +was completely removed, and hence the glass annealed. A common +gas-combustion furnace was used, the bends, etc, being suitably inclosed +in heavy metal and heated over a common ten-fold Bunsen burner. Thus far +no accident has happened to the annealed glass, even when cold drops of +mercury struck in rapid succession on portions heated considerably above +100° C. + +I wish, in conclusion, to express my thanks to my assistant, Dr. +Ihlseng, for the labor he has expended in making the large number of +computations necessarily involved in work of this kind.--_Amer. Jour. of +Science._ + + * * * * * + + + + +CRYSTALLIZATION TABLE. + + +The following table, prepared by E. Finot and Arm. Bertrand for the +_Jour. de Ph. et de Chim._, shows the point at which the evaporation of +certain solutions is to be interrupted in order to procure a good crop +of crystals on cooling. The density is according to Baumé's scale, the +solution warm: + + Aluminum sulphate 25 | Nickel acetate 30 + Alum (amm. or pot.) 20 | " ammon. sulphate 18 + Ammonium acetate 14 | " chloride 50 + " arsenate 5 | " sulphate 40 + " benzoate 5 | Oxalic acid 12 + " bichromate 28 | Potass. and sod. tartrate 36 + " bromide 30 | Potassium arsenate 36 + " chloride 12 | " benzoate 2 + " nitrate 29 | " bisulphate 35 + " oxalate 5 | " bromide 40 + " phosphate 35 | " chlorate 22 + " sulphate 28 | " chloride 25 + " sulphocyanide 18 | " chromate 38 + " tartrate 25 | " citrate 36 + Barium ethylsulphate 43 | " ferrocyanide 38 + " formate 32 | " iodide 17 + " hyposulphite 24 | " nitrate 28 + " nitrate 18 | " oxalate 30 + " oxide 12 | " permanganate 25 + Bismuth nitrate 70 | " sulphate 15 + Boric acid 6 | " sulphite 25 + Cadmium bromide 65 | " sulphocyanide 35 + Calcium chloride 40 | " tartrate 48 + " ethylsulphate 36 | Soda 28 + " lactate 8 | Sodium acetate 22 + " nitrate 55 | " ammon. phosp. 17 + Cobalt chloride 41 | " arsenate 36 + " nitrate 50 | " borate 24 + " sulphate 40 | " bromide 55 + Copper acetate 5 | " chlorate 43 + " ammon. sulph. 35 | " chromate 45 + " chloride 45 | " citrate 36 + " nitrate 55 | " ethylsulphate 37 + " sulphate 30 | " hyposulphite 24 + Iron-ammon. oxalate 30 | " nitrate 40 + " ammon. sulphate 31 | " phosphate 20 + " sulphate 31 | " pyrophosphate 18 + " tartrate 40 | " sulphate 30 + Lead acetate 42 | " tungstate 45 + " nitrate 50 | Stroutium bromide 50 + Magnesium chloride 35 | " chlorate 65 + " lactate 6 | " chloride 34 + " nitrate 45 | Tin choride (stannous) 75 + " sulphate 40 | + Manganese chloride 47 | Zinc acetate 20 + " lactate 8 | " ammon. chloride 43 + " sulphate 44 | " nitrate 55 + Mercury cyanide 20 | " sulphate 45 + + * * * * * + + + + +THE PRINCIPLES OF HOP-ANALYSIS. + +By Dr. G. O. CECH + +[Footnote: 'Zeitschrift fur Analyt. Chemie,' 1881.] + + +Hop flowers contain a great variety of different substances susceptible +of extraction with ether, alcohol, and water, and distinguishable from +one another by tests of a more or less complex character. The substances +are: Ethereal oil, chlorophyl, hop tannin, phlobaphen, a wax-like +substance, the sulphate, ammoniate, phosphate, citrate and malates of +potash, arabine, a crystallized white and an amorphous brown resin, and +a bitter principle. That the characteristic action of the hops is due to +such of these constituents only as are of an organic nature is easy to +understand; but up to the present we are in ignorance whether it is upon +the oil, the wax, the resin, the tannin, the phlobaphen, or the bitter +principle individually, or upon them all collectively, that the effect +of the hops in brewing depends. + +It is the rule to judge the strength and goodness of hops by the amount +of farina--the so-called lupuline; and as this contains the major +portion of the active constituents of the hop, there is no doubt that +approximately the amount of lupuline is a useful quantitative test. But +here we are confronted by the question whether the lupuline is to be +regarded as containing _all_ that is of any value in the hops and the +leaves, the organic principles in which pass undetected under such a +test, as supererogatory for brewers' purposes? Practical experience +negatives any such conclusion. Consequently, we are justified in +assuming that the concurrent development and the presence of the several +organic principles--the oil, the wax, the bitter, the tannin, the +phlobaphen, in the choicer sorts--are subject, within certain limits, to +variations depending on skilled culture and careful drying, and that the +aggregate of these principles has a certain attainable maximum in +the finer sorts, under the most favorable conditions of culture, and +another, lower maximum in less perfectly cultivated and wild sorts. The +difference in the proportion of active organic substance in each sort +must be determined by analysis. There then remains to be discovered +which of the aforesaid substances plays the leading role in brewing, and +also whether the presence of chlorophyl and inorganic salts in the hop +extract influences or alters the results. + +That in brewing hops cannot be replaced by lupuline alone, even when the +latter is employed in relatively large quantities is well known, as also +that a considerable portion of the bitter principle of the hop is found +in the floral leaves. Neither can the lupuline be regarded as the only +active beer agent, as both the hop-tannin and the hop-resin serve to +precipitate the albuminous matter, and clarify and preserve the beer. + +Both chemists and brewers would gladly welcome some method of testing +hops, which should be expeditious, and afford reliable results in +practical hands. To accomplish this account must be taken of all the +active organic constituents of the hops, which can be extracted either +with ether, alcohol, or water containing soda (for the conversion of the +hop tannin in phlobaphen).[1] It should further be ascertained whether +the chlorophyl percentage in the hop bells, new and old, is or is not +the same in cultivated and in wild hops, and whether the aggregate +percentages of organic and constituent observe the same limits. + +[Footnote 1: See C. Etti, in "Dingler's Polytech. Journ.," 1878, p. +354.] + +As wild hops nowadays are frequently introduced in brewing, the +proportion of chlorophyl and organic and inorganic constituents in them +should be compared with those of cultivated sorts, taking the best +Bavarian or Bohemian hops as the standard of measurement. The chlorophyl +is of minor importance, as it has little effect on the general results. + +By a series of comparative analysis of cultivated and wild hops, in +which I would lay especial stress on parity of conditions in regard +of age and vegetation, the extreme limits of variation of which their +active organic principles are susceptible could be determined. + +There is every reason to suppose that the chlorophyl and inorganic +constituents do not differ materially in the most widely different sorts +of hops. The more important differences lie in the proportions of hop +resin and tannin. When this is decided, the proportion of tannin or +phlobaphen in the hop extract or the beer can be determined by analysis +in the ordinary way. But whenever some quick and sure hop test shall +have been found, _appearance and aroma_ will still be most important +factors in any estimate of the value of hops. Here a question arises as +to whether hops from a warm or even a steppe climate, like that of +South Russia, contain the same proportion of ethereal oil--that is, of +aroma--as those from a cooler climate, like Bavaria and Bohemia, or +like certain other fruit species of southern growth, they are early +in maturing, prolific, large in size, and abounding in farina, but +_deficient in aroma_. + +The bearings of certain experimental data on this point I reserve for +consideration upon a future occasion.--_The Analyst_. + + * * * * * + + + + +WATER GAS. + +A DESCRIPTION OF APPARATUS FOR PRODUCING CHEAP GAS, AND SOME NOTES ON +THE ECONOMICAL EFFECT OF USING SUCH GAS WITH GAS MOTORS, ETC. + +[Footnote: Abstract of paper read in Section G. British Association, +York] + +By MR. J. EMERSON DOWSON, C.E., of London. + + +In many countries and for many years past, inventors have sought +some cheap and easy means of decomposing steam in the presence of +incandescent carbon in order to produce a cheap heating gas; and working +with the same object the writer has devised an apparatus which has been +fitted up in the garden of the Industrial Exhibition, and is there +making gas for a 3½ horse power (nominal) Otto gas engine. The retort or +generator consists of a vertical cylindrical iron casing which incloses +a thick lining of ganister to prevent loss of heat and oxidation of the +metal, and at the bottom of this cylinder is a grate on which a fire is +built up. Under the grate is a closed chamber, and a jet of superheated +steam plays into this and carries with it by induction a continuous +current of air. The pressure of the steam forces the mixture of steam +and air upward through the fire, so that the combustion of the fuel is +maintained while a continuous current of steam is decomposed, and in +this way the working of the generator is constant, and the gas is +produced without fluctuations in quality. The well-known reactions +occur, the steam is decomposed, and the oxygen from the steam and air +combines with the carbon of the fuel to form carbon dioxide (CO_2), +which is reduced to the monoxide (CO) on ascending the fuel column. +In this way the resulting gases form a mixture of hydrogen, carbon, +monoxide, and nitrogen, with a small percentage of carbon dioxide which +usually escapes without reduction. The steam should have a pressure of +1½ to 2 atmospheres, and is produced and superheated in a zigzag coil +fed with water from a neighboring boiler. The quantity of water required +is very small, being only about 7 pints for each 1,000 cubic feet of +gas, and, except on the first occasion when the apparatus is started, +the coil is heated by some of the gas drawn from the holder, so that +after the gas is lighted under the coil the superheater requires no +attention. + +For boiler and furnace work the gas can be used direct from the +generator; but where uniformity of pressure is essential, as for gas +engines, gas burners, etc., the gas should pass into a holder. The +latter somewhat retards the production, but the steam injector causes +gas to be made so rapidly that a holder is easily filled against a back +pressure of 1 in. to 1½ in. of water, and at this pressure the generator +can pass gas continuously into the holder, while at the same time it is +being drawn off for consumption. + +The nature of the fuel required depends on the purpose for which the gas +is used. If for heating boilers, furnaces, etc, coke or any kind of coal +maybe used; but for gas engines or any application of the gas requiring +great cleanliness and freedom from sulphur and ammonia it is best to use +anthracite, as this does not yield condensable vapors, and is very free +from impurities. Good qualities of this fuel contain over 90 per cent of +carbon and so little sulphur that, for some purposes, purification is +not necessary. For gas engines, etc., it is, however, better to pass +the gas through some hydrated oxide of iron to remove the sulphureted +hydrogen. The oxide can be used over and over again after exposure to +the air, and the purifying is thus effected without smell or appreciable +expense. Gas made by this process and with anthracite coal has no tar +and no ammonia, and the small percentage of carbon dioxide present does +not sensibly affect the heating power. A further advantage of this gas +is that it cannot burn with a smoky flame, and there is no deposition of +soot even when the object to be heated is placed over or in the flame, +and this is of importance for the cylinder and valves of a gas engine. + +To produce 1,000 cubic feet only 12 lb. of anthracite are required, +allowing 8 to 10 per cent, for impurities and waste; thus a generator +A size, which produces 1,000 cubic feet per hour, needs only 12 lb. in +that time, and this can be added once an hour or at longer intervals. No +skilled labor is necessary, and in practice it is usual to employ a man +who has other work to attend to near the generator, and to pay him a +small addition to his usual wages. + +The comparative explosive force of coal gas and the Dowson gas +calculated in the usual way is as 3.4:1, i. e., coal gas has 3.4 times +more energy than the writer's gas. Messrs. Crossley, of Manchester, the +makers of the Otto gas engines, have made several careful trials of this +gas with some of their 3½ horse power (nominal) engines, and in one +trial they took diagrams every half-hour for nine consecutive days. +These practical trials have shown that without altering the cylinder of +the engine it is possible to admit enough of the Dowson gas to give +the same power as with ordinary coal gas. It has been seen that the +comparative explosive force of the two gases is as 3.4:1, but as it is +well known the combustion of carbon monoxide proceeds at a comparatively +slow rate, and for this reason, and because of the diluents present in +the cylinder which affect the weaker gas more than coal gas, experience +has shown that it is best to allow five volumes of the Dowson gas for +one volume of coal gas, and then the same uniform power is obtained as +with the latter. + +This gives very important economical results; for if the cost of the +Dowson gas given in the tables as 4¼d., 3-1/3d., and 2¾d. per 1,000 +cubic feet, be multiplied by 5 there will be 1s. 9¼d., 1s. 4¾d., and 1s. +2¾d., or a mean of 1s. 5½d. for the equivalent of 1,000 cubic feet of +coal gas, which usually costs from 3s. to 4s., and this represents an +actual saving of about 50 to 60 per cent, in working cost. Another +practical consideration is that coal gas requires 224 lb. to 250 lb. of +coal per 1,000 cubic feet of gas, but the writer requires only 12 lb. +per 1,000 cubic feet, and multiplying this by 5 to give the equivalent +of 1,000 cubic feet of coal gas, for engine work, there are 60 lb. +instead of 224 lb. to 250 lb. This is only 24 to 27 per cent, of the +weight of the coal required for coal gas, and in many outlying districts +this will effect an appreciable saving in the cost of transport. + + +APPENDIX. + + TABLE I. + + _Generator A Size_ (producing 1,000 cubic feet per hour): + Anthracite to make gas at the rate of 1,000 s. d. + cubic feet per hour=l2 lb x 9 working + hours=l08 lb., or say, 1 cwt. at 20s. a + ton.................................... 1 0 + Allowance for wages of attendant......... 1 0 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent. on £l25)= + per working day........................ 0 5 + Interest on capital outlay, ditto........ 0 5 + ______ + + Total........................... 2 10 + cub. ft. + + Gas produced............................. 9.000 + Less gas used for generating and + superheating steam..................... 1,000 + _____ + Total effective gas for 2s. 10d. 8,000 + + Net cost 4¼ d. per 1,000 cubic feet. + + TABLE II. + + _Generator B Size_ (producing 1,500 cubic feet per hour) + Anthracite to make gas at the rate of 1,500 s. d. + cubic feet per hour=18 lb. x 9 working + hours=162 lb., or, say, 1½ cwt. 20s. + a ton.................................. 1 6 + Allowance for wages of attendant......... 1 0 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent, on £140) + =per working day....................... 0 5½ + Interest on capital outlay, ditto........ 0 5½ + ___ ___ + Total........................... 3 5 + cub. ft. + Gas produced............................. 13,500 + Less gas used for generating and + superheating steam..................... 1,200 + ______ + Total effective gas for 3s. 5d.. 12,300 + + Net cost 3 1/3d. per 1,000 cubic feet. + + TABLE III. + + _Generator C Size_ (producing 2,500 cubic feet per hour): + Anthracite to make gas at the rate of 2,500 s. d. + cubic feet per hour=30 lb. x 9 working + hours=270 lb. at 20s. a ton............ 2 4½ + Allowance for wages of attendant....... 1 6 + Repairs and depreciation of generator, + gasholder, etc. (5 per cent, on £160)= + per working day...................... 0 6½ + Interest on capital outlay, ditto...... 0 6½ + _______ + Total......................... 4 11½ + + cub. ft. + Gas produced........................... 22,500 + Less gas used for generating and + superheating steam................... 1,500 + ______ + Total effective gas for 4s. 11½d 21,000 + + Net cost, say, 2¾ d. per 1,000 cubic feet. + + * * * * * + + + + +ON THE FLUID DENSITY OF CERTAIN METALS. + +[Footnote: Abstract of paper read before Section C (Chemical Science), +British Association meeting, York.] + +By PROFESSOR W. CHANDLER ROBERTS, F.R.S., and T. WRIGHTSON. + + +The authors described their experiments on the fluid density of metals +made in continuation of those submitted to Section B at the Swansea +meeting of the Association. Some time since one of the authors gave an +account of the results of experiments made to determine the density of +metallic silver, and of certain alloys of silver and copper when in a +molten state. The method adopted was that devised by Mr. R. Mallet, and +the details were as follows: A conical vessel of best thin Lowmoor plate +(1 millimeter thick), about 16 centimeters in height, and having an +internal volume of about 540 cubic centimeters, was weighed, first +empty, and subsequently when filled with distilled water at a known +temperature. The necessary data were thus afforded for accurately +determining its capacity at the temperature of the air. Molten silver +was then poured into it, the temperature at the time of pouring being +ascertained by the calorimetric method. The precautions, as regards +filling, pointed out by Mr. Mallet, were adopted; and as soon as the +metal was quite cold, the cone with its contents was again weighed. +Experiments were also made on the density of fluid bismuth; and two +distinctive determinations gave the following results: + + 10.005 ) + ) mean 10.039. + 10.072 ) + +The invention of the oncosimeter, which was described by one of the +authors in the "Journal of the Iron and Steel Institute" (No. II., +1879, p. 418), appeared to afford an opportunity for resuming the +investigation on a new basis, more especially as the delicacy of the +instrument had already been proved by experiments on a considerable +scale for determining the density of fluid cast iron. The following is +the principle on which this instrument acts: + +If a spherical ball of any metal be plunged below the surface of a +molten bath of the same or another metal, the cold ball will displace +its own volume of molten metal. If the densities of the cold and molten +metal be the same, there will be equilibrium, and no floating or sinking +effect will be exhibited. If the density of the cold be greater than +that of the molten metal, there will be a sinking effect, and if less a +floating effect when first immersed. As the temperature of the submerged +ball rises, the volume of the displaced liquid will increase or decrease +according as the ball expands or contracts. In order to register these +changes the ball is hung on a spiral spring, and the slightest change in +buoyancy causes an elongation or contraction of this spring which can +be read off on a scale of ounces, and is recorded by a pencil on a +revolving drum. A diagram is thus traced out, the ordinates of which +represent increments of volume, or, in other words, of weight of fluid +displaced--the zero line, or line corresponding to a ball in a liquid of +equal density, being previously traced out by revolving the drum without +attaching the ball of metal itself to the spring, but with all other +auxiliary attachments. By means of a simple adjustment the ball is kept +constantly depressed to the same extent below the surface of the liquid; +and the ordinate of this pencil line, measuring from the line of +equilibrium, thus gives an exact measure of the floating or sinking +effect at every stage of temperature, from the cold solid to the state +when the ball begins to melt. + +If the weight and specific gravity of the ball be taken when cold, +there are obtained, with the ordinate on the diagram at the moment of +immersion, sufficient data for determining the density of the fluid +metal; for + +W / W1 = D / D1 + +the volumes being equal. And remembering that + +W (weight of liquid) = W1 (weight of ball) + x + +(where x is always measured as +_ve_ or -_ve_ floating effect), there is +obtained the equation: + + D1 x ( W1 + x) + D = --------------- . + W1 + +[TEX: D = \frac{D_1 \times (W_1 +x)}{W_1}] + +The results obtained with metallic silver are perhaps the most +interesting, mainly from the fact that the metal melts at a higher +temperature, which was determined with great care by the illustrious +physicist and metallurgist, the late Henri St. Claire Deville, whose +latest experiments led him to fix the melting point at 940° Cent. The +authors of the paper showed that the density of the fluid metal was 9.51 +as compared with 10.57, the density of the solid metal. Taking their +results generally, it is found that the change of volume of the +following metals in passing from the solid to the liquid state may be +thus stated: + + Specific Specific + Metal. Gravity, Gravity, Percentage of + Solid. Liquid. Change. + + Bismuth 9.82 10.055 Decrease of volume 2.3 + Copper 8.8 8.217 Increase " 7.1 + Lead 11.4 10.37 " " 9.93 + Tin. 7.5 7.025 " " 6.76 + Zinc 7.2 6.48 " " 11.10 + Silver 10.57 9.51 " " 11.20 + Iron 6.95 6.88 " " 1.02 + + * * * * * + + + + +HYDROPHOBIA PREVENTED BY VACCINATION. + + +M. Pasteur and other French savants have lately been devoting special +attention to hydrophobia. The great authority on germs has, in fact, +definitely announced that he does not intend to rest until he has made +known the exact nature and life-history of this terrible disease, and +discovered a means of preventing or curing it. The most curious result +yet attained in this direction, however, has been announced by Professor +V. Galtier, of the Lyons Veterinary School. This inquirer has found, in +the first place, that if the virus of rabies be injected into the veins +of a sheep, the animal does not subsequently exhibit any symptoms of +hydrophobia. This in itself would be a sufficiently curious result +to justify attention, though its importance, except as confirmatory +testimony, becomes less striking when it is remembered that M. Pasteur +has lately shown that the special _nidus_ of the disease appears to be +the nervous tissue, and particularly the ganglionic centers. But there +is this further curious consequence: sheep who have thus been treated +through the blood, and who are afterwards inoculated in the ordinary +way through the cellular tissue, as if by a bite, are proof against +the disease. It is as though the injection into the veins acted as a +vaccine. Twenty sheep were experimented upon; ten only were treated to +the venous injection, and then all were inoculated through the cellular +tissue. The ten which had been first "vaccinated" continue alive and +well; they have not even shown any adverse symptoms. The other ten have +all died of rabies. It remains to say why M. Galtier experimented +upon sheep, and not upon dogs and cats, which usually communicate the +disease. The incubation of the disease is much more rapid and less +capricious in the sheep than in the dog or in man, and hence M. Galtier +was able to get his results more certainly within a short period. Having +succeeded so far, he is now justified in undertaking the more protracted +series of observations which experiments upon the canine species will +involve; and this he proposes to do. Experiments of this nature are not +without a serious risk, and admiration is almost equally due to the +courage and the intelligence of the experimentalist. But what will the +anti-vaccinator say?--_Pall Mall Gazette_. + + * * * * * + + + + +ON DIPTERA AS SPREADERS OF DISEASE. + +By J.W. SLATER. + + +The two-winged flies, in their behavior to man, stand in a marked +contrast to all the other orders of insects. The Lepidoptera, the +Coleoptera, the Neuroptera, the Hymenoptera no doubt occasion, in some +of their forms at least, much damage to our crops. But none of them are +parasitic in or upon our bodies; none of them persistently intrude into +our dwellings, hover around us in our walks, and harass us with noise +and constant attempts to bite, or at least to crawl upon us. Even the +ants, except in a few tropical districts, rarely act upon the offensive. +The Hemiptera contain one semi-parasitic species which has attained a +"world-wide circulation," and one degraded, purely parasitic group. +But the Diptera, among which the fleas are now generally included as a +degenerated type, comprise more forms personally annoying to man than +all the remaining insect orders put together. These hostile species are, +further, incalculably numerous, and occur in every part of the globe. +Mosquitoes swarm not merely in the swampy forests of the Orinoco or the +Irrawaddy, but in the Tundras of Siberia, en the storm-beaten rocks of +the Loffodens, and are even encountered by voyagers in quest of the +North Pole. The common house fly was probably at one time peculiar to +the Eastern Continent, but it followed the footsteps of the Pilgrim +Fathers, and is now as great a nuisance in the United Slates and the +Dominion as in any part of Europe. It is curious, but distressing, to +note the tendency of evils to become international. We have communicated +to America the house-fly and the Hessian fly, the "cabbage-white," +the small pox, and the cholera. She, in return, has given us the +_Phylloxera_, a few visitations of yellow fever, the _Blatta gigantea_, +and, climate allowing, may perhaps throw in the Colorado beetle as a +make-weight. In this department, at least, free trade reigns undisputed. +It is a singular thing that no beautiful, useful, or even harmless +species of bird or insect seems capable of acclimatizing itself as do +those characterized by ugliness and noisomeness. + +But, returning from this digression, we find in the Diptera the habit of +obtrusion and intrusion, of coming in actual contact with our food and +our persons, combined with another propensity--that of feeding upon +carrion, excrement, blood, pus, and morbid matter of all kinds. This +is a combination far more serious than is generally imagined. If the +fly--which may at any moment settle upon our lips, our eyes, or upon +an abraded part of our skin--were cleanly in its habits, we need feel +little annoyance at its visits. Or if it were the most eager carrion +devourer, but did not, after having dined, think it necessary to +seek our company, we might hold it, as is done too hastily by some +naturalists, a valuable scavenger. I fear, however, that I have already +made too great a concession. So long as very many persons are suffering +from disease--so long as many diseases are capable of being transmitted +from the sick to the healthy--so long must any creature which is in the +habit of flying about, and touching first one person and then another, +be a possible medium of infection and death. + +Let us take the following case, by no means imaginary, but a +generalization from occurrences far too frequent: A healthy man, sitting +in his house or walking in the fields, especially in countries where the +insectivorous birds have been shot down, suddenly feels a sharp prick on +his neck or his cheek. Putting his hand to the place he perhaps crushes, +perhaps merely brushes away, a fly which has bitten him so as to draw +blood. The man thinks little of so trifling a hurt, but the next morning +he finds the puncture exceedingly painful. An inflamed pimple forms, +which quickly gets worse, while constitutional symptoms of a feverish +kind come on. In alarm he seeks medical advice. The doctor tells him +that it is a malignant pustule, and takes at once the most active +measures. In spite of all possible skill and care the patient too often +succumbs to the bite of a _mouche charbonneuse_, or carbuncle-fly. But +has any kind of fly the property of producing malignant pustule by +some specific inherent power of its own? Surely not. The antecedent +circumstances are these: A sheep or heifer is attacked with the disease +known in France as _charbon_, in Germany as _milz-brand_, and in England +as _splenic fever_. Its blood on examination would be found plentifully +peopled with bacteria. If a lancet were plunged into the body of the +animal, and were then used to slightly scratch or cut the skin of a man, +he would be inoculated with "charbon." The bite of the fly is precisely +similar in its action. Its rostrum has been smeared with the poisoned +blood, an infinitesimal particle of which is sufficient to inclose +several of the disease "germs," and these are then transferred to the +blood of the next man or animal which the fly happens to bite. The +disease is reproduced as simply and certainly as the spores of some +species of fern give rise to their like if scattered upon soil suitable +for their growth. But flies which do not bite may transfer infection. +Every one must know that if blood be spilt upon the ground a crowd of +flies will settle upon and eagerly absorb it. Animals suffering from +splenic fever in the later stages of the disease sometimes emit bloody +urine. Often they are shot or slaughtered by way of stamping out the +plague, and their carcasses are buried deep in the ground. But some loss +of blood is sure to happen, and this will mostly be left to soak into +the ground. Here again the flies will come, and their feet and mouth +will become charged with the contagion. Such a fly, settling upon +another animal or a man, and selecting--as it will do by preference, if +such exist--a wound, or a place where the skin is broken, will convey +the disease. + +Again, M. Pasteur has thoughtfully pointed out that if an animal has +died of splenic fever, and has been carefully buried, the earth-worms +may bring up portions of infectious matter to the surface, so that sheep +grazing, or merely being folded over the spot in question, may take the +plague and die. Hence be wisely counsels that the bodies of such animals +should be buried in sandy or calcareous soils where earth-worms are not +numerous. But it is perfectly legitimate to go a step farther. If such +worm-borings retain the slightest savor of animal matter, flies will +settle upon them and will convey the infectious dust to the most +unexpected places, giving wings to the plague. + +Now it is very true that no one has seen a fly feasting upon the blood +of a heifer or sheep dying or just dead of splenic fever, has then +watched it settle upon and bite some person, and has traced the +following stages of the disease. But it is positively known that a +person has been bitten by a fly, and has then exhibited all the symptoms +of charbon, the place of the bite being the primary seat of the +infection. We know also, beyond all doubt, the eagerness with which +flies will suck up blood, and we likewise know the strange persistence +of the disease "germs." + +Again, the avidity of flies for purulent matter is not a thing of mere +possibility. In Egypt, where ophthalmia is common, and where the "plague +of flies" seems never to have been removed, it is reported as almost +impossible to keep these insects away from the eyes of the sufferers. +The infection which they thus take up they convey to the eyes of persons +still healthy, and thus the scourge is continually multiplied. + +A third case which seems established beyond question is the agency of +mosquitoes in spreading elephantiasis. These so-called sanitary agents +suck from the blood of one person the Filariae, the direct cause of the +disease, and transfer them to another. The manner in which this process +is effected will appear simple enough if we reflect that the mosquito +begins operations by injecting a few drops of fluid into its victim, so +as to dilute the blood and make it easier to be sucked. + +So much being established it becomes in the highest degree probable that +every infectious disease may be, and actually is, at times propagated +by the agency of flies. Attention turned to this much neglected quarter +will very probably go far to explain obscure phenomena connected with +the distribution of epidemics and their sudden outbreaks in unexpected +quarters. I have seen it stated that in former outbreaks of pestilence +flies were remarkably numerous, and although mediaeval observations on +Entomology are not to be taken without a grain of salt, the tradition +is suggestive. Perhaps the Diptera have their seasons of unusual +multiplication and emigration. A wave of the common flea appears to have +passed over Maidstone in August, 1880. + +We now see the way to some practical conclusions not without importance. +Recognizing a very considerable part of the order of Diptera, or +two-winged flies, as agents in spreading disease, it surely follows +that man should wage war against them in a much more systematic and +consistent manner than at present. The destruction of the common +house-fly by "_papier Moure_," by decoctions of quassia, by various +traps, and by the so-called "catch 'em alive," is tried here and there, +now and then, by some grocer, confectioner, or housewife angry at the +spoliation and defilement caused by these little marauders. But there +is no concerted continuous action--which after all would be neither +difficult nor expensive--and consequently no marked success. Experiments +with a view of finding out new modes of fly-killing are few and far +between. + +Every one must occasionally have seen, in autumn, flies as if cemented +to the window-pane, and surrounded with a whitish halo. That in some +seasons numbers of flies thus perish--that the phenomenon is due to a +kind of fungus, the spores of which readily transfer the disease from +one fly to another--we know. But here our knowledge is at fault. We +have not learnt why this fly-epidemic is more rife in some seasons than +others. We are ignorant concerning the methods of multiplying this +fungus at will, and of launching it against our enemies. We cannot tell +whether it is capable of destroying _Stomoxys calcitram_, the blowflies, +gadflies, gnats, mosquitoes, etc. Experiment on these points is rendered +difficult by the circumstance that the fungus is rarely procurable +except in autumn, when some of the species we most need to destroy are +not to be found. Another question is whether the fungus, if largely +multiplied and widely spread, might not prove fatal to other than +Dipterous insects, especially to the Hymenoptera, so many of which, +in their character of plant-fertilizers, are highly useful, or rather +essential to man. + +Another fungus, the so-called "green muscardine" (_Isaria destructor_), +has been found so deadly to insects that Prof. Metschnikoff, who is +experimenting upon it, hopes to extirpate the _Phylloxera_, the Colorado +beetle, etc., by its agency. + +Coming to better known and still undervalued fly-destroyers, we have +interfered most unwisely with the balance of nature. The substitution of +wire and railings for live fences in so many fields has greatly lessened +the cover both for insectivorous birds and for spiders. The war waged +against the latter in our houses is plainly carried too far. Whatever +may be the case at the Cape, in Australia, or even in Southern Europe, +no British species is venomous enough to cause danger to human beings. +Though cobwebs are not ornamental, save to the eye of the naturalist, +there are parts of our houses where they might be judiciously tolerated: +their scarcity in large towns, even where their prey abounds, is +somewhat remarkable. + +But perhaps the most effectual phase of man's war against the flies will +be negative rather than positive, turning not so much on putting to +death the mature individuals as in destroying the matter in which the +larvae are nourished. Or if, from other considerations, we cannot +destroy all organic refuse, we may and should render it unfit for the +multiplication of these vermin. We have, indeed, in most of our large +towns and in their suburbs, abolished cesspools, which are admirable +breeding-places for many kinds of Diptera, and which sometimes presented +one wriggling mass of larvae. We have drained many marshes, ditches, +and unclean pools, rich in decomposing vegetable matter, and have thus +notably checked the propagation of gnats and midges. I know an instance +of a country mansion, situate in one of the best wooded parts of the +home counties, which twenty years ago was almost uninhabitable, owing to +the swarms of gnats which penetrated into every room. But the present +proprietor, being the reverse of pachydermatous, has substituted covered +drains for stagnant ditches, filled up a number of slimy ponds as +neither useful nor ornamental, and now in most seasons the gnats no +longer occasion any annoyance. + +But if we have to some extent done away with cesspools and ditches, and +have reaped very distinct benefit by so doing, there is still a grievous +amount of organic matter allowed to putrefy in the very heart of our +cities. The dust bins--a necessary accompaniment of the water-carriage +system of disposing of sewage--are theoretically supposed to be +receptacles mainly for organic refuse, such as coal-ashes, broken +crockery, and at worst the sweepings from the floors. In sober fact +they are largely mixed with the rinds, shells, etc., of fruits and +vegetables, the bones and heads of fish, egg-shells, the sweepings out +of dog-kennels and henhouses, forming thus, in short, a mixture of evil +odor, and well adapted for the breeding-place of not a few Diptera. + +The uses to which this "dust" is put when ultimately fetched away are +surprising: without being freed from its organic refuse it is used to +fill up hollows in building-ground, and even for the repair of roads. A +few weeks ago I passed along a road which was being treated according +to the iniquity of Macadam. Over the broken stones had been shot, to +consolidate them, a complex of ashes, cabbage-leaves, egg and periwinkle +shells, straw, potato-parings, a dead kitten (over which a few +carrion-flies were hovering), and other promiscuous nuisances. The road +in question, be it remarked, is highly "respectable," if not actually +fashionable. The houses facing upon it are severely rated, and are +inhabited chiefly by "carriage people." What, then, may not be expected +in lower districts? + +Much attention has lately been drawn to the fish trade of London. It has +_not_, however, come out in evidence that the fish retailers, if they +find a quantity of their perishable wares entering into decomposition, +send out late in the evening a messenger, who, watching his opportunity, +throws his burden down in some plot of building land, or over a fence. +When I say that I have seen in one place, close alongside a public +thoroughfare, a heap of about fifty herrings, in most active +putrefaction and buzzing with flies, and some days afterward, in another +place, some twenty soles, it will be understood that such nuisances +can only be occasioned by dealers. To get rid of, or at least greatly +diminish, carrion-flies, house-flies, and the whole class of winged +travelers in disease, it will be, before all things, essential to +abolish such loathsome malpractices. The dustbins must cease being made +the receptacle for putrescent and putrescible matter, the destruction of +which by fire should be insisted upon. + +The banishment of slaughter-houses to some truly rural situation, where +the blood and offal could be at once utilized, would be another step +toward depriving flies of their pabulum in the larva state. An equally +important movement would be the substitution of steam or electricity for +horsepower in propelling tram-cars and other passenger carriages, with a +view to minimize the number of horses kept within greater London. Every +large stable is a focus of flies--_Journal of Science_. + + * * * * * + + + + +ON THE RELATIONS OF MINUTE ORGANISMS TO CERTAIN SPECIFIC DISEASES. + + +At the recent Medical Congress in London, Professor Klebs undertook to +answer the question: "Are there specific organized causes of disease?" + +A short historical review of the various opinions of mankind as to the +origin of disease led, the speaker thought, to the presumption that +these causes were specific and organized. + +If we now, he said, consider the present state of this question, the +three following points of view present themselves as those from which +the subject may be regarded: + +I.--We have to inquire whether the lower organisms, which are found in +the diseased body, may arise there spontaneously; or whether even they +may be regarded as regular constituents of the body. + +II.--The morphological relations of these organisms have to be +investigated, and their specific nature in the different morbid +processes has to be determined. + +III.--We have to inquire into their biological relations, their +development inside and outside the body, and the conditions under which +they are able to penetrate into the body, and there to set up disease. + +_First_.--With regard to the first question, that of the possibility of +spontaneous generation, the speaker gave a decided negative. + +_Second and third_.--There is in microscopic organisms a difference of +form corresponding, as a rule, to difference of function. The facts +regarding these various lower forms are briefly reviewed. + +"Three groups of hyphomycetae, algae, and schizomycetae, have been +demonstrated to occur in the animal and human organism in infective +diseases. Their significance increases with the increase of their +capacity for development in the animal body. This depends partly upon +their natural or ordinary conditions of life, but partly also, and that +in a very high degree, upon their power of adaptation, which, as Darwin +has shown, is a property of all living things, and causes the production +of new species with new active functions. + +"1. The hyphomycetae, on account of their needing an abundant supply +of oxygen, give rise to but few morbid processes, and these run their +course on the surface of the body, and are hence relatively of less +importance. It will be sufficient here to refer to the forms, achorion, +trichophyton, oïdium, aspergillus, and the diseases produced by them, +favus, ringworm, and thrush, to show this peculiarity. Nevertheless, we +see that these organisms also (as was proved by the older observations +of Hannover and Zenker) may, under certain circumstances, penetrate into +the interior of the organs. Grawitz, moreover, has recently shown that +their faculty of penetrating into the interior of the organism, and +there undergoing further development, depends on their becoming +accustomed to nitrogenous food. + +"2. Only one of the algae, viz., leptothrix, has as yet acquired any +importance as a producer of disease. It gives rise to the formation of +concretions, and that not only in the mouth, but also, as I have shown, +in the salivary ducts and urinary bladder. + +"Another alga, the sarcina of Goodsir, may indeed pass through the +organism, without, however, producing in its passage either direct +or indirect disturbances. It seems more worthy of note that many +schizomycetae, and especially the group of bacilli, are evidently nearly +allied to the algae in their morphological and vegetative relations--so +as to be assigned to this class by several authors, and especially by +Cienkowski. + +"The schizomycetae furnish, without doubt, by far the most numerous +group of infective diseases. We distinguish within this group two +widely different series of forms, which we will speak of as bacilli and +cocco-bacteria respectively. The former, which was first exhaustively +described by Ferdinand Cohn, and the pathological importance of which, +especially in relation to the splenic disease of cattle, was first shown +by Koch, consist of threads, in the interior of which permanent or +resting-spores are developed. These spores becoming free, are able, +under suitable conditions of life, again to develop into threads. The +whole development of these organisms, and especially the formation +of spores, is completed on the surface of the fluids, and under the +influence of an abundant supply of oxygen. + +"The number of affections in which these organisms have been found, +and which may be to a certain extent produced artificially by the +introduction of these organisms into healthy animal bodies, has been +largely increased since the discovery of Koch, that the bacteria of +splenic fever (anthrax) belong to this group. Under this head must be +placed the bacillus malarise (Klebs and Tommassi-Crudeli), the bacillus +typhi abdominalis (Klebs, Ebert), the bacillus typhi exanthematici +(Klebs, observations not yet published), the bacillus of hog-cholera +(Klein), and, finally the bacillus leprosus (Neisser). It would exceed +the time appointed were I to attempt to describe these forms more +minutely. This may, perhaps, be better reserved for discussion and +demonstration. + +"Alongside of these general infective diseases produced by bacilli, +local affections also occur, which indicate the presence of these +organisms at the point where disease begins. As an example of these +processes, which probably occur in various organs, I would mention +gastritis bacillaris, of which I shall show you preparations. In this, +we can trace the entrance of the bacilli into the peptic glands, as well +as their further distribution in the walls of the stomach, and in the +vascular system. + +"The second group of the pathogenetic schizomycetae I propose to call, +with Billroth, cocco-bacteria, because they consist of collections of +micrococci, which are capable of transforming themselves into short +rods. The former usually form groups united by zoögloea; by prolongation +of the cocci rods are formed, which sprout out, break up by division +into chains, and further lead again to the formation of resting masses +of cocci. I distinguish, further, in this group, two genera--the +microsporina and the monadina; in the former of which the micrococci are +collected into spherical lumps, in the latter into layers. The one class +is developed in artificial cultivation fluid, the other on the surface. +The former requires a medium poor in oxygen, the latter a medium rich in +oxygen, for their development. + +"Among the affections produced by microsporina, I reckon especially the +septic processes, and also true diphtheria. On the other hand, to the +processes produced by monadina belong especially a large series of +diseases, which according to their clinical and anatomical features, +may be characterized as inflammatory processes, acute exanthemata, and +infective tumors, or leucocytoses. Of inflammatory processes, those +belong here which do not generally lead to suppuration, such as +rheumatic affections, including the heart, kidney, and liver affections, +which accompany this process, sequelae which, as is well known, +lead more especially to formation of connective tissue, and not to +suppuration. Here, also, belong croupous pneumonia, the allied disease +erysipelas, certain puerperal processes, and finally, parotitis +epidemica, or mumps. + +"Among the acute exanthemata, the following may, up to the present time, +be placed in this group; variola-vaccina, scarlatina, and measles. + +"The group of infective tumors is represented by tuberculosis, syphilis, +and glanders. Throughout the whole group of cocco-bacteria the +demonstration of organisms in the diseased parts encounters difficulties +which vary considerably in the different kinds." + +The speaker concluded by describing the methods (now well known) by +which the powers of the different organisms are tested. + +He also referred to Pasteur's, Chauveau's, and Toussaint's recent +experiments. + +His conclusion was that the specific communicable diseases are produced +by specific organisms. + + * * * * * + + + + +THE CENTENARY OF THE DISCOVERY OF URANUS. + +By W. F. DENNING, F.R.A.S. + + +The year 1781 was signalized by an astronomical discovery of great +importance, and one which marked the epoch as memorable in the annals +of science. A musician at Bath, William Herschel by name, who had been +constructing some excellent telescopes and making a systematic survey of +the heavens, observed an object on the night of March 13 of that year, +which ultimately proved to be a large planet revolving in an orbit +exterior to that of Saturn. The discovery was as unique as it was +significant. Only five planets, in addition to the Earth, had hitherto +been known; they were observed by the ancients, and by each succeeding +generation, but now a new light burst upon men. The genius of Herschel +had singled out from the host of stars which his telescope revealed +an object the true character of which had evaded human perception for +thousands of years! + +[Illustration: FIG. 1.--APPROXIMATE PLACE OF URANUS AMONGST THE STARS AT +ITS DISCOVERY ON MARCH 13, 1781] + +The centenary of this remarkable advance in knowledge naturally recalls +to mind the circumstances of the discovery, and makes us inquisitive to +know what new facts have been gleaned of Herschel's planet, now that +a hundred years have passed away, and we are enabled to look back and +review the vast amount of labor which has been accomplished in this wide +and attractive field of astronomical research. We may learn what new +features have been discerned of the new body, and what additional +discoveries in connection with other planets unknown in Herschel's day, +have been effected by aid of the powerful telescopes which have been +devoted to the work. We do not, however, intend dealing with the general +question of planetary discovery, for at a glance we are impressed with +its magnitude. While a century ago five planets only were known, we now +have some two hundred and thirty of these bodies, and the stream of +discovery flows on without abatement through each succeeding year. The +detection of Uranus seems, indeed, to have been the prelude to many +similar discoveries, and to have offered the incentive to greater +diligence and energy on the part of observers in various parts of the +world. + +[Illustration: Fig. 2.--ORBITS OF THE URANIAN SATELLITES.] + +Many great discoveries have resulted from accident; and the leading +facts attending that of Uranus prove that, in a large measure, the +result was brought about in a similar way. Herschel, as he unwearyingly +swept the heavens night after night, was in quest of sidereal +wonders--such as double stars and nebulae--and he happened to alight +upon the new planet in a purely chance way. He had no expectation of +finding such a remarkable object, and indeed, when he had found it, +wholly mistook its character. There could be no doubt that it was a body +wholly dissimilar to the fixed stars, and it was equally certain that it +could not be a nebula. It had a perceptible disk, for when it had first +come under the critical eye of its discoverer he had noticed immediately +that its appearance differed widely from the multitude of objects which +crossed the field of his telescope. He had been accustomed to see hosts +of stars pass in review, and their aspect was in one respect similar, +namely, they were invariably presented as points of light incapable of +being sensibly magnified, even with the highest powers. True, there was +a great variety of apparent brightness in these objects and a singular +diversity of configuration, but there was no exception to the invariable +feature referred to. The point of light was constant, and no striking +exception was anticipated until one night--March 13, 1781--Herschel +being intently engaged in the examination of some small stars in the +region of Gemini, brought an object under the range of, his telescope, +which his eye at once selected as one of anomalous character. + +Applying a higher power, he noticed that it exhibited a planetary disk, +but his instrument failed to define it with sufficient distinctness, and +hence he became doubtful as to its real nature. The object was found to +be in motion, and subsequent observations led him to the assumption that +it must be a comet of rather exceptional type. This appeared to be the +best explanation of the strange body, for history contained many records +of curious comets, some of which were observed as nearly circular +patches of nebulous light, and probably of similar aspect to the object +then visible; and apart from this it must be remembered that the idea of +a large planet exterior to Saturn was a fact of such momentous import +that Herschel, with a due regard to that modesty which accompanies +true genius, refrained from attaching such an interpretation to his +observations. He was content to direct the notice of astronomers to it +as a phenomenon requiring close attention, and suggested that it might +be a comet in consequence of its motion and the faint and somewhat +ill-defined character of its appearance. + +From the earliest ages five planets only were known, and the discovery +of another large planet beyond the sphere of Saturn must at once +revolutionize existing ideas as to the range of the solar system, and +immediately take rank as a scientific event of equal interest to the +discovery of the moons of Jupiter or the rings of Saturn, which each in +their day impressed men with new ideas of the celestial mechanism. But +the truth could not long be delayed. The new body being watched and its +orbit rigorously computed from a series of observed positions revealed +its true character, and Herschel was awarded the honor due to the author +of a discovery of such importance. His diligence and pertinacity alone +had enabled him to search out from among the multitude of stars thickly +strewn over the firmament this unknown and well-nigh invisible planet +which, during all the preceding years of the world's history, had eluded +human perception. Men had been all unconscious of its existence as it +had been slowly completing its circuits around the sun, obedient to the +same laws as the other planets of the solar system, and awaiting the +hour when the unfailing eve of Herschel should introduce it as the faint +and far-off planet girding our system within its expansive folds. + +As soon as the existence of the new orb was confirmed and the fact +rendered indisputable, the question naturally arose whether it had ever +been seen in former years by the authors of star catalogues, who could +hardly have overlooked an object like this though its planetary nature +had manifestly escaped detection. It was just perceptible to the naked +eye, shining like a star of the sixth magnitude, and ought to have been +distinguished by those who had reviewed the heavens with the purpose +of determining and mapping the positions of the stars. Reference was, +therefore, made to the chief catalogues, when it was found at once that +the planet had been unquestionably observed by Tobias Mayer, Le Monnier, +Bradley, and Flamsteed. It was several times noted by these observers: +by Le Monnier no less than twelve times, and by Flamsteed on six +occasions; and it is remarkable that in every instance its true +character escaped detection. Neither its special appearance nor its +motion attracted attention, so that it was merely catalogued as an +ordinary fixed star. Thus Herschel was not anticipated in his discovery. +It remained for him, in 1781, to note its exceptional aspect, and to +specify it as an object requiring critical investigation. But the early +observations above alluded to served a useful purpose in testing the +accuracy of the computed orbit, for without waiting many years to +compare the theoretical and observed positions, astronomers had in these +old records a reliable series of points through which the previous +course of the planet could be traced. + +The calculations showed that its mean distance from the sun was some +1,750,000,000 miles, and that a revolution was completed in about +eighty-four years. It was also found to be a very large planet, greatly +exceeding either Mercury, Venus, the Earth, or Mars, though considerably +inferior to either Jupiter or Saturn. + +Here, then, was a discovery of the utmost importance, and one of the +most salient additions to our knowledge which the telescope had ever +achieved. The new planet was now definitely assigned its proper place in +the solar system, and was regarded as of equal significance with the +old planets. True, the new planet of Herschel could not be compared as +regards its visible aspect with the other previously known members of +our system, but it was nevertheless an object of equal weight. Its vast +distance alone rendered it faint. It formed one of the constituent parts +of the solar system, which, though separated by immense intervals of +space, are yet coherent by the far-reaching effects of gravitation. +There is, indeed, a bond of harmony between the series of planetary +orbits, which exhibit a marked degree of regularity in their successive +distances from the sun; and though they are not connected by any visible +links, they are firmly held together by unseen influences, and their +motions are subject to certain laws which have been revealed by +centuries of observation. + +The question of suitably naming the new planet soon came to the fore. +Herschel himself proposed to designate it the "Georgium Sidus," in honor +of his patron, George III., just as Galileo had called the satellites +of Jupiter the "Medicean stars," after Cosmo de' Medici. But La Place +proposed that the planet should be named after its discoverer; and thus +it was frequently referred to as "Herschel," and sometimes as "The +Herschelian planet." Astronomers on the continent objected to this +system of personal nomenclature, and argued that the new body should +receive an appellative in accordance with those adopted for the old +planets, which had been selected from the heathen mythology. Several +names were suggested as suitable (on the basis of this principle), and +ultimately the one advanced by Bode received the most favor, and the +planet thereafter was called "Uranus." + +The varying positions of the new body as observed on successive nights +were determined by comparisons with a group of six small stars, termed +by Herschel [Greek: alpha, beta, gamma, delta, epsilon] and afterwards +formed into a constellation under the designation of "Britannia," though +it does not appear that this little asterism is acknowledged as one of +our constellations. Its position is about midway between Taurus and +Gemini, and the following are the principal stars computed for 1881.0, +as given by Mr. Marth: + + Star. Magnitude. Right Ascension. Declination. + h. m. s. + alpha 9.0 5 42 6.06 23° 35' 6.7" N. + eta 8.7 5 43 17.82 23 26' 7.2 N. + theta 8.8 5 44 0.99 23 53' 30.8 N. + epsilon 8.8 5 45 40.68 23 34' 46.8 N. + +The stars are therefore merely telescopic, and are confined to a small +area of space, so that the propriety of adopting the group as a distinct +constellation is very questionable. Their positions close to Uranus at +the time of its discovery, and the fact that the planet's motion was +detected by means of comparisons with them, has given to these stars an +historical interest which in future years must often attract the student +to their reobservation. But it would be unwise, as forming a bad +precedent, to accept a group of stars of this inferior type as meriting +to rank among the old constellations, when we have numbers of richer +groups, situated on their confines, which first deserve such a +distinction. However special or unique the circumstances connected with +certain telescopic stars may be, and however necessary it may appear +to signalize them by a specific title, we are inclined to question the +adoption of such means as likely to exercise a wrong influence, +inasmuch as it may hereafter originate further innovations of a similar +character, and ultimate complications will be certain to arise. + +Soon after the discovery of Uranus it was suspected that the planet +was encircled, like Saturn, by a luminous ring, but on subsequent +observation this was not confirmed, and no such appendage has ever been +revealed in the more perfected instruments of our own times. Indeed, if +Uranus displays a peculiarity of constitution in any way analogous to +the ring system of Saturn, it must be of the most minute character so as +to have thus evaded telescopic scrutiny during a hundred years. + +The discovery soon attracted the notice of royalty, and the reigning +sovereign, George III., anxious to practically express his appreciation +of the valuable labors of Herschel, awarded him a pension of £200 a year +and furnished him with a residence at Slough, near Windsor, and the +means to erect a gigantic telescope with which he might be enabled +to continue his important researches. This instrument consisted of a +reflector on the "Front-view" construction, with a speculum 4 feet in +diameter and of 40 feet focal length. Upon its completion, Herschel +immediately began to observe the region of the new planet with the idea +of discovering any satellites which might belong to it, for analogy +suggested that it was surrounded by a numerous retinue of such bodies. +He was soon successful, for, on the night of January 11, 1787. he saw +two minute objects near the planet, which renewed observations revealed +to be satellites; and he detected two additional ones in 1790, and two +others in 1794, making six in all. But the observations were of extreme +difficulty. The path of the planet frequently passed near minute stars, +and it became hard to distinguish between them and the suspected +satellites. Herschel, however, considered he had obtained conclusive +evidence of the existence of six satellites with sidereal periods +ranging from 5d. 21h. 25m. to 107d. 16h. 39m., and his means of +observation being much superior to those possessed by any of his +contemporaries it was impossible to have corroborative testimony. + +The matter was thus allowed to rest until the middle of the present +century, when Lassell, in the pure sky at Malta, endeavored to reobserve +the satellites with a two-foot reflector. This instrument was considered +superior to Herschel's telescope; and the atmosphere at this station +being decidedly more suitable for such delicate observations than +in England, it was removed there for the express purpose of dealing +successfully with objects of extreme difficulty. The results were very +important. Mr. Lassell became convinced that Uranus had only four +satellites, and that if any others existed they remained to be +discovered. Two of these were found to be identical with those seen by +Herschel in 1787, and now called Titania and Oberon. The other two, +Ariel and Umbriel, could not be identified with any of those alleged to +have been previously detected by Herschel, so that the inference was +that they were new bodies, and that the priority of discovery was due to +Mr. Lassell; whence it also followed that the older observations were +erroneous, and that in fact Herschel had been entirely mistaken with +regard to the four satellites he believed he had detected subsequently +to 1787. + +In November, 1873, a fine twenty-six-inch object glass, by Alvan Clark, +was mounted at the U. S. Naval Observatory at Washington, and it was +soon employed upon the difficult task of solving the problem as to the +exact periods of the Uranian satellites. This was very satisfactorily +effected, and with distinct and conclusive favor to Mr. Lassell, whose +observations were fully corroborated. Only four satellites could be +distinguished by the American observers, and their periods, as computed +from a valuable series of measures, agreed with those previously derived +at Malta. In Appendix I. to the "Washington Observations" for 1873, +Prof. Newcomb gave a valuable summary of results--the first obtained, be +it noted, with that splendid instrument which soon afterward, in 1877, +revealed the satellites of Mars--which included the elements of the +satellites of Uranus as follows: + + Mean Longitude. + + Satellite. Epoch 1871. Radius of Period of + Dec. 31, W.M.T. Orbit. Revolution in days. + I. Ariel........ 21.83° 13.78" 2.52038 + II. Umbriel..... 13.52 19.20 4.14418 + III. Titania..... 229.93 31.48 7.70590 + IV. Oberon...... 154.83 42.10 13.43327 + +Speaking of the comparative brightness of the satellites, Prof. Newcomb +says: + +"The greater proximity of the inner satellites to the planet makes it +difficult to compare them photometrically with the outer ones, as actual +feebleness of light cannot be distinguished from difficulty of seeing +arising from the proximity of the planet. However, that Umbriel is +intrinsically fainter than Titania is evinced by the fact that, although +the least distance of the latter is somewhat less than the greatest +distance of the former, there is never any difficulty in seeing it in +that position. From their relative aspects in these respective positions +I judge Umbriel to be about half as bright as Titania. Ariel must be +brighter than Umbriel, because I have never seen the latter unless it +was farther from the planet than the former at its maximum distance.... +I think I may say with considerable certainty that there is no satellite +within 2' of the planet, and outside of Oberon, having one-third the +brilliancy of the latter, and therefore that none of Sir William +Herschel's supposed outer satellites can have any real existence. The +distances of the four known satellites increase in so regular a way that +it can hardly be supposed that any others exist between them. Of what +may be inside of Ariel it is impossible to speak with certainty, since +in the state of atmosphere which prevails during our winter all the +satellites named disappear at 10" from the planet." + +Prof. Newcomb mentions that no systematic search for new satellites +was undertaken because it must have interfered with the fullness and +accuracy of the micrometer measures of the old satellites, which +constituted the main purpose of the observations. Some faint objects +were occasionally glimpsed near the planet, and their relative places +determined, but they were never found to accompany Uranus. The fact, +therefore, that no additional satellites were discovered is not to +be regarded as a strong point in favor of the theory of their +non-existence, because the great power and excellence of the telescope +was expressly directed to the attainment of other ends; and moreover the +season in which the planet came to opposition was distinctly unfavorable +for the prosecution of a rigorous search for new satellites. There +can, however, be no doubt that the analogies of the planetary systems +interior to Uranus plainly suggest that this planet is attended by +several satellites which the power of our greatest telescopes has +hitherto failed to reveal; and that it is in this direction and that of +Neptune we may anticipate further discoveries in future years when the +conditions are more auspicious and the work is entered upon with special +energy, aided by instruments of even greater capacity than those which +have already so far conduced to our knowledge of the heavenly bodies. + +Notwithstanding the extreme difficulty with which the Uranian satellites +are observed, the two brighter ones, Titania and Oberon, discovered by +William Herschel in 1787, have been occasionally detected in telescopes +of moderate power, and identified by means of an ephemeris which has +shown that the computed positions approximately agree with those +observed. During the last few years Mr. Marth has published ephemerides +of the satellites of both Saturn and Uranus, and many amateurs have to +acknowledge the valuable aid rendered by these tables, which supply a +ready means of identifying the satellites, and thus act as an incentive +to observers who are induced to pursue such work for the sake of the +interesting comparisons to be made afterward. In one exceptional +instance the two outer satellites of Uranus appear to have been glimpsed +with an object glass of only 43 inches aperture, and the facts are given +in detail in the "Monthly Notices of the R.A.S.," April 1876, pp. 294-6. +The observations were made in January, February, and March, 1876, by +Mr. J.W. Ward, of Belfast; and the positions of the satellites, as he +estimated them on several nights, are compared with those computed, the +two sets presenting tolerably good agreement. Indeed the corroborations +are such as to almost wholly negative any skepticism, though such +extraordinary feats should always be received with caution. + +In this particular case the chances of being misled are manifold; even +Herschel himself fell into error in taking minute stars to be satellites +and actually calculating their periods; so that when we remember the +difficulties of the question our doubts are not altogether dispelled. +Extreme acuteness of vision will, in individual instances, lead to +success of abnormal character, and certainly in Mr. Ward's case the +remarkable accordances in the observed and calculated positions appear +to be conclusive evidence that he was not mistaken. + +It will be readily inferred that the great distance and consequent +feebleness of Uranus must render any markings upon the disk of the +planet beyond the reach of our best telescopes; and indeed this appears +to have been a matter of common experience. Though the surface has been +often scanned for traces of spots, we seldom find mention that any have +been distinguished. Consequently the period of rotation has yet to be +determined. It is true that an approximate value was assigned by Mr. +T.H. Buffham from observations with a nine-inch reflector in 1870 and +1872. but the materials on which the computation was based were slender +and necessarily somewhat uncertain, so that his period of about twelve +hours stands greatly in need of confirmation. The bright spots and zones +seen on the disk in the years mentioned appear to have entirely eluded +other observers, though they are probably phenomena of permanent +character and within reach of instruments of moderate size. Mr. Buffham +[1] thus describes them: + +[Footnote 1: "Monthly Notices K. A. S.," January, 1873.] + +"1870, Jan. 25, 11h. to 12h. in clear and tolerably steady air; power +132 showed that the disk was not uniform. With powers 202 and 3.0, two +round, bright spots were perceived, not quite crossing the center but a +little nearer to the eastern side of the planet, the position angle of a +line passing through their centers being about 20º and 200--ellipticity +of Uranus seemed obvious, the major axis lying parallel to the line of +the spots. + +"Jan. 27, 10h. to 10½h.; some fog, and definition not good, but the +appearance of the spots was almost exactly the same as on the 25th." + +On March 19 glimpses were obtained of a light streak and two spots. +On April 1, 4, 6, and 8, a luminous zone was seen on the disk, and +in February and March, 1872, when observations were resumed, certain +regions were noted brighter than others, and underwent changes +indicating the rotation of the planet in a similar direction to that +derived from the results obtained in 1870. Mr. Buffham points out that, +if this is admitted, then the plane of the planet's equator is not +coincident with the plane of the orbits of the satellites. Nor need we +be surprised at this departure from the general rule, where such an +anomalous inclination exists. In singular confirmation of this is Mr. +Lassell's observation of 1862, Jan. 29, where he says: "I received an +impression which I am unable to render certain of an equatorial dark +belt, and of an ellipticity of form." + +Some observations made in 1872-3 with the great six-foot reflector of +Lord Rosse may here be briefly referred to. A number of measures, both +of position and distance, of Oberon and Titania, were made, [1] and a +few of Umbriel and Ariel, but "the shortness of the time available (40 +minutes) each night for the observation of the planet with the six-foot +instrument, the atmospheric disturbance, so often a source of annoyance +in using so large an aperture, and other unfavorable circumstances, +tended to affect the value of the observations, and to make the two +inner satellites rarely within detection." + +[Footnote 1: "Monthly Notices R. A. S.," March, 1875.] + +On Feb. 10, 1872, Lord Rosse notes that all four satellites were seen on +the same side of the planet. On Jan. 16, 1873, when definition was good, +no traces of any markings were seen. Diameter of Uranus = 5.29". Power +414 was usually employed, though at times the inner satellites could be +more satisfactorily seen with 625. + +It may be mentioned as an interesting point that, some fifty years +after the first discovery of Uranus by Herschel, it was accidentally +rediscovered by his son, Sir John Herschel, who recognized it by +its disk, and had no idea as to the identity of the object until an +ephemeris was referred to. Sir John mentions the fact as follows, in a +letter to Admiral Smyth, written in 1830, August 8: + +"I have just completed two twenty-foot reflectors, and have got some +interesting observations of the satellites of Uranus. The first sweep +I made with my new mirror I _re-discovered_ this planet by its _disk_, +having blundered upon it by the merest accident for 19 Capricorni." + +In commenting upon the centenary of an important scientific discovery we +are naturally attracted to inquire what progress has been made in the +same field during the comparatively short interval of one hundred years +which has elapsed since it occurred. We have called it a short interval, +because it cannot be considered otherwise from an astronomical or +geological point of view, though, as far as human life is concerned, +it can only be regarded as a very lengthy period, including several +generations within its limits. + +Since Herschel, in 1781, discovered Uranus, astronomy has progressed +with great rapidity, so that it would be impossible to enumerate in a +brief memoir the many additional discoveries which have resulted from +assiduous observation. A century ago only five planets were known +(excluding the Earth), now we are acquainted with about two hundred and +thirty of these bodies; and one of these, found in 1846, is a large +planet whose orbit lies exterior to that of Uranus. In fact, the state +of astronomical knowledge a century ago has undergone wonderful changes. +It has been rendered far more complete and comprehensive by the +diligence of its adherents and by the unwearying energy with which both +in theory and practice it has been pursued. A zone of small planets has +been discovered between Mars and Jupiter just where the analogies of the +planetary distances indicated the probable existence of a large planet. +The far-off Neptune was revealed in 1846 by a process of analytical +reasoning as unique as it was triumphant, and which proved how well +the theory of planetary perturbations was understood. The planet was +discovered by calculation, its position in the heavens assigned, and the +telescope was then employed merely as the instrument of its detection. +The number of satellites which a century ago numbered only ten has now +reached twenty, and the discovery in 1877 of two moons accompanying Mars +shows that the work is being continued with marked success. + +In other departments we also find similar evidence of increasing +knowledge. The periodicity of the sun spots, the existence of systems of +binary stars, meteor showers, and their affinity with cometary orbits +may be mentioned as among the more important, while a host of new +comets, chiefly telescopic, have been detected. Large numbers of nebulæ +and double stars have been catalogued, and we have evidence every year +of the activity with which these several branches are being followed up. + +In fine, it matters little to what particular department of astronomical +investigation we look for traces of advancement during the past hundred +years, for it is evident throughout them all, and sufficiently proves +that the interest formerly taken in the science has not only been well +sustained but has become more general and popular, and is extending its +attractive features to all classes of the community. + +In Herschel's day large telescopes were rare. A man devoting himself to +the study of the heavenly bodies as a means of intellectual recreation +was considered a phenomenon, and indeed that appellation might be +fittingly applied to the few isolated individuals who really occupied +themselves in such work. How different is the case now that the pleasant +ways of science have called so many to her side and so far perfected her +means of research as to make them accessible to all who care to see and +investigate for themselves the unique and wonderful truths so easily +within reach! Large telescopes have become common enough, and there is +no lack of hands and eyes to utilize them, nor of understanding, ever +ready to appreciate, in sincerity and humbleness, those objects which +display in an eminent degree the all-wise conceptions of a great +Creator! It is, therefore, a most gratifying sign to notice this rapid +development of astronomy, and to see year by year the increasing number +of its advocates and the record of many new facts gleaned by vigorous +observation. + +The character of recent discoveries distinctly intimates that, in future +years, some departments of the science will become very complicated, +owing to the necessity of dealing with a large number of minute bodies, +for the tendency of modern researches has been to reveal objects which +by their faintness had hitherto eluded detection. And when we consider +that these bodies are rapidly increasing year by year, the idea is +obviously suggested that, inasmuch as their numbers are comparatively +illimitable, and there is likely to be no immediate abatement in the +enthusiasm of observers, difficulties will arise in identifying them +apart and forming them into catalogues with their orbital elements +attached, so that the individual members may be redetected at any time. + +In this connection we allude particularly to minor planets, to +telescopic comets, and to meteoric streams, which severally form a very +numerous group of bodies of which the known members are accumulating to +a great extent. As complications arise, some remedies must be applied to +their solution, and one probable effect will be that astronomers will be +induced each one to have a specialty or branch to which his energies are +mainly directed. The science will become so wide in its application and +so intricate in its details that it will become more than ever necessary +for observers to select or single out definite lines of investigation +and pursue them closely, for success is far more likely to attend such +exertions than those which are not devoted to any special end, but +employed rather in a general survey of phenomena. + +We have already before us some excellent instances in which individual +energies have been aptly utilized in the prosecution of original work +in some specific branch of astronomy, and we are strongly disposed to +recommend such exclusive labors to those who have the means and the +desire to achieve something useful. Observers who find one subject +monotonous and then take up another for the sake of variation are not +likely to get far advanced in either. In the case of amateurs who use a +telescope merely for amusement, and indiscriminately apply it to nearly +every conspicuous object in the firmament without any particular purpose +other than to satisfy their curiosity, the matter is somewhat different, +and our remarks are not applicable to them. We refer more pointedly +to those who have a regard for the interests of the science and whose +enthusiasm enables them to work habitually and with some pertinacity. + +History tells us that the Great Alexander wept when he found he had no +other worlds to conquer, and we fear that some astronomers will lament +that they have little prospect of discovering anything fresh in a sphere +to which our giant telescopes have been so often directed, but this is +founded on a palpable misconception. Certain objects, such as comets for +example, do not require great power, and the revelation of new meteor +showers is entirely a question for the naked eye. In fact, it may be +confidently asserted that observations undertaken with energy and +persistency will, if rightly directed, more than compensate for defects +of instrumental power. + +It is true, however, that in certain quarters we must look to large +instruments alone for new discoveries. It would be useless searching for +an ultra-Neptunian planet, or for additional satellites to Uranus or +Neptune, or for the materials to determine the rotation periods of these +planets with a small telescope. Every observer will find objects suited +to the capacity of his instrument, and he may not only employ it +usefully but possibly make a discovery of nearly equal import with that +which rendered the name of Herschel famous a century ago.--_Popular +Science Review_. + + * * * * * + + + + +THE VARYING SUSCEPTIBILITY OF PLANTS AND ANIMALS TO POISONS AND +DISEASES. + + +Much attention is being devoted to the causes which determine the +aptitude or immunity with animals for maladies. This is in a general +sense called medical geography, as a physician who has prescribed for +patients in various parts of the world, and belonging to different +races--the white, yellow, and black--has been able to note the +diversities in the same disease, and the contradictions in the remedies +employed. + +The true social peril, hardly discovered before we became aware how +to conjure it, lies in those legions of animalcules or microbes that +surround us and in the middle of which we live. M. Pasteur has revealed +them to us as the factors in infectious diseases. Claude Bernard +has demonstrated the community which exists between animals and +vegetables--phenomena of movement, of sensibility, of production of +heat, of respiration, of digestion even, for there are the _Drosera_ and +kindred carnivorous plants. Iron cures chlorosis in vegetables as well +as in animals, and chloroform and ether render both insensible. There +resemblances are more striking still between animals. After Baudrimont, +insects are, in presence of alcohols, chloroform, and irrespirable +gases, similarly affected as man. Many maladies, too, are common to +man and several species of animals; and this organic identity is best +illustrated in the relationship between epidemics and epizootias, +cancer, asthma, phthisis, smallpox, rabies, glanders, charbon, etc., +afflict alike man and many species of animals. + +The differences between races are not less remarkable--odor and taste, +for example. According to anthropophagy, negroes are best, and white +people most detestable. Broca remarked, that, in the dissecting room, +the muscles of the negro putrefied less rapidly than those of whites. It +is perhaps to these anatomical differences that the diverse action of +the same poison, in the case of races or species, may be attributed. On +certain rodentia belladonna exercises no influence; morphine for a horse +is a violent stimulant; a snail remains insensible to digitalis; goats +eat tobacco with impunity; and in the Tarentin the inhabitants rear only +black sheep, because a plant abounds which is noxious for white sheep. + +The nature of these conditions is a mystery for science. The _Solanæ_ +tribe of plants furnish a principle which, as its name implies, produces +consolation or forgetfulness, by acting on the tissues of the brain +where resides the organ of thought; now, on the authority of Professor +Bouchardat, these opiates have the less of effect in proportion as the +animals possess the less of intelligence. + +To the same anatomical peculiarities must be ascribed the choice that +disease makes in such or such a race. Glanders, for instance, so +virulent with the horse, the ass, and man, produce in the case of the +dog only a local accident; peripneumonia, so contagious among horned +cattle, is more benign in its action on Dutch than other breeds of +stock; the cattle plague that decimates so many farms is communicated by +cattle to each other from the slightest contact, while the closest and +most constant association is necessary to communicate the disease +to sheep, and even when they are affected its action is not severe. +Further, that plague only attacks ruminant animals--oxen, goats, sheep, +zebras, gazelles, etc. Ten years ago this plague broke out in the Jardin +d'Acclimatation; not a ruminant escaped, and also one animal not of that +class, a little tenant nearly related to the pig--the _peccari_. + +Now, Dr. Condereau has demonstrated recently that the stomach of the pig +has a rudimentary organization recalling that of the ruminants. Clearly, +the stomach of the peccari, and perhaps that of the pig, present a +favorable medium for the parasitical microbe peculiar to the rinderpest. +In the potato disease, again, all the varieties are not affected with +the same degree of violence; it is more marked in its action on the +round yellows than the reds, and on the latter rather than the pink. But +the symptoms even of the same malady differ, the parasite's attacks on +the tissues being dissimilar. Oak galls are produced from the prickings +of insects; now around the same larva often four varieties of galls are +recognized. In the case of consumption in cattle, the disease marches +slowly; in that of pigs it takes the galloping form, as with man. + +Each people or nation has its peculiar pathology and also its peculiar +cures. A negro can take a dose of tartar ten times more excessive than a +white; the same dose of brandy given to a black, a yellow, and a white, +will not produce on the three men either drunkenness at the same moment, +or intoxication at all. Mulattoes can sustain more drastic aperients +than other races; the negro does not suffer from yellow fever, but he +readily falls to phthisis; he will catch the cholera more quickly than a +white. Human races, where they may catch the same intermittent fever at +the identical moment and in the same swamp, will not the less display +different types of fever. Dr. Crevaux has shown that a certain insect +with the North American Indian is not the same as with the negro or the +maroon, and both differ from that peculiar to Europeans. + +M. Pasteur's beautiful experiments have conclusively demonstrated that +fowls do not catch the _charbon_; now the vital warmth of birds is from +seven to nine degrees higher than in the case of mammiferous animals; +he imagined that if the fowl was cooled down by baths to the lower +temperature, it would be liable equally to become affected; he tried, +and the result proved he was correct. + +The absence, then, of a certain temperature would be the reason why +birds are exempt. The microbes are the agents of infectious disease; +when these swarm in the blood of an individual they seem to leave there +something pernicious for parasites resembling themselves, or to bring +away with them something necessary to the life of their successors. A +glass of sugar and water, where leaven has already fermented and yielded +alcohol, is incapable of producing a second crop of leaven; similarly +the blood of an individual, once contaminated, becomes uninhabitable +afterward for like microbes. The individual has acquired immunity. Such +is the principle of vaccination.--_Paris Correspondent of the Kansas +City Review_. + + * * * * * + + + + +KIND TREATMENT OF HORSES. + + +It has been observed by experienced horse trainers that naturally +vicious horses are rare, and that among those that are properly trained +and kindly treated when colts they are the exception. + +It is superfluous to say that a gentle and docile horse is always the +more valuable, other qualities being equal, and it is almost obvious +that gentle treatment tends to develop this admirable quality in the +horse as well as in the human species, while harsh treatment has the +contrary tendency. Horses have been trained so as to be entirely +governed by the words of his driver, and they will obey and perform +their simple but important duties with as much alacrity as the child +obeys the direction of the parent. + +It is true that all horses are not equally intelligent and tractable, +but it is probable that there is less difference among them in this +regard than there is among his human masters, since there are many +incitements and ambitions among men that do not affect animals. + +The horse learns to know and to have confidence in a gentle driver, and +soon discovers how to secure for himself that which he desires, and +to understand his surroundings and his duties. The tone, volume, and +inflection of his master's voice indicate much, perhaps more than the +words that are spoken. Soothing tones rather than words calm him if +excited by fear or anger, and angry and excited tones tend to excite or +anger him. In short, bad masters make bad horses. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. Six dollars a year, sent, prepaid, to any foreign +country. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. Price, 10 cents each. + +All the back volumes of THE SUPPLEMENT can likewise be supplied. Two +volumes are issued yearly. 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