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diff --git a/13939-0.txt b/13939-0.txt new file mode 100644 index 0000000..ab72419 --- /dev/null +++ b/13939-0.txt @@ -0,0 +1,3818 @@ +*** START OF THE PROJECT GUTENBERG EBOOK 13939 *** + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 484 + + + + +NEW YORK, APRIL 11, 1885 + +Scientific American Supplement. Vol. XIX, No. 484. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + * * * * * + + + + +TABLE OF CONTENTS. + + +I. ENGINEERING AND MECHANICS.--Bridge over the Blaauw + Krantz Ravine, Cape Colony.--2 engravings. + + Torpedo Ships. + + The Gas Engine.--By DUGALD CLERK.--Combustion engines.--First + cylinder and piston engine.--Watt's experiments.--First gas + engine.--Principles of the gas engine. + + Rapid Construction of the Canadian Pacific Railway.--By E.T. + ABBOTT. + + The Osgood Mammoth Excavator.--3 figures. + + Capstan Navigation on the Volga.--4 figures. + + Steamboat Equipment of War Vessels.--With engraving of winch + for raising and lowering torpedo boats. + + Improved Steam Trap.--1 engraving. + + +II. TECHNOLOGY.--Critical Methods of Detecting Errors in Plane + Surfaces.--By JOHN A. BRASHEAR.--11 figures. + + Photometric Standards.--9 figures. + + Bleaching or Dyeing Yarns and Goods in Vacuo.--1 figure. + + On the Moulding of Porcelain.--By CHAS. LAUTH.--Moulding by + pressure of the air.--Moulding by vacuum.--Drying the moulded + pieces.--2 figures. + + Photo-Tricycle Apparatus.--1 figure. + + A Photo Printing Light.--1 figure. + + A New Actinometer. + + Astronomical Photography. + + Electricity as a Preventive of Scale in Boilers. + + +III. DECORATIVE ART.--Alphabet designed by Godfrey Sykes.--An + engraving. + + Old Wrought Iron Gate.--An engraving. + + +IV. GEOLOGY.--The Organization and Plan of the United States + Geological Survey.--By J.W. POWELL.--A topographic map + of the United States.--Paleontology.--Chemistry.--Physical + researches.--Statistics.--Library.--Publications.--General + geology.--Economic geology.--Relation of the general survey + to the State survey. + + +V. BOTANY, ETC.--The Sunflowers.--Annuals, perennials, etc.--11 + engravings. + + Lye's Fuchsias.--1 engraving. + + +VI. HYGIENE, ETC.--Brief Sanitary Matters in Connection with + Isolated Country Houses.--By E.W. BOWDITCH. + + Sanitary Cooking.--By V.L. OPPENHEIMER. + + Time required to digest Different Foods. + + * * * * * + + + + +THE BLAAUW KRANTZ VIADUCT IN CAPE COLONY. + + +This viaduct is built over a rocky ravine on the railway from Port Alfred +to Grahamstown, at a height of about 200 ft. from the bottom. Its length +is 480 ft. 6 in., and the width of the platform is 15 ft., the gauge of +the railway being 3 ft. 6 in. The central span of the viaduct is an arch +of 220 ft. span between abutments, and about 90 ft. height; the remainder +of the space on each side is divided into two spans by an iron pier at a +distance of 68 ft. from the retaining wall. These piers are 36 ft. 2 in. +high, and carry girders 144 ft. long, balanced each on a pivot in the +center. One end of these girders is secured to the retaining walls by +means of horizontal and vertical anchorages, while the other end rests in +a sliding bearing on the top flange of the arch. + +[Illustration: BRIDGE OVER THE BLAAUW KRANTZ RAVINE, CAPE COLONY.] + +[Illustration: BRIDGE OVER THE BLAAUW KRANTZ RAVINE, CAPE COLONY.] + +In designing the structure the following points had to be considered: (1) +That, on account of the great height above the ground, and on account of +the high price of timber at the site, the structure could be easily +erected without the use of scaffolding supporting it as a whole. (2) That, +on account of the high freights to Port Alfred, the quantity of iron in +the structure should be as small as possible. (3) That the single parts of +the principal span should be easy to lift, and that there should be as few +of them as possible. For this latter reason most of them were made in +lengths of 20 ft. and more. The question of economy of material presented +itself as a comparison between a few standard types, viz., the girder +bridge of small independent spans; the cantilever bridge, or the +continuous girder bridge in three large spans; the single girder bridge +with one large span and several small spans; and the arch with small +girder spans on each side. The suspension bridge was left out of question +as inadmissible. A girder bridge with small independent spans on rocker +piers would probably have been the most economical, even taking into +account the great height of the piers near the middle of the ravine, but +there would have been some difficulty in holding those piers in position +until they could be secured to the girders at the top; and, moreover, such +a structure would have been strikingly out of harmony with the character +of the site. On the other hand, a cantilever or continuous girder bridge +in three spans--although such structures have been erected in similar +localities--could not enter into comparison of simple economy of material, +because such a design would entirely disregard the anomaly that the +greater part of the structure, viz., the side spans, being necessarily +constructed to carry across a large space, would be too near the ground to +justify the omission of further supports. The question was, therefore, +narrowed to a comparison between the present arch and a central +independent girder of the same span, including the piers on which it +rests. The small side spans could obviously be left out in each case. The +comparison was made with a view not only to arrive at a decision in this +particular case, but also of answering the question of the economy of the +arch more generally. The following table contains the weights of +geometrically similar structures of three different spans, of which the +second is the one here described. The so-called theoretical weight is that +which the structure would have if no part required stiffening, leaving out +also all connections and all wind bracing. The moving load is taken at one +ton per foot lineal, and the strain on the iron at an average of four tons +per square inch. The proportion of the girder is taken at 1 in 8. + +--------------+-----------------------+------------------------+ + | Theoretical Weight. | Total Weight. | +Span in Feet. +-----------------------+------------------------| + | Arch. | Girder. | Arch. | Girder. | +--------------+---------+-------------+------------+-----------| + 100 | 0.0724 | 0.1663 | 0.1866 | 0.2443 | + 220 | 0.1659 | 0.4109 | 0.4476 | 0.7462 | + 300 | 0.2414 | 0.6445 | 0.6464 | 1.2588 | +--------------+---------+-------------+------------+-----------+ + |<------------Tons per foot lineal.------------->| + +It can be seen from these results that the economical advantage of the +arch increases with the span. In small arches this advantage would not be +large enough to counterbalance the greater cost of manufacture; but in the +arch of 220 ft. span the advantage is already very marked. If the table +were continued, it would show that the girder, even if the platform were +artificially widened, would become impossible at a point where the arch +can still be made without difficulty. The calculations leading to the +above results would occupy too much space to make it desirable on this +occasion to produce them. Our two views are from photographs.--_The +Engineer._ + + * * * * * + + + + +TORPEDO SHIPS. + + +Commander Gallwey lately delivered an interesting lecture on the use of +torpedoes in war before the royal U.S. Institution, London, discussed +H.M.S. Polyphemus, and urged as arguments in her favor: 1. That she has +very high speed, combined with fair maneuvering powers. 2. That she can +discharge her torpedoes with certainty either ahead or on the beam when +proceeding at full speed. 3. That her crew and weapons of defense are +protected by the most perfect of all armor possible, namely, 10 ft. of +water. 4. That she only presents a mark of 4 ft. above the water line. + +Then, he asked, with what weapon is the ironclad going to vanquish these +torpedo rams? Guns cannot hit her when moving at speed; she is proof +against machine guns, and, being smaller, handier, and faster than most +ironclads, should have a better chance with her ram, the more especially +as it is provided with a weapon which has been scores of times discharged +with certainty at 300 yards. The ironclad, he answered, must use +torpedoes, and then he maintained that the speed and handiness of the +Polyphemus would enable her to place herself in positions where she could +use her own torpedo to advantage, and be less likely to be hit herself. He +then called attention to the necessity for well-protected conning towers +in these ships, and prophesied that if a submarine ship, armed with +torpedoes, be ever built, she will be the most formidable antagonist an +ironclad ever had; and the nearer the special torpedo ship approaches this +desideratum the better she will be. + + * * * * * + + + + +A PLUMBING TEST. + + +A recent trial of a smoke rocket for testing drains, described by Mr. +Cosmo Jones in the _Journal of the Society of Arts_, is deserving of +interest. The one fixed upon is 10 in. long, 2½ in. in diameter, and with +the composition "charged rather hard," so as to burn for ten minutes. This +gives the engineer time to light the fuse, insert the rocket in the drain, +insert a plug behind it, and walk through the house to see if the smoke +escapes into it at any point, finishing on the roof, where he finds the +smoke issuing in volumes from the ventilating pipes. The house +experimented upon had three ventilating pipes, and the smoke issued in +dense masses from each of them, but did not escape anywhere into the +house, showing that the pipes were sound. If the engineer wishes to +increase the severity of the test, he throws a wet cloth over the top of +the ventilating pipe, and so gets a slight pressure of smoke inside it. + + * * * * * + + + + +THE GAS ENGINE.[1] + +[Footnote 1: Lecture by Mr. Dugald Clerk, before the Literary and +Philosophical Society, Oldham.] + +By DUGALD CLERK. + + +In earlier days of mechanics, before the work of the great Scottish +engineer, James Watt, the crude steam engines of the time were known as +"fire engines," not in the sense in which we now apply the term to +machines for the extinguishing of fires, but as indicating the source from +which the power was derived, motive power engines deriving their vitality +and strength from fire. The modern name--steam engine--to some extent is a +misleading one, distracting the mind from the source of power to the +medium which conveys the power. Similarly the name "Gas Engine" masks the +fact of the motors so called being really fire or heat engines. + +The gas engine is more emphatically a "fire engine" than ever the steam +engine has been. In it the fire is not tamed or diluted by indirect +contact with water, but it is used direct; the fire, instead of being kept +to the boiler room, is introduced direct into the motor cylinder of the +engine. This at first sight looks very absurd and impracticable; +difficulties at once become apparent of so overwhelming a nature that the +problem seems almost an impossible one; yet this is what has been +successfully accomplished in the gas engine. Engineers accustomed to the +construction of steam engines would not many years ago have considered any +one proposing such a thing as having taken leave of his senses. + +The late Sir William Siemens worked for many years on combustion engines, +some of his patents on this subject dating back to 1860. In the course of +a conversation I had with him on the subject of his earlier patents, I +asked him why he had entitled one of those patents "steam engine +improvements" when it was wholly concerned with a gas engine using +hydrogen and air in the motive cylinder, the combustion of the hydrogen +taking place in the motive cylinder. He answered me that in 1860 he did +not care to entitle his patent gas or combustion engine simply because +engineers at that time would have thought him mad. + +Notwithstanding this widespread incredulity among engineers, and the +apparent novelty of the gas engine idea, fire or combustion engines have +been proposed long, long ago. The first Newcomen steam engine ever set to +work was used by a Mr. Back, of Wolverhampton, in the year 1711. +Thirty-one years before this time, in Paris--year 1680--Huyghens presented +a memoir to the Academy of Sciences describing a method of utilizing the +expansive force of gunpowder. This engineer is notable as being the very +first to propose the use of a cylinder and piston, as well as the first +combustion engine of a practical kind. + +The engine consists of a vertical open topped cylinder, in which works a +piston; the piston is connected by a chain passing over a pulley above it +to a heavy weight; the upstroke is accomplished by the descent of the +weight, which pulls the piston to the top of the cylinder; gunpowder +placed in a tray at the bottom of the cylinder is now ignited, and expels +the air with which the cylinder is filled through a shifting valve, and, +after the products of combustion have cooled, a partial vacuum takes place +and the atmospheric pressure forces down the piston to the bottom of its +stroke, during which work may be obtained. + +On the board I have made a sketch of this engine. Some years previous to +Huyghens' proposal, the Abbe Hautefeuille (1678) proposed a gunpowder +engine without piston for pumping water. It is similar to Savery's steam +engine, but using the pressure of the explosion instead of the pressure of +steam. This engine, however, had no piston, and was only applicable as a +pump. The Savery principle still survives in the action of the well-known +pulsometer steam pump. + +Denys Papin, the pupil and assistant of Huyghens, continued experimenting +upon the production of motive power, and in 1690 published a description +of his attempts at Leipzig, entitled "A New Method of Securing Cheaply +Motive Power of Considerable Magnitude." + +He mentions the gunpowder engine, and states that "until now all +experiments have been unsuccessful; and after the combustion of the +exploded powder there always remains in the cylinder one-fifth of its +volume of air." + +For the explosion of the gunpowder he substituted the generation and +condensation of steam, heating the bottom of his cylinder by a fire; a +small quantity of water contained in it was vaporized, and then on +removing the fire the steam condensed and the piston was forced down. This +was substantially the Newcomen steam engine, but without the separate +boiler. + +Papin died about the year 1710, a disappointed man, about the same time as +Newcomen. Thomas Newcomen, ironmonger and blacksmith, of Dartmouth, +England, had first succeeded in getting his engine to work. The hard fight +to wrest from nature a manageable motive power and to harness fire for +industrial use was continued by this clever blacksmith, and he succeeded +when the more profound but less constructively skillful philosophers had +failed. + +The success of the steam method and the fight necessary to perfect it to +the utmost absorbed the energy of most able engineers--Beighton, John +Smeaton--accomplishing much in applying and perfecting it before the +appearance of James Watt upon the scene. + +It is interesting to note that in England alone over 2,000 horse power of +Newcomen engines were at work before Watt commenced his series of +magnificent inventions; he commenced experimenting on a Newcomen engine +model in 1759 at Glasgow University, and in 1774 came to Birmingham, +entered into partnership with Boulton, and 1781 we find his beautiful +double acting beam condensing engine in successful work. + +From that time until now the steam engine has steadily advanced, +increasing in economy of fuel from 10 lb. of coal per horse power per hour +to about 1¾ lb. per horse power per hour, which is the best result of +to-day's steam engine practice. This result, according to the highest +authorities, is so near to the theoretical result possible from a steam +engine that further improvement cannot now be looked for. Simultaneously +with the development of the steam engine, inventors continued to struggle +with the direct acting combustion or gas engine, often without any +definite understanding of why they should attempt such apparent +impossibilities, but always by their experiments and repeated failures +increasing knowledge, and forming a firm road upon which those following +them traveled to success. + +In 1791 John Barber obtained a patent for an engine producing inflammable +gas, mixing it with air, igniting it, and allowing the current so produced +to impinge upon a reaction wheel, producing motion similar to the well +known Aelopile, which I have at work upon the table. About this time, +Murdoch (Jas. Watt's assistant at Birmingham) was busy introducing coal +gas into use for lighting; in 1792 Boulton and Watt's works were lighted +up with coal gas. From this time many gas engines were proposed, and the +more impracticable combustion of gunpowder received less attention. + +In 1794 Thomas Mead obtained a patent for an engine using the internal +combustion of gas; the description is not a clear one, his ideas seem +confused. + +In the same year Robert Street obtained a patent for an engine which is +not unlike some now in use. The bottom of a cylinder, containing a piston, +is heated by a fire, a few drops of spirits of turpentine are introduced +and evaporated by the heat, the piston is drawn up, and air entering mixes +with the inflammable vapor. A light is applied at a touch hole, and the +explosion drives up the piston, which, working on a lever, forces down the +piston of a pump for pumping water. Robt. Street adds to his description a +note: "The quantity of spirits of tar or turpentine to be made use of is +always proportional to the confined space, in general about 10 drops to a +cubic foot." This engine is quite a workable one, although the +arrangements described are very crude. + +The first gas engine that was actually at work for some years; and was +applied to a variety of purposes, was Samuel Buren's. His patent was +granted in 1823, and in 1826 he built a locomotive carriage with which he +made several experimental runs in London; he also propelled a vessel with +it upon the Thames, and fitted up a large engine for pumping purposes. A +company was formed to introduce his engine, but it proved too wasteful of +fuel, and the company went into voluntary liquidation. Like almost all +engines of this time, the combustion of gas and air was used to produce a +vacuum, the piston being driven by atmospheric pressure. + +Buren's locomotive carriage was thus in action three years before the +great trial in 1829, from which George Stephenson emerged victorious with +his wonderful engine "The Rocket." To those curious in the matter, I may +mention that S. Buren's patents are dated 1823, No. 4,874, and 1826, No. +5,350. + +From this time on, a continuous series of gas engine patents appear, 20 +engines being patented between 1826 and 1860, which is the next date +worthy of particular mention. + +In this year, 1860, the famous "Lenoir" engine appeared. The use of high +pressure steam engines had long been common, and Lenoir's engine was +analogous to the high pressure engine, as Buren's was to the condensing +engine. It created a very general interest, and many engines were +constructed and used in France, England, and America; it resembled very +much in external appearance an ordinary high pressure horizontal steam +engine, and it was double acting. + +During the following six years, other 20 British patents were granted, and +the gas engine passed from the state of a troublesome toy to a practicable +and widely useful machine. + +From 1791 to the end of 1866, in all 46 British patents were granted for +gas engines, and in these patents are to be found the principles upon +which the gas engines of to-day are constructed, many years elapsing +before experience enough was gained to turn the proposals of the older +inventors to practical account. + +The most important of these patents are: + + No. Year. +Robert Street 1,983 1794 Direct-acting engine. +Samuel Buren 4,874 1823 Vacuum engine. +Samuel Buren 5,350 1826 Vacuum engine. +W.L. Wright 6,525 1833 Direct-acting engine. +Wm. Barnett 7,615 1838 Compression first proposed. +Barsante & Matteucci 1,072 1854 Rack & clutch engine. +Drake 562 1855 Direct-acting engine. +Lenoir 335 1860 D.I. engine, electric ignition. +C.W. Siemens 2,074 1860 Compression, _constant + pressure_. +Hugon 2,902 1860 Platinum ignition. +Millein 1,840 1861 Compression, both constant vol. and + _pressure_. +F.H. Wenham 1,873 1864 Free piston. +Hugon 986 1865 Flame ignition. +Otto and Langen 434 1866 Rack and clutch, flame ignition. + +Leaving for the present the history of the gas engine, which brings us to +a stage comparable to the state of the steam engine during the Newcomen's +time, it will be advisable to give some consideration to the principles +concerned in the economical and efficient working of gas engines, in order +to understand the more recent developments. + +It has been seen that gunpowder was the explosive used to produce a vacuum +in Huyghens' engine, and that it was abandoned in favor of gas by Buren in +1823. The reason of departure is very obvious: a gunpowder explosion and a +gaseous explosion differ in very important practical points. + +Gunpowder being a solid substance is capable of being packed into a very +small space; the gas evolved by its decomposition is so great in volume +that, even in the absence of any evolution of heat, a very high pressure +would result. One cubic inch of gunpowder confined in a space of one cubic +inch would cause a pressure by the gas it contains alone of 15,000 lb. per +square inch; if the heating effect be allowed for, pressures of four times +that amount, or 60,000 lb. per square inch, are easily accounted for. +These pressures are far too high for use in any engine, and the bare +possibility of getting such pressure by accident put gunpowder quite +outside the purpose of the engineer, quite apart from any question of +comparative cost. In a proper mixture of inflammable gas and air is found +an exceedingly safe explosive, perfectly manageable and quite incapable of +producing pressures in any sense dangerous to a properly constructed +engine. + +The pressure produced by the explosion of any mixture of gas and air is +strictly determined and limited, whereas the pressure produced by the +explosion of gunpowder depends greatly upon the relation between the +volume of the gunpowder and the space in which it is confined. + +Engines of the "Lenoir" type are the simplest in idea and construction; in +them a mixture of gas and air is made in the cylinder during the first +half of the piston stroke, air being taken from the atmosphere and drawn +into the cylinder by the forward movement of the piston. At the same time +gas entering by a number of holes, and streaming into the air to form an +explosive mixture, the movement of a valve cuts off the supply, and brings +the igniting arrangement into action. The pressure produced by the +explosion acting upon the piston makes it complete its stroke, when the +exhaust valve opens exactly as in the steam engine. The Lenoir and Hugon +engines, the earlier forms of this type, were double acting, receiving two +impulses for every revolution of the crank, the impulse differing from +that in a high pressure steam engine in commencing at half stroke. + +The Lenoir igniting arrangement was complicated and troublesome. I have it +upon the table; the mixture was ignited at the proper time by the electric +spark produced from a primary battery and Ruhmkorff coil. + +The Hugon engine was an advance in this respect, using a flame ignited, +and securing greater certainty of action in a comparatively simple manner. + +It is really a modification of Barnett's lighting cock described in his +patent of 1838. + +Other difficulties were found in using these engines; the pistons became +exceedingly hot. In the case of the Lenoir larger engines, it sometimes +became red hot, and caused complete ruin of the cylinder by scoring and +cutting up. Hugon to prevent this injected some water. + +In the all important question of economy, these engines were found +grievously wanting, Lenoir consuming 95 cubic feet per I.H.P. per hour; +Hugon consuming 85 cubic feet per I.H.P. per hour. + +The surviving engines of this type are only used for very small powers, +from one to four man power, or 1/8 to 1/2 horse, the most widely known of +this kind being the "Bischoff," which is very largely used; its +consumption of gas is even greater than the Lenoir, being 110 cubic feet +per horse power per hour, as tested with a half-horse engine at a late +exhibition of gas apparatus at Stockport. + +So large a consumption of gas prevented these engines coming into extended +use for engines of moderate power, and led inventors to work to obtain +better results. The force generated by the explosion of a mixture of gas +and air is very short lived, and if it is to be fully utilized must be +used quickly; a high pressure is produced, but it very quickly disappears. + +The quicker the piston moves after the maximum pressure is reached, the +less will be the loss of heat to the sides of the cylinder. The flame +which fills the cylinder and causes the increase of pressure rapidly loses +heat, and the pressure falls. + +The idea of using a free piston was proposed as a remedy; it was thought +that a piston connected to a crank in the ordinary manner could not move +fast enough to utilize the pressure before it was lost. Many inventors +proposed to perform work upon a piston free from any direct connection +with the crank or shaft of the engine; the explosion after attaining its +maximum pressure expends its force in giving velocity to a piston; the +velocity so acquired carries it on against atmospheric pressure until the +energy is all absorbed, and a vacuum or deficit of pressure exists in the +cylinder instead of an excess of pressure. The return stroke is +accomplished by the atmospheric pressure, and the work is now done upon +the engine shaft on the return only. The method of connecting on the +return stroke while leaving the piston free on the out stroke varies, but +in many engines the principle was the same. + +Barsante and Matteucci, year 1857, British patent No. 1,625, describe the +first engine of this kind, but Messrs. Otto and Langen were the first to +successfully overcome all difficulties and make a marketable engine of it. +Their patent was dated 1866, No. 434. To distinguish it from Otto's later +patents, it may be called the rack and clutch engine. + +The economy obtained by this engine was a great advance upon the Lenoir. +According to a test by Prof. Tresca, at the Paris Exhibition of 1867, the +gas consumed was 44 cubic feet per indicated horse power per hour. +According to tests I have made myself in Manchester with a two horse power +engine, Otto and Langen's free piston engine consumes 40 cubic feet per +I.H.P. per hour. This is less than one-half of the gas used by the Hugon +engine for one horse power. + +The igniting arrangement is a very good modification of Barnett's lighting +cock, which I have explained already, but a slide valve is used instead of +a cock. + +Other engines carried out the same principle in a different manner, +including Gilles' engine, but they were not commercially so successful as +the Otto and Langen. Mr. F.H. Wenham's engine was of this type, and was +working in England, Mr. Wenham informed me, in 1866, his patent being +taken out in 1864. + +The great objection to this kind of engine is the irregularity and great +noise in working; this was so great as to prevent engines from being made +larger than three horse power. The engine, however, did good work, and was +largely used from 1866 until the end of 1876, when Mr. Otto produced his +famous engine, now known as "The Otto Silent Gas Engine." In this engine +great economy is attained without the objectionable free piston by a +method proposed first by Burnett, 1838, and also by a Frenchman, Millein, +in 1861; this method is compression before ignition. Other inventors also +described very clearly the advantages to be expected from compression, but +none were able to make it commercially successful till Mr. Otto. To him +belongs the great credit of inventing a cycle of operations capable of +realizing compression in a simple manner. + +Starting from the same point as inventors did to produce the free piston +engine--namely, that the more quickly the explosive force is utilized, the +less will be the loss, and the greater the power produced from a quantity +of burning gas--it is evident that if any method can be discovered to +increase the pressure upon the piston without increasing the temperature +of the flame causing this pressure, then a great gain will result, and +the engine will convert more of the heat given to it into work. This is +exactly what is done by compression before ignition. Suppose we take a +mixture of gas and air of such proportions as to cause when exploded, or +rather ignited (because explosion is too strong a term), a pressure of 45 +lb. above atmosphere, or 60 lb. per square inch absolute pressure. Then +this mixture, if compressed to half volume before igniting and kept at +constant temperature, would give, when ignited, a pressure of 120 lb. +total, or 105 lb. above atmosphere, and this without any increase of the +temperature of the flame. + +The effect of compression is to make a small piston do the work of a large +one, and convert more heat into work by lessening the loss of heat through +the walls of the cylinder. In addition to this advantage, greater +expansions are made possible, and therefore greatly increase economy. + +The Otto engine must be so familiar in appearance to all of you, that I +need hardly trouble you with details of its external appearance. I shall +briefly describe its action. Its strong points and its weak points are +alike caused by its cycle. One cylinder and piston suffices to carry out +its whole action. Its cycle is: First outstroke, gas and air sucked into +the cylinder; first instroke, gas and air compressed into space; second +outstroke, impulse due to ignition; second instroke, discharge of +exhausted gases. When working at full power, it gets one impulse for every +two revolutions; this seems to be a retrograde movement, but, +notwithstanding, the advantages obtained are very great. The igniting +arrangement is in the main similar to that used on the rack and clutch +engine. The engine has been exceedingly successful, and is very +economical. The Otto compression engine consumes 21 cubic feet of gas per +I.H.P. per hour, and runs with great smoothness. + +In 1876 I commenced my work upon gas engines, and very soon concluded that +the compression system was the true line to proceed upon. It took me two +years to produce a workable engine. My efforts have always been directed +toward producing an engine giving at least one impulse every revolution +and, if possible, to start without hand labor, just as a steam engine +does. My first gas engine was running in 1878, and patented and exhibited +in 1879. It was first exhibited at the Kilburn Royal Agricultural +Society's show. + +This engine was self-starting, gave an ignition at every revolution, and +ignited without external flame. It consisted of two cylinders, a motor, +and a compressing pump, with a small intermediate reservoir. Suitable +valves introduced the mixture of gas and air into the pump, and passed it +when compressed from the reservoir to the motor cylinder. The igniting +arrangement consisted of a platinum cage firmly fixed in a valve port; +this cage was heated in the first instance by a flame of gas and air +mixed; it became white hot in a few seconds, and then the engine was +started by opening a valve. + +The platinum was kept hot by the heat derived from the successive +ignitions, and, the engine once started, no further external flame was +required. I have here one of these platinum cages which has been in use. +Finding this method not well suited for small engines, I produced the +engine which is at present in the market under my name. + +The cycle is different, and is designed for greater simplicity and the +avoidance of back ignitions. It also consists of two cylinders, motor +cylinder and the displace or charging cylinder. There is no intermediate +reservoir. The displace crank leads the motor by a right angle, and takes +into it the mixed charge of gas and air, in some cases taking air alone +during the latter part of its stroke. + +The motor on the outstroke crosses V-shaped parts about from one-sixth to +one-seventh from the out end, the displacer charge now passing into the +motor cylinder, displacing the exhaust gases by these ports and filling +the cylinder and the space at the end of it with the explosive mixture. +The introduction of some air in advance of the charge serves the double +purpose of cooling down the exhaust gases and preventing direct contact of +the inflammable mixture with flame which may linger in the cylinder from +the previous stroke. The instroke of the motor compresses the charge into +the conical space at the end of the cylinder, and, when fully compressed, +ignition is effected by means of the slide I have upon the table. + +This system of ignition has been found very reliable, and capable of +acting as often as 400 times per minute, which the Otto ignite is quite +incapable of doing. By this cycle the advantages of compression are gained +and one step nearer to the steam engine is attained, that is, an impulse +is given for every revolution of the engine. + +As a consequence, I am able with my engine to give a greater amount of +power for a comparatively small weight. In addition to this, I have +introduced a method of self-starting; in this I believe I was the +first--about 100 of my engines are now using self-starting. + +The largest single engine I have yet made indicates 30 H.P. The +consumption of gas in Glasgow is: Clerk engine consumes in Glasgow 18 +cubic feet per I.H.P. per hour; Clerk engine consumes in Manchester 22 +cubic feet per I.H.P. per hour. So far as I know, the Otto engine and my +own are the only compression engines which have as yet made any success in +the market. Other engines are being continually prepared, gas engine +patents being taken out just now at the rate of 60 per annum, but none of +them have been able as yet to get beyond the experimental stage. The +reason is simply the great experience necessary to produce these machines, +which seem so very simple; but to the inexperienced inventor the subject +fairly bristles with pitfalls. + +I have here sections of some of the earlier engines, including Dr. +Siemens' and Messrs. Simon and Beechy. Although interesting and containing +many good points, these have not been practically successful. + +The Simon engine is an adaptation of the well-known American petroleum +motor, the Brayton, the only difference consisting in the use of steam as +well as flame. + +Dr. Siemens worked for some twenty years on gas engines, but he aimed +rather high at first to attain even moderate success. Had he lived, I +doubt not but that he would have succeeded in introducing them for large +powers. In 1882 he informed me that he had in hand a set of gas engines of +some hundreds of horse power for use on board ship, to be supplied with +gas from one of his gas producers modified to suit the altered +conditions. + +Summarizing the ground over which we have passed, we find the origin of +the gas engine in the minds of the same men as were first to propose the +steam engine, Huyghens and Papin, 1680 and 1690. Greater mechanical +difficulties and ignorance of the nature of explosives caused the +abandonment of the internal combustion idea, and the mechanical +difficulties with steam being less, the steam engine became successful, +and triumphed over its rival. The knowledge and skill gained in the +construction of steam engines made it possible once again to attack the +more difficult problem, and simultaneously with the introduction and +perfecting of the steam engine, the gas engine idea became more and more +possible, the practicable stage commencing with Lenoir and continuing with +Hugon, Millein, Otto and Langen, F.H. Wenham, then Otto and Clerk. In +1860, 95 cubic feet of gas produced one horse power for an hour; in 1867, +40 cubic feet accomplished the same thing; and now (1885) we can get one +horse power for an hour for from 15 to 20 cubic feet of gas, depending on +the size of the engine used. + +Considered as a heat engine, the gas engine is now twice as efficient as +the very best modern steam engine. It is true the fuel used at present +is more expensive than coal, and for large powers the steam engine is +the best because of this. But the way is clearing to change this. Gas +engines as at present, if supplied with producer gas, produced direct +from coal without leaving any coke, as is done in the Siemens, the +Wilson, and the Dawson producers, will give power at one-half the cost +of steam power. They will use 7/8 of a pound of coal per horse power per +hour, instead of 1-3/4 lb., as is done in the best steam engines. The +only producer that makes gas for gas engines at present is the Dawson, +and in it anthracite is used, because of the difficulty of getting rid +of the tar coming from the Siemens and Wilson producers, using any +ordinary slack. + +When this difficulty has been overcome, and that it will be overcome there +can be no manner of doubt, gas engines will rapidly displace the steam +engine, because a gas engine with a gas producer, producing gas from any +ordinary coal with the same ease as steam is produced from a boiler, will +be much safer, and will use one-half the fuel of the very best steam +engines for equal power. The first cost also will not be greater than that +of steam. The engine itself will be more expensive than a steam engine of +equal power, but the gas producer will be less expensive than the boiler +at present. Perfect as the gas engine now is, considered as a machine for +converting heat into work, the possibility of great development is not yet +exhausted. Its economy may be increased two or even three fold; in this +lies the brilliant future before it. The steam engine is nearly as perfect +as it can be made; it approaches very nearly the possibility of its +theory. Its defect does not lie in its mechanism, but in the very +properties of water and steam itself. The loss of heat which takes place +in converting liquid water into gaseous steam is so great that by far the +greater portion of the heat given out by the fuel passes away either in +the condenser or the exhaust of a steam engine; but a small proportion of +the heat is converted into work. + +The very best steam engines convert about 11 per cent. of the heat given +them into useful work, the remaining 89 per cent. being wasted, +principally in the exhaust of the engine. + +Gas engines now convert 20 per cent. of the heat given to them into work, +and very probably will, in a few years more, convert 60 per cent. into +useful work. The conclusion, then, is irresistible that, when engineers +have gained greater experience with gas engines and gas producers, they +will displace steam engines entirely for every use--mills, locomotives, +and ships. + + * * * * * + + + + +RAPID CONSTRUCTION OF THE CANADIAN PACIFIC RAILWAY. + +By E.T. ABBOTT, Member of the Engineers' Club of Minnesota. Read December +12, 1884. + + +During the winter of 1881 and 1882, the contract was let to Messrs. +Langdon, Sheppard & Co., of Minneapolis, to construct during the working +season of the latter year, or prior to January 1, 1883, 500 miles of +railroad on the western extension of the above company; the contract being +for the grading, bridging, track-laying, and surfacing, also including the +laying of the necessary depot sidings and their grading. The idea that any +such amount of road could be built in that country in that time was looked +upon by the writer hereof, as well as by railroad men generally, as a huge +joke, perpetrated to gull the Canadians. At the time the contract was let, +the Canadian Pacific Railway was in operation to Brandon, the crossing of +the Assiniboine River, 132 miles west of Winnipeg. The track was laid, +however, to a point about 50 miles west of this, and the grading done +generally in an unfinished state for thirty miles further. This was the +condition of things when the contract was entered into to build 500 +miles--the east end of the 500-mile contract being at Station 4,660 +(Station being at Brandon) and extending west to a few miles beyond the +Saskatchewan River. + +The spring of 1882 opened in the most unpromising manner for railroad +operations, being the wettest ever known in that country. Traffic over the +St. Paul, Minneapolis & Manitoba Railroad, between St. Paul and Winnipeg, +was entirely suspended from April 15 to the 28th, owing to the floods on +the Red River at St. Vincent and Emerson, a serious blow to an early +start, as on this single track depended the transportation of all +supplies, men, timber, and contractors' plant, together with all track +materials (except ties), all of these things having to come from or +through St. Paul and Minneapolis. The writer hereof was appointed a +division engineer, and reported at Winnipeg the 15th of April, getting +through on the last train before the St. Vincent flood. No sooner was the +line open from St. Paul to Winnipeg than the cotillon opened between +Winnipeg and Brandon, with a succession of washouts that defied and +defeated all efforts to get trains over, so it was not until the fifth day +of May that I left Winnipeg to take charge of the second division of 30 +miles. + +By extremely "dizzy" speed I was landed at the end of the track, 180 miles +from Winnipeg, on the evening of the 9th (4 days). My outfit consisted of +three assistant engineers and the necessary paraphernalia for three +complete camps, 30 days' provisions (which turned out to be about 20), 11 +carts and ponies, the latter being extremely poor after a winter's diet +on buffalo grass and no grain. On the 18th day of May I had my division +organized and camps in running order. The country was literally under +water, dry ground being the exception, and I look upon the feat of getting +across the country at all as the engineering triumph of my life. + +On May 20 a genuine blizzard set in, lasting 24 hours, snowed five inches, +and froze the sloughs over with half an inch of ice, a decidedly +interesting event to the writer, as he was 18 miles from the nearest wood, +therefore lay in his blankets and ate hard tack. I stabled my ponies in +the cook tent, and after they had literally eaten of the sod inside the +tent, I divided my floor with them. + +On 28th day of May I saw the first contractor, who broke ground at station +7,150. On the 1st of June I was relieved from this division, and ordered +to take the next, 50 miles west. On the 13th day of June ground was broken +on this division, at station 8,070, or only about 62 miles west of the +east end of the 500-mile contract. It looked at this time as though they +might build 150 miles, but not more. But from this time on very rapid +progress was made. On July 17 the track reached station 7,000, making +however up to this time but about 50 miles of track-laying, including that +laid on the old grade; but large forces were put on to surfacing, and the +track already laid was put in excellent condition for getting material to +the front. The weather from this until the freezing-up was all that could +be desired. Work ceased about the 1st of January, 1883, for the season, +and the final estimate for the work was as follows: 6,103,986 cubic yards +earth excavation, 2,395,750 feet B.M. timber in bridges and the culverts, +85,708 lineal feet piling, 435 miles of track-laying. This work was all +done in 182 working days, including stormy ones, when little, if anything, +could be done, making a daily average of 33,548 yards excavation, 13,150 +feet B.M. timber, 471 feet piling, 2-38/100 miles track-laying. We never +had an accurate force report made of the whole line, but roughly there +were employed 5,000 men and 1,700 teams. + +The admirable organization of the contractors was something wonderful. The +grading work was practically all done by sub-contractors, Messrs. Langdon, +Sheppard & Co. confining themselves to putting in the supplies and doing +the bridge work, surfacing, and track-laying. The grading forces were +scattered along about 150 miles ahead of the track and supply stores, +established about 50 miles apart, and in no case were sub-contractors +expected to haul supplies over 100 miles. If I remember rightly, there +were four trains of about forty wagons each, hauling supplies from the end +of track to the stores. + +As can be readily seen, the vital point of the whole work, and the problem +to solve, was food for men and horses. 1,700 bushels of oats every day and +15,000 pounds of provisions, Sundays and all, for an entire season, which +at the beginning of the work had to come about 170 miles by rail, and then +be taken from 50 to 150 miles by teams across a wilderness, is on the face +of it considerable of an undertaking, to say nothing about hauling the +pile-drivers, piles, and bridge-timber there. To keep from delaying the +track, sidings 1,500 feet long were graded, about 7 miles apart. A +side-track crew, together with an engine, four flats, and caboose, were +always in readiness; and as soon as a siding was reached, in five hours +the switches would be in, and the next day it would be surfaced and all in +working order, when the operating department would fill it with track +material and supplies. From the head of the siding to the end of the track +the ground was in hands of track-laying engine, never going back of the +last siding for supplies or material, and my recollection is that there +were but six hours' delay to the track from lack of material the whole +season, at any rate up to some time in November. The track-laying crew was +equal to 4 miles per day, and in the month of August 92 miles of track +were laid. The ties were cut on the line of the road about 100 miles east +of Winnipeg, so the shortest distance any ties were hauled was 270 miles; +the actual daily burden of the single track from Winnipeg west was 24 cars +steel, 24 cars ties, aside from the transportation of grain and +provisions, bridge material, and lumber for station houses. The station +buildings were kept right up by the company itself, and a depot built with +rooms for the agent every 15 miles, or at every second siding. The +importance of keeping the buildings up with the track was impressed on the +mind of the superintendent of this branch, and, as a satire, he +telegraphed asking permission to haul his stuff ahead of the track by +teams, he being on the track-layers' heels with his stations and tanks the +whole season. The telegraph line was also built, and kept right up to the +end of the track, three or four miles being the furthest they were at any +time behind. + +It might be supposed that work done so rapidly would not be well done, but +it is the best built prairie road I know of on this continent. It is built +almost entirely free from cuts, and the work is at least 20 per cent. +heavier than would ordinarily be made across the same country in the +States, on account of snow. 2,640 ties were laid to the mile, and the +track ballasting kept well up with the laying; so well, in fact, and so +well done, that as 100 mile sections were completed schedule trains were +put on 20 miles an hour, and the operating department had nothing to do +but make a time table; the road was _built_ by the construction department +before the operating department was asked to take it. The engineering was +organized in divisions of 30 miles each, and as each was finished the +parties moved ahead again to the front, the engineers usually finding men +sitting on their shovels waiting for the work to be laid out for them. It +was as much as the locating parties could do to keep out of the way of the +construction. The roadbed was built 14 ft. wide in embankment and 20 in +the very few cuts there were, there being no cuts of any moment except +through the Coteaus and the Saskatchewan crossing, and these have since +been widened out on account of snow, so that the road can be operated the +year round and the bucking-snow account cut no figure in the operating +expenses. + +The country is a virgin desert. From Winnipeg to the Pacific Ocean there +are a few places that might attain to the dignity of an _oasis_--at +Brandon, Portage la Prairie, etc.--but it is generally what I should call +worthless; 100 miles to wood and 100 feet to water was the general +experience west of the Moose jaw, and the months of June, July, and August +are the only three in the year that it is safe to bet you will not have +sleighing. I burned wood and used stakes that were hauled by carts 85 +miles, and none any nearer. It is a matter of some pride that both the +engineering and the construction were done by what our Canadian neighbors +kindly termed "Yankee importations." However, there was one thing that in +the building of this road was in marked contrast to any other Pacific road +ever constructed, that is, there was no lawlessness, no whisky, and not +even a knock-down fight that I ever heard of the whole season, and even in +the midst of 12,000 Indians, all armed with Winchester rifles and plenty +of ammunition, not one of the locating or construction parties ever had a +military escort, nor were any depredations ever committed, except the +running off of a few horses, which were usually recovered; and I think +there were but two fatal accidents during the season, one man killed on +the Grand Coule Bridge, and another from being kicked by a horse. + +The track was all laid from one end, and in no case were rails hauled +ahead by teams. Two iron cars were used, the empty returning one being +turned up beside the track to let the loaded one by. + +The feat in rapid construction accomplished by this company will never be +duplicated, done as it was by a reckless expenditure of money, the orders +to the engineers being to _get there_ regardless of expense and +horse-flesh; if you killed a horse by hard driving, his harness would fit +another, and there was no scrutiny bestowed on vouchers when the work was +done; and I must pay the tribute to the company to say that everything +that money would buy was sent to make the engineers comfortable. It was +bad enough at best, and the Chief Engineer (J.C. James) rightly considered +that any expense bestowed on the engineering part of the work was a good +investment. + + * * * * * + + + + +THE OSGOOD MAMMOTH EXCAVATOR. + + +In the accompanying illustration, we present to our readers a mammoth +excavator, built by the Osgood Dredge Company of Albany, N.Y., for the +Pacific Guano Company of California, for uncovering their phosphate +deposits on Chisholm Island, South Colombia. + +[Illustration: THE OSGOOD MAMMOTH EXCAVATOR.] + +In order to bring out more clearly the principal problem involved in the +construction of this machine, we shall state first the proposed method of +its operation. This is as follows, viz.: The excavator is to dig a trench +thirty feet wide, down to the phosphate rock, and the entire length of the +bed--about one quarter of a mile--dumping the earth of the first cut to +one side. The phosphate is taken out behind the excavator. On reaching the +end of the bed, the excavator is reversed and starts back, making a second +cut thirty feet wide, and dumping now into the cut from which the +phosphate has just been removed. In this way the entire bed is traversed, +the excavator turning over the earth in great furrows thirty feet wide, +and giving an opportunity to simultaneously get out all the phosphate. + +As will be seen, the main problem presented was to turn the car around at +each end of the cut in a very limited space. To accomplish this, the car +is mounted on a fixed axle at each end and on a truck under its center of +gravity; this is somewhat forward of the geometrical center of the car. +The frame of the truck is circular, thirteen feet in diameter, made of I +beams curved to shape. The circle carries a track, on which a ring of +coned rollers revolves, which in turn supports the car. By pulling out the +track from under both ends of the car, the whole weight is balanced on +this central turntable truck, thus admitting of the car being turned, end +for end, within its own length. This method of turning the car, and the +size of the machine, are the principal features. + +The car is 40' × 13', with arched truss sides. The track is seven feet +gauge, the spread between tracks 20 feet, the height of the A frame 38 +feet, length of boom 40 feet, swinging in a circle of 30 feet radius, and +through two-thirds of the entire circle. It has a steel dipper of 46 cubic +feet capacity, 1 inch steel chains, 10" × 12" double cylinder hoisting +engine, and 6¼" × 8" double cylinder reversible crowding engine. The +drums are fitted with friction clutches. Owing to the great distance at +which the dipper is handled, its size is reduced, and because it swings on +the arc of so large a circle the capacity of this machine is only one-half +of that of the No. 1 excavator built by the Osgood Dredge Company. +Nevertheless it will do the work of from 75 to 100 men, since its capacity +is from 800 to 1,000 cubic yards per day, the amount of rock _uncovered_ +depending, of course, upon the depth of earth overlying it. The excavator +will dump 30 feet from the center line of the car, and 26 feet above the +track, which is laid on the rock. Total weight about fifty tons. The crew +required for its operation consists of 1 engineer, 1 fireman, 1 craneman, +and 4 to 5 pit men to tend jacks, move track, etc. + +In the illustration the boiler connections are omitted, also the housing +for the protection of the crew. The design is characterized by the evident +care which has been bestowed upon securing simplicity and +durability.--_American Engineer._ + + * * * * * + + + + +THE OSGOOD EXCAVATOR. + + +At a recent meeting of the Engineers' Club of Philadelphia, Mr. John C. +Trautwine, Jr., exhibited and described drawings of a large land dredge +built by the Osgood Dredge Co., of Albany, New York, for the Pacific Guano +Co., to be used in removing 8 to 15 feet of material from the phosphate +rock at Bull River, S.C. + +The more prominent features of the machine are the car-body, the water +tank, boiler and engine, the A frame (so-called from its slight +resemblance to the letter A), the boom, the dipper-handle; and the dipper, +drawings of which were shown and described in detail. + +Before the excavation is begun, the forward end of the car (the end +nearest the dipper) is lifted clear of the track by means of 3 +screw-jacks. When the machine has excavated as far in advance of itself as +the length of the boom and that of the dipper-handle will permit, say +about 8 feet, the car is again lowered to the track, the screw-jacks +removed, and the car is moved forward about 8 feet by winding the rope +upon the drum, the other end of the rope being attached to any suitable +fixed object near the line of the track. The forward end of the car is +then again lifted by means of the 3 screw-jacks, and the digging is +resumed. The machine cuts a channel from 25 to 35 feet wide, and deposits +all the dirt upon one side. If necessary, it can dump earth about 25 feet +above the track. The miners follow in the wake of the machine, getting out +the phosphate as fast as it is uncovered. When the machine reaches the end +of the field it is lowered to the track and the screw-jacks are removed. +Shoes or skids are then placed upon the track, and the wheels of the +turntable are run up on them. This lifts the end wheels clear of the +track, so that the car and machine rest entirely upon the turntable. By +now blocking the turntable wheels and winding up only _one_ of the ropes, +the car body and the machine are swung around end for end. The digging is +then resumed in the opposite direction, the temporary track, upon which +the machine travels, being shifted to one side, so that the second channel +is made alongside of the first. The earth removed in cutting this second +channel is dumped into the first channel, the phosphate (as stated above) +having been first removed. + +The dipper is of plate steel, and holds 1¾ cubic yards of earth when even +full. + +The machine is manned by an engineer, a fireman, and a dipper-tender, +besides which from five to ten laborers are required. These look after the +track, etc. + + * * * * * + + + + +CAPSTAN NAVIGATION ON THE VOLGA. + + +On several of the large rivers on the Continent, with rapid currents, +cable towage has been introduced in addition to the older methods of +transporting merchandise by sailing and steam boats or by towage with +screw or paddle tugs. A chain or wire rope is laid on the bottom of the +river bed, fixed to anchors at the ends and passed over a chain pulley +driven by the steam engine and guided by pulleys on the steam tug, the tug +lifting it out of the water at the bow and dropping it over the stern and +winding itself with the barges attached to it along the chain, the latter +being utilized as a rule only for the up journey, while down the river the +tugs are propelled by paddles or screws, and can tow a sufficient number +of barges with the assistance of the current. The system has been found +advantageous, as, although the power required for drawing the barges and +tugs against the current is of course the same in all cases, the slip and +waste of power by screws and paddles is avoided. The size of the screws or +paddles is also limited by the nature of the river and its traffic, and +with cable towage a larger number of barges can be hauled, while the +progress made is definite and there is no drifting back, as occurs with +paddle or screw tugs when they have temporarily to slow or stop their +engines on account of passing vessels. Several streams, as the Elbe, +Rhine, and Rhone, have now such cables laid for long distances in those +parts of the rivers where the traffic is sufficient to warrant the +adoption of the system. While this has been introduced only during the +last 16 or 18 years, a similar method of transporting merchandise has been +in use in Russia on the river Volga for upward of 40 years. Navigation on +this river is interrupted for about half the year by the ice, and the +traffic is of larger amount only during part of the summer, while the +length of the river itself is very great, so that laying down permanent +cables would not pay; while, on the other hand, the current is so strong +that towage of some sort must be resorted to for the transport of large +quantities. The problem has been solved by the introduction of the capstan +navigation or towage. + +[Illustration: CAPSTAN NAVIGATION ON THE VOLGA.] + +There are two kinds of capstans in use, one actuated by horse-power and +the other by steam engines. A horse capstan boat carries according to size +150 to 200 horses, which are stabled in the hold. On deck a number of +horse gears are arranged at which the horses work. The power of the +separate gears is transmitted to a main shaft, which is connected to the +drums that wind on the rope. The horses work under an awning to protect +them from the burning sunshine, and are changed every three hours. Eight +and sometimes ten horses work at each horse gear. The horses are changed +without interruption of the work, the gears being disengaged from the main +shaft in rotation and the horses taken out and put in while the gear is +standing. The horses are bought at the place of departure in the south of +Russia and resold at the destination, usually Nishny-Novgorod, at a fair +profit, the capstan boat carrying fodder and provender for the attendants. +The capstan is accompanied by a steam launch which carries the anchor and +hawser forward in advance of the capstan. The latter has a diameter of as +much as 5 in., and is two to three miles in length. The anchor is dropped +by the tug and the hawser carried back to the capstan, where it is +attached to one of the rope drums, and the boat with the barges attached +to it towed along by the horse gears described above winding on the +hawser. The advance continues without interruption day and night, the +launch taking a second anchor and hawser forward and dropping the anchor +in advance of the first by a hawser's length, so that when the capstan has +wound up the first hawser it finds a second one ready for attachment to +the rope drum. The launch receives the first hawser, picks up the anchor, +and passes the capstan to drop it again in advance of the anchor +previously placed, and carries the hawser back to the capstan, and so on. +A capstan tows twelve or more barges, placed in twos or threes beside and +close behind each other, with a load of a million pounds, or about 16,000 +to 17,000 tons. From Astrachan and the mouth of the Kama the capstans make +during the season from the beginning of May to the end of July in the most +favorable case two journeys to the fair of Nishny-Novgorod; after this +time no more journeys are made, as the freights are wanting. At the end of +the up-stream journey the horses are sold, as mentioned before, and the +capstan towed down stream by the steam launch to Astrachan or the Kama +mouth, where meanwhile a fresh lot of barges has been loaded and got +ready, a new supply of horses is bought, and the operation repeated. + +Besides these horse capstans there are steam capstans which are less +complicated and have condensing steam engines of about 100 horse power, +the power being transmitted by gearing to the rope drum. The rope drum +shaft projects on both sides beyond the boards of the boat, and for the +return journey paddle wheels, are put on to assist the launch in towing +the clumsy and big capstan boat down the river. The steam capstans tow +considerably larger masses of goods than the horse capstans and also +travel somewhat quicker, so that the launch has scarcely sufficient time +to drop and raise the anchors and also to make double the journey. We do +not doubt that this system of towage might with suitable modifications be +advantageously employed on the large rivers in America and elsewhere for +the slow transport of large quantities of raw materials and other bulky +merchandise, a low speed being, as is well known, much more economical +than a high speed, as many of the resistances increase as the square and +even higher powers of the velocity. + + * * * * * + + + + +STEAMBOAT EQUIPMENT OF WAR VESSELS. + + +The larger ships in the navy, and some of the more recent small ones, such +as the new cruisers of the Phaeton class, are fitted with powerful steam +winches of a type made by Messrs. Belliss and Co. These are used for +lifting the pinnaces and torpedo boats. + +We give an illustration of one of these winches. The cylinders are 6 in. +in diameter and 10 in. stroke. The barrel is grooved for wire rope, and is +safe to raise the second class steel torpedo boats, weighing nearly 12 +tons as lifted. The worm gearing is very carefully cut, so that the work +can be done quietly and safely. With machinery of this kind a boat is soon +put into the water, and as an arrangement is fitted for filling the boat's +boilers with hot water from the ship's boilers, the small craft can be +under way in a very short time from the order being given. + +Mr. White is fitting compound engines with outside condensers to boats as +small as 21 ft. long, and we give a view of a pair of compound engines of +a new design, which Messrs. Belliss are making for the boats of this +class. The cylinders are 4 in. and 7 in. in diameter by 5 in. stroke. The +general arrangement is well shown in the engraving. On a trial recently +made, a 25 ft. cutter with this type of engines reached a speed of 7.4 +knots. + +About three years ago the late Controller of the Navy, Admiral Sir W. +Houston Stewart, wished to ascertain the relative consumption of fuel in +various classes of small vessels. An order was accordingly sent to +Portsmouth, and a series of trials were made. From the official reports of +these we extract the information contained in tables F and G, and we think +the details cannot fail to be of interest to our readers. The run around +the island was made in company with other boats, without stopping, and +observations were taken every half hour. The power given out by the +engines was fairly constant throughout. The distance covered was 56 knots, +and the total amount of fuel consumed, including that required for raising +steam, was 1,218 lb. of coal and 84 lb. of wood. The time taken in raising +steam to 60 lb. pressure was forty-three minutes. The rate of consumption +of fuel is of course not the lowest that could be obtained, as a speed of +over 10 knots is higher than that at which the machinery could be worked +most economically. + +[Illustration: STEAM WINCH FOR HOISTING AND LOWERING PINNACLES AND +TORPEDO BOATS.] + +The trials afterward made to find the best results that could be obtained +in fuel consumption were rather spoiled by the roughness of the weather on +the day they were made. The same boat was run for 10 miles around the +measured mile buoys in Stokes Bay. The following are some of the results +recorded: + +_Table F.--Report of Trials of Engines of H.M. 48 ft. +Twin Screw Steam Pinnace, No. 110._ + +Date August 4, 1881. + +Where tried Round the Isle of + Wight + +Draught of water / Forward 3 ft. ½ in. + \ Aft 3 ft. 6½ in. +Average boiler pressure 104.81 lb. +Average pressure in receivers / Starboard 16.27 " + \ Port 16.54 " +Mean air pressure in stokehold 1.4 in. water. +Vacuum in condenser, average 26.72 in. +Weather barometer 30.37 " +Revolutions per minute / Starboard 240.75 + \ Port 251.95 + lb. +Mean pressure in cylinders / Starboard / High 45.33 + | \ Low 16.16 + \ Port / High 43.16 + \ Low 15.3 +Indicated horse-power / Starboard / High 18.20 + | \ Low 16.32 + | Port / High 18.13 + | \ Low 16.17 + \ Collective Total 68.82 +Speed by log 10.18 knots. +Force of wind One. +Sea Smooth. +Quantity of coal on board 1 ton. +Description Nixon's navigation. +Consumption per indicated horse-power per hour 4.17 lb. +Time under way 5 hrs. 30 min. + + +_Table G.--Report of Trial of Engines of H.M. 48 ft. Steam Pinnace No. +110._ + +When tried August 3, 1881. +Where tried Stokes Bay. +Draught / Forward 3 ft. 1 in. + \ Aft 3 ft. 3¼ in. +Average boiler pressure 55.52 lb. +Vacuum 25.12 in. +Weather barometer 30.35 " +Revolutions per minute / starboard 165.54 + \ port 161.55 +Indicated horse-power[2] / Starboard / High 5.05 + | \ Low 5.53 + | Port / High 3.75 + | \ Low 4.02 + \ Collective Total 18.35 +Speed of vessel by log (approximate) 7.404 +Wind / Force 4 to 5 + \ Direction Bow and Quarter. +State of sea Rough. + +[Footnote 2: In consequence of the seas breaking over the boat, a large +number of diagrams were destroyed, and, on account of the roughness of the +weather, cards were only taken with the greatest difficulty. The records +of power developed are therefore not put forward as authoritative.] + +In connection with this subject it may perhaps be of interest to give +particulars of a French and American steam launch; these we extract from +the United States official report before mentioned. + +_Steam Launch of the French Steamer Mouche_. + +Length on low water level 27 ft. 10-1/2 in. +Breadth 5 ft. 11 in. +Depth to rabbet of keel 3 ft. 3-1/3 in. +Draught of water aft 2 ft. 1-1/2 in. +Weight of hull and fittings 2,646 lb. +Weight of machinery with water in boiler 3,473 lb. + +The boat is built of wood, and coppered. The engine consists of one +non-condensing cylinder, 7-1/2 in. in diameter and 5.9 in. stroke. The +boiler has 4.3 square feet of grate surface. The screw is 21-2/3 in. in +diameter by 43.3 in, pitch. The speed is 7 knots per hour obtained with +245 revolutions per minute, the slip being 19.7 per cent. of the speed. + +The United States navy steam cutters built at the Philadelphia navy yard +are of the following dimensions: + +Length 27 ft. 7½ in. +Breadth 7 ft. 10 in. +Depth to rabbet of keel 3 ft. 11¾ in. +Displacement (to two feet above rabbet of keel) 5.96 tons. +Weight of hull and fittings 4,675 lb. + " engine 1,240 " + " boiler 3,112 " + " water in boiler and tanks 2,696 " + +The engine has a single cylinder 8 in. in diameter and 8 in. stroke of +piston. The screw is four bladed, 4 in. long and 31 in. in diameter by 45 +in. pitch. The following is the performance at draught of water 2 feet +above rabbet of keel: + +Boiler pressure 90 lb. +Revolutions 353 +Speed 7.8 knots. +Indicated horse power. 53 + +These boats are of 1870 type, but may be taken as typical of a large +number of steam cutters in the United States navy. The naval authorities +have, however, been lately engaged in extensive experiments with compound +condensing engines in small boats, and the results have proved so +conclusively the advantages of the latter system that it will doubtless be +largely adopted in future.--_Engineer._ + + * * * * * + + + + +IMPROVED STEAM TRAP. + + +The illustrations we give represent an expansion trap by Mr. Hyde, and +made by Mr. S. Farron, Ashton-under-Lyne. The general appearance of this +arrangement is as in Fig. 1 or Fig. 3, the center view, Fig. 2, showing +what is the cardinal feature of the trap, viz., that it contains a +collector for silt, sand, or sediment which is not, as in most other +traps, carried out through the valve with the efflux of water. The escape +valve also is made very large, so that while the trap may be made short, +or, in other words, the expansion pipe may not be long, a tolerably large +area of outlet is obtained with the short lift due to the small movement +of the expansion pipe. + +[Illustration: IMPROVED STEAM TRAP.] + +The object of a steam trap is for the removal of water of condensation +without allowing the escape of steam from drying apparatus and steam pipes +used for heating, power, or other purposes. One of the plans employed is +by an expansion pipe having a valve fixed to its end, so that when the +pipe shortens from being cooler, due to the presence of the water, the +valve opens and allows the escape of the water until the steam comes to +the trap, which, being hotter, lengthens the pipe and closes the valve. +Now with this kind of trap, and, in fact, with any variety of trap, we +understand that it has been frequently the experience of the user to find +his contrivance inoperative because the silt or sand that may be present +in the pipes has been carried to the valve and lodged there by the water, +causing it to stick, and with expansion traps not to close properly or to +work abnormally some way or other. The putting of these contrivances to +rights involves a certain amount of trouble, which is completely obviated +by the arrangement shown in the annexed engravings, which is certainly a +simple, strong, and substantial article. The foot of the trap is made of +cast iron, the seat of the valve being of gun metal, let into the +diaphragm, cast inside the hollow cylinder. The valve, D, is also of gun +metal, and passing to outside through a stuffing box is connected to the +central expansion pipe by a nut at E. The valve is set by two brass nuts +at the top, so as to be just tight when steam hot; if, then, from the +presence of water the trap is cooled, the pipe contracts and the water +escapes. A mud door is provided, by which the mud can be removed as +required. The silt or dirt that may be in the pipes is carried to the trap +by the water, and is deposited in the cavity, as shown, the water rises, +and when the valve, D, opens escapes at the pipe, F, and may be allowed to +run to waste. A pipe is not shown attached to F, but needless to say one +may be connected and led anywhere, provided the steam pressure is +sufficient. For this purpose the stuffing-box is provided; it is really +not required if the water runs to waste, as is represented in the +engraving. To give our readers some idea of the dimensions of the valve, +we may say that the smallest size of trap has 1 in. expansion pipe and a +valve 3 in. diameter, the next size 1¼ in. expansion pipe and a valve 4½ +in. diameter, and the largest size has a pipe 1½ in. and a valve 6 in. +diameter. Altogether, the contrivance has some important practical +advantages to recommend it.--_Mech. World._ + + * * * * * + + + + +CRITICAL METHODS OF DETECTING ERRORS IN PLANE SURFACES.[3] + +[Footnote 3: A paper read before the Engineers' Society of Western +Pennsylvania, Dec. 10, 1884.] + +By JOHN A. BRASHEAR. + + +In our study of the exact methods of measurement in use to-day, in the +various branches of scientific investigation, we should not forget that it +has been a plant of very slow growth, and it is interesting indeed to +glance along the pathway of the past to see how step by step our micron of +to-day has been evolved from the cubit, the hand's breadth, the span, and, +if you please, the barleycorn of our schoolboy days. It would also be a +pleasant task to investigate the properties of the gnomon of the Chinese, +Egyptians, and Peruvians, the scarphie of Eratosthenes, the astrolabe of +Hipparchus, the parallactic rules of Ptolemy, Regimontanus Purbach, and +Walther, the sextants and quadrants of Tycho Brahe, and the modifications +of these various instruments, the invention and use of which, from century +to century, bringing us at last to the telescopic age, or the days of +Lippershay, Jannsen, and Galileo. + +[Illustration: FIG. 1.] + +It would also be a most pleasant task to follow the evolution of our +subject in the new era of investigation ushered in by the invention of +that marvelous instrument, the telescope, followed closely by the work of +Kepler, Scheiner, Cassini, Huyghens, Newton, Digges, Nonius, Vernier, +Hall, Dollond, Herschel, Short, Bird, Ramsden, Troughton, Smeaton, +Fraunhofer, and a host of others, each of whom has contributed a noble +share in the elimination of sources of error, until to-day we are +satisfied only with units of measurement of the most exact and refined +nature. Although it would be pleasant to review the work of these past +masters, it is beyond the scope of the present paper, and even now I can +only hope to call your attention to one phase of this important subject. +For a number of years I have been practically interested in the subject of +the production of plane and curved surfaces particularly for optical +purposes, _i.e._, in the production of such surfaces free if possible from +all traces of error, and it will be pleasant to me if I shall be able to +add to the interest of this association by giving you some of my own +practical experience; and may I trust that it will be an incentive to all +engaged in kindred work _to do that work well?_ + +[Illustration: FIG. 2.] + +In the production of a perfectly plane surface, there are many +difficulties to contend with, and it will not be possible in the limits of +this paper to discuss the methods of eliminating errors when found; but I +must content myself with giving a description of various methods of +detecting existing errors in the surfaces that are being worked, whether, +for instance, it be an error of concavity, convexity, periodic or local +error. + +[Illustration: FIG. 3] + +A very excellent method was devised by the celebrated Rosse, which is +frequently used at the present time; and those eminent workers, the Clarks +of Cambridge, use a modification of the Rosse method which in their hands +is productive of the very highest results. The device is very simple, +consisting of a telescope (_a_, Fig. 1) in which aberrations have been +well corrected, so that the focal plane of the objective is as sharp as +possible. This telescope is first directed to a distant object, preferably +a celestial one, and focused for parallel rays. The surface, _b_, to be +tested is now placed so that the reflected image of the same object, +whatever it may be, can be observed by the same telescope. It is evident +that if the surface be a true plane, its action upon the beam of light +that comes from the object will be simply to change its direction, but not +disturb or change it any other way, hence the reflected image of the +object should be seen by the telescope, _a_, without in any way changing +the original focus. If, however, the supposed plane surface proves to be +_convex_, the image will not be sharply defined in the telescope until the +eyepiece is moved _away_ from the object glass; while if the converse is +the case, and the supposed plane is concave, the eyepiece must now be +moved _toward_ the objective in order to obtain a sharp image, and the +amount of convexity or concavity may be known by the change in the focal +plane. If the surface has periodic or irregular errors, no sharp image can +be obtained, no matter how much the eyepiece may be moved in or out. + +[Illustration: FIG. 4] + +This test may be made still more delicate by using the observing +telescope, _a_, at as low an angle as possible, thereby bringing out with +still greater effect any error that may exist in the surface under +examination, and is the plan generally used by Alvan Clark & Sons. Another +and very excellent method is that illustrated in Fig. 2, in which a second +telescope, _b_, is introduced. In place of the eyepiece of this second +telescope, a diaphragm is introduced in which a number of small holes are +drilled, as in Fig. 2, _x_, or a slit is cut similar to the slit used in a +spectroscope as shown at _y_, same figure. The telescope, _a_, is now +focused very accurately on a celestial or other very distant object, and +the focus marked. The object glass of the telescope, _b_, is now placed +against and "square" with the object glass of telescope _a_, and on +looking through telescope a an image of the diaphragm with its holes or +the slit is seen. This diaphragm must now be moved until a sharp image is +seen in telescope _a_. The two telescopes are now mounted as in Fig. 2, +and the plate to be tested placed in front of the two telescopes as at +_c_. It is evident, as in the former case, that if the surface is a true +plane, the reflected image of the holes or slit thrown upon it by the +telescope, _b_, will be seen sharply defined in the telescope, _a_. + +[Illustration: FIG. 5.] + +If any error of convexity exists in the plate, the focal plane is +disturbed, and the eyepiece must be moved _out_. If the plate is concave, +it must be moved _in_ to obtain a sharp image. Irregular errors in the +plate or surface will produce a blurred or indistinct image, and, as in +the first instance, no amount of focusing will help matters. These methods +are both good, but are not satisfactory in the highest degree, and two or +three important factors bar the way to the very best results. One is that +the aberrations of the telescopes must be perfectly corrected, a very +difficult matter of itself, and requiring the highest skill of the +optician. Another, the fact that the human eye will accommodate itself to +small distances when setting the focus of the observing telescope. I have +frequently made experiments to find out how much this accommodation was in +my own case, and found it to amount to as much as 1/40 of an inch. This is +no doubt partly the fault of the telescopes themselves, but unless the eye +is rigorously educated in this work, it is apt to accommodate itself to a +small amount, and will invariably do so if there is a preconceived notion +or bias _in the direction of the accommodation_. + +[Illustration: FIG. 6.] + +Talking with Prof. C.A. Young a few months since on this subject, he +remarked that he noticed that the eye grew more exact in its demands as it +grew older, in regard to the focal point. A third and very serious +objection to the second method is caused by diffraction from the edges of +the holes or the slit. Let me explain this briefly. When light falls upon +a slit, such as we have here, it is turned out of its course; as the slit +has two edges, and the light that falls on either side is deflected both +right and left, the rays that cross from the right side of the slit toward +the left, and from the left side of the slit toward the right, produce +interference of the wave lengths, and when perfect interference occurs, +dark lines are seen. You can have a very pretty illustration of this by +cutting a fine slit in a card and holding it several inches from the eye, +when the dark lines caused by a total extinction of the light by +interference may be seen. + +[Illustration: FIG. 7.] + +If now you look toward the edge of a gas or lamp flame; you will see a +series of colored bands, that bring out the phenomenon of partial +interference. This experiment shows the difficulty in obtaining a perfect +focus of the holes or the slit in the diaphragm, as the interference +fringes are always more or less annoying. Notwithstanding these defects of +the two systems I have mentioned, in the hands of the practical workman +they are productive of very good results, and very many excellent surfaces +have been made by their use, and we are not justified in ignoring them, +because they are the stepping stones to lead us on to better ones. In my +early work Dr. Draper suggested a very excellent plan for testing a flat +surface, which I briefly describe. It is a well known truth that, if an +artificial star is placed in the exact center of curvature of a truly +spherical mirror, and an eyepiece be used to examine the image close +beside the source of light, the star will be sharply defined, and will +bear very high magnification. If the eyepiece is now drawn toward the +observer, the star disk begins to expand; and if the mirror be a truly +spherical one, the expanded disk will be equally illuminated, except the +outer edge, which usually shows two or more light and dark rings, due to +diffraction, as already explained. + +[Illustration: FIG. 8.] + +Now if we push the eyepiece toward the mirror the same distance on the +opposite side of the true focal plane, precisely the same appearance will +be noted in the expanded star disk. If we now place our plane surface any +where in the path of the rays from the great mirror, we should have +identically the same phenomena repeated. Of course it is presumed, and is +necessary, that the plane mirror shall be much less in area than the +spherical mirror, else the beam of light from the artificial star will be +shut off, yet I may here say that any one part of a truly spherical mirror +will act just as well as the whole surface, there being of course a loss +of light according to the area of the mirror shut off. + +This principle is illustrated in Fig. 3, where _a_ is the spherical +mirror, _b_ the source of light, _c_ the eyepiece as used when the plane +is not interposed, _d_ the plane introduced into the path at an angle of +45° to the central beam, and _e_ the position of eyepiece when used the +with the plane. When the plane is not in the way, the converging beam goes +back to the eyepiece, _c_. When the plane, _d_, is introduced, the beam is +turned at a right angle, and if it is a perfect surface, not only does the +focal plane remain exactly of the same length, but the expanded star +disks, are similar on either side of the focal plane. + +[Illustration: FIG. 9.] + +I might go on to elaborate this method, to show how it may be made still +more exact, but as it will come under the discussion of spherical +surfaces, I will leave it for the present. Unfortunately for this process, +it demands a large truly spherical surface, which is just as difficult of +attainment as any form of regular surface. We come now to an instrument +that does not depend upon optical means for detecting errors of surface, +namely, the spherometer, which as the name would indicate means sphere +measure, but it is about as well adapted for plane as it is for spherical +work, and Prof. Harkness has been, using one for some time past in +determining the errors of the plane mirrors used in the transit of Venus +photographic instruments. At the meeting of the American Association of +Science in Philadelphia, there was quite a discussion as to the relative +merits of the spherometer test and another form which I shall +presently mention, Prof. Harkness claiming that he could, by the +use of the spherometer, detect errors bordering closely on one +five-hundred-thousandth of an inch. Some physicists express doubt on this, +but Prof. Harkness has no doubt worked with very sensitive instruments, +and over very small areas at one time. + +I have not had occasion to use this instrument in my own work, as a more +simple, delicate, and efficient method was at my command, but for one +measurement of convex surfaces I know of nothing that can take its place. +I will briefly describe the method of using it. + +[Illustration: FIG. 10.] + +The usual form of the instrument is shown in Fig. 4; _a_ is a steel screw +working in the nut of the stout tripod frame, _b_; _c c c_ are three legs +with carefully prepared points; _d_ is a divided standard to read the +whole number of revolutions of the screw, _a_, the edge of which also +serves the purpose of a pointer to read off the division on the top of the +milled head, _e_. Still further refinement may be had by placing a vernier +here. To measure a plane or curved surface with this instrument, a perfect +plane or perfect spherical surface of known radius must be used to +determine the zero point of the division. Taking for granted that we have +this standard plate, the spherometer is placed upon it, and the readings +of the divided head and indicator, _d_, noted when the point of the screw, +_a_, just touches the surface, _f_. Herein, however, lies the great +difficulty in using this instrument, _i.e._, to know the exact instant of +contact of the point of screw, _a_, on the surface, _f_. Many devices have +been added to the spherometer to make it as sensitive as possible, such as +the contact level, the electric contact, and the compound lever contact. +The latter is probably the best, and is made essentially as in Fig. 5. + +[Illustration: FIG. 11.] + +I am indebted for this plan to Dr. Alfred Mayer. As in the previous +figure, _a_ is the screw; this screw is bored out, and a central steel pin +turned to fit resting on a shoulder at _c_. The end of _d_ projects below +the screw, _a_, and the end, _e_, projects above the milled head, and the +knife edge or pivot point rests against the lever, _f_, which in turn +rests against the long lever, _g_, the point, _h_, of which moves along +the division at _j_. It is evident that if the point of the pin just +touches the plate, no movement of the index lever, _g_, will be seen; but +if any pressure be applied, the lever will move through a multiplied arc, +owing to the short fulcri of the two levers. Notwithstanding all these +precautions, we must also take into account the flexure of the material, +the elasticity of the points of contact, and other idiosyncrasies, and you +can readily see that practice alone in an instrument so delicate will +bring about the very best results. Dr. Alfred Mayer's method of getting +over the great difficulty of knowing when all four points are in contact +is quite simple. The standard plate is set on the box, _g_, Fig. 4, which +acts as a resonater. The screw, _a_, is brought down until it touches the +plate. When the pressure of the screw is enough to lift off either or all +of the legs, and the plate is gently tapped with the finger, a _rattle_ is +heard, which is the tell-tale of imperfect contact of all the points. The +screw is now reversed gently and slowly until the _moment_ the rattle +ceases, and then the reading is taken. Here the sense of hearing is +brought into play. This is also the case when the electric contact is +used. This is so arranged that the instant of touching of the point of +screw, _a_, completes the electric circuit, in which an electromagnet of +short thick wire is placed. At the moment of contact, or perhaps a little +before contact, the bell rings, and the turning of the screw must be +instantly stopped. Here are several elements that must be remembered. +First, it takes time to set the bell ringing, time for the sound to pass +to the ear, time for the sensation to be carried to the brain, time for +the brain to send word to the hand to cease turning the screw, and, if you +please, it takes time for the hand to stop. You may say, of what use are +such refinements? I may reply, what use is there in trying to do anything +the very best it can be done? If our investigation of nature's profound +mysteries can be partially solved with good instrumental means, what is +the result if we have better ones placed in our hands, and what, we ask, +if the _best_ are given to the physicist? We have only to compare the +telescope of Galileo, the prism of Newton, the pile of Volta, and what was +done with them, to the marvelous work of the telescope, spectroscope, and +dynamo of to-day. But I must proceed. It will be recognized that in +working with the spherometer, only the points in actual contact can be +measured at one time, for you may see by Fig. 6 that the four points, _a a +a a_, may all be normal to a true plane, and yet errors of depression, as +at _e_, or elevation, as at _b_, exist between them, so that the +instrument must be used over every available part of the surface if it is +to be tested rigorously. As to how exact this method is I cannot say from +actual experience, as in my work I have had recourse to other methods that +I shall describe. I have already quoted you the words of Prof. Harkness. +Dr. Hastings, whose practical as well as theoretical knowledge is of the +most critical character, tells me that he considers it quite easy to +measure to 1/80000 of an inch with the ordinary form of instrument. Here +is a very fine spherometer that Dr. Hastings works with from time to time, +and which he calls his standard spherometer. It is delicately made, its +screw being 50 to the inch, or more exactly 0.01998 inch, or within +2/100000 of being 1/50 of an inch pitch. The principal screw has a point +which is itself an independent screw, that was put in to investigate the +errors of the main screw, but it was found that the error of this screw +was not as much as the 0.00001 of an inch. The head is divided into two +hundred parts, and by estimation can be read to 1/100000 of an inch. Its +constants are known, and it may be understood that it would not do to +handle it very roughly. I could dwell here longer on this fascinating +subject, but must haste. I may add that if this spherometer is placed on a +plate of glass and exact contact obtained, and then removed, and the hand +held over the plate without touching it, the difference in the temperature +of the glass and that of the hand would be sufficient to distort the +surface enough to be readily recognized by the spherometer when replaced. +Any one desiring to investigate this subject further will find it fully +discussed in that splendid series of papers by Dr. Alfred Mayer on the +minute measurements of modern science published in SCIENTIFIC AMERICAN +SUPPLEMENTS, to which I was indebted years ago for most valuable +information, as well as to most encouraging words from Prof. Thurston, +whom you all so well and favorably know. I now invite your attention to +the method for testing the flat surfaces on which Prof. Rowland rules the +beautiful diffraction gratings now so well known over the scientific +world, as also other plane surfaces for heliostats, etc., etc. I am now +approaching the border land of what may be called the abstruse in science, +in which I humbly acknowledge it would take a vast volume to contain all I +don't know; yet I hope to make plain to you this most beautiful and +accurate method, and for fear I may forget to give due credit, I will say +that I am indebted to Dr. Hastings for it, with whom it was an original +discovery, though he told me he afterward found it had been in use by +Steinheil, the celebrated optician of Munich. The principle was discovered +by the immortal Newton, and it shows how much can be made of the ordinary +phenomena seen in our every-day life when placed in the hands of the +investigator. We have all seen the beautiful play of colors on the soap +bubble, or when the drop of oil spreads over the surface of the water. +Place a lens of long curvature on a piece of plane polished glass, and, +looking at it obliquely, a black central spot is seen with rings of +various width and color surrounding it. If the lens is a true curve, and +the glass beneath it a true plane, these rings of color will be perfectly +concentric and arranged in regular decreasing intervals. This apparatus is +known as Newton's color glass, because he not only measured the phenomena, +but established the laws of the appearances presented. I will now endeavor +to explain the general principle by which this phenomenon is utilized in +the testing of plane surfaces. Suppose that we place on the lower plate, +lenses of constantly increasing curvature until that curvature becomes +nil, or in other words a true plane. The rings of color will constantly +increase in width as the curvature of the lens increases, until at last +one color alone is seen over the whole surface, provided, however, the +same angle of observation be maintained, and provided further that the +film of air between the glasses is of absolutely the same relative +thickness throughout. I say the film of air, for I presume that it would +be utterly impossible to exclude particles of dust so that absolute +contact could take place. Early physicists maintained that absolute +molecular contact was impossible, and that the central separation of the +glasses in Newton's experiment was 1/250,000 of an inch, but Sir Wm. +Thomson has shown that the separation is caused by shreds or particles of +dust. However, if this separation is equal throughout, we have the +phenomena as described; but if the dust particles are thicker under one +side than the other, our phenomena will change to broad parallel bands as +in Fig. 8, the broader the bands the nearer the absolute parallelism of +the plates. In Fig. 7 let _a_ and _b_ represent the two plates we are +testing. Rays of white light, _c_, falling upon the upper surface of plate +_a_, are partially reflected off in the direction of rays _d_, but as +these rays do not concern us now, I have not sketched them. Part of the +light passes on through the upper plate, where it is bent out of its +course somewhat, and, falling upon the _lower_ surface of the upper plate, +some of this light is again reflected toward the eye at _d_. As some of +the light passes through the upper plate, and, passing through the film of +air between the plates, falling on the upper surface of the _lower_ one, +this in turn is reflected; but as the light that falls on this surface has +had to traverse the film of air _twice_, it is retarded by a certain +number of half or whole wave-lengths, and the beautiful phenomena of +interference take place, some of the colors of white light being +obliterated, while others come to the eye. When the position of the eye +changes, the color is seen to change. I have not time to dwell further on +this part of my subject, which is discussed in most advanced works on +physics, and especially well described in Dr. Eugene Lommel's work on "The +Nature of Light." I remarked that if the two surfaces were perfectly +_plane_, there would be one color seen, or else colors of the first or +second order would arrange themselves in broad parallel bands, but this +would also take place in plates of slight curvature, for the requirement +is, as I said, a film of air of equal thickness throughout. You can see at +once that this condition could be obtained in a perfect convex surface +fitting a perfect concave of the same radius. Fortunately we have a check +to guard against this error. To produce a perfect plane, _three surfaces +must_ be worked together, unless we have a true plane to commence with; +but to make this true plane by this method we _must_ work three together, +and if each one comes up to the demands of this most rigorous test, we may +rest assured that we have attained a degree of accuracy almost beyond +human conception. Let me illustrate. Suppose we have plates 1, 2, and 3, +Fig. 11. Suppose 1 and 2 to be accurately convex and 3 accurately concave, +of the same radius. Now it is evident that 3 will exactly fit 1 and 2, and +that 1 and 2 will separately fit No. 3, _but_ when 1 and 2 are placed +together, they will only touch in the center, and there is no possible +way to make three plates coincide when they are alternately tested upon +one another than to make _perfect planes_ out of them. As it is difficult +to see the colors well on metal surfaces, a one-colored light is used, +such as the sodium flame, which gives to the eye in our test, dark and +bright bands instead of colored ones. When these plates are worked and +tested upon one another until they all present the same appearance, one +may be reserved for a test plate for future use. Here is a small test +plate made by the celebrated Steinheil, and here two made by myself, and I +may be pardoned in saying that I was much gratified to find the +coincidence so nearly perfect that the limiting error is much less than +0.00001 of an inch. My assistant, with but a few months' experience, has +made quite as accurate plates. It is necessary of course to have a glass +plate to test the metal plates, as the upper plate _must_ be transparent. +So far we have been dealing with perfect surfaces. Let us now see what +shall occur in surfaces that are not plane. Suppose we now have our +perfect test plate, and it is laid on a plate that has a compound error, +say depressed at center and edge and high between these points. If this +error is regular, the central bands arrange themselves as in Fig. 9. You +may now ask, how are we to know what sort of surface we have? A ready +solution is at hand. The bands _always travel in the direction of the +thickest film of air_, hence on lowering the eye, if the convex edge of +the bands travel in the direction of the arrow, we are absolutely certain +that that part of the surface being tested is convex, while if, as in the +central part of the bands, the concave edges advance, we know that part is +hollow or too low. Furthermore, any small error will be rigorously +detected, with astonishing clearness, and one of the grandest qualities of +this test is the absence of "personal equation;" for, given a perfect test +plate, _it won't lie_, neither will it exaggerate. I say, won't lie, but I +must guard this by saying that the plates must coincide absolutely in +temperature, and the touch of the finger, the heat of the hand, or any +disturbance whatever will vitiate the results of this lovely process; but +more of that at a future time. If our surface is plane to within a short +distance of the edge, and is there overcorrected, or convex, the test +shows it, as in Fig. 10. If the whole surface is regularly convex, then +concentric rings of a breadth determined by the approach to a perfect +plane are seen. If concave, a similar phenomenon is exhibited, except in +the case of the convex, the broader rings are near the center, while in +the concave they are nearer the edge. In lowering the eye while observing +the plates, the rings of the convex plate will advance outward, those of +the concave inward. It may be asked by the mechanician, Can this method be +used for testing our surface plates? I answer that I have found the +scraped surface of iron bright enough to test by sodium light. My +assistant in the machine work scraped three 8 inch plates that were tested +by this method and found to be very excellent, though it must be evident +that a single cut of the scraper would change the spot over which it +passed so much as to entirely change the appearance there, but I found I +could use the test to get the general outline of the surface under process +of correction. These iron plates, I would say, are simply used for +preliminary formation of polishers. I may have something to say on the +question of surface plates in the future, as I have made some interesting +studies on the subject. I must now bring this paper to a close, although I +had intended including some interesting studies of curved surfaces. There +is, however, matter enough in that subject of itself, especially when we +connect it with the idiosyncrasies of the material we have to deal with, a +vital part of the subject that I have not touched upon in the present +paper. You may now inquire, How critical is this "color test"? To answer +this I fear I shall trench upon forbidden grounds, but I call to my help +the words of one of our best American physicists, and I quote from a +letter in which he says by combined calculation and experiment I have +found the limiting error for white light to be 1/50000000 of an inch, and +for Na or sodium light about fifty times greater, or less than 1/800000 of +an inch. Dr. Alfred Mayer estimated and demonstrated by actual experiment +that the smallest black spot on a white ground visible to the naked eye is +about 1/800 of an inch at the distance of normal vision, namely, 10 +inches, and that a line, which of course has the element of extension, +1/5000 of an inch in thickness could be seen. In our delicate "color test" +we may decrease the diameter of our black spot a thousand times and still +its perception is possible by the aid of our monochromatic light, and we +may diminish our line ten thousand times, yet find it just perceivable on +the border land of our test by white light. Do not presume I am so foolish +as to even think that the human hand, directed by the human brain, can +ever work the material at his command to such a high standard of +exactness. No; from the very nature of the material we have to work with, +we are forbidden even to hope for such an achievement; and could it be +possible that, through some stroke of good fortune, we could attain this +high ideal, it would be but for a moment, as from the very nature of our +environment it would be but an ignis fatuus. There is, however, to the +earnest mind a delight in having a high model of excellence, for as our +model is so will our work approximate; and although we may go on +approximating _our_ ideal forever, we can never hope to reach that which +has been set for us by the great Master Workman. + + * * * * * + + + + +[JOURNAL OF GAS LIGHTING.] + +PHOTOMETRICAL STANDARDS. + + +In carrying out a series of photometrical experiments lately, I found that +it was a matter of considerable difficulty to keep the flames of the +standard candles always at their proper distance from the light to be +measured, because the wick was continually changing its position (of +course carrying the flame with it), and thus practically lengthening or +shortening the scale of the photometer, according as the flame was carried +nearer to or farther from the light at the other end of the scale. In +order, therefore, to obtain a correct idea of the extent to which this +variation of the position of the wick might influence the readings of the +photometer scale, I took a continuous number of photographs of the flame +of a candle while it was burning in a room quite free from draught; no +other person being in it during the experiment except a photographer, who +placed sensitive dry plates in a firmly fixed camera, and changed them +after an exposure of 30 seconds. In doing this he was careful to keep +close to the camera, and disturb the air of the room as little as +possible. In front of the candle a plumb-line was suspended, and remained +immovable over its center during the whole operation. The candle was +allowed to get itself into a normal state of burning, and then the wick +was aligned, as shown in the photographs Nos. 1 and 2, after which it was +left to itself. + +[Illustration: VARIATION IN PHOTOMETRICAL STANDARDS.] + +With these photographs (represented in the cuts) I beg to hand you +full-sized drawings of the scales of a 100 inch Evans and a 60 inch +Letheby photometer, in order to give your readers an opportunity of +estimating for themselves the effect which such variations from the true +distance between the standard light and that to be measured, as shown in +this series of photographs, must exercise on photometrical observations +made by the aid of either of the instruments named. + +W. SUGG. + + * * * * * + + + + +BLEACHING OR DYEING-YARNS AND GOODS IN VACUO. + + +[Illustration] + +Many attempts have been made to facilitate the penetration of textile +fabrics by the dyeing and bleaching solutions, with which they require to +be treated, by carrying out the treatment in vacuo, _i.e._, in such +apparatus as shall allow of the air being withdrawn. The apparatus shown +in the annexed engraving--Austrian Pat. Jan. 15, 1884--although not +essentially different from those already in use, embodies, the _Journal of +the Society of Chemical Industry_ says, some important improvements in +detail. It consists of a drum A, the sides of which are constructed of +stout netting, carried on a vertical axis working through a stuffing-box, +which is fitted in the bottom of the outer or containing vessel or keir B. +The air can be exhausted from B by means of an air pump. A contains a +central division P, also constructed of netting, into which is inserted +the extremity of the tube R, after being twice bent at a right angle. P is +also in direct connection with the efflux tube E, E and R serving to +convey the dye or bleach solutions to and from the reservoir C. The +combination of the rotary motion communicated to A, which contains the +goods to be dyed or bleached, with the very thorough penetration and +circulation of the liquids effected by means of the vacuum established in +B, is found to be eminently favorable to the rapidity and evenness of the +dye or bleach. + + * * * * * + + + + +ON THE MOULDING OF PORCELAIN. + +By CHAS. LAUTH. + + +The operation of moulding presents numerous advantages over other methods +of shaping porcelain, for by this process we avoid irregularities of form, +twisting, and visible seams, and can manufacture thin pieces, as well as +pieces of large dimensions, of a purity of form that it is impossible to +obtain otherwise. + +The method of moulding small objects has been described with sufficient +detail in technical works, but such is not the case with regard to large +ones, and for this reason it will be of interest to quote some practical +observations from a note that has been sent me by Mr. Constantine Renard, +who, for several years, has had the superintendence of the moulding rooms +of the Sevres works. + +The process of moulding consists in pouring porcelain paste, thinned with +water, into very dry plaster moulds. This mixture gradually hardens +against the porous sides with which it is in contact, and, when the +thickness of the hardened layer is judged sufficient, the mould is emptied +by inverting it. The excess of the liquid paste is thus eliminated, while +the thicker parts remain adherent to the plaster. Shortly afterward, the +absorption of the water continuing, the paste so shrinks in drying as to +allow the object to detach itself from the mould. As may be seen, nothing +is simpler when it concerns pieces of small dimensions; but the same is +not the case when we have to mould a large one. In this case we cannot get +rid of the liquid paste by turning the mould upside down, because of the +latter's size, and, on another hand, it is necessary to take special +precautions against the subsidence of the paste. Recourse is therefore had +to another method. In the first place, an aperture is formed in the lower +part of the mould through which the liquid may flow at the desired moment. +Afterward, in order to prevent the solidified but still slightly soft +paste from settling under its own weight at this moment, it is supported +by directing a current of compressed air into the mould, or, through +atmospheric pressure, by forming a vacuum in the metallic jacket in which +the mould is inclosed. + +The history and description of these processes have been several times +given, and I shall therefore not dwell upon them, but shall at once +proceed to make known the new points that Mr. Renard has communicated to +me. + +The first point to which it is well to direct the manufacturer's attention +is the preparation of the plaster moulds. When it concerns an object of +large dimensions, of a vase a yard in height, for example, the moulder is +obliged to cut the form or core horizontally into three parts, each of +which is moulded separately. To this effect, it is placed upon a core +frame and surrounded with a cylinder of sheet zinc. The workman pours the +plaster into the space between the latter and the core, and, while doing +so, must stir the mass very rapidly with a stick, so that at the moment +the plaster sets, it shall be as homogeneous as possible. In spite of such +precautions, it is impossible to prevent the densest parts of the plaster +from depositing first, through the action of gravity. These will naturally +precipitate upon the table or upon the slanting sides of the core, and the +mould will therefore present great inequalities as regards porosity. Since +this defect exists in each of the pieces that have been prepared in +succession, it will be seen that when they come to be superposed for the +moulding of the piece, the mould as a whole will be formed of zones of +different porosities, which will absorb water from the paste unequally. +Farther along we shall see the inconveniences that result from this, and +the manner of avoiding them. + +[Illustration: FIG. 1] + +The mould, when finished, is dried in a stove. Under such circumstances it +often happens that there forms upon the surface of the plaster a hard +crust which, although it is of no importance as regards the outside of the +mould, is prejudicial to the interior because it considerably diminishes +its absorbing power. This trouble may be avoided by coating the surfaces +that it is necessary to preserve with clear liquid paste; but Mr. Renard +advises that the mould be closed hermetically, so that the interior shall +be kept from contact with warm air. In this way it is possible to prevent +the plaster from hardening, as a result of too quick a desiccation. I now +come to the operation of moulding. In the very first place, it is +necessary to examine whether it is well to adopt the arrangement by +pressure of air or by vacuum. The form of the objects will determine the +choice. A very open piece, like a bowl, must be moulded by vacuum, on +account of the difficulty of holding the closing disk in place if it be of +very large dimensions. The same is the case with large vases of wood form. +On the contrary, an elongated piece tapering from above is more easily +moulded by pressure of the air, as are also ovoid vessels 16 to 20 inches +in height. In any case it must not be forgotten that the operation by +vacuum should be preferred every time the form of the objects is adapted +to it, because this process permits of following and directing the drying, +while with pressure it is impossible to see anything when once the +apparatus is closed. + +[Illustration: FIG. 2.] + +_Moulding by Pressure of the Air._--The plaster mould having been put in +place upon the mould board, and the liquid paste having been long and +thoroughly stirred in order to make it homogeneous, and get rid of the air +bubbles, we open the cock that puts the paste reservoir in communication +with the lower part of the mould, care having been taken beforehand to +pour a few pints of water into the bottom of the mould. The paste in +ascending pushes this water ahead of it, and this slightly wets the +plaster and makes the paste rise regularly. When the mould is entirely +filled, the paste is still allowed to flow until it slightly exceeds the +upper level, and, spreading out over the entire thickness of the plaster, +forms a sort of thick flange. The absorption of the liquid begins almost +immediately, and, consequently, the level lowers. A new quantity of paste +is introduced, and we continue thus, in regulating its flow so as to keep +the mould always full. This operation is prolonged until the layer is +judged to be sufficiently thick, this depending upon the dimensions, form, +or construction of the vessel. The operation may take from one to five +hours. + +The desired thickness having been obtained, it becomes a question of +allowing the paste to descend and at the same time to support the piece by +air pressure. The flange spoken of above is quickly cut, and the paste is +made to rise again for the last time, in order to form a new flange, but +one that this time will be extremely thin; then a perforated disk designed +for forming the top joint, and acting as a conduit for the air, is placed +upon the mould. This disk is fastened down with a screw press, and when +the apparatus is thus arranged the eduction cock is opened, and the air +pump maneuvered. + +If the flange did not exist, the air would enter between the mould and the +piece at the first strokes of the piston, and the piece would be +inevitably broken. Its object, then, is to form a hermetical joint, +although it must at the same time present but a slight resistance, since, +as soon as the liquid paste has flowed out, the piece begins to shrink, +and it is necessary that at the first movement downward it shall be able +to disengage itself, since it would otherwise crack. + +As soon as the piece begins to detach itself from the mould the air enters +the apparatus, and the pressure gauge connected with the air pump begins +to lower. It is then necessary, without a moment's loss of time, to remove +the screw press, the disk, and the upper part of the mould itself, in +order to facilitate as much as possible the contraction of the piece. +Finally, an hour or an hour and a half later, it is necessary to remove +the lower part of the mould, this being done in supporting the entire +affair by the middle. The piece and what remains of the mould are, in +reality, suspended in the air. All these preparations are designed to +prevent cracking. + +_Moulding by Vacuum._--The operation by vacuum follows the same phases as +those just described. It is well, in order to have a very even surface, +not to form a vacuum until about three hours after the paste has been made +to ascend. Without such a precaution the imperfections in the mould will +be shown on the surface of the object by undulations that are +irremediable. + +The first flange or vein must be preserved, and it is cut off at the +moment the piece is detached. + +Moulding by vacuum, aside from the advantages noted above, permits of +giving the pieces a greater thickness than is obtained in the pressure +process. According to Mr. Renard, when it is desired to exceed one inch at +the base of the piece (the maximum thickness usually obtained), the +operation is as follows: The piece is moulded normally, and it is +supported by a vacuum; but, at the moment at which, under ordinary +circumstances, it would be detached, the paste is made to ascend a second +time, when the first layer (already thick and dry) acts as a sort of +supplementary mould, and permits of increasing the thickness by about 2/5 +of an inch. The piece is held, as at first, by vacuum, and the paste is +introduced again until the desired thickness is obtained. + +Whatever be the care taken, accidents are frequent in both processes. They +are due, in general, to the irregular contraction of the pieces, caused by +a want of homogeneousness in the plaster of the moulds. In fact, as the +absorption of the water does not proceed regularly over the entire surface +of the piece, zones of dry paste are found in contact with others that are +still soft, and hence the formation of folds, and finally the cracking and +breaking of the piece. The joints of the moulds are also a cause of +frequent loss, on account of the marks that they leave, and that injure +the beauty of the form as well as the purity of the profile. + +Mr. Renard has devised a remedy for all such inconveniences. He takes +unglazed muslin, cuts it into strips, and, before beginning operations, +fixes it with a little liquid paste to the interior of the mould. This +light fabric in no wise prevents the absorption of the water, and so the +operation goes on as usual; but, at the moment of contraction, the piece +of porcelain being, so to speak, supported by the muslin, comes put of the +mould more easily and with extreme regularity. Under such circumstances +all trace of the joint disappears, the imperfections in the mould are +unattended with danger, and the largest pieces are moulded with entire +safety. In a word, we have here a very important improvement in the +process of moulding. The use of muslin is to be recommended, not only in +the manufacture of vases, but also in the difficult preparation of large +porcelain plates. It is likewise advantageous in the moulding of certain +pieces of sculpture that are not very delicate, and, finally, it is very +useful when we have to do with a damaged mould, which, instead of being +repaired with plaster, can be fixed with well ground wet sand covered with +a strip of muslin. + +_Drying of the Moulded Pieces._--When the moulded pieces become of a +proper consistency in the mould, they are exposed to the air and then +taken to the drying room. But, as with plaster, the surface of the paste +dries very quickly, and this inconvenience (which amounts to nothing in +pieces that are to be polished) is very great in pieces that carry +ornaments in relief, since the finishing of these is much more difficult, +the hardened paste works badly, and frequently flakes off. In order to +remedy this inconvenience, it suffices to dust the places to be preserved +with powdered dry paste.--_Revue Industrielle._ + + * * * * * + + + + +PHOTO-TRICYCLE APPARATUS. + + +[Illustration: A PHOTO-TRICYCLE APPARATUS.] + +This consists of a portable folding camera, with screw focusing +arrangement, swing back, and an adapter frame placed in the position of +the focus screen, allowing the dark slide to be inserted so as to give the +horizontal or vertical position to the dry plate when in the camera. To +the front and base-board a brass swiveled side bar, made collapsible by +means of a center slot, is attached by hinges, and this renders the camera +rigid when open or secure when closed. The base-board is supported on a +brass plate within which is inserted a ball-and-socket (or universal joint +in a new form), permitting the camera to be tilted to any necessary angle, +and fixed in such position at will. The whole apparatus is mounted upon a +brass telescopic draw-stand, which, by means of clamps, is attached to the +steering handle or other convenient part of the tricycle, preferably the +form made by Messrs. Rudge & Co., of Coventry, represented in the +cut.--_Photo. News._ + + * * * * * + + + + +A PHOTO PRINTING LIGHT. + + +[Illustration] + +A printing frame is placed in the carrier, and exposed to the light of a +gas burner kept at a fixed distance, behind which is a spherical +reflector. The same frame may be used for other purposes.-_Photographic +News._ + + * * * * * + + + + +A NEW ACTINOMETER. + + +A selenium actinometer has been described in the _Comptes Rendus_ in a +communication from M. Morize, of Rio de Janeiro. The instrument is used to +measure the actinic power of sunlight when the sun is at various +altitudes; but the same principle is applicable to other light sources. +The sensitive part of the apparatus consists of a cylinder formed of 38 +disks of copper, isolated from each other by as many disks of mica. The +latter being of smaller diameter than the copper disks, the annular spaces +between the two are filled with selenium, by the simple process of rubbing +a stick of this substance over the edges, and afterward gently warming. +The selenium then presents a grayish appearance, and is ready for use. +Connection is made by conductors, on opposite sides, with the odd and even +numbers of the disks, which diminishes the resistance of the selenium. The +cylinder thus formed is insulated by glass supports in the inside of a +vacuum tube, for the purpose of preserving it from the disturbing +influence of dark rays. The whole is placed upon a stand, and shielded +from reflected light, but fully exposed to that which is to be measured +for actinic intensity. If now a constant current of electricity is passed +through the apparatus, as indicated by a galvanometer, the variations of +the latter will show the effect produced upon the selenium. A scale must +be prepared, with the zero point at the greatest possible resistance of +the selenium, which corresponds with absolute darkness. The greatest +effect of the light would be to annul the resistance of the selenium. +Consequently, the cylinder must be withdrawn from the circuit to represent +this effect; and the maximum deviation of the galvanometer is then to be +observed, and marked 100. By dividing the range of the galvanometer thus +obtained into 100 equal parts, the requisite actinometric scale will be +established. In practice, the Clamond battery is used to supply the +constant current required. + + * * * * * + + + + +ASTRONOMICAL PHOTOGRAPHY. + + +During the last few years, or rather decades of years, it has become +rather a trite saying that to advance far in any branch of physical +research a fair proficiency in no inconsiderable number of the sister +sciences is an absolute necessity. But if this is true in general, none, I +think, will question the assertion that a proficient in any of the +physical sciences must be fairly conversant with photography as a science, +or at least as an art. If we take for example a science which has of late +years made rapid strides both in Europe and America, the science of +astronomy, we shall not have far to go to find convincing proof that a +great portion of the best work that is being done by its votaries is +effected by the aid of photography. One eminent astronomer has quite +lately gone so far as to declare that we no longer require observers of +the heavens, but that their place can be better supplied by the gelatine +plate of the photographer; and his words have been echoed by others not +less able than himself. "Abolish the observer, and substitute the +sensitive plate," is a sensational form of expressing the revolution in +observational astronomy that is taking place under our eyes; but, although +it suggests a vast amount of truth, it might leave upon the mind an +exaggerated impression inimical to the best interests of science. + +The award of the highest distinction in astronomy, the gold medal of the +Royal Astronomical Society, two years in succession, to those who have +been most successful in celestial photography is no doubtful sign of the +great value attached to such work. Last year it was Mr. Common who +received the highest testimony of the merit due to his splendid +photographs of the nebula of Orion; and this year Dr. Huggins, who has +drawn much attention to celestial photography, by his successful attempts +to picture the solar corona in full daylight, has received a similar +acknowledgment of his labors in photographing the spectra of stars and +comets and nebulæ. + +An adequate idea of the progress astronomy is now making by aid of +photography can only be formed by a comprehensive view of all that is +being at present attempted; but a rapid glance at some of the work may +prepare the way for a more thorough investigation. A few years since, the +astronomers who had advanced their science by aid of photography were few +in number, and their results are soon enumerated. Some good pictures of +the solar corona taken during solar eclipses, a series or two of sun-spot +photographs, and a very limited number of successful attempts made upon +the moon, and planets, and star clusters, were all the fruits of their +labors. But now each month we learn of some new and efficient laborer in +this field, which gives promise of so rich a harvest. + +Each day the sun is photographed at Greenwich, at South Kensington, in +India, and at the Physical Observatory of Potsdam, and thus a sure record +is obtained of all the spots upon its surface, which may serve for the +study of the periodicity of its changes, and for their probable connection +with the important phenomena of terrestrial magnetism and meteorology. In +France the splendid sun-pictures obtained by Dr. Janssen at the Physical +Observatory of Meudon have thrown into the shade all other attempts at a +photographic study of the most delicate features of the solar surface. + +Dr. Huggins has shown that it is possible to obtain a daily photographic +record of the solar prominences, and only lately he has secured results +that justified a special expedition to the Alps to photograph the sun's +corona, and he has now moved the Admiralty to grant a subsidy to Dr. Gill, +the government astronomer at the Cape, by aid of which Mr. Woods can carry +on the experiments that were so encouraging last summer in Switzerland. + +We may, then, reasonably hope to obtain before long a daily picture of the +sun and a photographic record of its prominences, and even of a certain +portion of the solar corona; but the precious moments of each solar +eclipse will always be invaluable for picturing those wondrous details in +the corona that are now shown us by photography, and which can be obtained +by photography alone. + +Again, how very much is to be learnt in solar physics from the marvelous +photographs of the sun's spectrum exhibited last summer by Professor +Rowland; photographs that show as many as one hundred and fifty lines +between H and K, and which he is still laboring to improve! The extension, +too, of the visible solar spectrum into the ultra-violet by Corun, +Mascart, and others, adds much to our knowledge of the sun; while the +photographs of Abney in the ultrared increase our information in a +direction less expected and certainly less easy of attainment. Both these +extensions we find most ably utilized in the recent discussion of the very +interesting photographs of the spectra of the prominences and of the +corona taken during the total eclipse of May 18, 1882; and the +photographic results of this eclipse afford ample proof that we can not +only obtain pictures of the corona by photography that it would be +impossible otherwise to procure, but also that in a few seconds +information concerning the nature of the solar atmosphere may be furnished +by photography that it would otherwise take centuries to accumulate, even +under the most favorable circumstances. + +The advantages to be gained by accurate photographs of the moon and +planets, that will permit great enlargements, are too obvious to call for +lengthened notice in such a rapid sketch as the present; for it is +principally in the observation of details that the eye cannot grasp with +the required delicacy, or with sufficient rapidity, that photography is so +essential for rapid and sure progress. + +Like the sketches of a solar eclipse, the drawings that are made of +comets, and still more of nebulæ, even by the most accomplished artists, +are all, to say the least, open to doubt in their delicate details. And +the truth of this is so obvious, that it is the expressed opinion of an +able astronomer that a single photograph of the nebula of Orion, taken by +Mr. Common, would be of more value to posterity than the collective +drawings of this interesting object so carefully made by Rosse, Bond, +Secchi, and so many others. + +Another most important branch of astronomy, that is receiving very great +attention at present, is the mapping of the starry heavens; and herein +photography will perhaps do its best work for the astronomer. The trial +star map by the brothers Henry, of a portion of the Milky Way, which they +felt unable to observe satisfactorily by the ordinary methods, is so near +absolute perfection that it alone proves the immense superiority of the +photographic method in the formation of star maps. Fortunately this +subject, which is as vast as it is fundamental, is being taken up +vigorously. The Henries are producing a special lens for the work; Mr. +Grubb is constructing a special Cassgrain reflector for Mr. Roberts of +Maghull; and the Admiralty have instructed Mr. Woods to make this part of +his work at the Cape Observatory, under the able direction of Dr. Gill. +Besides star maps, clusters, too, and special portions of the heavens are +being photographed by the Rev. T.E. Espin, of West Kirby; and such +pictures will be of the greatest value, not only in fixing the position at +a given date, but also aiding in the determination of magnitude, color, +variability, proper motion, and even of the orbits of double and multiple +stars, and the possible discovery of new planets and telescopic comets. + +Such are some of the many branches of astronomy that are receiving the +most valuable aid at present from photography; but the very value of the +gift that is bestowed should make exaggeration an impossibility. +Photography can well afford to be generous, but it must first be just, in +its estimate of the work that has still to be done in astronomy +independently of its aid; and although the older science points with just +pride to what is being done for her by her younger sister, still she must +not forget that now, as in the future, she must depend largely for her +progress, not only on the skill of the photographer and the mathematician, +but also on the trained eye and ear and hand of her own indefatigable +observers.--_S.J. Perry, S.J., F.R.S., in Br. Jour. of Photography._ + + * * * * * + + + + +ELECTRICITY AS A PREVENTIVE OF SCALE IN BOILERS. + + +The mineral sediment that generally sticks to the sides of steam boilers, +and the presence of which is fraught with the utmost danger, resulting in +many instances in great injury to life and property, besides eating away +the substance of the iron plate, was referred to in a paper lately read by +M. Jeannolle before the Paris Academy of Sciences, in which the author +described a new method for keeping boilers clean. This method is as +follows: + +The inside of a steam boiler is placed, by means of piles of a certain +power, in reciprocal communication, the current passing at one end through +positive, and at the other through negative, wires. In incrusted steam +boilers, at a temperature ranging from 212° to 300° Fahr., and a pressure +of from 30 to 90 lb. to the square inch, the current thus engendered +decomposes the accumulated salts, and precipitates them, from which they +may easily be removed, either by means of a special siphon or by means of +some other mechanical process. When boilers are free from fur, and where +it is intended to keep them free from such, a continuous current may be +set up, by means of which the sedimentary salts may be decomposed, and a +precipitate produced in a pulverized form, which can be removed with equal +facility. + +From a series of minute experiments made by M. Jeannolle, it appears that +in order to render the various actions of electricity, perfect, it is +necessary to coat either with red lead or with pulverized iron, or with +any other conductor of electricity, an operation which must be repeated +whenever the boiler is emptied with a view to cleaning out. The above +system Is being advantageously applied in Calais for removing the +incrustations of boilers. The two poles of a battery of ten to twelve +Bunsen elements are applied to the ends of the boilers, and after thirty +to forty hours the deposits fall from the sides to the bottom. When a +boiler has been thus cleared, the formation of new deposits may be +prevented by applying a much less energetic current under the same +conditions. + + * * * * * + + + + +ALPHABET DESIGNED BY GODFREY SYKES. + + +[Illustration: SUGGESTIONS IN DECORATIVE ART.--ALPHABET DESIGNED BY +GODFREY SYKES.] + +Among the many designs which have been issued by the South Kensington +Museum authorities is the alphabet which we have illustrated here to-day. +The letters appear frequently among the decorations of the museum +buildings, especially in the refreshment rooms and the Ceramic gallery, +where long inscriptions in glazed terra cotta form ornamental friezes. The +alphabet has also been engraved to several sizes, and is used for the +initial letters in the various official books and art publications +relating to the museum, which are published by the Science and Art +Department.--_Building News._ + + * * * * * + + + + +OLD WROUGHT IRON GATE. + + +[Illustration: OLD WROUGHT IRON GATE] + +This gate forms the entrance to Scraptoft Hall, a building of the +eighteenth century, now the seat of Captain Barclay, and which stands at +about five miles from Leicester, England.--_The Architect._ + + * * * * * + + + + +BRIEF SANITARY MATTERS IN CONNECTION WITH ISOLATED COUNTRY HOUSES.[4] + +[Footnote 4: Read before the Boston Society of Civil Engineers, April 1884 +_Journal A. of E. Societies_.] + +By E.W. BOWDITCH, C.E. + + +I am unable to tell you what is generally considered the best practice, +for I am not sure there are any definitely established rules; therefore I +can only explain _my_ ways of doing such work, which, though I try to make +as complete and at the same time as simple as possible, I know to be far +from perfect. + +Plumbing and drainage work has grown up unconsciously with my landscape +gardening, and not finding any texts or practice that seemed wholly +satisfactory, I have been forced to devise new arrangements from time to +time, according to the requirements of the case in hand. + +To give all the details of house plumbing this evening, or any _one_ +evening, would be impossible, for lack of time, and not worth while even +if there was time, as much of it would prove matter of little or no +interest. I will confine my remarks, therefore, to certain elements of the +work where my practice differs, I believe, essentially from that of most +engineers, and where perhaps my experience, if of no assistance to other +members of the Society, may excite their friendly criticism in such a way +as to help me. + +There are two kinds of country places that I am liable to be called upon +to prescribe for: + +_First._ A new place where nothing has been arranged. + +_Second._ An old place where the occupants have been troubled either by +their outside arrangements or by fixtures or pipes within. + +Under the first head let us suppose a small tract of perhaps two acres of +land in some inland town, where the family intends to live but six months +in the year, though they are liable to reside there the whole twelve. + +There are no sewers and no public water. The soil is a stiff, retentive +clay, rather wet in spring. The desire is expressed to have plumbing and +drainage that shall be as inexpensive as possible, but that shall be +entirely safe. + +In considering the arrangements inside the house, I find myself in the +same predicament as the French surgeon, a specialist upon setting the +bones of the arm, who, when a patient was brought him with his right arm +broke, expressed his sorrow at being unable to be of assistance, as his +specialty was the left arm. + +I have endeavored to post myself thoroughly upon house plumbing, but +confess to only knowing partially about the wastes; the supplies I do not +feel competent to pass upon. + +One class of annoyance caused by plumbing, perhaps the principal one, is +due to the soil pipe or some of its fittings. + +Second quality of iron, poor hanging, insufficient calking, careless +mechanics, putty, cement, rag, or paper joints--all these and a dozen +other things are liable to be sources of trouble. Subordinate wastes are +apt to be annoying, occasionally, too, to a less extent. + +The mechanical work can always be superintended, and within certain limits +may be made secure and tight; not so easy, however, with the materials. + +There is seldom a valid excuse for ever making waste pipes, within a +building, of anything but metal. + +Earthen tile is frequently used; also, to a limited extent, brick, stone, +and wood; twice I have found canvas--all these, however, are inferior, and +should never be accepted or specified. The writer believes that at the +present time, hereabouts, lead and iron are more used for wastes than any +other materials, and are found the most satisfactory on the whole. + +One or two arrangements, relative to the wastes, I have made use of that +are not, so far as known, in general use, and that may not be the best, +though they have served me many good turns, and I have not succeeded in +devising any better. + +Soil pipe, as it is usually put in, is apt to be of cast iron, four inches +in diameter, and is known in the market as "heavy" or "extra heavy." For +some years the tar-coated or black enameled pipe has been the favorite, as +being the more reliable, the writer in common with others making use of +the same freely, until one day a cracked elbow, tar coated, was detected. +Since that time plain, untarred pipe has been specified, and subjected to +the so-called kerosene test, which consists of swabbing out each pipe with +kerosene or oil and then allowing it to stand for a few hours. A moment's +thought will convince any one that when a pipe is asphalted or tar coated +it is very difficult to detect either sand holes or small cracks, and the +difficulty of proper calking is increased, as lead does not cling so well +to the tar as to plain iron. + +At present, the kerosene test, so far as the writer is concerned, is a +misnomer, because raw linseed oil is used exclusively as giving more +satisfactory results, and being less troublesome to apply. + +I have here a length of the ordinary "heavy 4" commercial soil pipe, +plain, and selected at random. Yesterday noon I had it oiled at my office, +in order to be ready for to-night, and you see, by the chalk marks I have +made, just where the leaks were and their area. I may say here that a +sound pipe of this caliber and standard weight is the exception rather +than the rule, and it was selected for this experiment merely to try and +show the reaction a little better than the heavier pipe might. + +Experiments of this nature I have carried along for the past two years, +and I am glad to say that, since I began, the quality of the soil pipe +furnished by the dealers for my work seems appreciably better than at +first. Whether the poorer pipe is still made and sold to other customers I +have no means of knowing; probably it is, however. + +A large quantity of the pipe is now being tested at my suggestion by the +Superintendent of Construction of the Johns Hopkins Hospital, at +Baltimore. I have not yet heard the results from him, but doubtless they +will be interesting. A brief summary of the results may be of some +interest. + +The different makers of soil pipe generally used by plumbers hereabouts +are: + +Mott & Company, Abendroth, Blakslee, Dighton, Phillips & Weeden, and +Bartlett, Hayward & Co. + +On 4" extra heavy pipe my results have been as follows: + +Percentage passed as good, single hub. 60 per ct. to 70 per ct. +Percentage passed as good, double. 20 per ct. to 80 per ct. +Percentage passed special castings, + including Y's and T's. 60 per ct. + +5" pipe extra heavy: + +Percentage passed as good, single hub. 25 per ct. to 35 per ct. +Percentage passed as good, double. No record. +Percentage special castings, +including Y's and T's. 60 per ct. + +It has been stated to me by dealers that the tar coating does away with +the necessity of any such test as the oil; while I am not prepared to +acknowledge or deny the statement, it is well known that much poor pipe is +tar-coated and sold in the market as good, and when coated it is almost +impossible to detect any but _very_ defective work. + +The price customers are obliged to pay for soil pipe, either "heavy" or +"extra heavy," is very high indeed, even taking off the discounts, and +amounts (as I figure it) to $70 per long ton for 4" pipe. The present rate +for the best water pipe of the same caliber is about $38 (now $29) per +long ton, and the additional charge for soil pipe should guarantee the +very best iron in the market, though it appears to be rarely furnished. + +It is asserted that all soil pipe is tested to a 50-pound water pressure. +I beg leave to question the absolute truth of this, unless it be +acknowledged that pipe is sold indiscriminately, whether it bears the test +or not, for more than once I have found a single length of soil pipe (5 +feet) that could not bear the pressure of a column of water of its own +height without leaking. + +Having obtained a satisfactory lot of soil pipe and fittings, the next +trouble comes with the lead calking. Unfortunately, it is frequently found +that very shallow joints are made instead of deep ones, and hard lead used +instead of soft. My rule is, soft lead, two runnings and two calkings. By +soft lead I mean pig lead, and by hard lead I mean old pipe and scrap lead +that may have been melted a dozen times. Incidentally it may be remarked +that it is quite difficult to calk a tight joint on the heavy pipe; the +process will crack the hub. + +The fixtures used in a house are of minor importance--there are dozens of +good patterns of every class. If they are carefully put in, and provided +with suitable traps placed just as close to the fixture as possible, the +result will usually be satisfactory. + +Very few instances occur where traps are placed as close to the fixtures +they serve as they might be, and yet a very short length of untrapped +pipe, when fouled, will sometimes smell dreadfully. A set bowl with trap +two feet away may become in time a great nuisance if not properly used. A +case in point where the fixture was used both as a bowl and a urinal was +in a few months exceedingly offensive--a fact largely (though not wholly) +due to its double service. + +I have never met two sanitarians who agreed upon the same water-closets, +bowls, faucets, traps, etc. + +Of course, the soil pipe will be carried, of full size, through the roof, +and sufficiently high to clear all windows. + +Avoid multiplicity of fixtures or pipes; cut off all fixtures not used at +least twice a week, lest their traps dry out; have all plumbing as simple +as possible, and try and get it all located so that outside air can be got +directly into all closets and bath-rooms. As far as possible, set your +fixtures in glass rather than tiles or wood. Carry the lower end of the +main drain at least five feet beyond the cellar walls of the building, of +cast iron. + +Let us now look at the outside work. The main drain (carrying everything +except the kitchen and pantry sinks) goes through a ventilated running +trap. An indirect fresh air inlet is provided on the house side of the +trap (example), to prevent annoyance from puffing or pumping, or, better +still, a pipe corresponding to the soil pipe is carried up on the outside +of the house. + +The running trap ventilator should be of the same diameter as the main +drain (4 inch), and serve as a main drain vent also. Carry this pipe on +the outside of the house as high as the top of the chimney. + +A grease-trap should be provided for the kitchen and pantry sinks. +Formerly my custom was to put in brick receptacles; it is now to put in +Portland cement traps (Henderson pattern), though perhaps I may succeed in +devising a cast-iron one that will answer better. The brick ones were +occasionally heaved by the frost, and cracked; the Portland cement ones +answer better, and when thoroughly painted with red lead do not soak an +appreciable quantity of sewage to be offensive, but are too high priced +($28 each). I have made one or two patterns for cast-iron ones, but none +as yet that I feel satisfied with. + +Beyond the running trap an Akron pipe should convey the sewage to a tank +or cesspool. + +Our supposable case is the second most difficult to take care of. The +worst would be ledge. We have to contend with, however, hard, wet, +impervious clay. + +The best way undoubtedly is to underdrain the land, and then to distribute +the sewage on the principle of intermittent downward filtration. This is +rather expensive, and a customer is rarely willing to pay the bills for +the same. I should always advise it as the best; but where not allowed to +do so, I have had fair success with shallow French drains connecting with +the tank or cesspool. + +Siphon tanks, such as are advised by many sanitarians, that were used +first in this country, I believe, by Mr. Waring, I have not been very +successful with. Obstructions get into the siphon and stop it up, or it +gets choked with grease. I prefer a tight tank, provided with a tell-tale, +and that is to be opened either by a valve operated by hand, or that is +arranged with a standing overflow like a bath tub, and that can be raised +and secured by a hook. + + * * * * * + + + + +SANITARY COOKING.[5] + +[Footnote 5: Read before the Indiana State Sanitary Society, Seymour, +March 13, 1884.--_The Sanitarian._] + +By VIRGINIA L. OPPENHEIMER, M.D., Seymour, Ind. + + + "We may live without poetry, music, and art, + We may live without conscience, and live without heart, + We may live without friends, + We may live without books, + But civilized man cannot live without cooks. + + "We may live without books-- + What is knowledge but grieving? + We may live without hope-- + What is hope but deceiving? + We may live without love--what is passion but pining? + But where is the man that can live without dining?" + +Thus saith the poet, and forthwith turns the world over into the hands of +the cook. And into what better hands could you fall? To you, my fat, +jolly, four-meals-a-day friend, Mr. Gourmand, but more especially to +_you_, my somber, lean, dyspeptic, two-meals-a-day friend, Mr. Grumbler, +the cook is indeed a valuable friend. The cook wields a scepter that is +only second in power to that of love; and even love has become soured +through the evil instrumentality of the good-looking or bad-cooking cook. +This is no jest, it is a very sad fact. + +Now, the question arises, how can the cook preserve the health of her +patrons, maintain happiness in the family, and yet not throw the gourmands +into bankruptcy? Very simple, I assure you. + +1. You must have _the_ cook. I mean by this, that not every one can occupy +that important office. The greatest consideration in the qualities of a +cook is, does she like the work? No one can fulfill the duties of any +noteworthy office unless he labors at them with vim and willingness. + +2. You must have good articles of food originally. + +3. As our honest Iago said, "You must have change." + +When one arrives at adult age, he should have learned by experience what +articles of food _do_, and what articles of food do _not_, agree with him, +and to shun the latter, no matter how daintily served or how tempting the +circumstances. The man who knows that _pates de foie gras_, or the livers +of abnormally fattened geese, disagree with him, and still eats them, is +not to be pitied when all the horrors of dyspepsia overtake him. + +The cooking of any article of food has evidently much, very much, to do +with its digestibility. It is not the purpose of this paper to teach +cooking, but merely to give some general hints as to the best as well as +the simplest methods of preparing staple articles of food. The same +articles of food can and should be prepared differently on each day of the +week. Changes of diet are too likely to be underestimated. By constant +change the digestive organs in the average person are prevented from +having that repulsion of food which, to a greater or less extent, is +likely to result from a sameness of diet continued for a long time. + +We often hear from our scientific men that this or that article of food is +excellent for muscle, another for brain, another for bone, etc., etc. Now, +stubborn facts are like stone walls, against which theories often butt out +their beauty and their power. It is well known to almost every one +nowadays that _well-cooked_ food, whether it be potatoes, meat and bread, +fish, or anything else worthy the name of food, will well maintain, +indefinitely, either the philosopher or the hodcarrier. + +Many of you know, and all of you ought to know, that the principal +ingredients of nearly all our foods are starch and albumen. Starch is the +principal nutritive ingredient of vegetables and breadstuffs. Albumen is +the principal ingredient of meats, eggs, milk, and other animal +derivatives. + +Starch never enters the system as starch, but must first be converted into +sugar either in the body or out of it. The process of this transformation +of starch into sugar is beautifully exemplified in certain plants, such as +the beet, the so-called sugar cane, and other growths. The young plant is, +to a great extent, composed of starch; as the plant grows older, a +substance is produced which is called _diastase_. Through the influence of +this _diastase_ the starch is converted into a peculiar non-crystallizable +substance called _dextrine_, and as the plant matures, this dextrine is +transformed into crystallizable sugar. + +"Dextrine is a substance that can be produced from starch by the action of +dilute acids, alkalies, and malt extract, and by roasting it at a +temperature between 284° and 330° F., till it is of a light brown color, +and has the odor of overbaked bread." + +A simple form of dextrine may be found in the brown crust of bread--that +sweetish substance that gives the crust its agreeable flavor. Pure +dextrine is an insipid, odorless, yellowish-white, translucent substance, +which dissolves in water almost as readily as sugar. As stated above, it +is easily converted into _dextrose_, or _glucose_, as it is usually named. + +This _glucose_ is often sold under the name of sugar, and is the same +against which so many of the newspapers waged such a war a year or two +ago. These critics were evidently, for the most part, persons who knew +little about the subject. Glucose, if free from sulphuric acid or other +chemicals, is as harmless as any other form of sugar. Most of our candies +contain more or less of it, and are in every way as satisfactory as when +manufactured wholly from other sugars. + +It is, therefore, self-evident that, as sugar is a necessary article of +food, the process which aids the transformation of our starchy foods must +necessarily aid digestion. Do not understand me to say by this that, if +all our starchy foods were converted into sugar, their digestion would +thereby be completed. As I stated a moment ago, this sweet food, if taken +into the stomach day after day, would soon cause that particular organ to +rebel against this sameness of diet. In order the more clearly to +illustrate this point, I will briefly show you how some of the every-day +articles of food can be each day differently prepared, and thus be +rendered more palatable, and, as a consequence, more digestible; for it is +a demonstrated fact that savory foods are far more easily digested than +the same foods unsavored. + +The art of serving and arranging dishes for the table is an accomplishment +in itself. It is very reasonable that all things that go to make up beauty +and harmony at the dinner table should add their full quota to the +appetite, and, I was about to say, "to the digestion;" but will qualify +the statement by saying, to the digestion if the appetite be not porcine. + +Our commonest article of food is the _potato_. Let us see how +potatoes--which contain only twenty per cent. of starch, as against +eighty-eight per cent. in rice, and sixty-six per cent. in wheat +flour--can be prepared as just mentioned. We will look for a moment at the +manner in which they are usually served by the average cook: + +1, boiled with their jackets on; 2, roasted in the embers; 3, roasted with +meat; 4, fried; 5, mashed; 6, salad. + +1. Potatoes boiled in their jackets are excellent if properly prepared. +But there's the rub. The trouble is, they are too often allowed to boil +slowly and too long, and thus become water-soaked, soggy, and solid, and +proportionately indigestible. They should be put over a brisk fire, and +kept at a brisk boil till done; then drain off the water, sprinkle a +little salt over them, and return to the fire a moment to dry thoroughly, +when you will find them bursting with their white, mealy contents. + +2. Roasted potatoes are general favorites, and very digestible. A more +agreeable flavor is imparted to them if roasted in hot embers (wood fire), +care being used to keep them covered with the hot embers. + +3. Fried potatoes, as they are very generally served, are almost as +digestible as rocks, but not so tempting in all their grease-dripping +beauty as the latter. Many of you have doubtless seen the potatoes neatly +sliced and dumped into a frying pan full of hot lard, where they were +permitted to sink or float, and soak and sob for about a half hour or +more. When served, they presented the picturesque spectacle of miniature +potato islands floating at liberty in a sea of yellow grease. Now, if any +of you can relish and digest such a mess as that, I would advise you to +leave this clime, and eat tallow candles with the Esquimaux. + +If you are fond of fried potatoes, cook them in this way: + +Take what boiled potatoes are left from breakfast or dinner; when cold, +remove the jackets, and cut into thin slices, season with salt, pepper, +and a little Cayenne; have ready a hot frying pan, with enough meat +drippings or sweet lard to cover the bottom; put in the potatoes and fry a +rich brown, stirring constantly with a knife to prevent burning. Serve +very hot. + +4. Mashed potatoes will be discussed further on. + +5. Potato salads are appetizing and piquant, because they are usually made +up with strong condiments, onions, etc. They are, therefore, not very +digestible in themselves. Nevertheless, they are so palatable that we +cannot easily dispense with them; but, after eating them, if you expect to +have inward peace, either split wood, walk eight and a half miles, or take +some other light exercise. + +More palatable, and proportionately digestible, are the following methods +of cooking this useful vegetable: + +1, Saratoga potatoes; 2, a la maitre d'hotel; 3, potato croquettes; 4, +potatoes and cream; 5, a la Lyonnaise. + +1. For _Saratogas_, pare and slice your potatoes as thin as possible, +dropping them into cold water in which is dissolved a tiny piece of alum +to make them crisp. Let them remain in the water for an hour or longer. +Drain, and wipe perfectly dry with a tea towel. Have ready a quantity of +boiling lard. Drop them in, and fry a delicate brown. Drain all grease +from them, sprinkle with salt, and serve. Here, in the crisp slices, you +will have the much desired dextrine. Or, in other words, your potato is +already half digested. Eat three or four potatoes prepared thus, and you +feel no inconvenience; but how would you feel did you devour three soggy, +water-soaked _boiled_ potatoes? + +2. For _a la maitre d'hotel_, pare the potatoes, cut into pieces half an +inch wide, and the length of the potato; drop into cold water until wanted +(an hour or so); then drain, and fry in boiling lard. Just as they begin +to brown take them out with a skimmer; let them slightly cool; then put +back, and fry a rich brown. This makes them puff up, and very attractive. + +3. For _croquettes_, take finely mashed potatoes, and mix with salt, +pepper, and butter, and sweet milk or cream enough to moisten thoroughly. +Mix with this one well-beaten egg, and form into small balls, taking care +to have them smooth. Have ready one plate with a beaten egg upon it, and +another with cracker crumbs. Dip each ball into the egg, and then into the +crumbs, and brown nicely. Lay the croquettes on brown paper first, to get +rid of any superfluous grease, then serve on a napkin. + +4. _Potatoes and cream_ are prepared by mincing cold boiled potatoes fine, +putting them in a spider with a little melted butter in it, and letting +them fry slightly, keeping them well covered. Add a very small piece of +fresh butter, season with pepper and salt, and pour over them cream or +rich milk. Let them boil up once, and serve. This is a very nice dish, and +may be safely taken into delicate stomachs. + +5. _A la Lyonnaise_ is prepared as follows: Take five cold potatoes, one +onion, butter, salt, and pepper. Slice the onion finely, and fry it in +butter until it begins to take color; add the sliced potatoes, salt and +pepper to taste, and keep shaking the saucepan until they are somewhat +browned. Serve hot. + +A few random remarks about the preparation of albuminous foods. If the +albumen in food is hardened by prolonged cooking, it is rendered _less_ +instead of more digestible. Therefore, the so-called _well-cooked_ meats +are really _badly-cooked_ meats. Meats should be only half done, or rare. +To do this properly, it is necessary to cook with a quick fire. Steaks +should be broiled, not fried. I am in accord with a well-known orator, who +said, recently, that "the person who fries a steak should be arrested for +cruelty to humanity." Some few meats should always be well cooked before +eating.[6] + +[Footnote 6: These are the exceptions. Pork, on account of the prevalence +of disease in hogs, should be well done.] + +The same law holds good with eggs as with meats. A hard-boiled egg is only +fit for the stomach of an ostrich; it was never intended by nature to +adorn the human stomach. There are very many ways of preparing eggs--by +frying, baking, poaching, shirring, etc. I will only describe briefly a +few simple methods of making omelets. + +In making this elegant dish, never use more than three eggs to an +_omelet_. Plain omelet: Separate the whites and yolks; add a teaspoonful +of water to the whites, and beat to a stiff froth; add to the yolks a +teaspoonful of water, and beat until light; then season with salt, and +about two tablespoonfuls of cream or rich milk. Have your spider very hot; +turn your whites and yolks together, and stir lightly to mix them; place a +bit of butter in the spider, and immediately pour in your eggs. When set +(which takes from ten to twenty seconds, and be careful that it does not +brown too much), fold together in a half moon, remove it, sprinkle with +powdered sugar, and serve on a hot plate. It should be eaten immediately. + +Fruit omelets are made by placing preserved fruits or jellies between the +folds. Baked omelets are prepared as above, with the addition of placing +in the oven and allowing to brown slightly. + +French omelet is prepared in this way: Take a half cup of boiling milk +with a half teaspoonful of butter melted in it; pour this over one-half +cup of bread crumbs (light bread); add salt, pepper, and the yolks of +three eggs beaten very light; mix thoroughly; and lastly, add the whites +whipped to a stiff froth. Stir lightly, and fry in butter. When nearly +done, fold together in a half moon, and serve immediately. + +And thus we might continue _ad infinitum_, but, as was stated before, it +is not my object to instruct you in special cooking, but to illustrate in +this manner how much easier it is, to both the cook and your stomachs, to +prepare healthful dishes than to do the reverse. + + * * * * * + + + + +TIME REQUIRED TO DIGEST DIFFERENT FOODS. + + +_The Monitor de la Salud_ contains in a recent number the results of some +experiments lately made by E. Jessen on the time required for the +digestion of certain kinds of food. The stomach of the person on whom the +experiments were made was emptied by means of a pump; 100 grammes, equal +to 1,544 grains, or about 2-2/3 ounces, of meat, finely chopped and mixed +with three times the quantity of water, were introduced. The experiment +was considered ended when the matter, on removal by the pump, was found to +contain no muscular fibre. + +It will be remembered that the gramme weighs nearly 15-1/2 grains, and the +cubic centigramme is equal to 1 gramme. The 2-2/3 ounces of meat were +therefore mixed with nearly eight ounces of water, before being introduced +into the stomach. + +The results were as follows: + + Beef, raw, and finely chopped. 2 hours. + " half cooked. 2½ " + " well cooked. 3 " + " slightly roasted. 3 " + " well roasted. 4 " + Mutton, raw. 2 " + Veal. 2½ " + Pork. 3 " + +The digestibility of milk was examined in the same way. The quantity used +was regulated so that the nitrogen should be the same as in the 100 +grammes of beef. + + 602 cubic centimeters, nearly sixteen ounces, + of cow's milk, not boiled, required. 3½ hours + 602 cubic centimeters, boiled. 4 " + 602 " " sour. 3½ " + 675 " " skimmed. 3½ " + 656 " " goat's milk, not boiled. 3½ " + + * * * * * + + + + +THE ORGANIZATION AND PLAN OF THE UNITED STATES GEOLOGICAL SURVEY.[7] + +[Footnote 7: Communicated to the National Academy of Sciences at the +October meeting in 1884.] + +By J.W. POWELL. + + +A Scientific institution or bureau operating under government authority +can be controlled by statute and by superior administrative authority but +to a limited extent. These operations are practically carried on by +specialists, and they can be controlled only in their financial operations +and in the general purposes for which investigations are made. Their +methods of investigation are their own--originate with themselves, and are +carried out by themselves. But in relation to the scientific operations of +such a government institution, there is an unofficial authority which, +though not immediately felt, ultimately steps in to approve or condemn, +viz., the body of scientific men of the country; and though their +authority is not exercised antecedently and at every stage of the work, +yet it is so potent that no national scientific institution can grow and +prosper without their approval, but must sooner or later fall and perish +unless sustained by their strong influence. + +As director of the Geological Survey, I deeply realize that I owe +allegiance to the scientific men of the country, and for this reason I +desire to present to the National Academy of Sciences the organization and +plan of operations of the Survey. + + +A TOPOGRAPHIC MAP OF THE UNITED STATUS. + +Sound geologic research is based on geography. Without a good topographic +map geology cannot even be thoroughly studied, and the publication of the +results of geologic investigation is very imperfect without a good map; +but with a good map thorough investigation and simple, intelligible +publication become possible. Impelled by these considerations, the Survey +is making a topographic map of the United States. The geographic basis of +this map is a trigonometric survey by which datum points are established +throughout the country; that is, base-lines are measured and a +triangulation extended therefrom. This trigonometric work is executed on a +scale only sufficiently refined for map-making purposes, and will not be +directly useful for geodetic purposes in determining the figure of the +earth. The hypsometric work is based upon the railroad levels of the +country. Throughout the greater part of the country, there is a system of +railroad lines, constituting a net-work. The levels or profiles of these +roads have been established with reasonable accuracy, and as they cross +each other at a multiplicity of points, a system of checks is afforded, so +that the railroad surface of the country can be determined therefrom with +all the accuracy necessary for the most refined and elaborate topographic +maps. From such a hypsometric basis the reliefs for the whole country are +determined, by running lines of levels, by trigonometric construction, and +in mountainous regions by barometric observation. + +The primary triangulation having been made, the topography is executed by +a variety of methods, adapted to the peculiar conditions found in various +portions of the country. To a large extent the plane-table is used. In the +hands of the topographers of the Geological Survey, the plane-table is not +simply a portable draughting table for the field; it is practically an +instrument of triangulation, and all minor positions of the details of +topography are determined through its use by trigonometric construction. + +The scale on which the map is made is variable. In some portions of the +prairie region, and in the region of the great plains, the topography and +the geology alike are simple, and maps on a comparatively small scale are +sufficient for practical purposes. For these districts it is proposed to +construct the sheets of the map on a scale of 1-250,000, or about four +miles to the inch. In the mountain regions of the West the geology is more +complex, and the topography more intricate; but to a large extent these +regions are uninhabited, and to a more limited extent uninhabitable. It +would therefore not be wise to make a topographic or geologic survey of +the country on an excessively elaborate plan. Over much of this area the +sheets of the map will also be constructed on a scale of 1-250,000, but in +special districts that scale will be increased to 1-125,000, and in the +case of important mining districts charts will be constructed on a much +larger scale. In the eastern portion of the United States two scales are +adopted. In the less densely populated country a scale of 1-125,000 is +used; in the more densely populated regions a scale of 1-62,500 is +adopted, or about one mile to the inch. But throughout the country a few +special districts of great importance, because of complex geologic +structure, dense population, or other condition, will require charts on +still larger scales. The area of the United States, exclusive of Alaska, +is about three million square miles, and a map of the United States, +constructed on the plan set forth above, will require not less than 2,600 +sheets. It may ultimately prove to require more than that, from the fact +that the areas to be surveyed on the larger scale have not been fully +determined. Besides the number of sheets in the general map of the United +States, there will be several hundred special maps on large scales, as +above described. + +Such is a brief outline of the plan so far as it has been developed at the +present time. In this connection it should be stated that the map of the +United States can be completed, with the present organization of the +Geological Survey, in about 24 years; but it is greatly to be desired that +the time for its completion may be materially diminished by increasing the +topographic force of the Geological Survey. We ought to have a good +topographic map of the United States by the year 1900. About one-fifth of +the whole area of the United States, exclusive of Alaska, has been +completed on the above plan. This includes all geographic work done in the +United States under the auspices of the General Government and under the +auspices of State Governments. The map herewith shows those areas that +have been surveyed by various organizations on such a scale and in such a +manner that the work has been accepted as sufficient for the purposes of +the Survey. + +Much other work has been done, but not with sufficient refinement and +accuracy to be of present value, though such work subserved its purpose in +its time. An examination of the map will show that the triangulation of +the various organizations is already largely in advance of the topography. +The map of the United States will be a great atlas divided into sheets as +above indicated. In all of those areas where the survey is on a scale of +1-250,000, a page of the atlas will present an area of one degree in +longitude and one degree in latitude. Where the scale is 1-125,000, a page +of the atlas-sheet will represent one-fourth of a degree. Where the scale +is 1-62,500, the atlas-sheet will represent one-sixteenth of a degree. The +degree sheet will be designated by two numbers--one representing latitude, +the other longitude. Where the sheets represent fractional degrees, they +will be labeled with the same numbers, with the addition of the +description of the proper fractional part. + +The organization, as at present established, executing this work, is as +follows: First, an astronomic and computing division, the officers of +which are engaged in determining the geographic coordinates of certain +primary points. Second, a triangulation corps engaged in extending a +system of triangulation over various portions of the country from measured +base-lines. Third, a topographic corps, organized into twenty-seven +parties, scattered over various portions of the United States. Such, in +brief outline, is the plan for the map of the United States, and the +organization by which it is to be made. Mr. Henry Gannett is the Chief +Geographer. + + +PALEONTOLOGY. + +Before giving the outline of the plan for the general geologic survey, it +will be better to explain the accessory plans and organizations. There are +in the Survey, as at present organized, the following paleontologic +laboratories: + +1. A laboratory of vertebrate paleontology for formations other than the +Quaternary. In connection with this laboratory there is a corps of +paleontologists. Professor O.C. Marsh is in charge. + +2. There is a laboratory of invertebrate paleontology of Quaternary age, +with a corps of paleontologists, Mr. Wm. H. Dall being in charge. + +3. There is a laboratory of invertebrate paleontology of Cenozoic and +Mesozoic age, with a corps of paleontologists. Dr. C.A. White is in +charge. + +4. There is a laboratory of invertebrate paleontology of Paleozoic age, +with a corps of paleontologists. Mr. C.D. Walcott is in charge. + +5. There is a laboratory of fossil botany, with a corps of paleobotanists, +Mr. Lester F. Ward being in charge. + +The paleontologists and paleobotanists connected with the laboratories +above described, study and discuss in reports the fossils collected by the +general geologists in the field. They also supplement the work of the +field geologists by making special collections in important districts and +at critical horizons; but the paleontologists are not held responsible for +areal and structural geology on the one hand, and the geologists are not +held responsible for paleontology on the other hand. In addition to the +large number of paleontologists on the regular work of the Geological +Survey, as above described, several paleontologists are engaged from time +to time to make special studies. + + +CHEMISTRY. + +There is a chemic laboratory attached to the Survey, with a large corps of +chemists engaged in a great variety of researches relating to the +constitution of waters, minerals, ores, and rocks. A part of the work of +this corps is to study the methods of metamorphism and the paragenesis of +minerals, and in this connection the chemists do work in the field; but to +a large extent they are occupied with the study of the materials collected +by the field geologists. Professor F.W. Clarke is in charge of this +department. + + +PHYSICAL RESEARCHES. + +There is a physical laboratory in the Survey, with a small corps of men +engaged in certain physical researches of prime importance to geologic +philosophy. These researches are experimental, and relate to the effect of +temperatures, pressures, etc., on rocks. This laboratory is under the +charge of the chief chemist. + + +LITHOLOGY. + +There is a lithologic laboratory in the Survey, with a large corps of +lithologists engaged in the microscopic study of rocks. These lithologists +are field geologists, who examine the collections made by themselves. + + +STATISTICS. + +There is in the Survey a division of mining statistics, with a large corps +of men engaged in statistic work, the results of which are published in an +annual report entitled "Mineral Resources." Mr. Albert Williams, Jr., is +the Chief Statistician of the Survey. + + +ILLUSTRATIONS. + +There is in the Survey a division organized for the purpose of preparing +illustrations for paleontologic and geologic reports. Mr. W.H. Holmes is +in charge of this division. Illustrations will not hereafter be used for +embellishment, but will be strictly confined to the illustration of the +text and the presentation of such facts as can be best exhibited by +figures and diagrams. All illustrations will, as far as possible, be +produced by relief methods, such as wood-engraving, photo-engraving, etc. +As large numbers of the reports of the Survey are published, this plan is +demanded for economic reasons; but there is another consideration believed +to be of still greater importance; illustrations made on stone cannot be +used after the first edition, as they deteriorate somewhat by time, and it +is customary to use the same lithographic stone for various purposes from +time to time. The illustrations made for the reports of the Survey, if on +relief-plates that can be cheaply electrotyped, can be used again when +needed. This is especially desirable in paleontology, where previously +published figures can be introduced for comparative purposes. There are +two methods of studying the extinct life of the globe. Fossils are indices +of geological formations, and must be grouped by formations to subserve +the purpose of geologists. Fossils also have their biologic relations, and +should be studied and arranged in biologic groups. Under the plan adopted +by the Survey, the illustrations can be used over and over again for such +purposes when needed, as reproduction can be made at the small cost of +electrotyping. These same illustrations can be used by the public at large +in scientific periodicals, text-books, etc. All the illustrations made by +the Geological Survey are held for the public to be used in this manner. + + +LIBRARY. + +The library of the Survey now contains more than 25,000 volumes, and is +rapidly growing by means of exchanges. It is found necessary to purchase +but few books. The librarian, Mr. C.C. Darwin, has a corps of assistants +engaged in bibliographic work. It is proposed to prepare a catalogue of +American and foreign publications upon American geology, which is to be a +general authors' catalogue. In addition to this, it is proposed to publish +bibliographies proper of special subjects constituting integral parts of +the science of geology. + + +PUBLICATIONS. + +The publications of the Survey are in three series: Annual Reports, +Bulletins, and Monographs. The Annual Report constitutes a part of the +Report of the Secretary of the Interior for each year, but is a distinct +volume. This contains a brief summary of the purposes, plans, and +operations of the Survey, prepared by the Director, and short +administrative reports from the chiefs of divisions, the whole followed by +scientific papers. These papers are selected as being those of most +general interest, the object being to make the Annual Report a somewhat +popular account of the doings of the Survey, that it may be widely read by +the intelligent people of the country. Of this 5,650 copies are published +as a part of the Secretary's report, and are distributed by the Secretary +of the Interior, Senators, and Members of the House of Representatives; +and an extra edition is annually ordered of 15,000 copies, distributed by +the Survey and members of the Senate and House of Representatives. Four +annual reports have been published; the fifth is now in the hands of the +printer. + +The Bulletins of the Survey are short papers, and through them somewhat +speedy publication is attained. Each bulletin is devoted to some specific +topic, in order that the material ultimately published in the bulletins +can be classified in any manner desired by scientific men. Nine bulletins +have been published, and seven are in press. The bulletins already +published vary in size from 5 to 325 pages each; they are sold at the cost +of press-work and paper, and vary in price from five to twenty cents each; +4,900 copies of each bulletin are published; 1,900 are distributed by +Congress, 3,000 are held for sale and exchange by the Geological Survey. + +The Monographs of the Survey are quarto volumes. By this method of +publication the more important and elaborate papers are given to the +public. Six monographs, with two atlases, have been issued; five +monographs, with two atlases, are in press; 1,900 copies of each monograph +are distributed by Congress; 3,000 are held for sale and exchange by the +Survey at the cost of press-work, paper, and binding. They vary in price +from $1.05 to $11. + +The chiefs of divisions supervise the publications that originate in their +several corps. The general editorial supervision is exercised by the Chief +Clerk of the Survey, Mr. James C. Pilling. + + +GENERAL GEOLOGY. + +In organizing the general geologic work, it became necessary, first, to +consider what had already been done in various portions of the United +States; and for this purpose the compilation of a general geologic map of +the United States was begun, together with a Thesaurus of American +formations. In addition to this the bibliographic work previously +described was initiated, so that the literature relating to American +geology should be readily accessible to the workers in the Survey. At this +point it became necessary to consider the best methods of apportioning the +work; that is, the best methods of dividing the geologic work into parts +to be assigned to the different corps of observers. A strictly geographic +apportionment was not deemed wise, from the fact that an unscientific +division of labor would result, and the same classes of problems would to +a large extent be relegated to the several corps operating in field and in +the laboratory. It was thought best to divide the work, as far as +possible, by subject-matter rather than by territorial areas; yet to some +extent the two methods of division will coincide. There are in the Survey +at present: + +First, a division of glacial geology, and Prof. T.C. Chamberlin, formerly +State Geologist of Wisconsin is at its head, with a strong corps of +assistants. There is an important field for which definite provision has +not yet been made, namely, the study of the loess that constitutes the +bluff formations of the Mississippi River and its tributaries. But as this +loess proves to be intimately associated with the glacial formations of +the same region, it is probable that it will eventually be relegated to +the glacial division. Perhaps the division may eventually grow to such an +extent that its field of operations will include the whole Quaternary +geology. + +Second, a division of volcanic geology is organized, and Capt. Clarence E. +Dutton, of the Ordnance Corps of the Army, is placed in charge, also with +a strong corps of assistants. + +Third and fourth, two divisions have been organized to prosecute work on +the archæan rocks, embracing within their field not only all rocks of +archæan age, but all metamorphic crystalline schists, of whatever age they +may be found. The first division has for its chief Prof. Raphael Pumpelly, +assisted by a corps of geologists, and the field of his work is the +crystalline schists of the Appalachian region, or eastern portion of the +United States, extending from northern New England to Georgia. He will +also include in his studies certain paleozoic formations which are +immediately connected with the crystalline schists and involved in their +orographic structure. + +The second division for the study of this class of rocks is in charge of +Prof. Roland D. Irving, with a corps of geologists, and his field of +operation is in the Lake Superior region. It is not proposed at present to +undertake the study of the crystalline schists of the Rocky Mountain +region. + +Fifth, another division has been organized for the study of the areal, +structural, and historical geology of the Appalachian region, extending +from the Atlantic, westward, to the zone which separates the mountain +region from the great valley of the Mississippi. Mr. G.K. Gilbert has +charge of this work, and has a large corps of assistants. + +Sixth, it seemed desirable, partly for scientific reasons and partly for +administrative reasons, that a thorough topographic and geologic survey +should be made of the Yellowstone Park, and Mr. Arnold Hague is in charge +of the work, with a corps of assistants. When it is completed, his field +will be expanded so as to include a large part of the Rocky Mountain +region, but the extent of the field is not yet determined. + +It will thus be seen that the general geologic work relating to those +areas where the terranes are composed of fossiliferous formations is very +imperfectly and incompletely organized. The reason for this is twofold: +First, the work cannot be performed very successfully until the maps are +made; second, the Geological Survey is necessarily diverting much of its +force to the construction of maps, and cannot with present appropriations +expand the geologic corps so as to extend systematic work in the field +over the entire country. + + +ECONOMIC GEOLOGY. + +Under the organic law of the Geological Survey, investigations in economic +geology are restricted to those States and Territories in which there are +public lands; the extension of the work into the eastern portion of the +United States included only that part relating to general geology. Two +mining divisions are organized. One, in charge of Mr. George F. Becker, +with headquarters at San Francisco, California, is at the present time +engaged in the study of the quicksilver districts of California. The +other, under charge of Mr. S.F. Emmons, with headquarters at Denver, +Colorado, is engaged in studying various mining districts in that State, +including silver, gold, iron, and coal areas. Each division has a corps of +assistants. The lignite coals of the upper Missouri, also, are under +investigation by Mr. Bailey Willis, with a corps of assistants. + + +EMPLOYES. + +The employes on the Geological Survey at the close of September, 1884, +were as follows: + +Appointed by the President, by and with the advice and consent of the +Senate (Director), 1. + +Appointed by the Secretary of the Interior, on the recommendation of the +Director of the Survey, 134. + +Employed by the chiefs of parties in the field, 148. + + +APPOINTMENTS. + +Three classes of appointments are made on the Survey. The statute provides +that "the scientific employes of the Geological Survey shall be selected +by the Director, subject to the approval of the Secretary of the Interior, +exclusively for their qualifications as professional experts." The +provisions of this statute apply to all those cases where scientific men +are employed who have established a reputation, and in asking for their +appointment the Director specifically states his reasons, setting forth +the work in which the person is to be employed, together with his +qualifications, especially enumerating and characterizing his published +works. On such recommendations appointments are invariably made. Young men +who have not established a reputation in scientific research are selected +through the agency of the Civil Service Commission on special examination, +the papers for which are prepared in the Geological Survey. About one-half +of the employes, however, are temporary, being engaged for services +lasting for a few days or a few months only, largely in the field, and +coming under two classes: Skilled laborers and common laborers. Such +persons are employed by the Director or by the heads of divisions, and are +discharged from the service when no longer needed. It will be seen that +the Director is responsible for the selection of the employes, directly +for those whom he recommends for appointment, and indirectly for those +selected by the Civil Service Commission, as he permanently retains in the +work. If, then, improper persons are employed, it is wholly the Director's +fault. + +The appropriations made for the Geological Survey for the fiscal year +ending June 30, 1885, aggregate the sum of $504,040. This sum does not +include the amount appropriated for ethnologic researches--$40,000. Nor +are the expenses for engraving and printing paid for from the above +appropriations, but from appropriations made for the work under the +direction of the public printer. It is estimated that the amount needed +for engraving and printing for the same fiscal year will exceed $200,000. + + +THE RELATION OF THE GOVERNMENT SURVEY TO STATE SURVEYS. + +The United States Geological Survey is on friendly relations with the +various State Surveys. Between the Government Survey and the State Survey +of New York, there is direct co-operation. The State Survey of +Pennsylvania has rendered valuable assistance to the Government Survey, +and negotiations have been entered into for closer relations and more +thorough co-operation. The State Surveys of North Carolina, Kentucky, and +Alabama are also co-operating with the Government Survey, and the director +of the Government Survey is doing all within his power to revive State +Surveys. The field for geologic research in the United States is of great +magnitude, and the best results can be accomplished only by the labors of +many scientific men engaged for a long term of years. For this reason it +is believed that surveys should be established in all of the States and +Territories. There is work enough for all, and the establishment of local +surveys would greatly assist the general work prosecuted under the +auspices of the government, and prevent it from falling into perfunctory +channels. Its vigor and health will doubtless be promoted by all thorough +local research. + +It may be of interest to scientific men to know that the Director finds +that in presenting the general results, interests, and needs of the Survey +to Congress, and to Committees of Congress, a thorough appreciation of the +value of scientific research is shown by the statesmen of the country. +Questions relating to immediately economic values are asked, as they +should be; but questions relating to sound administration, wise methods of +investigation, and important scientific results are vigorously urged, and +the principle is recognized that all sound scientific research conduces to +the welfare of the people, not only by increasing knowledge, but +ultimately by affecting all the industries of the people. + + * * * * * + + + + +[THE GARDEN.] + +THE SUNFLOWERS. + + +[Illustration: FLOWER OF HELIANTHUS ARGOPHYLLUS.] + +The genus Helianthus is almost entirely North-American, and for the +distinction and limitation of its species we are indebted to the labor of +Dr. Asa Gray, now universally recognized as the highest authority on North +American plants. In the recently published second part of his "Synoptical +Flora of North America" he has described thirty-nine species, six of which +are annual. The synonyms and cross-naming adopted by previous authors have +led to much confusion, which probably will not now be altogether cleared +up, for Dr. Gray warns us that the characters of some of the species are +variable, especially in cultivation. It may be added that some at least of +the species readily form hybrids. There is always more or less difficulty +with a variable genus in making garden plants fit wild specific types, but +in the following notes I have described no kinds which I have not myself +cultivated, selecting the best forms and giving them the names assigned +severally by Dr. Gray to the species to which our garden plants seem to +come nearest. + +[Illustration: HELIANTHUS ARGOPHYLLUS, SHOWING HABIT OF GROWTH.] + +_Helianthus multiflorus_, or, according to Asa Gray, speaking botanically, +H. decapetalus hort. var. multiflorus, is mentioned first, because it is +the subject of the colored illustration. The name multiflorus is +established by long usage, and perhaps was originally given in contrast to +the few-flowered habit of H. annuus, for the type of the species is more +floriferous than the variety of which Asa Gray says that it is "known only +in cultivation from early times, must have been derived from +decapetalus," a statement which gardeners would hardly have accepted on +less indisputable authority, as they will all think the habit and +appearance of the two plants widely different. The variety multiflorus has +several forms; the commonest form is double, the disk being filled with +ligules much shorter than those of the ray flowers, after the form of many +daisy-like composites. In this double form the day flowers are often +wanting. It is common also on old plants in poor soils to see double and +single flowers from the same root. In the single forms the size of the +flowers varies, the difference being due to cultivation as often as to +kind. I have obtained by far the finest flowers by the following +treatment: In early spring, when the young shoots are about an inch high, +cut some off, each with a portion of young root, and plant them singly in +deep rich soil, and a sheltered but not shaded situation. By August each +will have made a large bush, branching out from one stalk at the base, +with from thirty to forty flowers open at a time, each 5 inches across. +The same plants if well dressed produce good flowers the second season, +but after that the stalks become crowded, and the flowers degenerate. The +same treatment suits most of the perennial sunflowers. The following kinds +are mentioned in the order in which they occur in Asa Gray's book: + +[Illustration: HELIANTHUS MULTIFLORUS, SHOWING HABIT OF GROWTH.] + + +ANNUALS. + +_H. argophyllus_ (white-leaved, not argyrophyllus, silver-leaved, as +written in some catalogues).--An annual with woolly leaves, neater and +less coarse than H. annuus, with which it is said soon to degenerate in +gardens if grown together with it. + +_H. annuus._--The well known sunflower in endless varieties, one of the +most elegant having pale lemon-colored flowers; these, too, liable to pass +into the common type if grown in the same garden. + +[Illustration: HELIANTHUS ORGYALIS, SHOWING HABIT OF GROWTH IN +AUTUMN.] + +_H. debilis var. cucumerifolius._--I have never seen the typical species, +but the variety was introduced a few years ago by Mr. W. Thompson, of +Ipswich, from whose seed I have grown it. It becomes 4 feet or 5 feet +high, with irregularly toothed deltoid leaves and spotted stalks, making a +widely branched bush and bearing well-shaped golden flowers more than 3 +inches across, with black disks. It crosses with any perennial sunflower +that grows near it, simulating their flowers in an annual form. I had a +very fine cross with it and H. annuus, but the flowers of this produced no +good seed. + +[Illustration: JERUSALEM ARTICHOKE (HELIANTHUS TUBEROSUS).] + + +PERENNIALS. + +_H. orgyalis_ (the fathom-high sunflower).--The name is far within the +true measure, which is often 9 feet or 10 feet. A very distinct species, +increasing very slowly at the root and throwing all its growing efforts +upward. The long linear ribbon leaves, often exceeding a foot, spreading +in wavy masses round the tall stem, which has a palm-like tuft of them at +the summit, are a more ornamental feature than the flowers, which are +moderate in size and come late in the axils of the upper leaves. + +[Illustration: HELIANTHUS ANNUUS GLOBULUS FISTULOSUS.] + +_H. angustifolius._--A neat and elegant species, which I first raised from +seed sent by Mr. W. Thompson, of Ipswich. It has a very branching habit +quite from the base like a well-grown bush of the common wallflower. The +flowers are abundant, about 2½ inches across, with a black disk. The +plant, though a true herb, never comes up in my garden with more than one +stalk each year. + +[Illustration: HELIANTHUS RIGIDUS (SYN. HARPALIUM RIGIDUM).] + +_H. rigidus_ is well known as the best of the perennial sunflowers, and +has many synonyms, the commonest Harpalium rigidum. It need not be +described, but one or two things about it may be noted. The shoots, which +come up a yard or more from last year's stalk, may be transplanted as soon +as they appear without injury to the flowering, but if put back to the old +center, the soil, which should be deep and light, ought to be enriched. +The species is variable, and improved forms may be expected, as it +produces seed in England. The number of ray flowers is often very large. I +have one form which has several rows of them, nearly hiding the disk. A +variety is figured in _Botanical Magazine_, tab. 2,668, under the name of +H. atro-rubens. Another comes in the same series, tab. 2,020, as H. +diffusus. Other synonyms are H. missuricus and H. missouriensis. Its +native range extends across North America in longitude, and covers many +degrees of latitude. It likes a dry soil. In wet soil and wet seasons the +flower-stalk is apt to wither in the middle, and the bud falls over and +perishes prematurely. + +[Illustration: COMMON SUNFLOWER (H. ANNUUS) SHOWING HABIT OF GROWTH.] + +_H. Lætiflorus._--Under this name we grow in England a tall, +much-branched, late flowering kind, with smooth and very stout and stiff +stalks, sometimes black, sometimes green. It increases at the base of the +stalks; it makes close growth, and shows little disposition to run at the +root. The flowers are rather small, not more than 9 inches across, but so +durable and so well displayed by the numerous spreading branches as to +make the plant very useful for late decoration. I own that I cannot +identify this plant with the lætiflorus of Asa Gray, which he tells us +resembles tall forms of H. rigidus, with rough stalks, and bears flowers +with numerous rays 1½ inches long. + +[Illustration: FLOWER OF HELIANTHUS ANNUUS.] + +_H. occidentalis._--Recently introduced by Mr. W. Thompson, of Ipswich, +who gave me the plant two years ago. It is a neat species, growing about 2 +feet high, well branched, and producing at the end of July abundance of +flowers about 2 inches across. The lower leaves are small and broad, with +long stalks, ovate in form. + +[Illustration: HELIANTHUS MULTIFLORUS FL-PL.] + +_H. mollis_, so called from the soft white down with which the leaves are +covered, grows about 4 feet high. Leaves large, ovate, and sessile; growth +of the plant upright, with hardly any branches; flowers pale yellow, about +3 inches across, not very ornamental. Cultivated at Kew, whence I had it. + +_H. giganteus_ grows 10 feet high; stem much branched and disposed to +curve. Flowers about 2½ inches across, produced abundantly in August; rays +narrow and pointed, cupped, with the ends turning outward; leaves +lanceolate and sessile; rootstock creeping, forming tuberous thickenings +at the base of the stems, which Asa Gray tells us were "the Indian potato +of the Assiniboine tribe," mentioned by Douglas, who called the plant H. +tuberosus. + +[Illustration: FULL SIZED FLOWER OF HELIANTHUS MULTIFLORUS.] + +_H. maximiliani._--Half the height of the last, which it resembles, but +the stem is stouter, the leaves larger, as are also the flowers, which are +produced later. It is not so floriferous and ornamental as the last. + +_H. lævigatus._--Smooth stalked, very distinct, does not spread at the +roots, which are composed of finer fibers than those of most of the genus; +stalks slender and black, growing closely together, branched near the +summit, 5 feet high; leaves narrowly lanceolate and acute; flowers +plentiful and about 2 inches across; rays few, and disk small. + +We are warned that the following species are "difficult of extrication," +either confluent or mixed by intercrossing. + +_H. doronicoides._--I place this the third in merit among perennial +sunflowers, H. rigidus and H. multiflorus being first and second. It is 6 +feet or 7 feet high, upright in growth, with many stalks. Flowers 3½ +inches across, produced from the end of July to the end of September, +bright golden yellow; leaves large, ovate, tapering from the middle to +both ends; stalk leaves sessile and nearly connate, that is, clasping the +stalk by their opposite base. The plant spreads rapidly by running +rootstocks, and ripens seed in abundance. Figured as H. pubescens in +_Botanical Magazine_, tab. 2,778. + +_H. divaricatus_ resembles the last, but is inferior, being a smaller +plant in all parts, especially in the flowers, which come out a month +later. The cauline leaves are stalked and diverge widely, which habit +gives its name to the plant. A casual observer would hardly notice the +difference between this species and the last, but when grown together the +superiority of doronicoides as a garden plant is at once evident. + +_H. strumosus._--Fully 6 feet high; growth upright; rootstock less +spreading than the last two; leaves on very short stalks, broadest at the +base, ovate tapering by a long narrow point; flower disk narrow, but rays +large and orange-yellow; flowers showy, 3 inches across; they come out +late in August. I had this plant from Kew. The shape of the leaves would +have led me rather to refer it to H. trachelifolius, a closely allied +species. + +_H. decapetalus._--Five feet high; flowers from end of July; makes a dense +forest of weak, slender stalks, much branched at the top; spreads fast; +leaves serrate, oblong-ovate, rather large; flowers abundant, pale yellow, +about 2 inches across; rays nearly always more than ten, in spite of the +name. + +_H. tuberosus._--The well-known Jerusalem artichoke; not a plant grown for +ornament, being too coarse and late in flowering, but several things in +its history may be mentioned, as Dr. Asa Gray has spent labor and study +over it. It is believed to have been cultivated by the natives before the +discovery of America, and the edible tubers are thought to be a +development of cultivation. Forms of it without tuberous roots are found +wild, but whether indigenous to the place or degenerate from cultivation +was for long uncertain. Several species of Helianthus have a tendency to +produce similar fleshy tubers at the top of the roots. Dr. Gray used to +refer the origin of this species to H. doronicoides, but it is now +believed by him to be a distinct species, though one of which it is +difficult to identify with certainty the typical form. + +I omitted to say that the word Helianthus is Greek for sunflower. After +several years' careful observation, I believe the notion that the flowers +keep their face to the sun is quite a delusion. + +Edge Hall. C. WOLLEY DOD. + + * * * * * + + +A QUICK FILTER.--The _Druggists Circular_ recommends chamois skin, free +from thin places; cut it of the desired size; wash it in a weak solution +of sal soda, or any alkali, to remove the grease, and rinse thoroughly in +cold water before using. + +Tinctures, elixirs, sirups, and even mucilages are filtered rapidly. A +pint of the thickest sirup will run through in four or five minutes. By +washing thoroughly after each time of using, it will last a long time. + + * * * * * + + + + +LYE'S FUCHSIAS. + + +The group of fuchsias shown in our engraving represents a collection of +nine specimens raised and exhibited by that well known cultivator, Mr. +James Lye, of Clyffe Hall Gardens, Market Lavington, at an exhibition held +in Bath in September last, and which received the first prize in the +premier class for that number of plants. For many years past Mr. Lye has +exhibited fuchsias at exhibitions held at Bath, Trowbridge, Devizes, +Calne, Chippenham, and elsewhere; on all occasions staging specimens of a +high order of merit; but the plants appearing in our illustration were +universally regarded as the best he had ever placed in an exhibition tent. +So much were the committee of the Bath show pleased with the specimens +that they engaged the services of a photographer to make a picture of them +on the spot; but after being two hours making the attempt, no satisfactory +result occurred. After the plants were taken back to Clyffe Hall, they +were photographed as seen in the illustration. Some idea of their height +and dimensions can be realized by a comparison with the stature of Mr. +Lye, who is standing by his plants, and who is of average height. It +should be mentioned that previous to being photographed they had traveled +by road from Market Lavington to Bath and back, a distance of 52 miles, in +addition to having been exhibited two days. They returned to their home +apparently little the worse for wear, which immunity from harm is no doubt +owing to the admirable system of tying adopted by Mr. Lye. It is sometimes +said that the act of trying in the flowering shoots in this manner gives +the plants a somewhat severely formal appearance, but there is an +abundance of healthy foliage and a wonderful profusion of finely developed +flowers, showing the most careful and painstaking cultivation. It is only +those who are privileged to see these unrivaled plants who can appreciate +them at their proper worth. + +It has been stated already that the varieties figured are all of Mr. Lye's +own raising, which facts attests to the value of his seedlings, many of +which he has produced. Four of these are dark varieties, viz., Bountiful, +Charming, Elegance, and the Hon. Mrs. Hay--the latter one of the oldest, +but one of the freest, and scarcely without an equal for its great freedom +of bloom. The remaining five are light varieties, viz., Lye's Favorite, +Harriet Lye, Star of Wilts, Pink Perfection, and Beauty of the West. + +[Illustration: MR. LYE'S FUSCHIAS.] + +The specimens figured average from two to five years of age. It is really +marvelous what Mr. Lye can do with a fuchsia in two years; and lest it +might be supposed that he has plenty of glass accommodation, and can keep +his plants under glass continuously, it is due to him it should be stated +that he is very deficient in house accommodation, having but two small +houses, in one of which (an old house) he winters his plants and brings +them on until he can place them with safety in the open air in early +summer. His method of treating the specimens as set forth in his own words +may prove helpful to some of our readers: "After the plants have done +flowering, say about the third week in October, I cut them back into the +shape best fitted to form symmetrical specimens, and keep them dry for a +week or ten days, to check the bleeding of sap which follows; after that I +give a little water just to start them into growth, so as to make shoots +about three-quarters of an inch in length, in order to keep the old wood +active and living. I keep them in a cold house, and give but very little +water until the first or second week in February, when I shake the old +soil from the roots, and re-pot them into a fresh compost made up of three +parts good loam, one part well decomposed manure, and one part leaf-mould +and peat, with a good bit of silver or sea sand to keep it open. In order +to make large specimens, they are shifted as soon as the pots are filled +with roots. About the first week in June I place them out of doors on a +border somewhat sheltered, and syringe the plants freely every day during +hot weather to keep the foliage clean and healthy. I top them back till +about seven or eight weeks before I want to show them, according to the +requirements of the variety, as some of them require it to be done more +freely than others. I give them liquid manure, using what I get from the +cows, which with some soot is put into a tub, and allowed to stand a week +or ten days before using, and I give them a good dose once a week as they +show signs of flowering." + +In order to preserve his plants from the effects of hail and very heavy +rains, a rough framework is erected, and over this is stretched some +floral shading, which can be readily removed when required; it also serves +the purpose of shading the plants from the sun in very hot and scorching +weather. + +During his career as an exhibitor of fuchsias Mr. Lye has taken nearly one +hundred first prizes--a measure of success which fully justifies the +bestowal of the title of being the Champion Fuchsia Grower of his +day.--_R.D. in The Gardeners' Chronicle_. + + * * * * * + + +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. 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