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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..6833f05 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,3 @@ +* text=auto +*.txt text +*.md text diff --git a/17755-8.txt b/17755-8.txt new file mode 100644 index 0000000..b9f91bd --- /dev/null +++ b/17755-8.txt @@ -0,0 +1,4961 @@ +The Project Gutenberg EBook of Scientific American Supplement, No. 717, +September 28, 1889, by Various + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Scientific American Supplement, No. 717, September 28, 1889 + +Author: Various + +Release Date: February 12, 2006 [EBook #17755] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN *** + + + + +Produced by Amy Cunningham, Juliet Sutherland and the +Online Distributed Proofreading Team at http://www.pgdp.net + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 717 + + + + +NEW YORK, SEPTEMBER 28, 1889. + +Scientific American Supplement. Vol. XXVIII., No. 717. + +Scientific American established 1845. + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + * * * * * + + + + +TABLE OF CONTENTS. + + +I. CIVIL ENGINEERING.--The Girard Hydraulic Railway.--One of + the great curiosities of the Paris exposition, the almost + frictionless railway, with sectional illustrations of its + structure.--8 illustrations. 11451 + +II. ELECTRICITY.--Early Electric Lighting.--Electric lighting in + Salem in 1859, a very curious piece of early history. 11458 + + Electric Motor for Alternating Currents.--A motor on an + entirely new principle for the application of the alternating + current with results obtained, and the economic outlook of + the invention. 11458 + + Portable Electric Light.--A lamp for military and other use, + in which the prime motor, including the boiler and the lamp + itself, are carried on one carriage.--1 illustration. 11458 + + The Electric Age.--By CHARLES CARLETON COFFIN.--A short + _resume_ of the initial achievements of modern + electricity. 11458 + +III. GEOLOGY.--The Fuels of the Future.--A prognosis of the future + prospect of the world as regards a fuel supply, with a + special reference to the use of natural gas. 11457 + +IV. MISCELLANEOUS.--Preservation of Spiders for the Cabinet.--A + method of setting up spiders for preservation in the cabinet, + with formulę of solutions used and full details of the + manipulation.--1 illustration. 11461 + + The Ship in the New French Ballet of the "Tempest."--A + curious example of modern scenic perfection, giving the + construction and use of an appliance of the modern ballet.--5 + illustrations. 11450 + +V. NAVAL ENGINEERING.--Crank and Screw Shafts of the Mercantile + Marine.--By G. W. MANUEL.--This all-important subject of + modern naval engineering treated in detail, illustrating the + progress of the present day, the superiority of material and + method of using it, with interesting practical examples.--1 + illustration. 11448 + + Experimental Aid in the Design of High Speed Steamships.--By + D. P.--A plea for the experimental determination of the + probable speed of ships, with examples of its application in + practice. 11449 + + Forging a Propeller Shaft.--How large steamer shafts are + forged, with example of the operation as exhibited to the + Shah of Persia at Brown & Co.'s works, Sheffield, England.--1 + illustration. 11447 + + The Naval Forges and Steel Works at St. Chamond.--The forging + of a piece of ordnance from a 90 ton ingot of steel, an + artistic presentation of the subject.--1 illustration. 11447 + +VI. PHOTOGRAPHY.--The Pyro Developer with Metabisulphite of + Potash.--By Dr. J. M. EDER.--A new addition to the pyro + developer, with formulę and results. 11462 + +VII. PHYSICS.--Quartz Fibers.--A lecture by Mr. C. V. BOYS on his + famous experiments of the production of microscopic fibers, + with enlarged illustrations of the same, and a graphic + account of the entire subject.--7 illustrations. 11452 + + The Modern Theory of Light.--By Prof. OLIVER LODGE.--An + abstract of a lecture by the eminent investigator and + expositor of Prof. Hertz's experiments, giving a brief review + of the present aspect of this absorbing question. 11459 + +VIII. PHYSIOLOGY.--Heat in Man.--Experiments recently made by Dr. + Loewy on the heat of the human system.--Described and + commented on by Prof. ZUNTZ. 11461 + +IX. SANITATION.--On Purification of Air by Ozone--with an Account + of a New Method.--By Dr. B. W. RICHARDSON.--A very important + subject treated in full, giving the past attempts in the + utilization of ozone and a method now available. 11460 + +X. TECHNOLOGY.--Alkali Manufactories.--Present aspect of the + Leblanc process and the new process for the recovery of + sulphur from its waste. 11457 + + Dried Wine Grapes.--The preparation of the above wine on a + large scale in California, with full details of the process + adopted. 11461 + + The Production of Ammonia from Coal.--By LUDWIG MOND.--A + valuable review of this important industry, with actual + working results obtained in carrying out a retort process.--2 + illustrations. 11454 + + Nature, Composition, and Treatment of Animal and Vegetable + Fabrics.--The history of fabrics and fibers in the vegetable + and animal world, their sources, applications, and + treatments. 11453 + + Walnut Oil.--By Thomas T. P. BRUCE WARREN.--An excellent oil + for painters' use, with description of a simple method for + preparing it on a small scale. 11462 + + * * * * * + + + + +THE NAVAL FORGES AND STEEL WORKS AT ST. CHAMOND. + + +With the idyls and historic or picturesque subjects that the Universal +Exposition gives us the occasion to publish, we thought we would make +a happy contrast by selecting a subject of a different kind, by +presenting to our readers Mr. Layraud's fine picture, which represents +the gigantic power hammer used at the St. Chamond Forges and Steel +Works in the construction of our naval guns. By the side of the +machinery gallery and the Eiffel tower this gigantic apparatus is well +in its place. + +[Illustration: UNIVERSAL EXPOSITION--BEAUX ARTS--MARINE IRON AND STEEL +WORKS AT SAINT CHAMOND--PRESENTATION OF A PIECE OF ORDNANCE UNDER THE +VERTICAL HAMMER.--PICTURE BY M. JOSEPH LAYRAUD.] + +The following is the technical description that has been given to us +to accompany our engraving: In an immense hall, measuring 260 ft. in +length by 98 ft. in width, a gang of workmen has just taken from the +furnace a 90 ton ingot for a large gun for an armor-clad vessel. The +piece is carried by a steam crane of 140 tons power, and the men +grouped at the maneuvering levers are directing this incandescent mass +under the power hammer which is to shape it. This hammer, whose huge +dimensions allow it to take in the object treated, is one of the +largest in existence. Its striking mass is capable of reaching 100 +tons, and the height of the fall is 16 ft. To the left of the hammer +is seen a workman getting ready to set it in motion. It takes but one +man to maneuver this apparatus, and this is one of the characteristic +features of its construction. + +The beginning of this hammer's operation, as well as the operations of +the forge itself, which contains three other hammers of less power, +dates back to 1879. It is with this great hammer that the largest +cannons of the naval artillery--those of 16 inches--have been made +(almost all of which have been manufactured at St. Chamond), and +those, too, of 14, 13, and 12 inches. This is the hammer, too, that, a +few months ago, was the first to be set at work on the huge 13 in. +guns of new model, whose length is no less than 52 ft. in the rough. + +Let us add a few more figures to this account in order to emphasize +the importance of the installations which Mr. Layraud's picture +recalls, and which our great French industry has not hesitated to +establish, notwithstanding the great outlay that they necessitated. +This huge hammer required foundations extending to a depth of 32 ft., +and the amount of metal used in its construction was 2,640,000 pounds. +The cost of establishing the works with all the apparatus contained +therein was $400,000.--_Le Monde Illustré._ + + * * * * * + + + + +FORGING A PROPELLER SHAFT. + + +During the recent visit of the Shah of Persia to England, he visited, +among other places, the great works of John Brown & Co., at Sheffield, +and witnessed the pressing of a propeller shaft for one of the large +ocean steamships. The operation is admirably illustrated in our +engraving, for which we are indebted to the _Illustrated London News_. + +[Illustration: PROPELLER SHAFT BEING PRESSED AT MESSRS. JOHN BROWN & +CO.'S WORKS, SHEFFIELD.] + + * * * * * + + + + +CRANK AND SCREW SHAFTS OF THE MERCANTILE MARINE.[1] + +By G. W. MANUEL. + + [Footnote 1: A paper read before the Institute of Marine + Engineers, Stratford, 1889.] + + +Being asked to read a paper before your institute, I have chosen this +subject, as I think no part of the marine engine has given so much +trouble and anxiety to the seagoing engineer; and from the list of +shipping casualties in the daily papers, a large proportion seem due +to the shafting, causing loss to the shipowner, and in some instances +danger to the crew. My endeavor is to put some of the causes of these +casualties before you, also some of the remedies that have tended to +reduce their number. Several papers have been read on this subject, +chiefly of a theoretical description, dealing with the calculations +relating to the twisting and bending moments, effects of the angles of +the cranks, and length of stroke--notably that read by Mr. Milton +before the Institute of Naval Architects in 1881. The only _practical_ +part of this paper dealt with the possibility of the shafts getting +out of line; and regarding this contingency Dr. Kirk said that "if +superintendent engineers would only see that the bearings were kept in +line, broken crank and other shafts would not be so much heard of." Of +course this is one of those statements made in discussions of this +kind, for what purpose I fail to see, and as far as my own experience +goes is _misleading_; for having taken charge of steamers new from the +builders' hands, when it is at least expected that these shafts would +_be in line_, the crank shaft bearings heated very considerably, and +_continued_ to do so, rendering the duration of life of the crank +shaft a short one; and though they were never what is termed out of +line, the bearings could _not_ be kept cool without the use of sea +water, and occasionally the engines had to be stopped to cool and +smooth up the bearing surfaces, causing delays, worry, and anxiety, +for which the engineer in charge was in no way responsible. Happily +this state of what I might call _uncertainties_ is being gradually +remedied, thanks being largely due to those engineers who have the +skill to suggest improvements and the patience to carry them out +against much opposition. + +These improvements in many instances pertain to the engine builder's +duties, and are questions which I think have been treated lightly; +notably that of insufficient bearing surface, and one of the principal +causes of hot bearings, whereby the oil intended for lubrication was +squeezed out, and the metal surfaces brought too close in contact; and +when bearings had a pressure of 200 lb. per square inch, it has been +found that not more than 120 lb. per square inch should be exerted to +keep them cool (this varies according to the material of which the +bearing is composed), without having to use sea water and prevent them +being ground down, and thus getting out of line. I have known a +bearing in a new steamer, in spite of many gallons of oil wasted on +it, wear down one-eighth of an inch in a voyage of only 6,000 miles, +from insufficiency of bearing surface. + +Several good rules are in use governing the strength of shafts, which +treat of the diameter of the bearings only and angles of the cranks; +and the engine builder, along with the ship owner, has been chary of +increasing the surfaces by lengthening the bearings; for to do this +means increase of space taken up fore and aft the vessel, besides +additional weight of engine. Engine builders all aim in competing to +put their engines in less space than their rivals, giving same power +and sometimes more. I think, however, this inducement is now more +carefully considered, as it has been found more economical to give +larger bearing surfaces than to have steamers lying in port, refitting +a crank shaft, along with the consequences of heavy bills for salvage +and repairs, also the risk of losing the steamer altogether. +Proportioning the bearings to the weights and strains they have to +carry has also been an improvement. The different bearings of marine +engines were usually made alike in surface, irrespective of the work +each had to do, with a view to economy in construction. + +In modern practice the after bearings have more surface than the +forward, except in cases where heavy slide-valve gear has to be +supported, so that the wear down in the whole length of the shaft is +equal, thus avoiding those alternate bending strains at the top and +bottom of the stroke every revolution. Another improvement that has +been successfully introduced, adding to the duration of life of crank +shafts, is the use of white bearing metal, such as Parson's white +brass, on which the shafts run smoothly with less friction and +tendency to heat, so that, along with well proportioned surfaces, a +number of crank shafts in the Peninsular and Oriental Co.'s service +have not required lining up for eight years, and I hope with care may +last till new boilers are required. Large and powerful steamers can be +driven full speed from London to Australia and back without having any +water on the bearings, using oil of only what is considered a moderate +price, allowing the engineer in charge to attend to the economical +working of both engines and boilers (as well as many other engines of +all kinds now placed on board a large mail and passenger steamer), +instead of getting many a drenching with sea water, and worried by +close attention to one or two hot bearings all the watch. Compare +these results with the following: In the same service in 1864, and +with no blame to the engineer in charge, the crank shaft bearings of a +screw steamer had to be lined up every five days at intermediate +ports, through insufficient bearing surfaces. Sea water had +continually to be used, resulting in frequent renewal of crank shaft. +Steamers can now run 25,000 miles without having to lift a bearing, +except for examination at the end of the voyage. I would note here +that the form of the bearings on which the shafts work has also been +much improved. They are made more of a _solid character_, the metal +being more equally disposed _round_ the shaft, and the use of gun +metal for the main bearings is now fast disappearing. In large engines +the only metals used are cast iron and white brass, an advantage also +in reducing the amount of wear on the recess by corrosion and grinding +where sea water was used often to a considerable extent. + +[Illustration: Fig. 1 + Fig. 2] + +Figs. No. 1 and No. 2 show the design of the old and new main +bearings, and, I think, require but little explanation. Most of you +present will remember your feelings when, after a hot bearing, the +brasses were found to be cracked at top and bottom, and the trouble +you had afterward to keep these brasses in position. When a smoking +hot bearing occurred, say in the heating of a crank pin, it had the +effect of damaging the material of the shaft more or less, according +to its original soundness, generally at the fillets in the angles of +the cranks. For when the outer surface of the iron got hot, cold +water, often of a low temperature, was suddenly poured on, and the hot +iron, previously expanded, was suddenly contracted, setting up strains +which in my opinion made a small tear transversely where the metal was +_solid_; and where what is termed lamination flaws, due to +construction, existed, these were extended in their natural direction, +and by a repetition of this treatment these flaws became of such a +serious character that the shafts had to be condemned, or actually +gave way at sea. The introduction of the triple expansion engine, with +the three cranks, gave better balance to the shaft, and the forces +acting in the path of the crank pin, being better divided, caused more +regular motion on the shaft, and so to the propeller. This is +specially noticeable in screw steamers, and is taken advantage of by +placing the cabins further aft, nearer the propeller, the stern having +but little vibration; the dull and heavy surging sound, due to unequal +motions of the shaft in the two-crank engines, is exchanged for a more +regular sound of less extent, and the power formerly wasted in +vibrating the stern is utilized in propelling the vessel. In spite of +all these improvements I have mentioned, there remains the serious +question of defects in the material, due to variety of quality and the +extreme care that has to be exercised in all the stages during +construction of crank or other shafts built of iron. Many shafts have +given out at sea and been condemned, through no other cause than +_original defects_ in their construction and material. + +The process of welding and forging a crank shaft of large diameter now +is to make it up of so many small _pieces_, the _best shafts_ being +made of what is termed scrap, representing thousands of small pieces +of selected iron, such as cuttings of old iron boiler plates, +cuttings off forgings, old bolts, horseshoes, angle iron, etc., all +welded together, forged into billets, reheated, and rolled into bars. +It is then cut into lengths, piled, and formed into slabs of suitable +size for welding up into the shafts. No doubt this method is +preferable to the old method of "fagoting," so called, as the iron +bars were placed side by side, resembling a bundle of fagots of about +18 or 20 inches square. + +The result was that while the outside bars would be welded, the inside +would be improperly welded, or, the hammer being weak, the blow would +be insufficient to secure the proper weld, and it was no uncommon +thing for a shaft to break and expose the internal bars, showing them +to be quite separate, or only partially united. This danger has been +much lessened in late years by careful selection of the materials, +improved methods of cleaning the scrap, better furnaces, the use of +the most suitable fuels, and more powerful steam hammers. Still, with +all this care, I think I may say there is not a shaft without flaws or +defects, more or less, and when these flaws are situated in line of +the greatest strains, and though you _may not_ have a hot bearing, +they often extend until the shaft becomes unseaworthy. + +[Diagrams shown illustrated the various forms of flaws.] These flaws +were not observable when the shafts were new, although carefully +inspected. They gradually increased under strain, came to the outside, +and were detected. Considerable loss fell upon the owners of these +vessels, who were in no way to blame; nor could they recover any money +from the makers of the shafts, who were alone to blame. I am pleased +to state, and some of the members here present know, that considerable +improvement has been effected in the use of better material than iron +for crank shafts, by the introduction of a special mild steel, by +Messrs. Vickers, Sons & Co., of Sheffield, and that instead of having +to record the old familiar defects found in iron shafts, I can safely +say no flaws have been observed, when new or during eight years +running, and there are now twenty-two shafts of this mild steel in the +company's service. + +I may here state that steel was used for crank shafts in this service +in 1863, as then manufactured in Prussia by Messrs. Krupp, and +generally known as _Krupp's steel_, the tensile strength of which was +about 40 tons per square inch, and though free from flaws, it was +unable to stand the fatigue, and broke, giving little warning. It was +of too brittle a nature, more resembling chisel steel. It was broken +again under a falling weight of 10 cwt. with a 10 ft. drop = 12½ tons. + +The mild steel now used was first tried in 1880. It possessed tensile +strength of 24 to 25 tons per square inch. It was then considered +advisable not to exceed this, and err rather on the safe side. This +shaft has been in use eight years, and no sign of any flaw has been +observed. Since then the tensile strength of mild steel has gradually +been increased by Messrs. Vickers, the steel still retaining the +elasticity and toughness to endure fatigue. This has only been arrived +at by improvements in the manufacture and more powerful and better +adapted hammers to forge it down from the large ingots to the size +required. The amount of work they are now able to subject the steel to +renders it more fit to sustain the fatigue such as that to be endured +by a crank shaft. These ingots of steel can be cast up to 100 tons +weight, and require powerful machines to deal with them. For shafts +say of 20 inches diameter, the diameter of the ingot would be about 52 +inches. This allows sufficient work to be put on the couplings, as +well as the shaft. To make solid crank shafts of this material, say of +19 inches diameter, the ingot would weigh 42 tons, the forging, when +completed, 17 tons, and the finished shaft 11¾ tons; so that you see +there is 25 tons wasted before any machining is done, and 5¼ tons +between the forging and finished shaft. This makes it very expensive +for solid shafts of large size, and it is found better to make what is +termed a _built shaft_; the cranks are a little heavier, and engine +framings necessarily a little wider, a matter comparatively of little +moment. I give you a rough drawing of the hydraulic hammer, or +strictly speaking a _press_, used by Messrs. Vickers in forging down +the ingots in shafts, guns, or other large work. This hammer can give +a squeeze of 3,000 tons. The steel seems to yield under it like tough +putty, and, unlike the steam hammer, there is no _jarring_ on the +material, and it is manipulated with the same ease as a small hammer +by hydraulics. + +The tensile strength of steel used for shafts having increased from 24 +to 30 tons, and in some cases 31 tons, considering that this was 2 +tons above that specified, and that we were approaching what may be +termed _hard steel_, I proposed to the makers to test this material +beyond the usual tests, viz., tensile, extension, and cold bending +test. The latter, I considered, was much too easy for this fine +material, as a piece of fair iron will bend cold to a radius of 1½ +times its diameter or thickness, without fracture; and I proposed a +test more resembling the fatigue that a crank shaft has sometimes to +stand, and more worthy of this material; and in the event of its +standing this successfully, I would pass the material of 30 or 31 tons +tensile strength. Specimens of steel used in the shafts were cut off +different parts--crank pins and main bearings--(the shafts being built +shafts) and roughly planed to 1½ inches square, and about 12 inches +long. They were laid on the block as shown, and a cast iron block, +fitted with a hammer head ½ ton weight, let suddenly fall 12 inches, +the block striking the bar with a blow of about 4 tons. The steel bar +was then turned upside down, and the blow repeated, reversing the +piece every time until fracture was observed, and the bar ultimately +broken. The results were that this steel stood 58 blows before showing +signs of fracture, and was only broken after 77 blows. It is +noticeable how many blows it stood after fracture. A bar of good +wrought iron, undressed, of same dimensions, was tried, and broke the +first blow. A bar cut from a piece of iron to form a large chain, +afterward forged down and only filed to same dimensions, broke at 25 +blows. I was well satisfied with the results, and considered this +material, though possessing a high tensile strength, was in every way +suitable for the construction and endurance required in crank shafts. + +Sheet No. 1 shows you some particulars of these tests: + + Tensile Elong. Fractured Broke Fall + Tons. in 5" Bend. Blows. Blows. In. + A = 30.5 28 p. c. Good 61 78 12 + +In order to test the comparative value of steel of 24¾ up to 35 tons +tensile strength, I had several specimens taken from shafts tested in +the manner described, which may be called a _fatigue_ test. The +results are shown on the same sheet: + + B = 24½ Good 64 72 7 + B -- -- -- 48 54 12 + C = 27 25.9 p. c. Good 76 81 12 + D = 29.6 28.4 p. c. Good 71 78 12 + E = 30.5 28.9 p. c. Good 58 77 12 + F = 35.5 20 p. c. Good 80 91 12 + +The latter was very tough to break. Specimen marked A shows one of +these pieces of steel. I show you also fresh broken specimens which +will give you a good idea of the beautiful quality of this material. +These specimens were cut out of shafts made of Steel Co. of Scotland's +steel. I also show you specimens of cold bending: + + Tensile Elong. Fractured Broke Fall + Tons. in. 5" Bend. Blows. Blows. In. + G = 30.9 27½ p. c. Good 59 66 12 + H = 29.3 30 p. c. Good 66 90 12 + I = 28.9 28.9 p. c. Good 53 68 12 + +I think all of the above tests show that this material, when carefully +made and treated with sufficient mechanical work on forging down from +the ingot, is suitable up to 34 tons for crank shafts; how much higher +it would be desirable to go is a question of superior excellence in +material and manufacture resting with the makers. I would, however, +remark that no allowance has been made by the Board of Trade or Lloyds +for the excellence of this material above that of iron. I was +interested to know how the material in the best iron shafts would +stand this fatigue test compared with steel, and had some specimens of +same dimensions cut out of iron shafts. The following are the results: +Best iron, three good qualities, rolled into flat bars, cut and made +into 4½ cwt. blooms. + + J = 18.6 24.3 p. c. Good 17 18 12 + +Made of best double rolled scrap, 4½ cwt. blooms. + + K = 22 32½ p. c. Good 21 32 12 + +You will see from these results that steel stood this fatigue test, +Vickers' 73 per cent. and Steel Co.'s 68 per cent., better than iron +of the best quality for crank shafts; and I am of opinion that so long +as we use such material as these for crank shafts, along with the +present rules, and give ample _bearing surface_, there will be few +broken shafts to record. + +I omitted to mention that built shafts, both of steel and iron, of +large diameter, are now in general use, and with the excellent +machines, and under special mechanics, are built up of five separate +pieces in such a rigid manner that they possess all the solidity +necessary for a crank shaft. The forgings of iron and steel being much +smaller are capable of more careful treatment in the process of +manufacture. These shafts, for large mail steamers, when coupled up, +are 35 feet long, and weigh 45 tons. They require to be carefully +coupled, some makers finishing the bearings in the lathe, others +depend on the excellence of their work in each piece, and finish each +complete. To insure the correct centering of these large shafts, I +have had 6 in. dia. recesses ¾ inch deep turned out of each coupling +to one gauge and made to fit one disk. Duplicate disks are then fitted +in each coupling, and the centering is preserved, and should a spare +piece be ever required, there is no trouble to couple correctly on +board the steamer. + +The propeller shaft is generally made of iron, and if made _not less_ +than the Board of Trade rules as regards diameter, of the best iron, +and the gun metal liners carefully fitted, they have given little +trouble; the principal trouble has arisen from defective fitting of +the propeller boss. This shaft working in sea water, though running in +lignum vitę bearings, has a considerable wear down at the outer +bearings in four or five years, and the shaft gets out of line. This +wear has been lessened considerably by fitting the wood so that the +grain is endway to the shaft, and with sufficient bearing surface +these bearings have not required lining up for nine years. It is, +however, a shaft that cannot be inspected except when in dry dock, and +has to be disconnected from the propeller, and drawn inside for +examination at periods suggested by experience. Serious accidents have +occurred through want of attention to the examination of this shaft; +when working in salt water, with liners of gun metal, galvanic action +ensues, and extensive corrosion takes place in the iron at the ends of +the brass liners, more especially if they are faced up at right angles +to the shaft. Some engineers have the uncovered part of the shaft +between the liners, inside the tube, protected against the sea water +by winding over it tarred line. As this may give out and cause some +trouble, by stopping the water space, I have not adopted it, and shall +be pleased to have the experience of any seagoing engineer on this +important matter. A groove round the shaft is formed, due to this +action, and in some cases the shaft has broken inside the stern tube, +breaking not only it, but tearing open the hull, resulting in the +foundering of the vessel. Steel has been used for screw shafts, but +has not been found so suitable, as it corrodes more rapidly in the +presence of salt water and gun metal than iron, and unless protected +by a solid liner for the most part of its length, a mechanical feat +which has not yet been achieved in ordinary construction, as this +liner would require to be 20 ft. long. I find it exceedingly difficult +to get a liner of only 7 ft. long in one piece, and the majority of 6 +ft. liners are fitted _in two pieces_. The joint of the two liners is +rarely _watertight_, and many shafts have been destroyed by this +method of fitting these liners. + +I trust that engine builders will make a step further in the fitting +of these liners on these shafts, as it is against the interest of the +_shipowner_ to keep ships in dry dock from such causes as defective +liners, and I think it will be only a matter of time when the screw +shaft will be completely protected from sea water, at least inside the +stern tube; and when this is done, I would have no hesitation in using +steel for screw shafts. Though an easier forging than a crank shaft, +these shafts are often liable to flaws of a very serious character, +owing to the contraction of the _mass_ of metal forming the coupling; +the outside cooling first tears the center open, and when there is not +much metal to turn off the face of the coupling, it is sometimes +undiscovered. Having observed several of these cavities, some only +when the _last cut_ was being taken off, I have considered it +advisable to have holes bored in the end and center of each coupling, +as far through as the thickness of the flange; when the shafts are of +large size, this is sure to find these flaws out. Another flaw, which +has in many cases proved serious when allowed to extend, is situated +immediately abaft the gun metal liner, in front of the propeller. + +This may be induced by corrosion, caused by the presence of sea water, +gun metal, and iron, assisted by the rotation of the shaft. It may +also be caused under heavy strain, owing to the over-finishing of the +shaft at this part under the steam hammer. + +The forgemen, in these days of competition and low prices, are +instructed to so finish that there won't be much weight to turn off +when completing the shaft in the lathe. This is effected by the use of +half-round blocks under the hammer, at a lower temperature than the +rest of the forging is done, along with the use of a little water +flung on from time to time; and it is remarkable how near a forging is +in truth when centered in the lathe, and how little there is to come +off. The effect of this manipulation is to form a hard ring of close +grain about one inch thick from the circumference of the shaft inward. +The metal in this ring is much harder than that in the rest of the +shaft, and takes all the strain the inner section gives; consequently, +when strain is brought on, either in heavy weather or should the +propeller strike any object at sea or in the Suez canal, a fracture is +caused at the circumference. This, assisted by slight corrosion, has +in my experience led in the course of four months to a screw shaft +being seriously crippled. + +I show you a section of a screw shaft found to be flawed, and which I +had broken under the falling weight of a steam hammer, when the +decided difference of the granules near the circumference from that in +the central part conveyed to me that it was weakened by treatment I +have referred to. I think more material should be left on the forging, +and the high finish with a little cold water should be discontinued. +Doing away with the outer bearing in rudder post is an improvement, +provided the bearing in the outer end of screw shaft in the stern tube +is sufficiently large. It allows the rudder post to have its own work +to do without bringing any strain on the screw shaft, and in the event +of the vessel's grounding and striking under the rudder post, it does +not throw any strain on the screw shaft. It also tends to reduce +weight at this part, where all the weight is overhung from the stern +of the vessel. + + * * * * * + + + + +EXPERIMENTAL AID IN THE DESIGN OF HIGH SPEED STEAMSHIPS. + +By D. P. + + +The achievement of one triumph after another in the matter of high +speed steamships, and especially the confidence with which pledges of +certain results are given and accepted long before actual trials are +made, form one of the most convincing proofs of the important part +which scientific methods play in modern shipbuilding. This is evident +in the case of ships embodying novel or hitherto untried features, and +more especially so in cases where shipbuilders, having no personal +practical experience or data, achieve such results. This was notably +illustrated in the case of the Fairfield Co. undertaking some five +years ago to build and engine a huge craft of most phenomenal form and +proportions, and to propel the vessel at a given speed under +conditions which appeared highly impracticable to many engaged in the +same profession. The contract was proceeded with, however, and the +Czar of Russia's wonderful yacht Livadia was the result, which +(however much she may have justified the professional strictures as to +form and proportions) entirely answered the designer's anticipations +as to speed. Equally remarkable and far more interesting instances are +the Inman liners City of Paris and City of New York, in whose design +there was sufficient novelty to warrant the degree of misgiving which +undoubtedly existed regarding the Messrs. Thomson's ability to attain +the speed required. In the case at least of the City of Paris, Messrs. +Thomson's intrepidity has been triumphantly justified. An instance +still more opposite to our present subject is found in the now +renowned Channel steamers Princess Henrietta and Princess Josephine, +built by Messrs. Denny, of Dumbarton, for the Belgian government. The +speed stipulated for in this case was 20½ knots, and although in one +or two previous Channel steamers, built by the Fairfield Co., a like +speed had been achieved, still the guaranteeing of this speed by +Messrs. Denny was remarkable, in so far as the firm had never +produced, or had to do with, any craft faster than 15 or 16 knots. The +attainment not only of the speed guaranteed, but of the better part of +a knot in excess of that speed, was triumphant testimony to the skill +and care brought to bear upon the undertaking. In this case, at least, +the result was not one due to a previous course of "trial and error" +with actual ships, but was distinctly due to superior practical skill, +backed and enhanced by knowledge and use of specialized branches in +the science of marine architecture. Messrs. Denny are the only firm of +private shipbuilders possessing an experimental tank for recording the +speed and resistance of ships by means of miniature reproductions of +the actual vessels, and to this fact may safely be ascribed their +confidence in guaranteeing, and their success in obtaining, a speed so +remarkable in itself and so much in excess of anything they had +previously had to do with. Confirmatory evidence of their success with +the Belgian steamers is afforded by the fact that they have recently +been instructed to build for service between Stranraer and Larne a +paddle steamer guaranteed to steam 19 knots, and have had inquiries as +to other high speed vessels. + +In estimating the power required for vessels of unusual types or of +abnormal speed, where empirical formulę do not apply, and where data +for previous ships are not available, the system of experimenting with +models is the only trustworthy expedient. In the case of the Czar's +extraordinary yacht, the Livadia, already referred to, it may be +remembered that previous to the work of construction being proceeded +with, experiments were made with a small model of the vessel by the +late Dr. Tideman, at the government tank at Amsterdam. On the strength +of the data so obtained, coupled with the results of trials made with +a miniature of the actual vessel on Loch Lomond, those responsible for +her stipulated speed were satisfied that it could be attained. The +actual results amply justified the reliance placed upon such +experiments. + +The design of many of her Majesty's ships has been altered after +trials with their models. This was notably the case in connection with +the design of the Medway class of river gunboats. The Admiralty +constructors at first determined to make them 110 ft. long, by only 26 +ft. in breadth. A doubt arising in their minds, the matter was +referred to the late Mr. Froude, who had models made of various +breadths, with which he experimented. The results satisfied the +Admiralty officers that a substantial gain, rather than a loss, would +follow from giving them much greater beam than had been proposed, and +this was amply verified in the actual ships. + +So long ago as the last decade of last century, an extended series of +experiments with variously shaped bodies, ships as well as other +shapes, were conducted by Colonel Beaufoy, in Greenland dock, London, +under the auspices of a society instituted to improve naval +architecture at that time. Robert Fulton, of America, David Napier, of +Glasgow, and other pioneers of the steamship, are related to have +carried out systematic model experiments, although of a rude kind in +modern eyes, before entering on some of their ventures. About 1840 Mr. +John Scott Russell carried on, on behalf of the British Association, +of which he was at that time one of its most distinguished members, an +elaborate series of investigations into the form of least resistance +in vessels. For this purpose he leased the Virginia House and grounds, +a former residence of Rodger Stewart, a famous Greenock shipowner of +the early part of the century, the house being used as offices, while +in the grounds an experimental tank was erected. In it tests were made +of the speed and resistance of the various forms which Mr. Russell's +ingenuity evolved--notably those based on the well-known stream line +theory--as possible types of the steam fleets of the future. All the +data derived from experiment was tabulated, or shown graphically in +the form of diagrams, which, doubtless, proved of great interest to +the _savants_ of the British Association of that day. Mr. Russell +returned to London in 1844, and the investigations were discontinued. + +It will thus be seen that model experiments had been made by +investigators long before the time of the late Dr. William Froude, of +Torquay. It was not, however, until this gentleman took the subject of +resistance of vessels in hand that designers were enabled to render +the results from model trials accurately applicable to vessels of full +size. This was principally due to his enunciation and verification by +experiment of what is now known as the "law of comparison," or the law +by which one is enabled to refer accurately the resistance of a model +to one of larger size, or to that of a full sized vessel. In effect, +the law is this--for vessels of the same proportional dimensions, or, +as designers say, of the same lines, there are speeds appropriate to +these vessels, which vary as the square roots of the ratio of their +dimensions, and at these appropriate speeds the resistances will vary +as the cubes of these dimensions. The fundament upon which the law is +based has recently been shown to have found expression in the works of +F. Reech, a distinguished French scientist who wrote early in the +century. There are no valid grounds for supposing that the discovery +of Reech was familiar to Froude; but even were this so, it is +abundantly evident that, although never claimed by himself, there are +the best of grounds for claiming the law of comparison, as now +established, to be an independent discovery of Froude's. + +Dr. Froude began his investigations with ships' models at the +experimental tank at Torquay about 1872, carrying it on +uninterruptedly until his death in 1879. Since his decease, the work +of investigation has been carried on by his son, Mr. R. E. Froude, who +ably assisted his father, and originated much of the existing +apparatus. At the beginning of 1886, the whole experimental appliances +and effects were removed from Torquay to Haslar, near Portsmouth, +where a large tank and more commodious offices have been constructed, +with a view to entering more extensively upon the work of experimental +investigation. The dimensions of the old tank were 280 ft. in length, +36 ft. in width, and 10 ft. in depth. The new one is about 400 ft. +long, 20 ft. wide, and 9 ft. deep. The new establishment is more +commodious and better equipped than the old, and although the +experiments are taken over a greater length, the operators are enabled +to turn out results with as great dispatch as in the Torquay tank. The +adjacency of the new tank to the dockyard at Portsmouth enables the +Admiralty authorities to make fuller and more frequent use of it than +formerly. Since the value of the work carried on for the British +government has become appreciated, several experimental establishments +of a similar character have been instituted in other countries. The +Dutch government in 1874 formed one at Amsterdam which, up till his +death in 1883, was under the superintendence of Dr. Tideman, whose +labors in this direction were second only to those of the late Dr. +Froude. In 1877 the French naval authorities established an +experimental tank in the dockyard at Brest, and the Italian government +have just completed one on an elaborate scale in the naval dockyard at +Spezia. The Spezia tank, which is 500 ft. in length by about 22 ft. in +breadth, is fully equipped with all the special and highly ingenious +instruments and appliances which the scientific skill of the late Dr. +Froude brought into existence, and have been since his day improved +upon by his son, Mr. R. E. Froude, and other experts. + +Through the courtesy of our own Admiralty and of Messrs. Denny, of +Dumbarton, the Italians have been permitted to avail themselves of the +latest improvements which experience has suggested, and the +construction of the special machinery and apparatus required has been +executed by firms in this country having previous experience in this +connection--Messrs. Kelso & Co., of Commerce Street, Glasgow; and Mr. +Robert W. Munro, of London. + +Having briefly traced the origin and development of the system of +model experiment, it may now be of interest to describe the _modus +operandi_ of such experiments, and explain the way in which they are +made applicable to actual ships. The models with which experiments are +made in those establishments conducted on the lines instituted by Mr. +Froude are made of paraffin wax, a material well adapted for the +purpose, being easily worked, impervious to water, and yielding a fine +smooth surface. Moreover, when done with, the models may be remelted +for further use and all parings utilized. They are produced in the +following manner: A mould is formed in clay by means of cross sections +made somewhat larger than is actually required, this allowance being +made to admit of the cutting and paring afterward required to bring +the model to the correct point. Into this mould a core is placed, +consisting of a light wooden framework covered with calico and coated +with a thick solution of clay to make it impervious to the melted +paraffin. This latter substance is run into the space between the core +and the mould and allowed to cool. This space, forming the thickness +of the model, is usually from ¾ in. for a model of 10 ft. long to 1¼ +in. and 1½ in. for one of 16 ft. and 18 ft. long. When cold, the model +is floated out of the mould by water pressure and placed bottom upward +on the bed of a shaping machine, an ingenious piece of mechanism +devised by the late Dr. Froude, to aid in reducing the rough casting +to the accurate form. The bed of this machine, which travels +automatically while the machine is in operation, can be raised or +lowered to any desired level by adjusting screws. A plan of water +lines of the vessel to be modeled is placed on a tablet geared to the +machine, the travel of which is a function of the travel of the bed +containing the model. With a pointer, which is connected by a system +of levers to the cutting tools, the operator traces out the water +lines upon the plan as the machine and its bed are in motion, with the +result that corresponding lines are cut upon the model. The cutting +tools are swiftly revolving knives which work on vertical spindles +moved in a lateral direction (brought near or removed from each +other), according to the varying breadth of the water lines throughout +the length of the model, as traced out by the operator's pointer. In +this way a series of longitudinal incisions are made on the model at +different levels corresponding to the water lines of the vessel. The +model is now taken from the bed of the machine and the superfluous +material or projection between the incisions is removed by means of a +spokeshave or other sharp hand tool, and the whole surface brought to +the correct form, and made fair and smooth. + +To test accuracy of form, the weight of model is carefully taken, and +the displacement at the intended trial draught accurately determined +from the plan of lines. The difference between the weight of model and +the displacement at the draught intended is then put into the bottom +of the model in the form of small bags of shot, and by unique and very +delicately constructed instruments for ascertaining the correct +draught, the smallest error can at once be detected and allowed for. +The models vary in size from about one-tenth to one-thirtieth of the +size of the actual ship. A model of the largest size can be produced +and its resistance determined at a number of speeds in about two days +or so. The mode of procedure in arranging the model for the resistance +experiment, after the model is afloat in the tank at the correct +draught and trim, consists in attaching to it a skillfully devised +dynamometric apparatus secured to a lightly constructed carriage. This +carriage traverses a railway which extends the whole length of the +tank about 15 in. or 18 in. above the water. The floating model is +carefully guided in its passage through the water by a delicate +device, keeping it from deviating either to the right or left, but at +the same time allowing a free vertical and horizontal motion. The +carriage with the model attached is propelled by means of an endless +steel wire rope, passing at each end of the tank around a drum, driven +by a small stationary engine, fitted with a very sensitive governor, +capable of being so adjusted that any required speed may be given to +the carriage and model. The resistance which the model encounters in +its passage through the water is communicated to a spiral spring, and +the extension this spring undergoes is a measure of the model's +resistance. The amount of the extension is recorded on a revolving +cylinder to a much enlarged scale through the medium of levers or bell +cranks supported by steel knife edges resting on rocking pieces. On +the same cylinder are registered "time" and "distance" diagrams, by +means of which a correct measure of the speed is obtained. The time +diagram is recorded by means of a clock attached to an electric +circuit, making contact every half second, and actuating a pen which +forms an indent in what would otherwise be a straight line on the +paper. The distance pen, by a similar arrangement, traces another line +on the cylinder in which are indents corresponding to fixed distances +of travel along the tank, the indents being caused by small +projections which strike a trigger at the bottom of the carriage as it +passes, and make electric contact. From these time and distance +diagrams accurate account can be taken of the speed at which the model +and its supporting carriage have been driven. Thus on the same +cylinder is recorded graphically the speed and resistance of the +model. The carriage may be driven at any assigned speed by adjusting +the governor of the driving engine already alluded to, but the record +of the speed by means of the time and distance diagrams is more +definite. When the resistances of the model have been obtained at +several speeds, varying in some cases from 50 to 1,000 feet per +minute, the speeds are set off in suitable units along a base line, +and for every speed at which resistance is measured, the resistance is +set off to scale as an ordinate value at those speeds. A line passing +through these spots forms the "curve of resistance," from which the +resistance experienced by the model at the given trial speeds or any +intermediate speed can be ascertained. The resistance being known, the +power required to overcome resistance and drive the actual ship at any +given speed is easily deduced by applying the rule before described as +the law of comparison.--_The Steamship._ + + * * * * * + + + + +THE SHIP IN THE NEW FRENCH BALLET OF THE "TEMPEST." + + +A new ballet, entitled the "Tempest," by Messrs. Barbier and Thomas, +has recently been put upon the stage of the Opera at Paris with superb +settings. One of the most important of the several tableaux exhibited +is the last one of the third act, in which appears a vessel of unusual +dimensions for the stage, and which leaves far behind it the +celebrated ships of the "Corsaire" and "L'Africaine." This vessel, +starting from the back of the stage, advances majestically, describes +a wide circle, and stops in front of the prompter's box. + +[Illustration: FIG. 1.--SHIP OF THE "TEMPEST," IN PROCESS OF +CONSTRUCTION.] + +[Illustration: FIG. 2.--SETTING OF THE SCENERY BEFORE AND AFTER THE +APPEARANCE OF THE SHIP.] + +As the structure of this vessel and the mechanism by which it is moved +are a little out of the ordinary, we shall give some details in regard +to them. First, the sea is represented by four parallel strips of +water, each formed of a vertical wooden frame entirely free in its +movements (Fig. 2). The ship (Figs. 1, 2, 3, 4 and 5) is carried by +wheels that roll over the floor of the stage. It is guided in its +motion by two grooved bronze wheels and by a rail formed of a simple +reversed T-iron which is fixed to the floor by bolts. In measure as it +advances, the strips of water open in the center to allow it to pass, +and, as the vessel itself is covered up to the water line with painted +canvas imitating the sea, it has the appearance of cleaving the waves. +As soon as it has passed, the three strips of water in the rear rise +slightly. When the vessel reaches the first of the strips, the three +other strips, at first juxtaposed against the preceding, spread out +and thus increase the extent of the sea, while the inclined plane of +the preceding tableau advances in order to make place for the vessel. +The shifting of this inclined place is effected by simply pulling upon +the carpet that covers it, and which enters a groove in the floor in +front of the prompter's box. At this moment, the entire stage seems to +be in motion, and the effect is very striking. + +[Illustration: FIG. 3.--SHIP OF THE NEW BALLET, THE "TEMPEST."] + +We come now to the details of construction of the vessel. It is not +here a question of a ship represented simply by means of frames and +accessories, but of a true ship in its entirety, performing its +evolutions over the whole stage. Now, a ship is not constructed at a +theater as in reality. It does not suffice to have it all entire upon +the stage, but it is necessary also to be able to dismount it after +every representation, and that, too, in a large number of pieces that +can be easily stored away. Thus, the vessel of the Tempest, which +measures a dozen yards from stem to stern, and is capable of carrying +fifty persons, comes apart in about 250 pieces of wood, without +counting all the iron work, bolts, etc. Nevertheless, it can be +mounted in less than two hours by ten skilled men. + +[Illustration: FIG. 4.--THE SHIP WITH ITS OCCUPANTS.] + +The visible hull of the ship is placed upon a large and very strong +wooden framework, formed of twenty-six trusses. In the center, there +are two longitudinal trusses about three feet in height by twenty-five +in length, upon which are assembled, perpendicularly, seven other +trusses. In the interior there are six transverse pieces held by +stirrup bolts, and at the extremity of each of these is fixed a +thirteen-inch iron wheel. It is upon these twelve wheels that the +entire structure rolls. + +There are in addition the two bronze guide wheels that we have already +spoken of. In the rear there are two large vertical trusses sixteen +feet in height, which are joined by ties and descend to the bottom of +the frame, to which they are bolted. These are worked out into steps +and constitute the skeleton of the immense stern of the vessel. The +skeleton of the prow is formed of a large vertical truss which is +bolted to the front of the frame and is held within by a tie bar. On +each side of this truss are placed the _parallels_ (Figs. 1 and 3), +which are formed of pieces of wood that are set into the frame below +and are provided above with grooves for the passage of iron rods that +support the foot rests by means of which the supernumeraries are +lifted. As a whole, those rods constitute a jointed parallelogram, so +that the foot rest always remains horizontal while describing a curve +of five feet radius from the top of the frame to the deck of the +vessel. They are actuated by a cable which winds around a small +windlass fixed in the interior of the frame. + +[Illustration: FIG. 5.--THE SHIP AS SEEN FROM THE STAGE.] + +The large mast consists of a vertical sheath 10 ft. high, which is set +into the center of the frame, and in the interior of which slides a +wooden spar that exceeds it by 5 ft. at first, and is capable of being +drawn out as many more feet for the final apotheosis. This part of the +mast carries three footboards and a platform for the reception of +"supers." It is actuated by a windlass placed upon the frame. + +To form the skeleton of the vessel there are mounted upon the frame a +series of eight large vertical trusses parallel with each other and +cross-braced by small trusses. The upper part of these supports the +flooring of the deck, and their exterior portion affects the curve of +a ship's sides. It is to these trusses that are attached the panels +covered with painted canvas that represent the hull. These panels are +nine in number on each side. Above are placed those that simulate the +nettings and those that cover the prow or form its crest. + +The turret that surrounds the large mast is formed of vertical trusses +provided with panels of painted canvas and carrying a floor for the +figurants to stand upon. + +The bowsprit is in two parts, one sliding in the other. The front +portion is at first pulled back, in order to hide the vessel entirely +in the side scenes. It begins to make its appearance before the vessel +itself gets under way. Light silken cordages connect the mast, the +bowsprit, and the small mast at the stern. + +On each side of the vessel, there are bolted to the frame that +supports it five iron frames covered with canvas (Fig. 3), which reach +the level of the water line, and upon which stand the "supers" +representing the naiads that are supposed to draw the ship upon the +beach. Finally at the bow there is fixed a frame which supports a +danseuse representing the living prow of the vessel. + +The vessel is drawn to the middle of the stage by a cable attached to +its right side and passing around a windlass placed in the side scenes +to the left (Fig. 2). It is at the same time pushed by machinists +placed in the interior of the framework. The latter, as above stated, +is entirely covered with painted canvas resembling water. + +As the vessel, freighted with harmoniously grouped spirits, and with +naiads, sea fairies, and graceful genii seeming to swim around it, +sails in upon the stage, puts about, and advances as if carried along +by the waves to the front of the stage, the effect is really +beautiful, and does great credit to the machinists of the Opera. + +We are indebted to _Le Genie Civil_ and _Le Monde Illustré_ for the +description and engravings. + + * * * * * + + + + +THE GIRARD HYDRAULIC RAILWAY. + + +[Illustration: FIG. 1.] + +[Illustration: FIG. 2.] + +We give herewith some illustrations of this railway which has recently +excited so much technical interest in Europe and America, and which +threatens to revolutionize both the method and velocity of traveling, +if only the initial expense of laying the line can be brought within +moderate limits. A short line of railway has been laid in Paris, and +we have there examined it, and traveled over the line more than once; +so that we can testify to the smoothness and ease of the motion. Sir +Edward Watkin examined the railway recently, and we understand that a +line two miles long is to be laid in London, under his auspices. He +seems to think it might be used for the Channel tunnel, being both +smokeless and noiseless. It might also, if it could be laid at a +sufficiently low price, be useful for the underground railways in +London, of one of which he is chairman. We are favorably impressed by +the experiments we have witnessed; our misgivings are as to the cost. +The railway is the invention of the well known hydraulic engineer, +Monsieur Girard, who, as early as 1852, endeavored to replace the +ordinary steam traction on railways by hydraulic propulsion, and in +1854 sought to diminish the resistance to the movement of the wagons +by removing the wheels, and causing them to slide on broad rails. In +order to test the invention, Mons. Girard demanded, and at the end of +1869 obtained, a concession for a short line from Paris to Argenteuil, +starting in front of the Palais de l'Industrie, passing by Le Champ de +Courses de Longchamps, and crossing the Seine at Suresnes. +Unfortunately, the war of 1870-71 intervened, during which the works +were destroyed and Mons. Girard was killed. After his death the +invention was neglected for some years. A short time ago, however, one +of his former colleagues, Mons. Barre, purchased the plans and +drawings of Mons. Girard from his family, and having developed the +invention, and taken out new patents, formed a company to work them. +The invention may be divided into two parts, which are distinct, the +first relating to the mode of supporting the carriages and the second +to their propulsion. Each carriage is carried by four or six shoes, +shown in Figs. 3, 4, and 5; and these shoes slide on a broad, flat +rail, 8 in. or 10 in. wide. The rail and shoe are shown in section in +Fig. 1. The rail is bolted to longitudinal wooden sleepers, and the +shoe is held on the rail by four pieces of metal, A, two on each side, +which project slightly below the top of the rail. The bottom of the +shoe which is in contact with the rail is grooved or channeled, so as +to hold the water and keep a film between each shoe and the rail. The +carriage is supported by vertical rods, which fit one into each shoe, +a hole being formed for that purpose; and the point of support being +very low, and quite close to the rail, great stability is insured. It +is proposed to make the rail of the form shown in Fig. 2 in future, as +this will avoid the plates, A, and the flanges, B, will help to keep +the water on the rail. Figs. 3, 4, and 5 show the shoe in detail. Fig. +3 gives a longitudinal section, Fig. 4 is a plan, and Fig. 5 is a plan +of the shoe inverted, showing the grooves in its face. Fig. 3 shows +the hollow shoe, into which water at a pressure of ten atmospheres is +forced by a pipe from a tank on the tender. The water enters by the +pipe, C, and fills the whole of the chamber, D. The water attempts to +escape, and in doing so lifts the shoe slightly, thus filling the +first groove of the chamber. The pressure again lifts the shoe, and +the second chamber is filled; and so on, until ultimately the water +escapes at the ends, E, and sides, F. Thus a film of water is kept +between the shoe and the rail, and on this film the carriage is said +to float. The water runs away into the channels, H H (Fig. 6), and is +collected to be used over again. Fig. 3 also shows the means of +supporting the carriage on the shoe by means of K, the point of +support being very low. The system of grooves on the lower face of the +shoe is shown in Fig. 5. So much for the means by which wheels are +dispensed with, and the carriage enabled to slide along the line. + +[Illustration: FIG. 3.] + +[Illustration: FIG. 4.] + +[Illustration: FIG. 5.] + +[Illustration: FIG. 6.] + +The next point is the method of propulsion. Figs. 7 and 8 give an +elevation and plan of one of the experimental carriages. Along the +under side of each of the carriages a straight turbine, L L, extends +the whole length, and water at high pressure impinges on the blades of +this turbine from a jet, M, and by this means the carriage is moved +along. A parabolic guide, which can be moved in and out of gear by a +lever, is placed under the tender, and this on passing strikes the +tappet, S, and opens the valve which discharges the water from the +jet, M, and this process is repeated every few yards along the whole +line. The jets, M, must be placed at such a distance apart that at +least one will be able to operate on the shortest train that can be +used. In this turbine there are two sets of blades, one above the +other, placed with their concave sides in opposite directions, so that +one set is used for propelling in one direction and the other in the +opposite direction. In Fig. 6 it is seen that the jet, M, for one +direction is just high enough to act against the blades, Q, while the +other jet is higher, and acts on the blades, P, for propulsion in the +opposite direction. The valves, R, which are opened by the tappet, S, +are of peculiar construction, and we hope soon to be able to give +details of them. Reservoirs (Fig. 6) holding water at high pressure +must be placed at intervals, and the pipe, T, carrying high pressure +water must run the whole length of the line. Fig. 6 shows a cross +section of the rail and carriage, and gives a good idea of the general +arrangements. The absence of wheels and of greasing and lubricating +arrangements will alone effect a very great saving, as we are informed +that on the Lyons Railway, which is 800 kilometers long, the cost of +oil and grease exceeds £400,000 per annum. As Sir Edward Watkin +recently explained, all the great railway companies have long tried to +find a substitute for wheels, and this railway appears to offer a +solution of that problem. Mons. Barre thinks that a speed of 200 +kilometers (or 120 miles) per hour may be easily and safely attained. + +[Illustration: FIG. 7.] + +[Illustration: FIG. 8.] + +Of course, as there is no heavy locomotive, and as the traction does +not depend upon pressure on the rail, the road may be made +comparatively light. The force required to move a wagon along the road +is very small, Mons. Barre stating, as the result of his experiments, +that an effort amounting to less than half a kilogramme is sufficient +to move one ton when suspended on a film of water with his improved +shoes. It is recommended that the stations be placed at the summit of +a double incline, so that on going up one side of the incline the +motion of the train may be arrested, and on starting it may be +assisted. No brakes are required, as the friction of the shoe against +the rail, when the water under pressure is not being forced through, is +found to be quite sufficient to bring the train to a standstill in a +very short distance. The same water is run into troughs by the side of +the line, and can be used over and over again indefinitely, and in the +case of long journeys, the water required for the tender could be taken +up while the train is running. The principal advantages claimed for +the railway are: The absence of vibration and of side rolling motion; +the pleasure of traveling is comparable to that of sleighing over a +surface of ice, there is no noise, and what is important in town +railways, no smoke; no dust is caused by the motion of the train during +the journey. It is not easy for the carriages to be thrown from the +rails, since any body getting on the rail is easily thrown off by the +shoe, and will not be liable to get underneath, as is the case with +wheels; the train can be stopped almost instantly, very smoothly, and +without shock. Very high speed can be attained; with water at a +pressure of 10 kilogrammes, a speed of 140 kilometers per hour can be +attained; great facility in climbing up inclines and turning round the +curves; as fixed engines are employed to obtain the pressure, there is +great economy in the use of coal and construction of boilers, and +there is a total absence of the expense of lubrication. It is, +however, difficult to see how the railway is to work during a long and +severe frost. We hope to give further illustrations at an early date +of this remarkable invention.--_Industries._ + + * * * * * + + + + +QUARTZ FIBERS.[1] + + [Footnote 1: Lecture delivered at the Royal Institution, on + Friday, June 14, by Mr. C. V. Boys, F.R.S.--_Nature._] + + +In almost all investigations which the physicist carries out in the +laboratory, he has to deal with and to measure with accuracy those +subtile and to our senses inappreciable forces to which the so-called +laws of nature give rise. Whether he is observing by an electrometer +the behavior of electricity at rest or by a galvanometer the action of +electricity in motion, whether in the tube of Crookes he is +investigating the power of radiant matter, or with the famous +experiment of Cavendish he is finding the mass of the earth--in these +and in a host of other cases he is bound to measure with certainty and +accuracy forces so small that in no ordinary way could their existence +be detected, while disturbing causes which might seem to be of no +particular consequence must be eliminated if his experiments are to +have any value. It is not too much to say that the very existence of +the physicist depends upon the power which he possesses of producing +at will and by artificial means forces against which he balances those +that he wishes to measure. + +I had better perhaps at once indicate in a general way the magnitude +of the forces with which we have to deal. + +The weight of a single grain is not to our senses appreciable, while +the weight of a ton is sufficient to crush the life out of any one in +a moment. A ton is about 15,000,000 grains. It is quite possible to +measure with unfailing accuracy forces which bear the same relation to +the weight of a grain that a grain bears to a ton. + +To show how the torsion of wires or threads is made use of in +measuring forces, I have arranged what I can hardly dignify by the +name of an experiment. It is simply a straw hung horizontally by a +piece of wire. Resting on the straw is a fragment of sheet iron +weighing ten grains. A magnet so weak that it cannot lift the iron yet +is able to pull the straw round through an angle so great that the +existence of the feeble attraction is evident to every one in the +room. + +Now it is clear that if, instead of a straw moving over the table +simply, we had here an arm in a glass case and a mirror to read the +motion of the arm, it would be easy to observe a movement a hundred or +a thousand times less than that just produced, and therefore to +measure a force a hundred or a thousand times less than that exerted +by this feeble magnet. + +Again, if instead of wire as thick as an ordinary pin I had used the +finest wire that can be obtained, it would have opposed the movement +of the straw with a far less force. It is possible to obtain wire ten +times finer than this stubborn material, but wire ten times finer is +much more than ten times more easily twisted. It is ten thousand times +more easily twisted. This is because the torsion varies as the fourth +power of the diameter. So we say 10 × 10 = 100, 100 × 100 = 10,000. +Therefore, with the finest wire, forces 10,000 times feebler still +could be observed. + +It is therefore evident how great is the advantage of reducing the +size of a torsion wire. Even if it is only halved, the torsion is +reduced sixteenfold. To give a better idea of the actual sizes of such +wires and fibers as are in use, I shall show upon the screen a series +of such photographs taken by Mr. Chapman, on each of which a scale of +thousandths of an inch has been printed. + +[Illustration: Scale of 1000ths of an inch for Figs. 1 to 7. The scale +of Figs. 8 and 9 is much finer.] + +[Illustration: FIG. 1.] + +[Illustration: FIG. 2.] + +[Illustration: FIG. 3.] + +The first photograph (Fig. 1) is an ordinary hair--a sufficiently +familiar object, and one that is generally spoken of as if it were +rather fine. Much finer than this is the specimen of copper wire now +on the screen (Fig. 2), which I recently obtained from Messrs. Nalder +Brothers. It is only a little over one-thousandth of an inch in +diameter. Ordinary spun glass, a most beautiful material, is about +one-thousandth of an inch in diameter, and this would appear to be an +ideal torsion thread (Fig. 3). Owing to its fineness, its torsion +would be extremely small, and the more so because glass is more easily +deformed than metals. Owing to its very great strength, it can carry +heavier loads than would be expected of it. I imagine many physicists +must have turned to this material in their endeavor to find a really +delicate torsion thread. I have so turned only to be disappointed. It +has every good quality but one, and that is its imperfect elasticity. +For instance, a mirror hung by a piece of spun glass is casting an +image of a spot of light on the scale. If I turn the mirror, by means +of a fork, twice to the right, and then turn it back again, the light +does not come back to its old point of rest, but oscillates about a +point on one side, which, however, is slowly changing, so that it is +impossible to say what the point of rest really is. Further, if the +glass is twisted one way first and then the other way, the point of +rest moves in a manner which shows that it is not influenced by the +last deflection alone: the glass remembers what was done to it +previously. For this reason spun glass is quite unsuitable as a +torsion thread; it is impossible to say what the twist is at any time, +and therefore what is the force developed. + +[Illustration: FIG. 4.] + +So great has the difficulty been in finding a fine torsion thread that +the attempt has been given up, and in all the most exact instruments +silk has been used. The natural cocoon fibers, as shown on the screen +(Fig. 4), consist of two irregular lines gummed together, each about +one two-thousandth of an inch in diameter. These fibers must be +separated from one another and washed. Then each component will, +according to the experiment of Gray, carry nearly 60 grains before +breaking, and can be safely loaded with 15 grains. Silk is therefore +very strong, carrying at the rate of from 10 to 20 tons to the square +inch. It is further valuable in that its torsion is far less than that +of a fiber of the same size of metal or even of glass, if such could +be produced. The torsion of silk, though exceedingly small, is quite +sufficient to upset the working of any delicate instrument, because it +is never constant. At one time the fiber twists one way and another +time in another, and the evil effect can only be mitigated by using +large apparatus in which strong forces are developed. Any attempt that +may be made to increase the delicacy of apparatus by reducing their +dimensions is at once prevented by the relatively great importance of +the vagaries of the silk suspension. + +The result, then, is this. The smallness, the length of period, and +therefore delicacy, of the instruments at the physicist's disposal +have until lately been simply limited by the behavior of silk. A more +perfect suspension means still more perfect instruments, and therefore +advance in knowledge. + +It was in this way that some improvements that I was making in an +instrument for measuring radiant heat came to a deadlock about two +years ago. I would not use silk, and I could not find anything else +that would do. Spun glass, even, was far too coarse for my purpose, it +was a thousand times too stiff. + +[Illustration: FIG. 5.] + +There is a material invented by Wollaston long ago, which, however, I +did not try because it is so easily broken. It is platinum wire which +has been drawn in silver, and finally separated by the action of +nitric acid. A specimen about the size of a single line of silk is now +on the screen, showing the silver coating at one end (Fig. 5). + +As nothing that I knew of could be obtained that would be of use to +me, I was driven to the necessity of trying by experiment to find some +new material. The result of these experiments was the development of a +process of almost ridiculous simplicity which it may be of interest +for me to show. + +The apparatus consists of a small crossbow, and an arrow made of straw +with a needle point. To the tail of the arrow is attached a fine rod +of quartz which has been melted and drawn out in the oxyhydrogen jet. +I have a piece of the same material in my hand, and now after melting +their ends and joining them together, an operation which produces a +beautiful and dazzling light, all I have to do is to liberate the +string of the bow by pulling the trigger with one foot, and then if +all is well a fiber will have been drawn by the arrow, the existence +of which can be made evident by fastening to it a piece of stamp +paper. + +In this way threads can be produced of great length, of almost any +degree of fineness, of extraordinary uniformity, and of enormous +strength. I do not believe, if any experimentalist had been promised +by a good fairy that he might have anything he desired, that he would +have ventured to ask for any one thing with so many valuable +properties as these fibers possess. I hope in the course of this +evening to show that I am not exaggerating their merits. + +[Illustration: FIG. 6.] + +[Illustration: FIG. 7.] + +In the first place, let me say something about the degree of fineness +to which they can be drawn. There is now projected upon the screen a +quartz fiber one five-thousandth of an inch in diameter (Fig. 6). This +is one which I had in constant use in an instrument loaded with about +30 grains. It has a section only one-sixth of that of a single line of +silk, and it is just as strong. Not being organic, it is in no way +affected by changes of moisture and temperature, and so it is free +from the vagaries of silk which give so much trouble. The piece used +in the instrument was about 16 inches long. Had it been necessary to +employ spun glass, which hitherto was the finest torsion material, +then, instead of 16 inches, I should have required a piece 1,000 feet +long, and an instrument as high as the Eiffel tower to put it in. + +There is no difficulty in obtaining pieces as fine as this yards long +if required, or in spinning it very much finer. There is upon the +screen a single line made by the small garden spider, and the size of +this is perfectly evident (Fig. 7). You now see a quartz fiber far +finer than this, or, rather, you see a diffraction phenomenon, for no +true image is formed at all; but even this is a conspicuous object in +comparison with the tapering ends, which it is absolutely impossible +to trace in a microscope. The next two photographs, taken by Mr. +Nelson, whose skill and resources are so famous, represent the extreme +end of a tail of quartz, and, though the scale is a great deal larger +than that used in the other photographs, the end will be visible only +to a few. Mr. Nelson has photographed here what it is absolutely +impossible to see. What the size of these ends may be, I have no means +of telling. Dr. Royston Piggott has estimated some of them at less +than one-millionth of an inch, but, whatever they are, they supply for +the first time objects of extreme smallness the form of which is +certainly known, and, therefore, I cannot help looking upon them as +more satisfactory tests for the microscope than diatoms and other +things of the real shape of which we know nothing whatever. + +Since figures as large as a million cannot be realized properly, it +may be worth while to give an illustration of what is meant by a fiber +one-millionth of an inch in diameter. + +A piece of quartz an inch long and an inch in diameter would, if drawn +out to this degree of fineness, be sufficient to go all the way round +the world 658 times; or a grain of sand just visible--that is, +one-hundredth of an inch long and one hundredth of an inch in +diameter--would make one thousand miles of such thread. Further, the +pressure inside such a thread due to a surface tension equal to that +of water would be 60 atmospheres. + +Going back to such threads as can be used in instruments, I have made +use of fibers one ten-thousandth of an inch in diameter, and in these +the torsion is 10,000 times less than that of spun glass. + +As these fibers are made finer their strength increases in proportion +to their size, and surpasses that of ordinary bar steel, reaching, to +use the language of engineers, as high a figure as 80 tons to the +inch. Fibers of ordinary size have a strength of 50 tons to the inch. + +While it is evident that these fibers give us the means of producing +an exceedingly small torsion, and one that is not affected by weather, +it is not yet evident that they may not show the same fatigue that +makes spun glass useless. I have, therefore, a duplicate apparatus +with a quartz fiber, and you will see that the spot of light comes +back to its true place on the screen after the mirror has been twisted +round twice. + +I shall now for a moment draw your attention to that peculiar property +of melted quartz that makes threads such as I have been describing a +possibility. A liquid cylinder, as Plateau has so beautifully shown, +is an unstable form. It can no more exist than can a pencil stand on +its point. It immediately breaks up into a series of spheres. This is +well illustrated in that very ancient experiment of shooting threads +of resin electrically. When the resin is hot, the liquid cylinders, +which are projected in all directions, break up into spheres, as you +see now upon the screen. As the resin cools, they begin to develop +tails; and when it is cool enough, i.e., sufficiently viscous, the +tails thicken and the beads become less, and at last uniform threads +are the result. The series of photographs show this well. + +[Illustration: FIG. 8.] + +[Illustration: FIG. 9.] + +There is a far more perfect illustration which we have only to go into +the garden to find. There we may see in abundance what is now upon the +screen--the webs of those beautiful geometrical spiders. The radial +threads are smooth like the one you saw a few minutes ago, but the +threads that go round and round are beaded. The spider draws these +webs slowly, and at the same time pours upon them a liquid, and still +further to obtain the effect of launching a liquid cylinder in space +he, or rather she, pulls it out like the string of a bow, and lets it +go with a jerk. The liquid cylinder cannot exist, and the result is +what you now see upon the screen (Fig. 8). A more perfect illustration +of the regular breaking up of a liquid cylinder it would be impossible +to find. The beads are, as Plateau showed they ought to be, +alternately large and small, and their regularity is marvelous. +Sometimes two still smaller beads are developed, as may be seen in the +second photograph, thus completely agreeing with the results of +Plateau's investigations. + +I have heard it maintained that the spider goes round her web and +places these beads there afterward. But since a web with about 360,000 +beads is completed in an hour--that is at the rate of about 100 a +second--this does not seem likely. That what I have said is true, is +made more probable by the photograph of a beaded web that I have made +myself by simply stroking a quartz fiber with a straw wetted with +castor oil (Fig. 9); it is rather larger than a spider line; but I +have made beaded threads, using a fine fiber, quite indistinguishable +from a real spider web, and they have the further similarity that they +are just as good for catching flies. + +Now, going back to the melted quartz, it is evident that if it ever +became perfectly liquid, it could not exist as a fiber for an instant. +It is the extreme viscosity of quartz, at the heat even of an electric +arc, that makes these fibers possible. The only difference between +quartz in the oxyhydrogen jet and quartz in the arc is that in the +first you make threads and in the second are blown bubbles. I have in +my hand some microscopic bubbles of quartz showing all the perfection +of form and color that we are familiar with in the soap bubble. + +An invaluable property of quartz is its power of insulating perfectly, +even in an atmosphere saturated with water. The gold leaves now +diverging were charged some time before the lecture, and hardly show +any change, yet the insulator is a rod of quartz only three-quarters +of an inch long, and the air is kept moist by a dish of water. The +quartz may even be dipped in the water and replaced with the water +upon it without any difference in the insulation being observed. + +Not only can fibers be made of extreme fineness, but they are +wonderfully uniform in diameter. So uniform are they that they +perfectly stand an optical test so severe that irregularities +invisible in any microscope would immediately be made apparent. Every +one must have noticed when the sun is shining upon a border of flowers +and shrubs how the lines which spiders use as railways to travel from +place to place glisten with brilliant colors. These colors are only +produced when the fibers are sufficiently fine. If you take one of +these webs and examine it in the sunlight, you will find that the +colors are variegated, and the effect, consequently, is one of great +beauty. + +A quartz fiber of about the same size shows colors in the same way, +but the tint is perfectly uniform on the fiber. If the color of the +fiber is examined with a prism, the spectrum is found to consist of +alternate bright and dark bands. Upon the screen are photographs +taken by Mr. Briscoe, a student in the laboratory at South Kensington, +of the spectra of some of these fibers at different angles of +incidence. It will be seen that coarse fibers have more bands than +fine, and that the number increases with the angle of incidence of the +light. There are peculiarities in the march of the bands as the angle +increases which I cannot describe now. I may only say that they appear +to move not uniformly, but in waves, presenting very much the +appearance of a caterpillar walking. + +So uniform are the quartz fibers that the spectrum from end to end +consists of parallel bands. Occasionally a fiber is found which +presents a slight irregularity here and there. A spider line is so +irregular that these bands are hardly observable; but, as the +photograph on the screen shows, it is possible to trace them running +up and down the spectrum when you know what to look for. + +To show that these longitudinal bands are due to the irregularities, I +have drawn a taper piece of quartz by hand, in which the two edges +make with one another an almost imperceptible angle, and the spectrum +of this shows the gradual change of diameter by the very steep angle +at which the bands run up the spectrum. + +Into the theory of the development of these bands I am unable to +enter; that is a subject on which your professor of natural philosophy +is best able to speak. Perhaps I may venture to express the hope, as +the experimental investigation of this subject is now rendered +possible, that he may be induced to carry out a research for which he +is so eminently fitted. + +Though this is a subject which is altogether beyond me, I have been +able to use the results in a practical way. When it is required to +place into an instrument a fiber of any particular size, all that has +to be done is to hold the frame of fibers toward a bright and distant +light, and look at them through a low-angled prism. The banded spectra +are then visible, and it is the work of a moment to pick out one with +the number of bands that has been found to be given by a fiber of the +desired size. A coarse fiber may have a dozen or more, while such +fibers as I find most useful have only two dark bands. Much finer ones +exist, showing the colors of the first order with one dark band; and +fibers so fine as to correspond to the white or even the gray of +Newton's scale are easily produced. + +Passing now from the most scientific test of the uniformity of these +fibers, I shall next refer to one more homely. It is simply this: The +common garden spider, except when very young, cannot climb up one of +the same size as the web on which she displays such activity. She is +perfectly helpless, and slips down with a run. After vainly trying to +make any headway, she finally puts her hands (or feet) into her mouth +and then tries again, with no better success. I may mention that a +male of the same species is able to run up one of these with the +greatest ease, a feat which may perhaps save the lives of a few of +these unprotected creatures when quartz fibers are more common. + +It is possible to make any quantity of very fine quartz fiber without +a bow and arrow at all, by simply drawing out a rod of quartz over and +over again in a strong oxyhydrogen jet. Then, if a stand of any sort +has been placed a few feet in front of the jet, it will be found +covered with a maze of thread, of which the photograph on the screen +represents a sample. This is hardly distinguishable from the web spun +by this magnificent spider in corners of greenhouses and such places. +By regulating the jet and the manipulation, anything from one of these +stranded cables to a single ultro-microscope line may be developed. + +And now that I have explained that these fibers have such valuable +properties, it will no doubt be expected that I should perform some +feat with their aid which, up to the present time, has been considered +impossible, and this I intend to do. + +Of all experiments, the one which has most excited my admiration is +the famous experiment of Cavendish, of which I have a full size model +before you. The object of this experiment is to weigh the earth by +comparing directly the force with which it attracts things with that +due to large masses of lead. As is shown by the model, any attraction +which these large balls exert on the small ones will tend to deflect +this 6 ft. beam in one direction, and then if the balls are reversed +in position, the deflection will be in the other direction. Now, when +it is considered how enormously greater the earth is than these balls, +it will be evident that the attraction due to them must be in +comparison excessively small. To make this evident, the enormous +apparatus you see had to be constructed, and then, using a fine +torsion wire, a perfectly certain but small effect was produced. The +experiment, however, could only be successfully carried out in cellars +and underground places, because changes of temperature produced +effects greater than those due to gravity.[2] + + [Footnote 2: Dr. Lodge has been able, by an elaborate + arrangement of screens, to make this attraction just evident to + an audience.--C. V. B.] + +Now I have in a hole in the wall an instrument no bigger than a +galvanometer, of which a model is on the table. The balls of the +Cavendish apparatus, weighing several hundredweight each, are replaced +by balls weighing 1¾ pounds only. The smaller balls of 1¾ pounds are +replaced by little weights of 15 grains each. The 6 foot beam is +replaced by one that will swing round freely in a tube three-quarters +of an inch in diameter. The beam is, of course, suspended by a quartz +fiber. With this microscopic apparatus, not only is the very feeble +attraction observable, but I can actually obtain an effect eighteen +times as great as that given by the apparatus of Cavendish, and what +is more important, the accuracy of observation is enormously +increased. + +The light from a lamp passes through a telescope lens, and falls on +the mirror of the instrument. It is reflected back to the table, and +thence by a fixed mirror to the scale on the wall, where it comes to a +focus. If the mirror on the table were plane, the whole movement of +the light would be only about eight inches, but the mirror is convex, +and this magnifies the motion nearly eight times. At the present +moment the attracting weights are in one extreme position, and the +line of light is quiet. I will now move them to the other position, +and you will see the result--the light slowly begins to move, and +slowly increases in movement. In forty seconds it will have acquired +its highest velocity, and in forty more it will have stopped at 5 +feet 8½ inches from the starting point, after which it will slowly +move back again, oscillating about its new position of rest. + +It is not possible at this hour to enter into any calculations; I will +only say that the motion you have seen is the effect of a force of +less than one ten-millionth of the weight of a grain, and that with +this apparatus I can detect a force two thousand times smaller still. +There would be no difficulty even in showing the attraction between +two No. 5 shot. + +And now, in conclusion, I would only say that if there is anything +that is good in the experiments to which I have this evening directed +your attention, experiments conducted largely with sticks, and string, +and straw and sealing wax, I may perhaps be pardoned if I express my +conviction that in these days we are too apt to depart from the simple +ways of our fathers, and instead of following them, to fall down and +worship the brazen image which the instrument maker hath set up. + + * * * * * + + + + +NATURE, COMPOSITION, AND TREATMENT OF ANIMAL AND VEGETABLE FABRICS. + + +The inseparable duties of studying the composition of the various +animal and vegetable fabrics, as also their nature--when in contact +with the various mineral, vegetable, animal, and gaseous bodies +applied in the individual industries--should not devolve upon the +heads, chemists, or managers of firms alone. It is most important that +every intelligent workman, whom we cannot expect to acquire a very +extensive knowledge of chemistry and perfect acquaintance of the +particular nature and component parts of fabrics, should, at least, be +able to thwart the possibility of the majority of accidents brought +about in regard to the quality and aspect of materials treated by +them. + +In the treatment of wool the first operations are of no mean +importance, and the whole subsequent operations and final results, +almost as a whole, depend on the manner in which the fleece washing +had been effected. In presence of suintine, as also fatty matters, as +well as the countless kinds of acids deposited on the wool through +exudation from the body, etc., the various agents and materials cannot +act and deposit as evenly as might be desired, and the complete +obliteration of the former, therefore, becomes an absolute necessity. + +For vegetable fabrics a great technical and practical knowledge is +already requisite in their cultivation itself, and before any +operations are necessary at all. One of the greatest points is the +ripeness of the fibers. It is almost an impossibility to produce +delicate colors on vegetable fabrics which were gathered +inopportunely. Numerous experiments have been made on cotton +containing smaller or larger quantities of unripe fibers, and after +the necessary preceding operations, have been dyed in rose, purple, +and blue colors, and the beauty of the shades invariably differed in +proportion to the greater or lesser quantities of unripe fibers +contained in the samples, and by a careless admixture of unripe and +unseasoned fibers the most brilliant colors have been completely +spoiled in the presence of the former. These deficiencies of unripe +vegetable fibers are so serious that the utmost precautions should be +taken, not only by planters to gather the fibers in a ripe state, but +the natural aspect of ripe and unripe fibers and their respective +differences should be known to the operators of the individual +branches in the cotton industry themselves. + +The newest vegetable fabrics, as _ma_ (China grass), pina, _abaca_, or +Manila hemp, _agave_, jute, and that obtained from the palm tree, must +be tended with equal care to that of cotton. The _ma_, or China grass, +is obtained from the _Boehmeria nivea_, as also from the less known +_Boehmeria puya_. The fibers of this stalk, after preparing and +bleaching, have the whiteness of snow and the brilliancy of silk. By a +special process--the description of which we must for the present +leave in abeyance--the China grass can be transformed into a material +greatly resembling the finest quality of wool. The greatest advantage +afforded in the application of China grass is, moreover, that the +tissues produced with this fiber are much more easily washed than +silks, and in this operation they lose none of their beauty or their +quality. + +The _abaca_ is produced from the fibrous parts of the bark of the wild +banana tree, found in the Philippines. Its botanical denomination is +_Musa troglodytarum_. The _abaca_ fiber is not spun or wrung, but is +jointed end to end. The threads are wound and subsequently beaten for +softening, and finally bleached by plunging in lime water for +twenty-four hours, and dried in the sun. + +The _pina_ is a fiber obtained from the leaf of the anana tree +(_Bromelias ananas_), and is prepared in the same way as the abaca, +but extreme care must in this case be observed in culling the fibers, +in order to sort in accordance with their degree of fineness. + +The Arabs manufacture the stuff for their tents with a mixture of +camel's hair and the fibrous flocks (kind of wadding) obtained from +the stalks of the wafer palm (the _Chamęrops humilis_). + +The tissues used by the Arabs are coarse and colored, but the palm +fibers--when freed from gluten, which makes them adhere more +strongly--are susceptible to divide in a most astonishing manner. + +The _Agave americana_ is a coarse fiber, mostly used in France for the +manufacture of Gobelin carpets and the production of ropes. Great +efforts have been made to bleach it in a satisfactory manner, as is +done with the _Phormium tenax_, but the former kind of fiber resists +the ordinary treatment with lyes, etc., and an appropriate bleaching +process has only been discovered quite recently. + +Jute, which by many is confounded with _Phormium tenax_, or New +Zealand lint, is a fiber which can be divided as finely as desired, +and can be most beautifully bleached. + +The jute or Indian _paat_ is generally known as a fibrous and textile +fabric, obtained chiefly from Calcutta, and is similar in nature to +the _Corchorus capsularis_, an Oriental species, known in Oriental +India by the name of _hatta jute_ and _gheenatlapaat_. This fibrous +plant has the property of dividing into the finest parallel fibers, +which can be carded without difficulty, and may be said to have the +excellent properties of linen, hemp, and cotton at once. When properly +bleached, it has an aspect which is as beautiful as that of silk. A +mixture of silk and jute can be easily worked together, and can also +be mixed with such vegetable fibers as cotton and linen. An immense +quantity of flannel and other stuffs are now manufactured and imitated +with the different mixtures containing jute. + +The _suun_ is a fiber of a plant in the form of a cane (_Crotalaria +juncea_), and the paat or _suncheepaat_ is the thread of a species of +spiral (_Corchorus olitarius_), sold under the name of jute tissues. + +The cotton tissues lose about twenty-five per cent. of their weight in +bleaching, five per cent. of the substances are dissolved through +alkalies, and the other twenty per cent., which are not attacked +directly through the alkalies, are removed through chlorine, acids, +and the water itself. The linen and hemp tissues contain eighteen per +cent. of substances which are soluble in alkalies, and they lose from +twenty-seven to thirty per cent. of their weight when taken through +the consecutive bleaching operations. + +The substances do not alone include the substances contained in the +fabric originally, but also such as are deposited in the preliminary +treatment of the fabrics, as dirt from the hands of the operator, and +gluten soluble in warm water; as also glue or gelatine, potash or +soda, starch, albumen, and sugar, used by weavers, etc., and which are +all soluble in water; further, such as greasy matters, calcareous +soap, coppery soap, resinous or gummo-resinous matters, and the yellow +and green coloring matters contained in textile fabrics, which are +soluble in caustic soda; and finally, the earthy constituents which +are soluble in acids. + +The nature and composition of silk and wool is diametrically opposed +to that of the former. The silk is more of a gummy nature, and is +susceptible to decompose into a kind of gelatinous mass if specially +treated. + +The yellow coloring principle in silk was found only to be contained +in a very small proportion, and consisting of several distinct bodies. + +The wool contains, first, a fatty matter which is solid at an ordinary +temperature, and perfectly liquid at 60° C.; secondly, a fatty matter +which is liquid at 15° C.; thirdly, a fibrous substance which +essentially constitutes the wool in the strict sense of the word. + +The wool at least contains three important principles, as it will be +known that the fibrous substance disengages sulphur and +hydro-sulphuric acid without losing its peculiar properties; and it, +therefore, appears probable that the sulphur entered as an element in +the composition of a body which is perfectly distinct from the fibrous +substance aforementioned. + +In treating wool with nitric acid, and taking all possible precautions +to determine as accurately as possible the quantity of sulphuric acid +produced by the contents of sulphur in the wool by the reaction with +chloride of barium, it will be found to contain from 1.53 to 1.87 per +cent. of sulphur.--_Wool and Textile Fabrics._ + + * * * * * + + + + +THE PRODUCTION OF AMMONIA FROM COAL.[1] + +By LUDWIG MOND. + + [Footnote 1: A paper read at the annual general meeting of the + Society of Chemical Industry, London, July 10, 1889.] + + +As exemplifying to a certain extent the application of methodical +research to an industrial problem, I propose to bring before you +to-day an account of the work I have been engaged in for many years in +relation to the procuring of new and abundant supplies of ammonia, and +to investigations connected therewith. + +Through the classic researches of Lawes and Gilbert, who proved, in +opposition to no less an authority than Liebig, that ammonia is a most +valuable manure which enables us not only to maintain, but to +multiply, the yield of our fields, and thus to feed on the same area a +much larger number of inhabitants, the immense importance of an +abundant supply of ammonia, more particularly for the Old World, with +its teeming population and worn-out soil, has been apparent to every +one. + +For many years Europe has paid to South America millions upon millions +of pounds for ammonia in the shape of guano, and more recently, since +the supply of guano practically ceased, for nitrate of soda, which +effectually serves the same purpose as ammonia. During the past year +South America exported 750,000 tons of nitrate, of which 650,000 went +to Europe, representing a value of not less than 6,500,000l. + +The problem of saving this immense expenditure to Europe, of making +ourselves independent of a country so far away for the supply of a +material upon which the prosperity of our agriculture--our most +important industry--depends, by supplying this ammonia from sources at +our own command, is certainly one of the most important which our +science has to solve. + +It is more than 100 years since Berthollet ascertained that ammonia +consists of nitrogen and hydrogen, two elements which we have in great +abundance at our command, and innumerable attempts have been made +during this century to produce this valuable product by the direct +combination of the elements, as well as by indirect means. It has been +equally well known that we are in possession of three abundant sources +of nitrogen: + + (1.) In the shape of matter of animal origin. + + (2.) In the shape of matter of vegetable origin. + + (3.) In the atmosphere, which contains no less than 79 per cent. + of uncombined nitrogen. + +In olden times ammonia was principally obtained from animal matter, +originally in Egypt by the distillation of camel dung, later on from +urine, and from the distillation of bones and horn. The quantity so +obtained was very small and the products very expensive. The +introduction of coal gas for illumination gave us a considerable and +constantly increasing supply of ammonia as a by-product of the gas +manufacture, and until recently all practical efforts to increase our +supply of ammonia were directed toward collecting and utilizing in the +best possible manner the ammonia so obtained. The immense extension of +the coal gas industry all over the world has in this way put us into +possession of a very considerable amount of sulphate of ammonia, +amounting in Europe now to 140,000 tons per annum. In recent years +this has been augmented by the ammonia obtained by the distillation of +shale, by the introduction of closed ovens for the manufacture of +coke, combined with apparatus for condensing the ammonia formed in +this manufacture, and also by the condensation of the ammonia +contained in the gases from blast furnaces working with coal. But all +these new sources have so far added only about 40,000 tons of +sulphate of ammonia to our supply, making a total of 180,000 tons per +annum, of which about 120,000 are produced in the United Kingdom, +while we still import 650,000 tons of nitrate of soda, equivalent to +500,000 tons of sulphate of ammonia, to make up our requirements. + +Many processes have from time to time been proposed to obtain ammonia +from other sources. The distillation of turf, which contains upward of +3 per cent. of nitrogen, has received much attention, and a large +number of inventors have endeavored to produce ammonia from the +nitrogen of the air; but none of these processes has to my knowledge +been successful on a manufacturing scale. + +My attention was called to this subject at an early part of my career. +Already, as far back as 1861, I undertook experiments to utilize, for +the production of ammonia, waste leather, a waste material of animal +origin at once abundant and very rich in nitrogen, containing from 12 +per cent. to 15 per cent. of this element. Distillation in iron +retorts yielded about half the nitrogen of this material in the form +of ammonia, the carbon remaining in the retorts containing still from +6 per cent. to 8 per cent. Distillation with a moderate quantity of +hydrate of lime increased the yield of ammonia only by 1 per cent. to +1½ per cent. A rather better result was obtained by distilling the +ground residual carbon with hydrate of lime, but this operation +proceeded very slowly, and the total yield of ammonia still remained +very far below the quantity theoretically obtainable, so that I came +to the conclusion that it was more rational to utilize the leather, +reduced to powder by mechanical means, by mixing it directly with +other manures. + +A few years later I became connected with a large animal charcoal +works, in which sulphate of ammonia was obtained as a by-product. Here +again I was met with the fact that the yield of ammonia by no means +corresponded with the nitrogen in the raw material and that the +charcoal remaining in the retorts contained still about half as much +nitrogen as had been present in the bones used. + +From this time forward my attention was for many years given +exclusively to the soda manufacture, and it was only in 1879 that I +again took up the question of ammonia. I then determined to submit the +various processes which had been proposed for obtaining ammonia from +the nitrogen of the air to a searching investigation, and engaged Mr. +Joseph Hawliczek to carry out the experimental work. + +These processes may be broadly divided into three classes: + + (1.) Processes which propose to combine nascent hydrogen with + nitrogen at high temperatures or by electricity, with or without + the presence of acid gases. + + (2.) Processes in which nitrides are first formed, from which + ammonia is obtained by the action of hydrogen or steam. + + (3.) Processes in which cyanides are first formed and the ammonia + obtained from these by the action of steam. + +We began with an investigation of those processes in which a mixture +of steam and nitrogen or of steam and air is made to act upon coke at +a high temperature, sometimes in the presence of lime, baryta, or an +alkali, sometimes in the presence of hydrochloric acid. + +Very numerous patents have been taken out in this direction and there +is no doubt that ammonia has been obtained by these processes by many +inventors, but as I was aware that coke contains a considerable +quantity of nitrogen, frequently as much as 1.5 per cent., which might +be the source of the ammonia obtained, I determined to carry on the +investigation in such a way as to make quite certain whether we +obtained the ammonia from the coke or from the nitrogen of the +atmosphere, or from both. For this purpose we made for every +experiment carried on by a mixture of nitrogen or air with steam +another experiment with steam alone, carefully excluding nitrogen from +the apparatus. A very large number of experiments carried on at +carefully determined temperatures, ranging from 500° to 1,200°C., and +in which the directions given by the various inventors were most +carefully observed, all led to the same result, viz., that the +quantities of ammonia obtained were the same whether nitrogen was +introduced into the apparatus with the steam or whether steam alone +was used, thus proving conclusively that the ammonia obtained was +derived from the nitrogen contained in the coke. + +Further, on carefully determining the nitrogen in the coke used, it +was found that the quantity of ammonia we had obtained in burning coke +in a current of nitrogen and steam very nearly corresponded with the +total nitrogen in the coke, so that we subsequently made our nitrogen +determinations in the coke by simply burning it in a current of steam. + +A process belonging to this class, proposed by Hugo Fleck, in which a +mixture of carbonic oxide, steam, and nitrogen is made to pass over +lime at a moderate red heat in order to obtain ammonia, was also +carefully tried. It was claimed for this process that it produced +nascent hydrogen at temperatures at which the ammonia is not +dissociated, and for this reason succeeded where others had failed. We +found that a considerable amount of hydrogen was obtained in this way +at a temperature not exceeding 350°C., and that the reaction was +nearly complete at 500°C.; but although we tried many experiments over +a great range of temperatures, we never obtained a trace of ammonia by +this process. + +Among experiments with processes of the second class, based upon the +formation of nitrides and their subsequent decomposition, the nitrides +of boron and titanium had received most attention from inventors. The +nitride of boron, which is obtained by treating boracic acid with +carbon in the presence of nitrogen, when acted upon by steam, forms +boracic acid again and yields the whole of its nitrogen in the form of +ammonia, but the high temperature at which the first reaction takes +place, and the volatility of boracic acid in a current of steam, make +it impossible to utilize this reaction industrially. + +There seemed to be a better chance for a process patented by M. +Tessier du Mothay, who proposed to bring a mixture of nitrogen and +hydrogen into contact with titanium nitride and thus to form ammonia +continuously. Titanium is the only element of which we know at present +several combinations with nitrogen, and the higher of these does, on +being acted upon by a current of hydrogen at an elevated temperature, +produce ammonia and a lower nitride of titanium; but this lower +nitride does not absorb nitrogen under any of the conditions under +which we tried it, which explains the fact that if we passed a current +of hydrogen and nitrogen over the higher nitride, we at first obtained +a quantity of ammonia corresponding to the quantity which the nitride +would give with hydrogen alone, but that the formation of ammonia then +ceased completely. + +Thus far we had quite failed to get the nitrogen of the air into +action. + +With the third class of processes, however, based upon the formation +in the first instance of cyanides, we found by our very first +experiments that the nitrogen of the atmosphere can be easily led into +combination. A few experiments showed that the cyanide of barium was +much more readily formed than any other cyanide; so we gave our full +attention from this time to the process for obtaining ammonia by means +of cyanide of barium invented by MM. Margueritte and Sourdeval. This +process consists in heating a mixture of carbonate of barium with +carbon in the presence of nitrogen, and subsequently treating the +cyanide of barium produced with steam, thus producing ammonia and +regenerating the carbonate of barium. A great difficulty in this +process is that the carbonate of barium fuses at high temperatures, +and when fused attacks fireclay goods very powerfully. + +We found that this can be overcome by mixing the carbonate of barium +with a sufficient quantity of carbon and a small quantity of pitch, +and that in this way balls can be made which will not fuse, so that +they can be treated in a continuous apparatus in which the broken +briquettes can be charged from the top, and after treatment can be +withdrawn from the bottom. + +We found that the formation of cyanides required a temperature of at +least 1,200° C., and proceeded most readily at 1,400° C., temperatures +which, although difficult to attain, are still quite within the range +of practical working, and we found no difficulty in obtaining a +product containing 30 per cent. of barium cyanide, corresponding to a +conversion into cyanide of 40 per cent. of the barium present. + +We found, however, that the cyanide when exposed to the atmosphere at +a temperature above 300° C. is readily destroyed under reformation of +carbonate of barium, so that it is absolutely necessary to cool it +down to this temperature before exposing it to the atmosphere, a fact +of great importance that had hitherto been overlooked. + +The operation for producing ammonia and regenerating the carbonate of +barium by acting upon the cyanide with steam offers no difficulty +whatever, and if the temperature is not allowed to exceed 500° C., the +results are quantitative. The regenerated carbonate of barium acts +actually better than the ground witherite used in the first instance, +and if care is taken that no impurities are introduced by the pitch +which is used to remake the briquettes and to replace the small amount +of carbon consumed at each operation, I see no reason why it should +not continue to act for a very long time. + +The cyanide is not acted on by carbonic oxide, but carbonic acid +destroys it at high temperatures, so that it is not possible to +produce it by heating the briquettes directly in a flame free from +oxygen, but containing carbonic acid. The process has, therefore, to +be carried out in closed vessels, and I designed for this purpose the +following apparatus: + +Clay retorts of moderate dimensions and thin walls are placed +vertically in a furnace, passing through the hearth as well as through +the arch of the furnace. These are joined at the bottom to cast iron +retorts of the same shape as the earthenware retort. Through a cast +iron mouthpiece on the top of the retort the material was introduced, +while in the cast iron retort below the material was cooled to the +necessary temperature by radiation and by the cold nitrogen gas +introduced into the bottom of it. The lower end of the cast iron +retort was furnished with an arrangement for taking out from time to +time small quantities of the material, while fresh material was in the +same proportion fed in at the top. As a source of nitrogen I used the +gases escaping from the carbonating towers of the ammonia-soda +process. The formation of cyanide of barium from barium carbonate, +carbon, and nitrogen absorbs a very large amount of heat--no less than +97,000 calories per equivalent of the cyanide formed--which heat has +to be transmitted through the walls of the retort. I therefore +considered it necessary to use retorts with very thin walls, but I did +not succeed in obtaining retorts of this description which would +resist the very high temperatures which the process requires, and for +this reason I abandoned these experiments. I was at that time not +acquainted with the excellent quality of clay retorts used in zinc +works, with which I have since experimented for a different purpose. I +have no doubt that with such retorts the production of cyanides by +this process can be carried out without great difficulty. + +I believe that the process will prove remunerative for the manufacture +of cyanogen products, which, if produced more cheaply, may in the +future play an important role in organic synthesis, in the extraction +of noble metals, and possibly other chemical and metallurgical +operations. + +The process certainly also offers a solution of the problem of +obtaining ammonia from the nitrogen of the atmosphere, but whether +this can be done with satisfactory commercial results is a question I +cannot at present answer, as I have not been able to secure the data +for making the necessary calculations. + +I am the more doubtful about this point, as in the course of our +investigations I have found means to produce ammonia at small cost and +in great abundance from the immense store of combined nitrogen which +we possess in our coal fields. + +Among the processes for obtaining ammonia from the nitrogen of the air +which we investigated, was one apparently of great simplicity, +patented by Messrs. Rickman and Thompson. These gentlemen state that +by passing air and steam through a deep coal fire, the nitrogen so +passed through is to a certain extent converted into ammonia. In +investigating this statement we found that the process described +certainly yields a considerable quantity of ammonia, but when we +burned the same coal at a moderate temperature by means of steam +alone in a tube heated from the outside, we obtained twice as much +ammonia as we had done by burning it with a mixture of air and steam, +proving in this case, as in all others, the source of the ammonia to +have been the nitrogen contained in the coal. The quantity of ammonia +obtained was, however, so large that I determined to follow up this +experience, and at once commenced experiments on a semi-manufacturing +scale to ascertain whether they would lead to practical and economic +results. + +I came to the conclusion that burning coal by steam alone at a +temperature at which the ammonia formed should not be dissociated, +although it yielded more ammonia, would not lead to an economic +process, because it would require apparatus heated from the outside, +of great complication, bulk, and costliness, on account of the immense +quantity of raw material to be treated for a small amount of ammonia +obtainable. + +On the other hand, if the coal could be burned in gas producers by a +mixture of air and steam, the plant and working of it would be simple +and inexpensive, the gas obtained could be utilized in the same way as +ordinary producer gas, and would pay to a large extent for the coal +used in the operation, so that although only one-half of the ammonia +would be obtained, it seemed probable that the result would be +economical. + +I consequently constructed gas producers and absorbing plant of +various designs and carried on experiments for a number of years. +These experiments were superintended by Mr. G. H. Beckett, Dr. Carl +Markel, and, during the last four years, by Dr. Adolf Staub, to whose +zeal and energy I am much indebted for the success that has been +achieved. The object of these experiments was to determine the most +favorable conditions for the economic working of the process with +respect to both the cost of manufacture as well as the first cost and +simplicity of plant. The cost of manufacture depends mainly upon the +yield of ammonia, as the expenses remain almost the same whether a +large or a small amount of ammonia is obtained; the only other item of +importance is the quantity of steam used in the process. We found the +yield of ammonia to vary with the temperature at which the producer +was working, and to be highest when the producer was worked as cool as +was compatible with a good combustion of the fuel. The temperature +again depended upon the amount of steam introduced into the producer, +and of course decreased the more steam increased. We obtained the best +practical results by introducing about two tons of steam for every ton +of fuel consumed. We experimented upon numerous kinds of fuel, common +slack and burgy of the Lancashire, Staffordshire, and Nottinghamshire +districts. We found not much difference in the amount of nitrogen +contained in these fuels, which varied between 1.2 and 1.6 per cent., +nor did we find much difference in the ammonia obtained from these +fuels if worked under similar conditions. Employing the quantity of +steam just named we recovered about half the nitrogen in the form of +ammonia, yielding on an average 0.8 per cent. of ammonia, equal to 32 +kilos, of sulphate per ton of fuel. In order to obtain regular results +we found it necessary to work with a great depth of fuel in the +producers, so that slight irregularities in the working would not +affect results. Open burning kinds of slack do of course work with the +greater ease, but there is no difficulty in using a caking fuel, as +the low temperature at which the producers work prevents clinkering +and diminishes the tendency of such fuels to cake together. + +The quantity of steam thus required to obtain a good yield of ammonia +is rather considerable, and threatened to become a serious item of +expense. Only one-third of this steam is decomposed, in its passage +through the producer, and two-thirds remain mixed with the gases which +leave the producer. My endeavors were consequently directed toward +finding means to recover this steam, and to return it to the +producers, and also to utilize the heat of the gases which leave the +producers with a temperature of 450° to 500° C., for raising steam for +the same purpose. The difficulties in the way of attaining this end +and at the same time of recovering, in a simple manner, the small +amount of ammonia contained in the immense volume of gas we have to +deal with, were very great. We obtain from one ton of coal 160,000 +cubic feet of dry gas at 0° C. and atmospheric pressure. The steam +mixed with this gas as it leaves the producer adds another 80,000 +cubic feet to this, and the large amount of latent heat in this +quantity of steam makes the problem still more difficult. The +application of cooling arrangements, such as have been successfully +applied to blast furnace gases, in which there is no steam present, +and which depend upon the cooling through the metallic sides of the +apparatus, is here practically out of the question. After trying a +number of different kinds of apparatus, I have succeeded in solving +the problem in the following way: + +The gases issuing from the producers are led through a rectangular +chamber partly filled with water, which is thrown up in a fine spray +by revolving beaters so as to fill the whole area of the chamber. This +water, of course, becomes hot; a certain quantity of it evaporates, +the spray produced washes all dust and soot out of the gases, and also +condenses the fixed ammonia. The water thus becomes, to a certain +degree, saturated with ammonia salts, and a certain portion of it is +regularly removed from the chamber and distilled with lime to recover +the ammonia. + +[Illustration: Longitudinal Section of Plant for obtaining Ammonia +from Gas Producers. + +Cross Section through Gas Producers.] + +This chamber is provided with water lutes, through which the tar +condensed in it is from time to time removed. From this chamber the +gases, which are now cooled down to about 100° C., and are loaded with +a large amount of water vapor, are passed through a scrubber filled +with perforated bricks, in which the ammonia contained in the gases is +absorbed by sulphuric acid. In this scrubber a fairly concentrated +solution of sulphate of ammonia containing 36 to 38 per cent. is used, +to which a small quantity of sulphuric acid is added, so that the +liquid leaving the scrubber contains only 2.5 per cent. of free acid. +This is necessary, as a liquid containing more acid would act upon the +tarry matter and produce a very dark-colored solution. The liquid +running from the scrubber is passed through a separator in which the +solution of sulphate of ammonia separates from the tar. The greater +portion of the clear liquid is, after adding a fresh quantity of acid +to it, pumped back through the scrubber. A certain portion of it is, +after treatment with a small quantity of heavy tar oils, which take +the tarry matter dissolved in it out, evaporated in conical lead-lined +pans furnished with lead steam coils, and which are kept constantly +filled by the addition of fresh liquor until the whole mass is thick. +This is then run out on a strainer and yields, after draining and +washing with a little water, a sulphate of ammonia of very fair +quality, which finds a ready sale. The mother liquor, which contains +all the free acid, is pumped back to the scrubber. + +The gas on entering this scrubber contains only 0.13 volume per cent. +of ammonia, and on leaving the scrubber it contains not more than +one-tenth of this quantity. Its temperature has been reduced to +80° C., and is fully saturated with moisture, so that practically no +condensation of water takes place in the scrubber. The gas is next +passed through a second scrubber filled with perforated wood blocks. +In this it meets with a current of cold water which condenses the +steam, the water being thereby heated to about 78° C. In this scrubber +the gas is cooled down to about 40°-50° C., and passes from it to the +gas main leading to the various places where it is to be consumed. The +hot water obtained in this second scrubber is passed through a vessel +suitably constructed for separating the tar which is mixed with it, +and is then pumped through a third scrubber, through which, in an +opposite direction to the hot water, cold air is passed. This is +forced by means of a Roots blower through the scrubber into the +producer. + +The air gets heated to about 76° C. and saturated with moisture at +that temperature by its contact with the hot water, and the water +leaves this third scrubber cold enough to be pumped back through the +second scrubber. The same quantity of water is thus constantly used +for condensing the water vapor in one scrubber and giving it up to the +air in the other. In this way we recover and return to the producer +fully two-thirds of the steam which has been originally introduced, so +that we have to add to the air, which has thus been loaded with +moisture, an additional quantity of steam equal to only one-third of +the total quantity required before it enters the producer. This +additional quantity of steam, which amounts to 0.6 ton of steam for +every ton of fuel burnt, we obtain as exhaust steam from the engines +driving the blowers and pumps required for working the plant. + +The gas producers which I prefer to use are of rectangular shape, so +that a number of them can be put into a row. They are six feet wide +and 12 feet long inside. The air is introduced and the ashes removed +at the two small sides of the producer which taper toward the middle +and are closed at the bottom by a water lute of sufficient depth for +the pressure under which the air is forced in, equal to about 4 inches +of water. The ashes are taken out from underneath the water, the +producers having no grate or fire bars at all. The air enters just +above the level of the water through a pipe connected with the blower. +These small sides of the producer rest upon cast iron plates lined to +a certain height with brickwork, and this brickwork is carried by +horizontal cast iron plates above the air entrance. In this way a +chamber is formed of triangular shape, one side of which is closed by +the ashes, and thus the air is distributed over the whole width of the +producer. + +The gas is taken out in the middle of the top of the producer by an +iron pipe, and fuel charged in by hoppers on both sides of this pipe. +Between the pipe and the hoppers two hanging arches are put into the +producers a certain distance down, and the fuel is kept above the +bottom level of these hanging arches. This compels the products of +distillation, produced when fresh fuel is charged in, to pass through +the incandescent fuel between the two hanging arches, whereby the +tarry products are to a considerable extent converted into permanent +gas, and the coal dust arising from the charging is kept back in the +producer. + +The details of construction of this plant will be easily understood by +reference to the diagrams before you. + +The fuel we use is a common kind of slack, and contains, on an +average, 33.5 per cent. of volatile matter, including water, and 11.5 +per cent. of ashes, leaving 55 per cent. of non-volatile carbon. + +The cinders which we take out of the producer contain, on an average, +33 per cent. of carbon. Of this we recover about one-half by riddling +or picking, which we return to the producer. The amount of unburnt +carbon lost in the cinders is thus not more than 3 per cent. to 4 per +cent. on the weight of fuel used. + +The gas we obtain contains, in a dry state, on an average, 15 per +cent. of carbonic acid, 10 per cent. of carbonic oxide, 23 per cent. +of hydrogen, 3 per cent. of hydrocarbons, and 49 per cent. of +nitrogen. + +The caloric value of this gas is very nearly equal to 73 per cent. of +the caloric value of the fuel used, but in using this gas for heating +purposes, such as raising steam or making salt, we utilize the heat it +can give very much better than in burning fuel, as we can completely +burn it with almost the theoretical quantity of air, so that the +products of combustion resulting do not contain more than 1 to 2 per +cent. of free oxygen. Consequently the heat escaping into the chimney +is very much less than when fuel is burnt direct, and we arrive at +evaporating, by means of the gas, 85 per cent. of the water that we +would evaporate by burning the fuel direct, in ordinary fireplaces. + +We have, however, to use a certain quantity of steam in the producers +and in evaporating the sulphate of ammonia liquors, which has to be +deducted from the steam that can be raised by the gas in order to get +at the quantity of available steam therefrom obtainable. The former +amounts, as already stated, to 0.6 ton, the latter to 0.1 ton of steam +per ton of fuel burnt, making a total of 0.7 ton. The gas obtained +from one ton of fuel evaporates 5.8 tons of water in good steam +boilers, working at a rate of evaporation of 50 to 55 tons per 24 +hours under 90 lb. pressure. Deducting from this the 0.7 ton necessary +for working the plant leaves an available amount of steam raised by +the gas from one ton of fuel of 5.1 tons, equal to 75 per cent. of the +steam that we can obtain from the same fuel by hand firing. + +In addition to the gas, we obtain about 3 per cent. of tar from the +fuel. This tar is very thick, and of little commercial value. It +contains only 4 per cent. of oils volatile below 200° C., and 38 per +cent. of oils of a higher boiling point, consisting mostly of creosote +oils very similar to those obtained from blast furnaces; and only +small quantities of anthracene and paraffin wax. + +I have made no attempts to utilize this tar except as fuel. It +evaporates nearly twice as much water as its weight of coal, and we +have thus to add its evaporative efficiency to that of the gas given +above, leading to a total of about 80 per cent. of the evaporative +efficiency of the fuel used in the producers. The loss involved in +gasifying the fuel to recover the ammonia therefrom amounts thus to 20 +per cent. of the fuel used. This means that, where we have now to burn +100 tons of fuel, we shall have to burn 125 tons in the producers in +order to obtain ammonia equal to about half the nitrogen contained +therein. Our actual yield of ammonia on a large scale amounting on an +average to 32 kilos., equal to 70.6 lb. per ton of fuel, 125 tons of +fuel will turn out 4 tons of sulphate of ammonia. We thus consume 6.25 +tons of fuel for every ton of sulphate obtained, or nearly the same +quantity as is used in producing a ton of caustic soda by the Le Blanc +process--a product not more than half the value of ammonium sulphate. +At present prices in Northwich this fuel represents a value of 35s. If +we add to this the extra cost of labor over and above the cost of +burning fuel in ordinary fireplaces, the cost of sulphuric acid, bags, +etc., we come to a total of 4l. 10s. to 5l. per ton of sulphate of +ammonia, which at the present selling price of this article, say 12l. +per ton, leaves, after a liberal allowance for wear and tear of plant, +an ample margin of profit. With a rise in the price of fuel, this +margin, however, rapidly decreases, and the working of the process +will, of course, be much more expensive on a small scale, as will also +be the cost of the plant, which under all circumstances is very +considerable. The great advantages incidental to this process over and +above the profit arising from the manufacture of sulphate of ammonia, +viz., the absolute impossibility of producing smoke and the great +regularity of the heating resulting from the use of gas, are, +therefore, as far as I can see for the present, only available for +large consumers of cheap fuel. + +We have tried many experiments to produce hydrochloric acid in the +producers, with the hope of thereby increasing the yield of ammonia, +as it is well known that ammonium chloride vapor, although it consists +of a mixture of ammonia gas and hydrochloric acid gas, is not at all +dissociated at temperatures at which the dissociation of ammonia alone +has already taken place to a considerable extent. + +I had also hoped that I might in this way produce the acid necessary +to combine with the ammonia at very small cost. For this purpose we +moistened the fuel used with concentrated brine, and also with the +waste liquors from the ammonia soda manufacture, consisting mainly of +chloride of calcium; and we also introduced with the fuel balls made +by mixing very concentrated chloride of calcium solution with clay, +which allowed us to produce a larger quantity of hydrochloric acid in +the producer than by the other methods. + +We did in this way succeed in producing hydrochloric acid sometimes +less and sometimes more than was necessary to combine with the +ammonia, but we did not succeed in producing with regularity the exact +amount of acid necessary to neutralize the ammonia. When the ammonia +was in excess, we had therefore to use sulphuric acid as before to +absorb this excess, and we were never certain that sometimes the +hydrochloric acid might not be in excess, which would have +necessitated to construct the whole plant so that it could have +resisted the action of weak hydrochloric acid--a difficulty which I +have not ventured to attack. The yield of ammonia was not in any case +increased by the presence of the hydrochloric acid. This explains +itself if we consider that there is only a very small amount of +ammonia and hydrochloric acid diffused through a very large volume of +other gases, so that the very peculiar protective action which the +hydrochloric acid does exercise in retarding the dissociation of +ammonia in ammonium chloride vapor, where an atom of ammonia is always +in contact with an atom of hydrochloric acid, will be diminished +almost to zero in such a dilute gas where the atoms of hydrochloric +acid and ammonia will only rarely come into immediate contact with +each other. + +When we burnt coke by a mixture of air and steam in presence of a +large excess of hydrochloric acid, the yield of ammonia certainly was +thereby considerably increased, but such a large excess cannot be used +on an industrial scale. I have therefore for the present to rest +satisfied with obtaining only half the nitrogen contained in the fuel +in the form of ammonia. + +The enormous consumption of fuel in this country--amounting to no less +than 150 million tons per annum--would at this rate yield as much as +five million tons of sulphate of ammonia a year, so that if only +one-tenth of this fuel would be treated by the process, England alone +could supply the whole of the nitrogenous compounds, sulphate of +ammonia, and nitrate of soda at present consumed by the Old World. As +the process is especially profitable for large consumers of fuel +situated in districts where fuel is cheap, it seems to me particularly +suitable to be adopted in this country. It promises to give England +the privilege of supplying the Old World with this all-important +fertilizer, and while yielding a fair profit to the invested capital +and finding employment for a considerable number of men, to make us, +last not least, independent of the New World for our supply of so +indispensable a commodity. + +Before leaving my subject, I will, if you will allow me, give you in a +few words a description of two other inventions which have been the +outcome of this research. While looking one day at the beautiful, +almost colorless, flame of the producer gas burning under one of our +boilers, it occurred to me that a gas so rich in hydrogen might be +turned to better use, and that it might be possible to convert it +direct into electricity by means of a gas battery. + +You all know that Lord Justice Grove showed, now fifty years ago, that +two strips of platinum partly immersed in dilute sulphuric acid, one +of which is in contact with hydrogen and the other with oxygen, +produce electricity. I will not detain you with the many and varied +forms of gas batteries which Dr. Carl Langer (to whom I intrusted this +investigation) has made and tried during the last four years, in order +to arrive at the construction of a gas battery which would give a +practical result, but I will call your attention to the battery before +me on the table, which is the last result of our extended labors in +this direction, and which we hope will mark a great step in advance in +the economic production of electricity. + +The distinguishing feature of this battery is that the electrolyte is +not employed as a mobile liquid, but in a quasi-solid form, and it is, +therefore, named dry gas battery. It consists of a number of elements, +which are formed of a porous diaphragm of a non-conducting material +(in this instance plaster of Paris), which is impregnated with dilute +sulphuric acid. Both sides of this diaphragm are covered with very +fine platinum leaf perforated with very numerous small holes, and over +this a thin film of platinum black. Both these coatings are in contact +with frameworks of lead and antimony, insulated one from the other, +which conduct the electricity to the poles of the battery. + +A number of these elements are placed side by side, with +non-conducting frames intervening, so as to form chambers through +which the hydrogen gas is passed along one side of the element and air +along the other. + +This peculiar construction allows us to get a very large amount of +duty from a very small amount of platinum. One of the batteries before +you, consisting of seven elements, with a total effective surface of +half a square meter, contains 2½ grammes of platinum leaf and 7 +grammes of platinum black, a total of 9½ grammes of platinum, and +produces a current of 2 amperes and 5 volts, or 10 watts, when the +outer resistance is properly adjusted. This current is equal to nearly +50 per cent. of the total energy obtainable from the hydrogen absorbed +in the battery. + +In order to maintain a constant current, we have from time to time +(say once an hour) to interchange the gases, so as to counteract the +disturbing influence produced by the transport of the sulphuric acid +gas from one side of the diaphragm to the other. This operation can +easily be performed automatically by a commutator worked by a clock. + +The water produced in the battery by the oxidation of the hydrogen is +carried off by the inert gas mixed with the hydrogen, and by the air, +of which we use a certain excess for this purpose. This is important, +as if the platinum black becomes wet, it loses its absorbing power for +the gases almost completely and stops the work of the battery. To +avoid this was in fact the great difficulty in designing a powerful +gas battery, and all previous constructions which employed the +electrolyte as a mobile liquid failed in consequence. + +The results obtained by our battery are practically the same whether +pure oxygen and hydrogen or air and gases containing 25 per cent. of +hydrogen are used; but we found that the latter gases must be +practically free from carbonic oxide and hydrocarbons, which both +interfere very much with the absorbing power of the platinum black. + +We had thus to find a cheap method of eliminating these two gases from +the producer gas, and converting them at the same time into their +equivalent of hydrogen. The processes hitherto known for this purpose, +viz., passing a mixture of such gases with steam over lime (which I +mentioned some time ago) or over oxide of iron or manganese, require +high temperatures, which render them expensive, and the latter do not +effect the reaction to a sufficient extent for our purpose. + +We have succeeded in attaining our object at a temperature below that +at which the gases leave my producers, viz., at 350° C. to 450° C., by +passing the producer gases, still containing a considerable excess of +steam, over metallic nickel or cobalt. These metals have the +extraordinary property of decomposing almost completely, even at the +low temperature named, carbonic oxide into carbon and carbonic acid +and hydrocarbons into carbon and hydrogen. + +In order to carry the process out with small quantities of nickel and +cobalt, we impregnate pumice stone or similar material with a salt of +nickel or cobalt, and reduce this by means of hydrogen or producer +gas. These pieces of pumice stone are filled into a retort or chamber +and the hot gases passed through them. As the reaction produces heat, +it is not necessary to heat the chambers or retorts from the outside +when the necessary temperature has once been attained. This process +has not yet been carried out on a large scale, but the laboratory +experiments have been so satisfactory that we have no doubt as to its +complete success. It will enable us to obtain gases containing 36 per +cent. to 40 per cent. of hydrogen and practically free from carbonic +oxide and hydrocarbons from producer gas at a very small cost, and +thus to make the latter suitable for the production of electricity by +our gas battery. We obtain, as stated before, 50 per cent. of the +energy in the hydrogen absorbed in the battery in the form of +electricity, while, if the same gas was consumed under steam boilers +to make steam, which, as I have shown before, could in this way be +raised cheaper than by burning fuel direct, and if this steam was +turned into motive power by first-rate steam engines, and the motive +power converted into electricity by a dynamo, the yield of electricity +would in the most favorable case not exceed 8 per cent. of the energy +in the gas. I hope that this kind of battery will one day enable us to +perform chemical operations by electricity on the largest scale, and +to press this potent power into the service of the chemical +industries. + +The statement is frequently made that "Necessity is the mother of +invention." If this has been the case in the past, I think it is no +longer so in our days, since science has made us acquainted with the +correlation of forces, teaching us what amount of energy we utilize +and how much we waste in our various methods for attaining certain +objects, and indicating to us where and in what direction and how far +improvement is possible; and since the increase in our knowledge of +the properties of matter enables us to form an opinion beforehand as +to the substances we have available for obtaining a desired result. + +We can now foresee, in most cases, in what direction progress in +technology will move, and in consequence the inventor is now +frequently in advance of the wants of his time. He may even create new +wants, to my mind a distinct step in the development of human culture. +It can then no longer be stated that "Necessity is the mother of +invention;" but I think it may truly be said that the steady, +methodical investigation of natural phenomena is the father of +industrial progress. + +Sir Lowthian Bell, Bart., F.R.S., in moving a vote of thanks, said +that the meeting had had the privilege of listening to a description +of results obtained by a man of exceptional intelligence and learning, +supplemented by that devotion of mind which qualified him to pursue +his work with great energy and perseverance. The importance of the +president's address could not possibly be overrated. At various +periods different substances had been put forward as indications of +the civilization of the people. He remembered hearing from Dr. Ure +that he considered the consumption of sulphuric acid to be the most +accurate measure of the civilization of the people. + +In course of time sulphuric acid gave way to soap, the consumption of +which was probably still regarded as the great exponent of +civilization by such of his fellow citizens as had thereby made their +name. From what he had heard that morning, however, he should be +inclined to make soap yield to ammonia, as sulphuric acid had in its +time succumbed to soap. For not only was ammonia of great importance +to us as a manufacturing nation, but it almost appeared to be a +condition of our existence. England had a large population +concentrated on an area so small as to make it almost a matter of +apprehension whether the surface could maintain the people upon it. + +We were now importing almost as much food as we consumed, and were +thus more and more dependent on the foreigner. Under certain +conditions this would become a very serious matter, and thus any one +who showed how to produce plenty of ammonia at a cheap rate was a +benefactor to his country. Mr. Mond's process seemed to come nearer to +success than any which had preceded it, and it needed no words from +him to induce the meeting to accord a hearty vote of thanks to the +president for his admirable paper. + +Mr. J. C. Stevenson, M.P., in seconding the motion, said that no paper +could be more interesting and valuable to the society than that +delivered by the president. It opened out a future for the advancement +of chemical industry which almost overcame one by the greatness of its +possibilities. Mr. Mond had performed an invaluable service by +investigating the various methods proposed for the manufacture of +ammonia, and clearing the decks of those processes supposed by their +inventors to be valuable, but proved by him to be delusive. It gave +him hearty pleasure therefore to second the vote of thanks proposed by +Sir Lowthian Bell. + +The vote having been put and carried by acclamation, after a brief +reply from the president: + +The secretary read the report of the scrutators, which showed that 158 +ballot papers had been sent in, 154 voting for the proposed list +intact, and four substituting other names. The gentlemen nominated in +the list issued by the Council were therefore declared elected. + + * * * * * + + +In his brief report for the year ending May 1, 1889, the director of +the Pasteur Institute, Paris, announces the treatment of 1,673 +subjects, of whom 6 were seized with rabies during and 4 within a +fortnight after the process. But 3 only succumbed after the treatment +had been completely carried out, making 1 death in 554, or, including +all cases, 1 in 128. + + * * * * * + + + + +ALKALI MANUFACTORIES. + + +When the alkali, etc., Works Regulation Act was passed in 1881, it was +supposed that the result would be that the atmosphere in the districts +where such works are situated would be considerably improved, and, +consequently, that vegetation would have a better chance in the +struggle for existence, and the sanitary conditions of human dwellings +would be advanced. In all these respects the act has been a success. +But perhaps the most notable result is the effect which the act and +those which have preceded it have had upon the manufactures which they +control. + +This was not anticipated by manufacturers, but now one of the +principal of them (Mr. A. M. Chance) has stated that "Government +inspection has not only led to material improvement in the general +management of chemical works, but it has also been in reality a +distinct benefit to, rather than a tax upon, the owners of such +works." + +This expression of opinion is substantiated by the chief inspector +under the act, whose report for last year has recently been laid +before the local government board. + +There are 1,057 works in the United Kingdom which are visited by the +inspectors, and in only two of these during 1888 did the neglect to +carry out the inspectors' warnings become so flagrant as to call for +legal interference; viz., in the case of Thomas Farmer & Co. +(limited), Victoria Docks, E., who were fined 20l. and costs for +failing to use the "best practicable means" for preventing the escape +of acid gas from manure plant; and in the case of Joseph Fison & Co., +Bramford, who were fined 50l. and costs for excessive escape of acid +gas from sulphuric acid plant. There were seven other cases, but these +were simply for failure to register under the act. + +It is very evident, therefore, that from a public point of view the +act is splendidly successful, and from the practical or scientific +side it is no less satisfactory. + +Of the total number of chemical works (1,057) 866 are registered in +England, 131 in Scotland, and 44 in Ireland--a decrease in the case of +Scotland of 8, and in Ireland of 2 from the previous year, while +England has increased by 1. This must not, however, be taken as a sign +of diminished production, because there is a tendency for the larger +works to increase in size and for the smaller ones to close their +operations. The principal nuisances which the inspectors have to +prevent are the escape of hydrochloric acid gas from alkali works and +of sulphurous gas from vitriol and manure works. + +The alkali act forbids the manufacturer to allow the escape of more +than 5 per cent. of the hydrochloric acid which he produces, or that +that acid must not exist to a greater extent than 0.2 grain in 1 cubic +foot of air, steam, or chimney gas which accompanies. The inspectors' +figures for last year show that the percentage of the acid which +escaped amounted to only 1.96 of the total produced, which is equal to +0.089 grain per cubic foot, and much below the figures for previous +years. The figures in regard to sulphurous gas are equally +satisfactory. The act allows 4 grains of sulphuric anhydride (SO3) per +cubic foot to escape into the air, and last year's average was only +0.737 grain, or less than a fifth of the limit. + +Of course it is now the aim of the Leblanc alkali manufacturers to +reduce the escape of hydrochloric acid to the lowest possible amount, +as their profits depend solely upon the sale of chlorine products, +soda products being sold at a loss. In this connection it is +interesting to note that the amount of common salt manufactured in the +United Kingdom in 1888 was 2,039,867 tons, and of this nearly 600,000 +tons were taken by Leblanc soda makers, and over 200,000 tons by the +ammonia-soda makers. The figures are very largely in excess of +previous years, and indicate a gratifying growth in trade. + +The salt used in the Leblanc process yields the hydrochloric acid, and +that in the ammonia-soda method none, so that we may put down the +theoretical production of acid as 380,000 tons, 7,600 tons of which +was allowed to escape. + +What was a mere trace in the chimney gases amounts, therefore, to a +good round figure at the end of a year, and if it were converted into +bleaching powder it would be worth nearly 150,000l. These figures are, +it should be understood, based on theory, but they serve to show to +what importance a gas has now reached which twenty-five years ago was +a perfect incubus to the manufacturers, and wrought desolation in the +country sides miles and miles around the producing works. There has +long been an expectation that the ammonia-soda makers would add the +manufacture of bleaching powder to their process, but they appear to +be as far as ever from that result, and meanwhile the Leblanc makers +are honestly striving to utilize every atom of the valuable material +which they handle. Hence the eagerness to recover the sulphur from +tank waste by one or other of the few workable processes which have +been proposed. + +This waste contains from 11 to 15 per cent. of sulphur, and when it is +stated that the total amount of tank waste produced yearly is about +750,000 tons, containing about 100,000 tons of sulphur, it will be +seen how large is the reward held out to the successful manipulator. +Moreover, the value of the sulphur that might possibly be saved is not +the only prize held out to those who can successfully deal with the +waste, for this material is not only thrown away as useless, but much +expense is incurred in the throwing. + +In Lancashire and in other inland districts land must be found on +which to deposit it, and the act of depositing is costly, for unless +it is beaten together so as to exclude the air, an intolerable +nuisance arises from it. The cost of haulage and deposit on land +varies, according to the district, from 1s. to 1s. 6d. a ton. In +Widnes it is about 1s. + +In the Newcastle district the practice is to carry this material out +to sea at a cost of about 4d. a ton. + +Mr. Chance's process for the recovery of sulphur from the waste +signalizes the centenary of the Leblanc process; Parnell and Simpson +are following in his wake, and lately Mr. F. Gossage, of Widnes, has +been working on a process for the production of alkali, which enables +him to save the sulphur of the sulphuric acid. In his process a +mixture of 70 parts Leblanc salt cake (sulphate of soda) and 30 parts +common salt is mixed with coal and heated in a furnace, and so reduced +to sulphide of sodium. The resulting "ash" is then dissolved in water +and exposed to the action of carbonic acid, when sulphureted hydrogen +is given off, to be dealt with as in Mr. Chance's sulphur process, +while bicarbonate of soda is formed and separates by precipitation +from the solution of undecomposed common salt. + +Ere long it is expected this new method will be in active operation in +some Leblanc works, the plant of which will, in all probability, be +utilized. It has these great advantages: The absence of lime, the +recovery of the sulphur used in the first instance and the consequent +absence of the objectionable tank waste. Thus a bright promise is held +out that the days of alkali waste are numbered, and that the air in +certain parts of Lancashire will be more balmy than it has been in the +memory of the oldest inhabitant.--_Chemist and Druggist._ + + * * * * * + + + + +THE FUELS OF THE FUTURE. + + +It is undeniable that in this country, at least, we are accustomed to +regard coal as the chief, and, indeed, the only substance which falls +to be considered under the name of fuel. In other countries, however, +the case is different. Various materials, ranging from wood to oil, +come within the category of material for the production of heat. The +question of fuel, it may be remarked, has a social, an antiquarian, +and a chemical interest. In the first place, the inquiry whether or +not our supplies of coal will hold out for say the next hundred +thousand years, or for a much more limited period only, has been very +often discussed by sociologists and by geological authorities. + +Again, it is clear that as man advances in the practice of civilized +arts, his dependence upon fuel becomes of more and more intimate +character. He not merely demands fire wherewith to cook his food, and +to raise his own temperature or that of his dwelling, but requires +fuel for the thousand and one manufacturing operations in which he is +perpetually engaged. It is obvious that without fuel civilized life +would practically come to an end. We cannot take the shortest journey +by rail or steamboat without a tacit dependence upon a fuel supply; +and the failure of this supply would therefore mean and imply the +extinction of all the comforts and conveniences on which we are +accustomed to rely as aids to easy living in these latter days. Again, +socially regarded, man is the only animal that practices the +fire-making habit. Even the highest apes, who will sit round the fire +which a traveler has just left, and enjoy the heat, do not appear to +have developed any sense or idea of keeping up the fire by casting +fresh fuel upon it. It seems fairly certain, then, that we may define +man as being a "fuel-employing animal," and in so doing be within the +bounds of certitude. He may be, and often is, approached by other +animals in respect of many of his arts and practices. Birds weave nest +materials, ants make--and maul--slaves, beavers build dams, and other +animals show the germs and beginnings of human contrivances for aiding +the processes of life, but as yet no animal save man lights and +maintains a fire. That the fire-making habit must have dawned very +early in human history appears to be proved by the finding of ashes +and other evidences of the presence of fire among the remains and +traces of primitive man. + +All we know, also, concerning the history of savage tribes teaches us +that humanity is skillful, even in very rude stages of its progress, +in the making of fire. The contrivances for obtaining fire are many +and curious in savage life, while, once attained, this art seems to +have not only formed a constant accompaniment but probably also a +determining cause in the evolution of civilization. Wood, the fat of +animals, and even the oils expressed from plants, probably all became +known to man as convenient sources of fuel in prehistoric times. From +the incineration of wood to the use of peat and coal would prove an +easy stage in the advance toward present day practices, and with the +attainment of coal as a fuel the first great era in man's fire-making +habits may be said to end. + +Beyond the coal stage, however, lies the more or less distinctively +modern one of the utilization of gas and oil for fuel. The existence +of great natural centers, or underground stores, of gas and oil is +probably no new fact. We read in the histories of classic chroniclers +of the blazing gases which were wont to issue from the earth, and to +inspire feelings of superstitious awe in the minds of beholders. Only +within a few years, however, have geologists been able to tell us much +or anything regarding these reservoirs of natural fuel which have +become famous in America and in the Russian province of Baku. + +For example, it is now known that three products--gas, oil, and salt +or brine--lie within natural receptacles formed by the rock strata in +the order of their weight. This law, as has well been said, forms the +foundation of all successful boring experiments, and the search for +natural fuel, therefore, becomes as easy and as reliable a duty as +that for artesian water or for coal. The great oil fever of the West +was attended at first, as Professor M'Gee tells us, with much waste of +the product. Wells were sunk everywhere, and the oil overflowed the +land, tainting the rivers, poisoning the air, and often driving out +the prospectors from the field of discovery. In Baku accidents and +catastrophes have, similarly, been of frequent occurrence. We read of +petroleum flowing from the ground in jets 200 feet high, and as thick +as a man's body; we learn how it swept away the huge cranes and other +machinery, and how, as it flowed away from the orifices, its course +was marked by the formation of rivers of oil many miles in length. + +In America the pressure of rock gas has burst open stills weighing +over a ton, and has rushed through huge iron tanks and split open the +pipes wherewith it was sought to control its progress. The roar of +this great stream of natural gas was heard for miles around as it +escaped from the outlet, and when it was ignited the pillar of flame +illumined the surrounding country over a radius extending in some +cases to forty miles. It is clear that man having tapped the earth's +stores of natural fuel, stood in danger of having unloosed a monster +whose power he seemed unable to control. Yet, as the sequel will show, +science has been able to tackle with success the problems of mastering +the force and of utilizing the energy which are thus locked up within +the crust of the globe. + +As regards the chemistry of rock gas, we may remark in the first place +that this natural product ranks usually as light carbureted hydrogen +gas. In this respect it is not unlike the marsh gas with which +everyone is familiar, which is found bubbling up from swamps and +morasses, and which constitutes the "will o' the wisp" of romance. In +rock gas, marsh gas itself is actually found in the proportion of +about 93 per cent. The composition of marsh gas is very simple. It +consists of the two elements carbon and hydrogen united in certain +proportions, indicated chemically by the symbol CH4. We find, in fact, +that rock gas possesses a close relationship, chemically speaking, +with many familiar carbon compounds, and of these latter, petroleum +itself, asphaltum, coal, jet, graphite or plumbago, and even the +diamond itself--which is only crystallized carbon after all--are +excellent examples. + +The differences between these substances really consist in the degree +of fixing of the carbon or solid portion of the product, as it were, +which exists. Thus in coal and jet the carbon is of stable character, +such as we might expect to result from the slow decomposition of +vegetable matter, and the products of this action are not volatile or +liable to be suddenly dissociated or broken up. On the other hand, +when we deal with the _hydrocarbons_ as they are called, in the shape +of rock gas, naphtha, petroleum, tar, asphaltum, and similar +substances, we see how the carbon has become subordinated to the +hydrogen part of the compounds, with the result of rendering them more +or less unstable in their character. As Professor M'Gee has shown us, +there is in truth a graduated series leading us from the marsh gas and +rock gas as the lightest members of this class of compounds onward +through the semi-gaseous naphtha to the fluid petroleum, the +semi-fluid tar, the solid asphaltum, and the rigid and brittle +substance known as albertite, with other and allied products. Having +said so much regarding the chemistry of the fuels of the future, we +may now pass to consider their geological record. A somewhat curious +distribution awaits the man of science in this latter respect. Most +readers are aware that the geologists are accustomed to classify +rocks, according to their relative age, into three great groups, known +respectively as the primary, secondary, and tertiary periods. In the +secondary period we do not appear to meet with the fuels of the +future, but as far back as the Devonian or old Red Sandstone period, +and in the still older Silurian rocks, stores of gas and petroleum +abound. In the latest or tertiary period, again, we come upon nearly +all the forms of fuels we have already specified. + +The meaning of this geological distribution of the fuels is entirely +fortuitous. Dr. M'Gee tells us that as their formation depended on +local conditions (such as plant growth), and as we have no means of +judging why such local conditions occurred within any given area, so +must we regard the existence of fuel products in particular regions as +beyond explanation. Of one point, however, we are well assured, namely +that the volume of the fuels of the future is developed in an inverse +proportion to their geological age. The proportionate volume, as it +has been expressed, diminishes progressively as the geological scale +is descended. Again, the weight of the fuels varies directly with +their age; for it is in the older formation of any series that we come +upon the oils and tars and asphaltum, while the marsh gas exists in +later and more recently formed deposits. Further geological research +shows us that the American gas fields exist each as an inverted trough +or dome, a conformation due, of course, to the bending and twisting of +the rocks by the great underground heat forces of the world. The +porous part of the dome may be sandstone or limestone, and above this +portion lie shales, which are the opposite of porous in texture. The +dome, further, contains gas above, naphtha in the middle, and +petroleum below, while last of all comes water, which is usually very +salt. In the Indiana field, however, we are told that the oils lie +near the springing or foundation of the arch of the dome, and at its +crown gas exists, and overlies brine. + +A very important inquiry, in relation to the statement that upon the +products whose composition and history have just been described the +fuel supply of the future will depend, consists in the question of the +extent and duration of these natural gas and oil reservoirs. If we are +beginning to look forward to a time when our coal supply will have +been worked out, it behooves us to ask whether or not the supply of +natural gas and oil is practically illimitable. The geologist will be +able to give the coming man some degree of comfort on this point, by +informing him that there seems to be no limit to the formation of the +fuel of the future. + +Natural gas is being manufactured to-day by nature on a big scale. +Wherever plant material has been entombed in the rock formations, and +wherever its decomposition proceeds, as proceed it must, there natural +gas is being made. So that with the prospect of coal becoming as rare +as the dodo itself, the world, we are told by scientists, may still +regard with complacency the failure of our ordinary carbon supply. The +natural gases and oils of the world will provide the human race with +combustible material for untold ages--such at least is the opinion of +those who are best informed on the subject. For one thing, we are +reminded that gas is found to be the most convenient and most +economical of fuels. Rock gas is being utilized abroad even now in +manufacturing processes. Dr. M'Gee says that even if the natural +supply of rock gas were exhausted to-morrow, manufacturers of glass, +certain grades of iron, and other products would substitute an +artificial gas for the natural product rather than return to coal. He +adds that "enormous waste would thereby be prevented, the gas by which +the air of whole counties in coke-burning regions is contaminated +would be utilized, and the carbon of the dense smoke clouds by which +manufacturing cities are overshadowed would be turned to good +account." So that, as regards the latter point, even Mr. Ruskin with +his horror of the black smoke of to-day and of the disfigurement of +sky and air might become a warm ally of the fuel of the future. The +chemist in his laudation of rock gas and allied products is only +re-echoing, when all is said and done, the modern eulogy pronounced on +ordinary coal gas as a cooking and heating medium. + +We are within the mark when we say that the past five years alone have +witnessed a wonderful extension in the use of gas in the kitchen and +elsewhere. It would be singular, indeed, if we should happen to be +already anticipating the fuel of the future by such a practice. +Whether or not this is the case, it is at least satisfactory for +mankind to know that the mother earth will not fail him when he comes +to demand a substitute for coal. I may be too early even to think of +the day of extinction; but we may regard that evil day with +complacency in face of the stores of fuel husbanded for us within the +rock foundations of our planet.--_Glasgow Herald._ + + * * * * * + + + + +PORTABLE ELECTRIC LIGHT. + + +The famous house of MM. Sautter, Lemonnier & Co. takes a conspicuous +part in the Paris exhibition, and from the wide range of its +specialties exhibits largely in three important branches of industry: +mechanics, electricity, and the optics of lighthouses and projectors. +In these three branches MM. Sautter, Lemonnier & Co. occupy a leading +position in all parts of the world. + +The invention of the aplanetic projector, due to Col. Mangin, was a +clever means of overcoming difficulties, practically insurmountable, +that were inseparable from the construction of parabolic mirrors; this +contributed chiefly to the success of MM. Sautter, Lemonnier & Co. in +this direction. The firm has produced more than 1,500 of these +apparatus, representing a value of nearly £500,000, for the French and +other governments. + +Besides the great projector, which forms the central and crowning +object of the exhibit of MM. Sautter, Lemonnier & Co. in the machinery +hall, the firm exhibits a projector 90 centimeters in diameter mounted +on a crane traveling on wheels, in the pavilion of the War Department. +The lamp used for this apparatus has a luminous value of 6,000 +carcels, with a current of 100 amperes; the amplifying power of the +mirror is 2,025, which gives an intensity of ten millions to twelve +millions of carcels to the beam. + +Projectors used for field work are mounted on a portable carriage, +which also contains the electric generator and the motor driving it. + +[Illustration: MILITARY PORTABLE ELECTRIC LIGHT AT THE PARIS +EXHIBITION.] + +It consists of a tubular boiler (Dion, Bouton & Trepardoux system). +This generator is easily taken to pieces, cleaned, and repaired, and +steam can be raised to working pressure in 20 minutes. The mechanical +and electrical part of the apparatus consists of a Parsons +turbo-motor, of which MM. Sautter, Lemonnier & Co. possess the license +in France for application to military and naval purposes. The speed of +the motor is 9,000 revolutions per minute, and the dynamo is driven +direct from it; at this speed it gives a current of 100 amperes with +and from 55 to 70 volts; the intensity of the light is from 5,500 to +6,000 carcels. The carriage upon which the whole of this apparatus is +mounted is carried on four wheels, made of wood with gun metal +mountings. These are more easy to repair when in service than if they +were wholly of iron. The weight of the carriage is three +tons.--_Engineering._ + + * * * * * + + + + +ELECTRIC MOTOR FOR ALTERNATING CURRENTS. + + +Prof. Galileo Ferraris, of Turin, who has carefully studied +alternating currents and secondary transformers, has constructed a +little motor based upon an entirely new principle, which is as +follows: If we take two inductive fields developed by two bobbins, the +axes of which cut each other at right angles, and a pole placed at the +vertex of the angle, this pole will be subjected to the simultaneous +action of the two bobbins, and the resultant of the magnetic actions +will be represented in magnitude and direction by the diagonal of the +parallelogram, two consecutive sides of which have for their length +the intensity of the two fields, and for their direction the axes of +the two bobbins. + +If into each of these bobbins we send alternating currents having +between one bobbin and the other a difference of phase of 90°, the +extremity of the resultant will describe a circle having for its +center the vertex of the right angle. + +If, instead of a fixed pole, we use a metal cylinder movable on its +axis, we shall obtain a continuous rotatory motion of this part, and +the direction of the movement will change when we interchange the +difference of phase in the exciting currents. This rotatory movement +is not due to the Foucault currents, for the metal cylinder may +consist of plates of iron insulated from each other. + +In order to realize the production of these fields, several means can +be employed: The current is sent from an alternating current machine +into the primary circuit of a transformer and thence into one of the +bobbins, the other being supplied by means of the secondary current of +the transformer. A resistance introduced into the circuit will produce +the required difference of phase, and the equality of the intensities +of the fields will be obtained by multiplying the number of turns of +the secondary wire on the bobbin. Moreover, the two bobbins may be +supplied by the secondary current of a transformer by producing the +difference of phase, as in the first case. + +In the motor constructed by Prof. Ferraris the armature consisted of a +copper cylinder measuring 7 centimeters in diameter and 15 centimeters +in length, movable on its axis. The inductors were formed of two +groups of two bobbins. The bobbins which branched off from the primary +circuit of a Gaulard transformer, and were connected in series, +comprised 196 spirals with a resistance of 13 ohms; the bobbins +comprising the secondary circuit were coupled in parallel, and had 504 +spirals with 3.43 ohms resistance. In order to produce the difference +of phase, a resistance of 17 ohms was introduced into the second +circuit, when the dynamo produced a current of 9 amperes with 80 +inversions per second. Under these conditions the available work +measured on the axis of the motor was found for different speeds: +Revolutions per minute: 262--400--546--650--722--770. Watts measured +at the brake: 1.32--2.12--2.55--2.77--2.55--2.40. The maximum +rendering corresponds to a speed of rotation of 650 revolutions, and +Prof. Ferraris attributes the loss of work for higher speeds to the +vibrations to which the machine is exposed. At present the apparatus +is but a laboratory one.--_Bulletin International de l'Electricite._ + + * * * * * + + + + +THE ELECTRIC AGE. + +By CHARLES CARLETON COFFIN. + + +The application of electricity for our convenience and comfort is one +of the marvels of the age. Never in the history of the world has there +been so rapid a development of an occult science. Prior to 1819 very +little was known in regard to magnetism and electricity. During that +year Oersted discovered that an electric current would deflect a +magnetic needle, thus showing that there was some relationship between +electric and magnetic force. A few months later, Arago and Sir Humphry +Davy, independently of each other, discovered that by coiling a wire +around a piece of iron, and passing an electric current through it, +the iron would possess for the time being all the properties of a +magnet. In 1825 William Sturgeon, of London, bent a piece of wire in +the form of the letter U, wound a second wire around it, and, upon +connecting it with a galvanic battery, discovered that the first wire +became magnetic, but lost its magnetic property the moment the battery +was disconnected. The idea of a telegraphic signal came to him, but +the electric impulse, through his rude apparatus, faded out at a +distance of fifty feet. In 1830 Prof. Joseph Henry, of this country, +constructed a line of wire, one and a half miles in length, and sent a +current of electricity through it, ringing a bell at the farther end. +The following year Professor Faraday discovered magnetic induction. +This, in brief, is the genesis of magnetic electricity, which is the +basis of all that has been accomplished in electrical science. + +The first advance after these discoveries was in the development of +the electric telegraph--the discovery in 1837, by the philosopher +Steinhill, that the earth could serve as a conductor, thus requiring +but one wire in the employment of an electric current. Simultaneously +came Morse's invention of the mechanism for the telegraph in 1844, +foreshadowed by Henry in the ringing of bells, thus transmitting +intelligence by sound. Four years later, in 1848, Prof. M. G. Farmer, +still living in Eliot, Me., attached an electro-magnet to clockwork +for the striking of bells to give an alarm of fire. The same idea came +to William F. Channing. The mechanism, constructed simply to +illustrate the idea by Professor Farmer, was placed upon the roof of +the Court House in Boston, and connected with the telegraph wire +leading to New York, and an alarm rung by the operator in that city. +The application of electricity for giving definite information to +firemen was first made in Boston, and it was my privilege to give the +first alarm on the afternoon of April 12, 1852. + +At the close of the last century, Benjamin Thompson, born in Woburn, +Mass., known to the world as Count Rumford, was in the workshop of the +military arsenal of the King of Bavaria in Munich, superintending the +boring of a cannon. The machinery was worked by two horses. He was +surprised at the amount of heat which was generated, for when he threw +the borings into a tumbler filled with cold water, it was set to +boiling, greatly to the astonishment of the workmen. Whence came the +heat? What was heat? The old philosopher said that it was an element. +By experiment he discovered that a horse working two hours and twenty +minutes with the boring machinery would heat nineteen pounds of water +to the boiling point. He traced the heat to the horse, but with all +his acumen he did not go on with the induction to the hay and oats, to +the earth, the sunshine and rain, and so get back to the sun. One +hundred years ago there was no chemical science worthy of the name, no +knowledge of the constitution of plants or the properties of light and +heat. The old philosophers considered light and heat to be fluids, +which passed out of substances when they were too full. Count Rumford +showed that motion was convertible into heat, but did not trace the +motion to its source, so far as we know, in the sun. + +It is only forty-six years since Professor Joule first demonstrated +the mutual relations of all the manifestations of nature's energy. +Thirty-nine years only have passed since he announced the great law of +the convertibility of force. He constructed a miniature churn which +held one pound of water, and connected the revolving paddle of the +churn with a wheel moved by a pound weight, wound up the weight, and +set the paddle in motion. A thermometer detected the change of +temperature and a graduated scale marked the distance traversed by the +descending weight. Repeated experiments showed that a pound weight +falling 772 feet would raise the temperature of water one degree, and +that this was an unvarying law. This was transferring gravitation to +heat, and the law held good when applied to electricity, magnetism, +and chemical affinity, leading to the conclusion that they were +severally manifestations of one universal power.--_Congregationalist._ + + * * * * * + + + + +EARLY ELECTRIC LIGHTING. + + +The opening of the new station of the Electric Lighting Co., of Salem, +Mass., was recently celebrated with appropriate festivities. + +Among the letters of regret from those unable to attend the opening +was the following from Prof. Moses G. Farmer: + + "ELIOT, Me., Aug. 5, 1889. + +"_To the Salem Electric Lighting Company, Charles H. Price, +President_: + +"GENTLEMEN: It would give me great pleasure to accept your kind +invitation to be present at the opening of your new station in Salem +on the 8th of this present August. + +"It is now thirty years since the first dwelling house in Salem was +lighted by electricity. That little obscure dwelling, 11 Pearl Street, +formerly owned by 'Pa' Webb, had the honor to be illuminated by the +effulgent electric beam during every evening of July, 1859, as some of +your honored residents, perhaps, well remember. Mr. George D. Phippen +can doubtless testify to one or more evenings; Mr. Wm. H. Mendell, of +Boston, can also add his testimony; dozens of others could also do the +same, had not some of them already passed to the 'great beyond,' among +whom I well recollect the interest taken by the late and honored Henry +L. Williams, Mr. J. G. Felt, and I do not know how many others. I well +remember reading some of the very finest print standing with my back +to the front wall and reading by the light of a 32 candle power lamp +on the northernmost end of the mantel piece in the parlor; very +possibly the hole in which the lamp was fastened remains to this day. +In a little closet in the rear sleeping room was a switch which could +be turned in one direction and give a beautiful glow light, while if +turned in the other direction, it instantly gave as beautiful a dark. +My then 12 year old daughter used to surprise and please her visitors +by suddenly turning on and off the 'glim.' It is not well to despise +the day of small things, for although the dynamo had not at that date +put in an appearance, and though I used thirty-six Smee cells of six +gallons capacity each, yet I demonstrated then and there that the +incandescent electric light was a possibility, and although I +innocently remarked to the late Samuel W. Bates, of Boston, who with +his partner, Mr. Chauncey Smith, furnished so generously in the +interest of science, not wholly without hope of return, the funds for +the experiment, that it 'did not take much zinc,' and though Mr. Bates +as naively replied, 'I notice that it takes some silver, though,' +still it was then and there heralded as the coming grand illuminant +for the dwelling. I am thankful to have lived to see my predictions +partly fulfilled. + +"During the early fifties I published a statement something like this: +'One pound of coal will furnish gas enough to maintain a candle light +for fifteen hours. One pound of gas (the product of five pounds of +coal) will, in a good fishtail gas burner, furnish one candle light +for seventy-five hours. One pound of coal burned in a good furnace, +under a good boiler, driving a good steam engine, turning a good +magneto-electric machine, will give a candle light for one thousand +hours. But if all the energy locked up in one pound of pure carbon +could be wholly converted into light, it would maintain one candle +light for more than one and a half years.' + +"So, gentlemen, _nil desperandum_; there is still room for +improvement. Let your motto be 'Excelsior.' Possibly you may have +already extracted from one-fifteenth to one-twelfth of the energy +stored in the pound of carbon, but hardly more. Go on, go on, and +bring it so cheap as to reach the humblest dwelling when you shall +celebrate the centennial of the opening of your new station. + +"I do most sincerely regret that I cannot be with you in the flesh. I +am, like Ixion of old, confined to a wheel (chair in my case), cannot +walk, cannot even stand; hence, owing to the impairment of my +understanding (???), I must wish you all the enjoyments of the +evening, and gladly content myself that you have made so much +possible. + + "Very truly yours, MOSES G. FARMER." + + * * * * * + + + + +THE MODERN THEORY OF LIGHT.[1] + + [Footnote 1: Being the general substance of a lecture to the + Ashmolean Society in the University of Oxford, on Monday, June + 3, 1889. [Reprinted from the _Liverpool University College + Magazine_.]] + +By Prof. OLIVER LODGE. + + +To persons occupied in other branches of learning, and not directly +engaged in the study of physical science, some rumor must probably +have traveled of the stir and activity manifest at the present time +among the votaries of that department of knowledge. + +It may serve a useful purpose if I try and explain to outsiders what +this stir is mainly about, and why it exists. There is a proximate and +there is an ultimate cause. The proximate cause is certain experiments +exhibiting in a marked and easily recognizable way the already +theoretically predicted connection between electricity and light. The +ultimate cause is that we begin to feel inklings and foretastes of +theories, wider than that of gravitation, more fundamental than any +theories which have yet been advanced; theories which if successfully +worked out will carry the banner of physical science far into the dark +continent of metaphysics, and will illuminate with a clear philosophy +much that is at present only dimly guessed. More explicitly, we begin +to perceive chinks of insight into the natures of electricity, of +ether, of elasticity, and even of matter itself. We begin to have a +kinetic theory of the physical universe. + +We are living, not in a Newtonian, but at the beginning of a perhaps +still greater Thomsonian era. Greater, not because any one man is +probably greater than Newton,[2] but because of the stupendousness of +the problems now waiting to be solved. There are a dozen men of great +magnitude, either now living or but recently deceased, to whom what we +now know toward these generalizations is in some measure due, and the +epoch of complete development may hardly be seen by those now alive. +It is proverbially rash to attempt prediction, but it seems to me that +it may well take a period of fifty years for these great strides to be +fully accomplished. If it does, and if progress goes on at anything +like its present rate, the aspect of physical science bequeathed to +the latter half of the twentieth century will indeed excite +admiration, and when the populace are sufficiently educated to +appreciate it, will form a worthy theme for poetry, for oratorios, and +for great works of art. + + [Footnote 2: Though, indeed, a century hence it may be premature + to offer an opinion on such a point.] + +To attempt to give any idea of the drift of progress in all the +directions which I have hastily mentioned, to attempt to explain the +beginnings of the theories of elasticity and of matter, would take too +long, and might only result in confusion. I will limit myself chiefly +to giving some notion of what we have gained in knowledge concerning +electricity, ether, and light. Even that is far too much. I find I +must confine myself principally to light, and only treat of the others +as incidental to that. + +For now well nigh a century we have had a wave theory of light; and a +wave theory of light is quite certainly true. It is directly +demonstrable that light consists of waves of some kind or other, and +that these waves travel at a certain well-known velocity, seven times +the circumference of the earth per second, taking eight minutes on the +journey from the sun to the earth. This propagation in time of an +undulatory disturbance necessarily involves a medium. If waves setting +out from the sun exist in space eight minutes before striking our +eyes, there must necessarily be in space some medium in which they +exist and which conveys them. Waves we cannot have unless they be +waves in something. + +No ordinary medium is competent to transmit waves at anything like the +speed of light; hence the luminiferous medium must be a special kind +of substance, and it is called the ether. The _luminiferous_ ether it +used to be called, because the conveyance of light was all it was then +known to be capable of; but now that it is known to do a variety of +other things also, the qualifying adjective may be dropped. + +Wave motion in ether, light certainly is; but what does one mean by +the term wave? The popular notion is, I suppose, of something heaving +up and down, or, perhaps, of something breaking on the shore in which +it is possible to bathe. But if you ask a mathematician what he means +by a wave, he will probably reply that the simplest wave is + + y = a sin (p t - n x), + +and he might possibly refuse to give any other answer. + +And in refusing to give any other answer than this, or its equivalent +in ordinary words, he is entirely justified; that is what is meant by +the term wave, and nothing less general would be all-inclusive. + +Translated into ordinary English the phrase signifies "a disturbance +periodic both in space and time." Anything thus doubly periodic is a +wave; and all waves, whether in air as sound waves, or in ether as +light waves, or on the surface of water as ocean waves, are +comprehended in the definition. + +What properties are essential to a medium capable of transmitting wave +motion? Roughly we may say two--_elasticity_ and _inertia_. Elasticity +in some form, or some equivalent of it, in order to be able to store +up energy and effect recoil; inertia, in order to enable the disturbed +substance to overshoot the mark and oscillate beyond its place of +equilibrium to and fro. Any medium possessing these two properties can +transmit waves, and unless a medium possesses these properties in some +form or other, or some equivalent for them, it may be said with +moderate security to be incompetent to transmit waves. But if we make +this latter statement, one must be prepared to extend to the terms +elasticity and inertia their very largest and broadest signification, +so as to include any possible kind of restoring force and any possible +kind of persistence of motion respectively. + +These matters may be illustrated in many ways, but perhaps a simple +loaded lath or spring in a vise will serve well enough. Pull aside one +end, and its elasticity tends to make it recoil; let it go, and its +inertia causes it to overshoot its normal position; both causes +together cause it to swing to and fro till its energy is exhausted. A +regular series of such springs at equal intervals in space, set going +at regular intervals of time one after the other, gives you at once a +wave motion and appearance which the most casual observer must +recognize as such. A series of pendulums will do just as well. Any +wave-transmitting medium must similarly possess some form of +elasticity and of inertia. + +But now proceed to ask what is this ether which in the case of light +is thus vibrating? What corresponds to the elastic displacement and +recoil of the spring or pendulum? What corresponds to the inertia +whereby it overshoots its mark? Do we know these properties in the +ether in any other way? + +The answer, given first by Clerk Maxwell, and now reiterated and +insisted on by experiments performed in every important laboratory in +the world, is: + +The elastic displacement corresponds to electrostatic charge (roughly +speaking, to electricity). + +The inertia corresponds to magnetism. + +This is the basis of the modern electro-magnetic theory of light. Now +let me illustrate electrically how this can be. + +The old and familiar operation of charging a Leyden jar--the storing +up of energy in a strained dielectric, any electrostatic charging +whatever--is quite analogous to the drawing aside of our flexible +spring. It is making use of the elasticity of the ether to produce a +tendency to recoil. Letting go the spring is analogous to permitting a +discharge of the jar--permitting the strained dielectric to recover +itself, the electrostatic disturbance to subside. + +In nearly all the experiments of electrostatics, ethereal elasticity +is manifest. + +Next consider inertia. How would one illustrate the fact that water, +for instance, possesses inertia--the power of persisting in motion +against obstacles--the power of possessing kinetic energy? The most +direct way would be to take a stream of water and try suddenly to stop +it. Open a water tap freely and then suddenly shut it. The impetus or +momentum of the stopped water makes itself manifest by a violent shock +to the pipe, with which everybody must be familiar. The momentum of +water is utilized by engineers in the "water ram." + +A precisely analogous experiment in electricity is what Faraday called +"the extra current." Send a current through a coil of wire round a +piece of iron, or take any other arrangement for developing powerful +magnetism, and then suddenly stop the current by breaking the circuit. +A violent flash occurs if the stoppage is sudden enough, a flash which +means the bursting of the insulating air partition by the accumulated +electro-magnetic momentum. + +Briefly, we may say that nearly all electro-magnetic experiments +illustrate the fact of ethereal inertia. + +Now return to consider what happens when a charged conductor (say a +Leyden jar) is discharged. The recoil of the strained dielectric +causes a current, the inertia of this current causes it to overshoot +the mark, and for an instant the charge of the jar is reversed; the +current now flows backward and charges the jar up as at first; back +again flows the current, and so on, charging and reversing the charge +with rapid oscillations until the energy is all dissipated into heat. +The operation is precisely analogous to the release of a strained +spring or to the plucking of a stretched string. + +But the discharging body thus thrown into strong electrical vibration +is embedded in the all-pervading ether, and we have just seen that the +ether possesses the two properties requisite for the generation and +transmission of waves--viz., elasticity and inertia or density; hence, +just as a tuning fork vibrating in air excites aerial waves or sound, +so a discharging Leyden jar in ether excites ethereal waves or light. + +Ethereal waves can therefore be actually produced by direct electrical +means. I discharge here a jar, and the room is for an instant filled +with light. With light, I say, though you can see nothing. You can see +and hear the spark indeed--but that is a mere secondary disturbance we +can for the present ignore--I do not mean any secondary disturbance. I +mean the true ethereal waves emitted by the electric oscillation going +on in the neighborhood of this recoiling dielectric. You pull aside +the prong of a tuning fork and let it go; vibration follows and sound +is produced. You charge a Leyden jar and let it discharge; vibration +follows and light is excited. + +It is light just as good as any other light. It travels at the same +pace, it is reflected and refracted according to the same laws; every +experiment known to optics can be performed with this ethereal +radiation electrically produced, and yet you cannot see it. Why not? +For no fault of the light; the fault (if there be a fault) is in the +eye. The retina is incompetent to respond to these vibrations--they +are too slow. The vibrations set up when this large jar is discharged +are from a hundred thousand to a million per second, but that is too +slow for the retina. It responds only to vibrations between 4,000 +billions and 7,000 billions per second. The vibrations are too quick +for the ear, which responds only to vibrations between 40 and 40,000 +per second. Between the highest audible and the lowest visible +vibrations there has been hitherto a great gap, which these electric +oscillations go far to fill up. There has been a great gap simply +because we have no intermediate sense organ to detect rates of +vibration between 40,000 and 4,000,000,000,000,000 per second. It was, +therefore, an unexplored territory. Waves have been there all the time +in any quantity, but we have not thought about them nor attended to +them. + +It happens that I have myself succeeded in getting electric +oscillations so slow as to be audible. The lowest I have got at +present are 125 per second, and for some way above this the sparks +emit a musical note; but no one has yet succeeded in directly making +electric oscillations which are visible, though indirectly every one +does it when they light a candle. + +Here, however, is an electric oscillator, which vibrates 300 million +times a second, and emits ethereal waves a yard long. The whole range +of vibrations between musical tones and some thousand million per +second is now filled up. + +These electro-magnetic waves have long been known on the side of +theory, but interest in them has been immensely quickened by the +discovery of a receiver or detector for them. The great though simple +discovery by Hertz of an "electric eye," as Sir W. Thomson calls it, +makes experiments on these waves for the first time easy or even +possible. We have now a sort of artificial sense organ for their +appreciation--an electric arrangement which can virtually "see" these +intermediate rates of vibration. + +The Hertz receiver is the simplest thing in the world--nothing but a +bit of wire or a pair of bits of wire adjusted so that when immersed +in strong electric radiation they give minute sparks across a +microscopic air gap. + +The receiver I have here is adapted for the yard-long waves emitted +from this small oscillator; but for the far longer waves emitted by a +discharging Leyden jar an excellent receiver is a gilt wall paper or +other interrupted metallic surface. The waves falling upon the +metallic surface are reflected, and in the act of reflection excite +electric currents, which cause sparks. Similarly, gigantic solar waves +may produce aurorę; and minute waves from a candle do electrically +disturb the retina. + +The smaller waves are, however, far the most interesting and the most +tractable to ordinary optical experiments. From a small oscillator, +which may be a couple of small cylinders kept sparking into each other +end to end by an induction coil, waves are emitted on which all manner +of optical experiments can be performed. + +They can be reflected by plain sheets of metal, concentrated by +parabolic reflectors, refracted by prisms, concentrated by lenses. I +have at the college a large lens of pitch, weighing over three +hundredweight, for concentrating them to a focus. They can be made to +show the phenomenon of interference, and thus have their wave length +accurately measured. They are stopped by all conductors and +transmitted by all insulators. Metals are opaque, but even imperfect +insulators such as wood or stone are strikingly transparent, and waves +may be received in one room from a source in another, the door between +the two being shut. + +The real nature of metallic opacity and of transparency has long been +clear in Maxwell's theory of light, and these electrically produced +waves only illustrate and bring home the well known facts. The +experiments of Hertz are in fact the apotheosis of that theory. + +Thus, then, in every way Maxwell's 1865 brilliant perception of the +real nature of light is abundantly justified; and for the first time +we have a true theory of light, no longer based upon analogy with +sound, nor upon a hypothetical jelly or elastic solid. + +Light is an electro-magnetic disturbance of the ether. Optics is a +branch of electricity. Outstanding problems in optics are being +rapidly solved now that we have the means of definitely exciting light +with a full perception of what we are doing and of the precise mode of +its vibration. + +It remains to find out how to shorten down the waves--to hurry up the +vibration until the light becomes visible. Nothing is wanted but +quicker modes of vibrations. Smaller oscillators must be used--very +much smaller--oscillators not much bigger than molecules. In all +probability--one may almost say certainly--ordinary light is the +result of electric oscillation in the molecules of hot bodies, or +sometimes of bodies not hot--as in the phenomenon of phosphorescence. + +The direct generation of _visible_ light by electric means, so soon as +we have learnt how to attain the necessary frequency of vibration, +will have most important practical consequences. + +Speaking in this university, it is happily quite unnecessary for me to +bespeak interest in a subject by any reference to possible practical +applications. But any practical application of what I have dealt with +this evening is apparently so far distant as to be free from any +sordid gloss of competition and company promotion, and is interesting +in itself as a matter of pure science. + +For consider our present methods of making artificial light; they are +both wasteful and ineffective. + +We want a certain range of oscillation, between 7,000 and 4,000 +billion vibrations per second; no other is useful to us, because no +other has any effect upon our retina; but we do not know how to +produce vibrations of this rate. We can produce a definite vibration +of one or two hundred or thousand per second; in other words, we can +excite a pure tone of definite pitch; and we can demand any desired +range of such tones continuously by means of bellows and a keyboard. +We can also (though the fact is less well known) excite momentarily +definite ethereal vibrations of some million per second, as I have +explained at length; but we do not at present seem to know how to +maintain this rate quite continuously. To get much faster rates of +vibration than this we have to fall back upon atoms. We know how to +make atoms vibrate; it is done by what we call "heating" the +substance, and if we could deal with individual atoms unhampered by +others, it is possible that we might get a pure and simple mode of +vibration from them. It is possible, but unlikely; for atoms, even +when isolated, have a multitude of modes of vibration special to +themselves, of which only a few are of practical use to us, and we do +not know how to excite some without also the others. However, we do +not at present even deal with individual atoms; we treat them crowded +together in a compact mass, so that their modes of vibration are +really infinite. + +We take a lump of matter, say a carbon filament or a piece of +quicklime, and by raising its temperature we impress upon its atoms +higher and higher modes of vibration, not transmuting the lower into +the higher, but superposing the higher upon the lower, until at length +we get such rates of vibration as our retina is constructed for, and +we are satisfied. But how wasteful and indirect and empirical is the +process. We want a small range of rapid vibrations, and we know no +better than to make the whole series leading up to them. It is as +though, in order to sound some little shrill octave of pipes in an +organ, we are obliged to depress every key and every pedal, and to +blow a young hurricane. + +I have purposely selected as examples the more perfect methods of +obtaining artificial light, wherein the waste radiation is only useless +and not noxious. But the old-fashioned plan was cruder even than this; +it consisted simply in setting something burning; whereby not the fuel +but the air was consumed, whereby also a most powerful radiation was +produced, in the waste waves of which we were content to sit stewing, +for the sake of the minute--almost infinitesimal--fraction of it which +enabled us to see. + +Every one knows now, however, that combustion is not a pleasant or +healthy mode of obtaining light; but every one does not realize that +neither is incandescence a satisfactory and unwasteful method which is +likely to be practiced for more than a few decades, or perhaps a +century. + +Look at the furnaces and boilers of a great steam engine driving a +group of dynamos, and estimate the energy expended; and then look at +the incandescent filaments of the lamps excited by them, and estimate +how much of their radiated energy is of real service to the eye. It +will be as the energy of a pitch pipe to an entire orchestra. + +It is not too much to say that a boy turning a handle could, if his +energy were properly directed, produce quite as much real light as is +produced by all this mass of mechanism and consumption of material. +There might, perhaps, be something contrary to the laws of nature in +thus hoping to get and utilize some specific kind of radiation without +the rest, but Lord Rayleigh has shown in a short communication to the +British Association at York that it is not so, and that, therefore, we +have a right to try to do it. + +We do not yet know how, it is true, but it is one of the things we +have got to learn. + +Any one looking at a common glow-worm must be struck with the fact +that not by ordinary combustion, nor yet on the steam engine and +dynamo principle, is that easy light produced. Very little waste +radiation is there from phosphorescent things in general. Light of the +kind able to affect the retina is directly emitted; and for this, for +even a large supply of this, a modicum of energy suffices. + +Solar radiation consists of waves of all sizes, it is true; but then +solar radiation has innumerable things to do besides making things +visible. The whole of its energy is useful. In artificial lighting +nothing but light is desired; when heat is wanted it is best obtained +separately by combustion. And so soon as we clearly recognize that +light is an electric vibration, so soon shall we begin to beat about +for some mode of exciting and maintaining an electrical vibration of +any required degree of rapidity. When this has been accomplished the +problem of artificial lighting will have been solved. + + * * * * * + + + + +ON PURIFICATION OF AIR BY OZONE--WITH AN ACCOUNT OF A NEW METHOD.[1] + + [Footnote 1: Paper read in Section C, Domestic Health, at the + Hastings Health Congress, on Friday, May 3, 1889.] + +By Dr. B. W. RICHARDSON. + + +During the time when I was engaged in my preliminary medical +studies--for I never admit to this day of being anything less than a +medical student--the substance called ozone became the topic of much +conversation and speculation. I cannot say that ozone was a discovery +of that date, for in the early part of the century Von Marum had +observed that when electrical discharges were made through oxygen in a +glass cylinder inverted over water, the water rose in the cylinder as +if something had either been taken away from the gas, or as if the gas +itself had been condensed, and was therefore occupying a smaller +space. It had also been observed by many electricians that during a +passage of the electric spark through air or oxygen, there was a +peculiar emanation or odor which some compared to fresh sea air, +others to the air after a thunderstorm, when the sky has become very +clear, the firmament blue, and the stars, if visible, extremely +bright. + +But it was not until the time, or about the time, of which I have +spoken, 1846-49, that these discovered but unexplained phenomena +received proper recognition. The distinguished physicist Schonbein +first, if I may so say, isolated the substance which yielded the +phenomena, and gave to it the name, by which it has since generally +been known, of _ozone_, which means, to emit an odor; a name, I have +always thought, not particularly happy, but which has become, +practically, so fully recognized and understood, that it would be +wrong now to disturb it. + +Schonbein made ozone by the action of the electric spark on oxygen. He +collected it, he tested its chemical properties, he announced it to be +oxygen in a modified form, and he traced its action as an active +oxidizer of various substances, and especially of organic substances, +even when they were in a state of decomposition. + +But Schonbein went further than this. He argued that ozone was a +natural part of the atmosphere, and that in places where there was no +decomposition, that is to say, in places away from great towns, ozone +was present. On the high tower of a cathedral in a big city he +discovered ozone; in the city, at the foot of the tower, he found no +ozone at the same time. He argued, therefore, that the ozone above was +used up in purifying the town below, and so suggested quite a new +explanation of the purification of air. + +The subject was very soon taken up by English observers, and I +remember well a lecture upon it by Michael Faraday, in which that +illustrious philosopher, confirming Schonbein, stated that he had +discovered ozone freely on the Brighton Downs, and had found the +evidence of it diminishing as he approached Brighton, until it was +lost altogether in the town itself. + +Such was the beginning of our knowledge of ozone, the precise nature +of which has not yet been completely made out. At the present time it +is held to be oxygen condensed. To use a chemical phrase, the molecule +of oxygen, which in the ordinary state is composed of two atoms, is +condensed, in ozone, as three atoms. By the electric spark discharged +in dry oxygen as much as 15 per cent. may, under proper conditions, be +turned into ozone. Ozone has also been found to be heavier than air. +Professor Zinno says, that compared with an equal volume of air its +density is equal to 1,658, and that it is forty-eight times heavier +than hydrogen. Heat decomposes it; at the temperature of boiling water +it begins to decompose. In water it is much less soluble than oxygen, +and indeed is practically insoluble; when made to bubble through +boiling water, it ceases to be ozone. The oxidizing power of ozone is +very much greater than that of oxygen, and, according to Saret, when +ozone is decomposed, one part of it enters into combination, the other +remains simply as oxygen. + +It is remarkable that some substances, like turpentine and cinnamon, +absorb ozone and combine with it, a simple fact of much greater +importance than has ever been attached to it. I found, for instance, +that cinnamon which by exposure to the air has been made odorless and, +as it is said, "spoiled," can be made to reabsorb ozone and gain a +kind of freshness. It is certain also that some substances which are +supposed to have disinfecting properties owe what virtues they possess +to the presence of ozone. + +On some grand scale ozone is formed in the air, and my former friend +and colleague, the late Dr. Moffatt, of Hawarden, with whom I wrote a +paper on "Meteorology and Disease," read before the Epidemiological +Society in 1852-53, described what he designated ozone periods of the +atmosphere, connecting these with storms. When the atmospheric +pressure is decreasing, when with that there is increasing warmth and +moisture, and when south and southwesterly winds prevail, then ozone +is active; but when the atmospheric pressure is increasing, when the +air is becoming dry and cold, and north and northeasterly winds +prevail, then the presence of ozone is less active. These facts have +also been put in another way, namely, that the maximum period of ozone +occurs when there is greatest evaporation of water from the earth, and +the minimum when there is greatest condensation of water on the earth; +a theory which tallies well with the idea that ozone is most freely +present when electricity is being produced, least present when +electricity is in smallest quantity. Mr. Buchan, reporting on the +observations of the Scottish Meteorological Society, records that +ozone is most abundant from February to June, when the average amount +is 6.0; and least from July to January, when the average is 5.7; the +maximum, 6.2, being reached in May, and the minimum, 5.3, in November. +This same excellent observer states that "ozone is more abundant on +the sea coast than inland; in the west than the east of Great Britain; +in elevated than in low situations; with southwest than with northeast +winds; in the country than in towns; and on the windward than the +leeward side of towns." + +Recently a very singular hypothesis has been broached in regard to the +blue color of the firmament and ozone. It has been observed that when +a tube is filled with ozone, the light transmitted through it is of a +blue color; from which fact it is assumed that the blue color of the +sky is due to the presence of this body in the higher atmospheric +strata. The hypothesis is in entire accord with the suggestion of +Professor Dove, to which Moffatt always paid the greatest respect, +viz., that the source of ozone for the whole of the planet is +equatorial, and that the point of development of ozone is where the +terrestrial atmosphere raised to its highest altitude, at the equator, +expands out north and south in opposite directions toward the two +poles, to return to the equator over the earth as the trade winds. + +It is necessary for all who would understand the applications of ozone +for any purpose, whether for bleaching purposes or pure chemical +purposes, or for medical or sanitary purposes, to understand these +preliminary facts concerning it, facts which bring me to the +particular point to which I wish to refer to-day. + +In my essay describing the model city, Hygeiopolis, it was suggested +that in every town there should be a building like a gas house, in +which ozone should be made and stored, and from which it should be +dispensed to every street or house at pleasure. This suggestion was +made as the final result of observations which had been going on since +I first began to work at the subject in 1852. It occurred to me from +the moment when I first made ozone by Schonbein's method, that the +value of it in a hygienic point of view was incalculable. + +To my then young and enthusiastic mind it seemed that in ozone we had +a means of stopping all putrefaction, of destroying all infectious +substances, and of actually commanding and destroying the causes which +produced the great spreading diseases; and, although increase of years +and greater experience have toned down the enthusiasm, I still believe +that here one of the most useful fields for investigation remains +almost unexplored. + +In my first experiments I subjected decomposing blood to ozone, and +found that the products of decomposition were instantly destroyed, and +that the fluid was rendered odorless and sweet. I discovered that the +red corpuscles of fresh blood decomposed ozone, and that coagulated +blood underwent a degree of solution through its action. I put dead +birds and pieces of animal substances that had undergone extreme +decomposition into atmospheres containing ozone, and observed the +rapidity with which the products of decomposition were neutralized and +rendered harmless. I employed ozone medicinally, by having it inhaled +by persons who were suffering from foetor of the breath, and with +remarkable success, and I began to employ it and have employed it ever +since (that is to say, for thirty-seven years), for purposes of +disinfection and deodorization, in close rooms, closets, and the like. +I should have used it much more largely but for one circumstance, +namely, the almost impracticable difficulty of making it with +sufficient ease and in sufficient quantities to meet the necessities +of sanitary practice. We are often obstructed in this way. We know of +something exceedingly useful, but we cannot utilize it. This was the +case with ozone. I hope now that difficulty is overcome. If it is, we +shall start from this day on a new era in regard to ozone as an +instrument of sanitation. + +As we have seen, ozone was originally made by charging dry oxygen or +common dry air with electricity from sparks or points. Afterward +Faraday showed that it could be made by holding a warm glass rod in +vapor of ether. Again he showed that it could be made by passing air +over bright phosphorus half immersed in water. Then Siemens modified +the electric process by inventing his well known ozone tube, which +consists of a wide glass tube coated with tinfoil on its outside, and +holding within it a smaller glass tube coated with tinfoil on its +surface. When a current of dry air or oxygen was passed in current +between these two tubes, and the electric spark from a Ruhmkorf coil +was discharged by the terminal wires connected with tinfoil surfaces, +ozone was freely produced, and this was no doubt the best method, for +by means of a double-acting hand bellows currents of ozone could be +driven over very freely. One of these tubes with hand bellows +attached, which I have had in use for twenty-four years, is before the +meeting, and answers as well as ever. The practical difficulty lies in +the requirement of a battery, a large coil, and a separate bellows as +well as the tube. + +My dear and most distinguished friend, the late Professor Polli, of +Milan, tried to overcome the difficulties arising from the use of the +coil by making ozone chemically, namely, by the decomposition of +permanganate of potassa with strong sulphuric acid. He placed the +permanganate in glass vessels, moistened it gradually with the acid, +and then allowed the ozone, which is formed, to diffuse into the air. +In this way he endeavored, as I had done, to purify the air of rooms, +especially those vitiated by the breaths of many people. When he +visited me, not very long before his death, he was enthusiastic as to +the success that must attend the utilization of ozone for +purification, and when I expressed a practical doubt, he rallied me by +saying I must not desert my own child. At the theater La Scala, on the +occasion of an unusually full attendance, Polli collected the +condensible part of the exhaled organic matter, by means of a large +glass bell filled with ice and placed over the circular opening in the +roof, which corresponds with the large central light. The deposit on +this bell was liquid and had a mouldy smell; was for some few days +limpid, but then became very thick and had a nauseous odor. When mixed +with a solution of one part glucose to four parts of water, and kept +at a temperature of from 20° to 24° C., this liquid underwent a slow +fermentation, with the formation, on the superficies, of green must; +during the same period of time, and placed under the same conditions, +a similar glucose solution underwent no change whatever. + +By the use of his ozone bottles Polli believed that he had supplied a +means most suitable for directly destroying in the air miasmatic +principles, without otherwise interfering with the respiratory +functions. The ozonized air had neither a powerful nor an offensive +smell, and it might be easily and economically made. The smell of +ozone was scarcely perceptible, and was far less disagreeable than +chlorine, bromine, and iodine, while it was more efficacious than +either of these; if, therefore, its application as a purifier of a +vitiated air succeeded, it would probably supply all the exigences of +defective ventilation in crowded atmospheres. In confined places +vessels might be placed containing mixtures of permanganate of potassa +or soda and acid in proper quantities, and of which the duration of +the action was known; or sulphuric acid could be dropped upon the +permanganate. + +This idea of applying ozone was no doubt very ingenious, and in the +bottles before us on the table, which have been prepared in Hastings +by Mr. Rossiter, we see it in operation. The disadvantages of the plan +are that manipulation with strong sulphuric acid is never an agreeable +or safe process, and that the ozone evolved cannot be on a large scale +without considerable trouble. + +In 1875 Dr. Lender published a process for the production of ozone. In +this process he used equal parts of manganese, permanganate of potash, +and oxalic acid. When this mixture is placed in contact with water, +ozone is quickly generated. For a room of medium size two spoonfuls of +this powder, placed in a dish and occasionally diluted with water, +would be sufficient. As the ozone is developed, it disinfects the +surrounding air without producing cough. + +Lender's process is very useful when ozone is wanted on a limited +scale. We have some of it here prepared by Mr. Rossiter, and it +answers exceedingly well; but it would be impossible to generate +sufficient ozone by this plan for the large application that would be +required should it come into general use. The process deserves to be +remembered, and the physician may find it valuable as a means by which +ozone may be medically applied, to wounds, or by inhalation when there +are foetid exhalations from the mouth or nostrils. + + +A NEW METHOD. + +For the past ten or fifteen years the manufacture of ozone, for the +reasons related above, has remained in abeyance, and it is to a new +mode, which will, I trust, mark another stage of advancement, that I +now wish to direct attention. Some years since, Mr. Wimshurst, a most +able electrician, invented the electrical machine which goes by his +name. The machine, as will be seen from the specimen of it on the +table, looks something like the old electrical machine, but differs in +that there is no friction, and that the plates of glass with their +metal sectors, separated a little distance from each other, revolve, +when the handle of the machine is turned, in opposite directions. The +machine when it is in good working order (and it is very easily kept +in good working order) produces electricity abundantly, and in working +it I observed that ozone was so freely generated, that more than once +the air of my laboratory became charged with ozone to an oppressive +degree. The fact led me to use this machine for the production of +ozone on a large scale, in the following way. + +From the terminals of the machine two wires are carried and are +conducted, by their terminals, to an ozone generator formed somewhat +after the manner of Siemens', but with this difference, that the +discharge is made through a series of fine points within the +cylinders. The machine is placed on a table with the ozone generator +at the back of it, and can be so arranged that with the turning of the +handle which works the machine a blast of air is carried through the +generator. Thus by one action electricity is generated, sparks are +discharged in the ozone generator, air is driven through, and ozone is +delivered over freely. + +If it be wished to use pure oxygen instead of common air, nothing more +is required than to use compressed oxygen and to allow a gentle +current to pass through the ozone generator in place of air. For this +purpose Brin's compressed oxygen is the purest and best; but for +ordinary service atmospheric air is sufficient.[2] + + [Footnote 2: For illustration to-day, Messrs Mayfield, the + electrical engineers of Queen Victoria Street, E. C., have been + good enough to lend me a machine fitted up on the plan named. It + works so effectively that I can make the ozone given off from it + detectable in every part of this large hall.] + +The advantages of this apparatus are as follows: + +1. With care it is always ready for use, and as no battery is required +nor anything more than the turning of a handle, any person can work +it. + +2. It can be readily moved about from one part of a room or ward to +another part. + +3. If required for the sick it can be wheeled near the bedside and, by +a tube, the ozone it emits can be brought into action in any way +desired by the physician. + +I refer in the above to the minor uses of ozone by this method, but I +should add that it admits of application on a much grander scale. It +would now be quite easy in any public institution to have a room in +which a large compound Wimshurst could be worked with a gas engine, +and from which, with the additional apparatus named, ozone could be +distributed at pleasure into any part of the building. On a still +larger scale ozone could be supplied to towns by this method, as +suggested in Hygeiopolis, the model city. + +It will occur, I doubt not, to the learned president of this section, +and to others of our common profession, that care will have to be +taken in the application of ozone that it be used with discretion. +This is true. It has been observed in regard to diseases, that in the +presence of some diseases ozone is absent in the atmosphere, but that +with other diseases ozone is present in abundance. During epidemics of +cholera, ozone is at a minimum. During other epidemics, like +influenza, it has been at a maximum. In our paper Dr. Moffatt and I +classified diseases under both conditions, and the difference must +never be forgotten, since in some diseases we might by the use of +ozone do mischief instead of good. Moreover, as my published +experiments have shown, prolonged inhalation of ozone produces +headache, coryza, soreness of the eyes, soreness of the throat, +general malaise, and all the symptoms of severe influenza cold. +Warm-blooded animals, also, exposed to it in full charge, suffer from +congestion of the lungs, which may prove rapidly fatal. With care, +however, these dangers are easily avoided, the point of practice being +never to charge the air with ozone too abundantly or too long. + +A simple test affords good evidence as to presence of ozone. If into +twenty ounces of water there be put one ounce of starch and forty +grains of potassium iodide, and the whole be boiled together, a starch +will be made which can be used as a test for ozone. If ozone be passed +through this starch the potassium is oxidized, and the iodine, set +free, strikes a blue color with the starch. Or bibulous paper can be +dipped in the starch, dried and cut into slips, and these slips being +placed in the air will indicate when ozone is present. In disinfecting +or purifying the air of a room with ozone, there is no occasion to +stop until the test paper, by change of color, shows that the ozone +has done its work of destroying the organic matter which is the cause +of impurity or danger. For my own part, I have never seen the +slightest risk from the use of ozone in an impure air. The difficulty +has always been to obtain sufficient ozone to remove the impurity, and +it is this difficulty which I hope now to have conquered.--_The +Asclepiad._ + + * * * * * + + + + +HEAT IN MAN. + + +At a recent meeting of the Physiological Society of Berlin, Prof. +Zuntz spoke on heat regulation in man, basing his remarks on +experiments made by Dr. Loewy. The store of heat in the human body at +any one time is very large, equal, in fact, to nearly all the heat +produced by the body during twenty hours, hence the heat given off to +a calorimeter during a given period cannot be taken as a measure of +the heat production. This determination must be based rather upon the +amount of oxygen consumed and of carbonic acid gas given off. The +purpose of the experiments was to ascertain what alteration the +gaseous interchange of the body undergoes by the application of cold, +inasmuch as existing data on this point are largely contradictory. + +The observations were made on a number of men whose respiratory gases +were compared, during complete rest, when they were at one time +clothed, at another time naked, at temperatures from 12° to 15° C., +and in warm and cold baths. Each experiment lasted from half an hour +to an hour, during which period the gases were repeatedly analyzed. As +a result of fifty-five experiments, twenty showed no alteration of +oxygen consumption as the result of cooling, nine gave a lessened +consumption, while the remaining twenty-six showed an increased using +up of oxygen. This diversity of result is explicable on the basis of +observations made by Prof. Zuntz, who was himself experimented upon, +as to his subjective heat sensations during the experiments. He found +that after the first impression due to the application of cold is +overcome, it was quite easy to maintain himself in a perfectly passive +condition; subsequently it required a distinct effort of the will to +refrain from shivering and throwing the muscles into activity, and +finally even this became no longer possible, and involuntary shivering +and muscular contraction supervened, as soon as the body temperature +(_in ano_) had fallen ½° to 1° C. During the first stage of cooling, +Zuntz's oxygen consumption showed a uniform diminution; during the +period also in which shivering was repressed by an effort of the will, +cooling led to no increased consumption of oxygen, but as soon as +shivering became involuntary there was at once an increased using up +of oxygen and excretion of carbonic acid. + +This explains the differences in the results of Dr. Loewy's +experiments, and may be taken to show that in man, and presumably in +_large_ animals, heat regulation as directly dependent upon alteration +(fall) in temperature of the surrounding medium does not exist; the +increased heat production is rather the outcome of the movements +resulting from the application of cold to the body. In _small_ +animals, on the other hand, there undoubtedly exists a heat regulation +dependent upon an increased activity of chemical changes in the +tissues set up by the application of cold to the surface of the body, +and in this case the thermotaxic centers in the brain most probably +play some part.--Dr. Herter gave an account of experiments made by Dr. +Popoff on the artificial digestion of various and variously cooked +meats. Lean beef and the flesh of eels and flounders were digested in +artificial gastric juice; the amount of raw flesh thus peptonized was +in all cases greater than that of cooked meat similarly treated. The +flesh was shredded and heated by steam to 100° C. The result was the +same for beef as for fish. When compared with each other, beef was, on +the whole, the most digestible, but the amount of fish flesh which was +peptonized was sufficiently great to do away with the evil repute +which fish still has in Germany as a proteid food. Smoked meat +differed in no essential extent from raw meat as regards its +digestibility. + + * * * * * + + + + +PRESERVATION OF SPIDERS FOR THE CABINET. + + +For several years past, I have devoted a portion of my leisure time to +the arrangement of the collection of Arachnidę of the Natural History +Museum of the University of Gand. This collection, which is partially +a result of my own captures, is quite a large one, for a university +museum, since it comprises more than six hundred European and foreign +specimens. Each group of individuals of the small forms and each +individual of the large forms is contained in a bottle of alcohol +closed with a ground glass stopper, and, whenever possible, the +specimens have been spread out and fixed upon strips of glass. + +The loss of alcohol through evaporation is almost entirely prevented +by paraffining the stoppers and tying a piece of bladder over them. + +Properly labeled, the series has a very satisfactory aspect, and is +easily consulted for study. The reader, however, will readily +understand how much time and patience such work requires, and can +easily imagine how great an amount of space the collection occupies, +it being at least twenty times greater than that that would be taken +up by a collection of an equal number of insects mounted in the +ordinary way on pins and kept in boxes. + +These inconveniences led me to endeavor to find out whether there was +not some way of preserving spiders, properly so called, in a dry +state, and without distortion or notable modification of their colors. + +Experience long ago taught me that pure and simple desiccation, after +a more or less prolonged immersion in alcohol, gives passable results +only with scorpions, galeodes, phrynes, and mygales, and consequently +with arachnides having thick integuments, while it is entirely +unsuccessful with most of the spiders. The abdomen of these shrivels, +the characteristic colors disappear in great part, and the animals +become unrecognizable. + +Something else was therefore necessary, and I thought of carbolated +glycerine. My process, which I have tried only upon the common species +of the country--_Tegenaria domestica_, _Epeira cucurbitina_, _Zilla +inclinata_, etc., having furnished me with preparations that were +generally satisfactory. I think I shall be doing collectors a service +by publishing it in the _Naturaliste_. + +The specimens should first be deprived of moisture, that is to say, +they should be allowed to remain eight or ten days in succession in 50 +per cent. alcohol and in pure commercial alcohol. Absolute alcohol is +not necessary. + +After being taken from the alcohol, and allowed to drain, the +specimens are immersed in a mixture compound of + + Pure glycerine 2 volumes, + Pure carbolic acid in crystals 1 volume. + +In this they ought to remain at least a week, but there will be no +harm if they are left therein indefinitely, so that the collections of +summer may be mounted during winter evenings. + +What follows is a little more delicate, although very easy. After +being removed from the carbolated glycerine, the spiders are placed +upon several folds of white filtering paper, and are changed from time +to time until the greatest part of the liquid has been absorbed. An +insect pin is then passed through the cephalothorax of each individual +and is inserted in the support upon which the final desiccation is to +take place. This support consists of a piece of sheet cork tacked or +glued at the edges to a piece of wood at least one inch in thickness. +Upon the cork are placed four or five folds of filtering paper, so +that the ventral surface of the pinned spider is in contact with this +absorbing surface. For the rest, the legs, palpi, spinnerets, etc., +are spread out by means of fine pins, precisely as would be done in +the case of coleoptera. + +[Illustration: SETTING BOARD FOR SPIDERS. + +A. Absorbent papers. B. Sheet cork. C. Wooden support.] + +The setting board is put for two or three months in a very dry place +under cover from dust. + +The spiders thus treated will scarcely have changed in appearance, the +abdomen of the largest Epeiras will have preserved its form, the hairs +will in nowise have become agglutinated, and a person would never +suspect that glycerine had performed the role. + +The forms with a large abdomen require a special precaution; it is +necessary to pass the mounting pin through a piece of thin cardboard +or of gelatine prolonged behind under the abdomen, because the latter +is heavy, and the pedicel that connects it with the cephalothorax +easily breaks. + +The specimens are mounted in boxes lined with cork, just as insects +are. + +As there is nothing simpler than to have in one's laboratory three +bottles, two of them containing alcohol and the other containing +carbolated glycerine, and as it is easy to make setting boards capable +of holding from twenty to thirty individuals at once, it will be seen +that, with a little practice, the method is scarcely any more +complicated than the one daily employed for coleoptera and orthoptera, +which latter, too, must pass through alcohol, and be pinned, spread +out, and dried. There are but two additional elements, carbolated +glycerine and absorbent paper. I do not estimate the time necessary +for desiccation as being very long, since the zoologist can occupy +himself with other subjects while the specimens are drying. Let us add +that the process renders the preservation indefinite, and that +destructive insects are not to be feared. Some vertebrates, such as +monkeys, that I preserved in the flesh ten years ago, by a nearly +identical method, are still intact.--_F. Plateau, in Le Naturaliste._ + + * * * * * + + + + +DRIED WINE GRAPES. + + +According to a report of the Committee of the Grape Growers' and Wine +Maker's Association of California, the drying of wine grapes on a +large scale was begun during the vintage season of 1887, in which +season about eight carloads in all were made and sold, the bulk of +which came from the vicinity of Fresno; that year, the committee are +informed, the growers netted about three and a half cents per pound. +During the season of 1888 about 112 carloads were dried, packed, and +sold, netting the growers from two and a half to three and a half +cents per pound, depending on the quality of the fruit. The great bulk +of that year's product has entered into consumption, but there yet +remains unsold to consumers, we are informed, about ten carloads, +which, it is expected, will be sold during the next three months. It +has been observed by those handling this product that the largest +sales of dried wine grapes in 1888 and 1889 took place at those points +to which the first lots were shipped in 1887, which would show that as +the product becomes better known it finds a readier market. + +Dried wine grapes are prepared in a similar manner to raisins; that is +they are dried in the sun, but do not require the same care in +handling that are given to raisins. Wooden trays 2 × 3 are sometimes +used, but it is by no means necessary to go to the expense of +procuring trays, as it has been found that a good quality of coarse +brown paper will answer every purpose, and this, with care, may be +made to last two or three seasons. The drying was last season +principally done on the bare ground, but there is much loss by +shelling, as those dried are required to be turned; a pitchfork is +used for that purpose. Brown building paper can be procured of city +paper dealers in large rolls at four and a half cents per pound; +according to the thickness, it will cost from one and three-quarters +to three and a half cents per square yard. A thin, tough, waterproof +paper is also made in rolls at about six cents a square yard. Wine +grapes dry in from ten days to three weeks, according to variety and +weather, and with the exception of Malvoisie, Rose of Peru, and Black +Hamburg, from three and a half to four and a half tons of the green +fruit are required to make one of the dried; these three varieties, +however, being large, meaty, and a firm pulp, do not require more than +from three to three and a half tons of the green fruit to produce one +ton of dried, and are, therefore, the most profitable for drying; they +also command better values in the market. The grapes are sufficiently +dried when, on being rolled between the thumb and finger, no moisture +exudes, and also when the stems are found to be dry and brittle, so +that they can be separated readily from the berries. After the grapes +have reached the proper state of dryness, they are taken in boxes or +sacks to the packing house, where they are stemmed and cleaned, after +which they are packed in white cotton sacks, holding from fifty to +seventy-five pounds each, and when marked are ready for shipment. + +The stemming and cleaning of the dried grapes is done by special +machines designed for that purpose, which leaves the fruit in a +bright, clean condition attractive to purchasers. These machines are +at present built only by James Porteous, Fresno, and are operated +either by hand or power. The cost of a stemmer and cleaner complete is +$80, f. o. b. cars at Fresno. Where several producers can do so, it +would be advisable to club together and get the machine in this way. +Much extra expense could be avoided and one set of machinery would +serve several vineyards, possibly an entire district where time was +not a great object; or some one person in a district could purchase an +outfit and do the work by contract, going from place to place. The +capacity of the stemmer and cleaner is from five to eight tons per +day, when the grapes are in proper condition; and the cost or charge +for stemming, cleaning, sacking, and sewing up the sacks is from four +to five dollars per ton when the producer furnishes the sacks. Good +cotton sacks, holding about seventy-five pounds, cost from eight to +ten cents each, including the necessary twine. Last year dried grapes +were generally sold for cash, f. o. b., but it is probable that other +markets could be secured by selling on consignment. + +As to the advisability of such a course, each producer must himself be +the judge. It is, however, quite certain that until consumers have an +opportunity to try this product, the sales will necessarily be more or +less limited, unless vigorously pushed by merchants and others +interested in extending the markets for California products in the +Eastern cities not yet tried. The varieties most suitable and +profitable for drying, and especially for consumption in the Eastern +markets, are the Malvoisie, Rose of Peru, Black Hamburg, Mission, +Zinfandel, Charbono, Grenache, and in some localities the Carignan, of +the dark varieties, and the Feher Zagos and Golden Chasselas of the +white grapes; there are many other white grapes that are excellent +when dried, but are too valuable for wine-making purposes, or are too +small or deficient in sugar for use as dried grapes. + +The same is true of the dark grapes, some of which ripen so late that +it would be impossible to dry them in the sun, and the use of +artificial heat is, at present prices, too expensive. Therefore, the +varieties mentioned, which generally mature early, are found to be the +most suitable for this purpose. This product is sold by dealers in the +Eastern cities for cooking purposes, and as a substitute for dried +fruits, such as peaches, apples, apricots, etc., in comparison with +which it is usually much cheaper; while for stewing and for puddings +and pies it answers the same purpose. The demand for this product will +probably be gauged by the Eastern fruit crop; that is, the quantity +that can be disposed of will depend upon the quantity of Eastern fruit +in the market, and the prices will be largely dependent upon that of +dried fruit. + + * * * * * + + + + +WALNUT OIL. + +By THOMAS T. P. BRUCE WARREN. + + +This oil, which I obtained from the fully ripened nut of the _Jugluns +regia_, has so many excellent properties, especially for mixing with +artists' colors for fine art work, that I am surprised at the small +amount of information available on this interesting oil. + +Walnut oil is largely used for adulterating olive oil, and to +compensate for its high iodine absorption it is mixed with pure lard +oil olein, which also retards the thickening effect due to oxidation. +The marc left on expression of the oil is said to be largely used in +the manufacture of chocolate. Many people, I am told, prefer walnut +oil to olive oil for cooking purposes. + +The value of this oil for out-door work has been given me by a friend +who used it for painting the verandas and jalousies of his house (near +Como, Italy) some twenty years ago, and which have not required +painting since. In this country, at least, walnut oil is beyond the +reach of the general painter, and I do not know that the pure oil is +to be obtained as a commercial article, even on a small scale. + +It was in examining the properties of this and other oils, used as +adulterants of olive oil, that I was obliged to prepare them so as to +be sure of getting them in a reliable condition as regards purity. The +walnuts were harvested in the autumn of 1887, and kept in a dry airy +room until the following March. The kernels had shrunk up and +contracted a disagreeable acrid taste, so familiar with old olive oil +in which this has been used as an adulterant. Most oxidized oils, +especially cotton seed oil, reveal a similar acrid taste, but walnut +oil has, in addition, an unmistakable increase in viscosity. The nuts +were opened and the kernels thrown into warm water, so as to loosen +the epidermis; they were then rubbed in a coarse towel, so as to +blanch them. The decorticated nuts were wiped dry and rubbed to a +smooth paste in a marble mortar. The paste was first digested in CS2, +then placed in a percolator and exhausted with the same solvent, which +was evaporated off. The yield of oil was small, but probably, if the +nuts had been left to fully ripen on the trees without knocking them +off, the yield might have been greater. It is by no means improbable +that oxidation may have rendered a portion of the oil insoluble. The +decorticated kernels gave a perfectly sweet, inodorous, and almost +colorless oil, which rapidly thickens to an almost colorless, +transparent, and perfectly elastic skin or film, which does not darken +or crack easily by age. These are properties which, for fine art +painting, might be of great value in preserving the tinctorial purity +and freshness of pigments. + +Sulphur chloride gives a perfectly white product with the fresh oil, +but, when oxidized, the product is very dark, almost black. The iodine +absorption of the fresh oil thus obtained is very high, but falls +rapidly by oxidation or blowing. A curious fact has been disclosed +with reference to the oxidation of this and similar oils. If such an +oil be mixed with lard oil, olive oil, or sperm oil, it thickens by +oxidation, but is perfectly soluble. Such a mixture is largely used in +weaving or spinning. Commercial samples of linseed oil, when +cold-drawn, have a much higher iodine absorption, probably due to the +same cause. Oils extracted by CS2 are very much higher than the same +oils, especially if hot-pressed.--_Chem. News._ + + * * * * * + + + + +THE PYRO DEVELOPER WITH METABISULPHITE OF POTASH. + +By Dr. J. M. EDER. + + +Lately I called attention to the metabisulphite of potassium as an +addition to the pyro solution for development, and can give now some +of my experiences with this salt. + +The metabisulphite of potassium, which was introduced into the market +by Dr. Schuchardt, and whose correct analysis is not known yet, is a +white crystal, which in a solid condition, as well as in an aqueous +solution, has a strong smell of sulphurous acid. An aqueous 2 per +cent. solution of this salt dissolves pyrogallic acid to a weak +yellowish color, being distinguished from the more light brown +solution of sulphite of soda and pyro. The solution kept very well for +four weeks in half-filled bottles, and showed a better preservation +than the usual solution of pyro and sulphite of soda. More than 2 per +cent. of the metabisulphite of potassium is without any advantage. If +this solution is mixed with soda, a picture will develop rapidly, but +the same will show a strongly yellow coloration in the gelatine film. +Sulphite of soda has to be added to the soda solution to obtain an +agreeable brownish or black tone in the negatives. + +If the contents of metabisulphite and pyro-soda developer are +increased, it will act very slowly; larger quantities of the +metabisulphite of potassium, therefore, act like a strong retarder. In +small quantities there is no injurious retarding action, but it will +have the effect that the plates obtain very clear shadows in this +developer, and that the picture appears slower, and will strengthen +more slowly. The strongly retarding action of larger quantities of +metabisulphite might be accounted for in that the bisulphite will +give, with the carbonate of soda, monosulphite and soda bicarbonate, +which latter is not a strong enough alkali to develop the bromide of +silver strongly with pyro. An increase of soda compensates this +retarding action of the metabisulphite of potassium. + +Good results were obtained by me with this salt after several tests, +by producing the following solutions: + + A. + + Pyrogallic acid 4 grammes. + Metabisulphite of potassium 1½ " + Water 100 c. c. + +This solution keeps for weeks in corked bottles. + + B. + + Crystallized soda 10 grammes. + Neutral sulphite of soda 15 " + Water 100 c. c. + +Before using mix-- + + Pyro solution A 20 c. c. + Soda solution B 20 " + Water 20 " + +The developer acts about one and a half times slower than the ordinary +pyro soda developer, approaching to the latter pretty nearly, and +gives to the negatives an agreeable color and softness, with clear +shadows. If the negatives are to be thinner, more water, say 30 to 40 +c. c., is taken. If denser, then the soda is increased, and the water +in the developer is reduced. An alum bath before fixing is to be +recommended. + +An advantage of this development is the great durability of the +pyro-meta sulphite solution. The cost price is about the same as +that of the ordinary pyro developer. At all events, it is worth while +to make further investigation with the metabisulphite of potassium, +the same being also a good preservative for hydroquinone +solutions.--_Photographische Correspondenz; Reported in the Photo. +News._ + + * * * * * + + +A New Catalogue of Valuable Papers + +Contained in SCIENTIFIC AMERICAN SUPPLEMENT during the past ten years, +sent _free of charge_ to any address. MUNN & CO., 361 Broadway, New +York. + + * * * * * + + +THE SCIENTIFIC AMERICAN + +Architects and Builders Edition. + +$2.50 a Year. Single Copies, 25 cts. + +This is a Special Edition of the SCIENTIFIC AMERICAN, issued +monthly--on the first day of the month. 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Thus, we do not necessarily +keep eBooks in compliance with any particular paper edition. + + +Most people start at our Web site which has the main PG search facility: + + http://www.gutenberg.org + +This Web site includes information about Project Gutenberg-tm, +including how to make donations to the Project Gutenberg Literary +Archive Foundation, how to help produce our new eBooks, and how to +subscribe to our email newsletter to hear about new eBooks. diff --git a/17755-8.zip b/17755-8.zip Binary files differnew file mode 100644 index 0000000..7a0a7cb --- /dev/null +++ b/17755-8.zip diff --git a/17755-h.zip b/17755-h.zip Binary files differnew file mode 100644 index 0000000..6a2e7d2 --- /dev/null +++ b/17755-h.zip diff --git a/17755-h/17755-h.htm b/17755-h/17755-h.htm new file mode 100644 index 0000000..988969d --- /dev/null +++ b/17755-h/17755-h.htm @@ -0,0 +1,6520 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> + +<html xmlns="http://www.w3.org/1999/xhtml"> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> + +<title> +The Project Gutenberg eBook of Scientific American Supplement, September 28, 1889 +</title> + +<style type="text/css"> +<!-- + body {margin-left: 15%; margin-right: 15%; background-color: white} + + h1,h2,h3 {text-align: center;} + + hr {text-align: center; width: 50%; margin-top: 2em; margin-bottom: 2em;} + + div.note {margin-left: 2em; margin-right: 2em; margin-bottom: 1em;} + div.ind {margin-left: 10%; margin-right: 10%;} + + p {text-align: justify;} + p.center {text-align: center;} + p.letter {text-align: right; margin-right: 5%;} + p.address {margin-left: 10%; padding-left: 3em; text-indent: -3em;} + + ul {list-style-type: none;} + + a {text-decoration: none;} + a[name] {position:absolute;} + + .sc {font-variant: small-caps;} + + sub {font-size: 0.7em;} + sup {font-size: 0.7em;} + + table {margin-left: auto; margin-right: auto;} + .toc1 {vertical-align: top; text-align: left;} + .toc2 {text-align: left; padding-bottom: .25em; } + .toc3 {text-align: left; vertical-align: bottom;} + + .caption {font-weight: bold; + text-align: center; + margin-top: .25em; } + + img {border: 0;} + .figcenter {margin: auto; + text-align: center;} + .figleft {float: left; + margin-left: 0; + margin-bottom: .5em; + margin-top: 0em; + margin-right: 1em; + padding: 0; + text-align: center;} + .figright {float: right; + clear: right; + margin-left: 1em; + margin-bottom: .5em; + margin-top: 0em; + margin-right: 0; + padding: 0; + text-align: center;} + + ins.correction { text-decoration: none; + border-bottom-style: dashed; + border-bottom-color: gray; + border-bottom-width: 1px;} + +--> + +</style> +</head> +<body> + + +<pre> + +The Project Gutenberg EBook of Scientific American Supplement, No. 717, +September 28, 1889, by Various + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Scientific American Supplement, No. 717, September 28, 1889 + +Author: Various + +Release Date: February 12, 2006 [EBook #17755] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN *** + + + + +Produced by Amy Cunningham, Juliet Sutherland and the +Online Distributed Proofreading Team at http://www.pgdp.net + + + + + + +</pre> + + +<p class="center" style="margin-left: -10%; margin-right: -10%;"> +<a href="./images/title.png"> +<img src="./images/title_th.png" width="800" height="217" alt="Issue Title" /> +</a></p> + +<h1>SCIENTIFIC AMERICAN SUPPLEMENT NO. 717</h1> + +<h2>NEW YORK, SEPTEMBER 28, 1889.</h2> + +<h4>Scientific American Supplement. Vol. XXVIII., No. 717.</h4> +<h4>Scientific American, established 1845.</h4> +<h4>Scientific American Supplement, $5 a year.</h4> +<h4>Scientific American and Supplement, $7 a year.</h4> + +<hr /> + +<table summary="Contents" border="0" cellspacing="5"> +<tr> +<th colspan="3">TABLE OF CONTENTS.</th> +</tr> +<tr><td></td> +<td></td> +<td>PAGE</td> +</tr> + +<tr> +<td class="toc1">I.</td> +<td class="toc2"><a href="#art06">CIVIL ENGINEERING.—The Girard +Hydraulic Railway.—One of +the great curiosities of the Paris exposition, the almost frictionless +railway, with sectional illustrations of its structure.—8 +illustrations.</a></td> +<td class="toc3">11451</td> +</tr> + +<tr> +<td class="toc1">II.</td> +<td class="toc2"><a href="#art16">ELECTRICITY.—Early Electric +Lighting.—Electric lighting in +Salem in 1859, a very curious piece of early history.</a></td> +<td class="toc3">11458</td> +</tr> + +<tr> +<td></td> +<td class="toc2"><a href="#art14">Electric Motor for Alternating +Currents.—A motor on an entirely +new principle for the application of the alternating current +with results obtained, and the economic outlook of the invention.</a></td> +<td class="toc3">11458</td> +</tr> + +<tr> +<td></td> +<td class="toc2"><a href="#art13">Portable Electric +Light.—A lamp for military and other use, in +which the prime motor, including the boiler and the lamp itself, +are carried on one carriage.—1 illustration.</a></td> +<td class="toc3">11458</td> +</tr> + +<tr> +<td></td> +<td class="toc2"><a href="#art15">The Electric +Age.—By <span class="sc">Charles Carleton Coffin</span>.—A short +<i>resume</i> of the initial achievements of modern electricity.</a></td> +<td class="toc3">11458</td> +</tr> + +<tr> +<td class="toc1">III.</td> +<td class="toc2"><a href="#art12">GEOLOGY.—The +Fuels of the Future.—A prognosis of the future +prospect of the world as regards a fuel supply, with a special +reference to the use of natural gas.</a></td> +<td class="toc3">11457</td> +</tr> + +<tr> +<td class="toc1">IV.</td> +<td class="toc2"><a href="#art20">MISCELLANEOUS.—Preservation +of Spiders for the Cabinet.—A +method of setting up spiders for preservation in the cabinet, +with formulæ of solutions used and full details of the manipulation.—1 +illustration.</a></td> +<td class="toc3">11461</td> +</tr> + +<tr> +<td></td> +<td class="toc2"><a href="#art05">The Ship in +the New French Ballet of the "Tempest."—A curious +example of modern scenic perfection, giving the construction +and use of an appliance of the modern ballet.—5 illustrations.</a></td> +<td class="toc3">11450</td> +</tr> + +<tr> +<td class="toc1">V.</td> +<td class="toc2"><a href="#art03">NAVAL +ENGINEERING.—Crank and Screw Shafts of the Mercantile +Marine.—By <span class="sc">G. W. Manuel.</span>—This all-important subject +of modern naval engineering treated in detail, illustrating the progress +of the present day, the superiority of material and method +of using it, with interesting practical examples.—1 illustration.</a></td> +<td class="toc3">11448</td> +</tr> + +<tr> +<td></td> +<td class="toc2"><a href="#art04">Experimental Aid +in the Design of High Speed Steamships.—By +D. P.—A plea for the experimental determination of the probable +speed of ships, with examples of its application in practice.</a></td> +<td class="toc3">11449</td> +</tr> + +<tr> +<td></td> +<td class="toc2"><a href="#art02">Forging a Propeller +Shaft.—How large steamer shafts are forged, +with example of the operation as exhibited to the Shah of Persia +at Brown & Co.'s works, Sheffield, England.—1 illustration.</a></td> +<td class="toc3">11447</td> +</tr> + +<tr> +<td></td> +<td class="toc2"><a href="#art01">The Naval Forges +and Steel Works at St. Chamond.—The forging +of a piece of ordnance from a 90 ton ingot of steel, an artistic +presentation of the subject.—1 illustration.</a></td> +<td class="toc3">11447</td> +</tr> + +<tr> +<td class="toc1">VI.</td> +<td class="toc2"><a href="#art23">PHOTOGRAPHY.—The +Pyro Developer with Metabisulphite of +Potash.—By Dr. <span class="sc">J. M. Eder.</span>—A +new addition to the pyro developer, +with formulæ and results.</a></td> +<td class="toc3">11462</td> +</tr> + +<tr> +<td class="toc1">VII.</td> +<td class="toc2"><a href="#art07">PHYSICS.—Quartz +Fibers.—A lecture by Mr. <span class="sc">C. V. Boys</span> on his +famous experiments of the production of microscopic fibers, with +enlarged illustrations of the same, and a graphic account of the +entire subject.—7 illustrations.</a></td> +<td class="toc3">11452</td> +</tr> + +<tr> +<td></td> +<td class="toc2"><a href="#art17">The Modern +Theory of Light.—By Prof. <span class="sc">Oliver Lodge.</span>—An +abstract of a lecture by the eminent investigator and expositor of +Prof. Hertz's experiments, giving a brief review of the present aspect +of this absorbing question.</a></td> +<td class="toc3">11459</td> +</tr> + +<tr> +<td class="toc1">VIII.</td> +<td class="toc2"><a href="#art19">PHYSIOLOGY.—Heat +in Man.—Experiments recently made by +Dr. Loewy on the heat of the human system.—Described and commented +on by Prof. <span class="sc">Zuntz.</span></a></td> +<td class="toc3">11461</td> +</tr> + +<tr> +<td class="toc1">IX.</td> +<td class="toc2"><a href="#art18">SANITATION.—On +Purification of Air by Ozone—with an Account +of a New Method.—By Dr. <span class="sc">B. W. Richardson.</span>—A very important +subject treated in full, giving the past attempts in the +utilization of ozone and a method now available.</a></td> +<td class="toc3">11460</td> +</tr> + +<tr> +<td class="toc1">X.</td> +<td class="toc2"><a href="#art11">TECHNOLOGY.—Alkali +Manufactories.—Present aspect of the +Leblanc process and the new process for the recovery of sulphur +from its waste.</a></td> +<td class="toc3">11457</td> +</tr> + +<tr> +<td></td> +<td class="toc2"><a href="#art21">Dried Wine +Grapes.—The preparation of the above wine on a +large scale in California, with full details of the process adopted.</a></td> +<td class="toc3">11461</td> +</tr> + +<tr> +<td></td> +<td class="toc2"><a href="#art09">The Production +of Ammonia from Coal.—By <span class="sc">Ludwig Mond.</span>—A +valuable review of this important industry, with actual working +results obtained in carrying out a retort process.—2 illustrations.</a></td> +<td class="toc3">11454</td> +</tr> + +<tr> +<td></td> +<td class="toc2"><a href="#art08">Nature, Composition, +and Treatment of Animal and Vegetable +Fabrics.—The history of fabrics and fibers in the vegetable and +animal world, their sources, applications, and treatments.</a></td> +<td class="toc3">11453</td> +</tr> + +<tr> +<td></td> +<td class="toc2"><a href="#art22">Walnut Oil.—By +Thomas <span class="sc">T. P. Bruce Warren.</span>—An excellent +oil for painters' use, with description of a simple method for preparing +it on a small scale.</a></td> +<td class="toc3">11462</td> +</tr> +</table> + +<hr /> + + + + +<h2><a name="Page_11448" id="Page_11448"></a><a name="art01" id="art01"></a> +THE NAVAL FORGES AND STEEL WORKS AT +ST. CHAMOND.</h2> + + +<p>With the idyls and historic or picturesque subjects +that the Universal Exposition gives us the occasion to +publish, we thought we would make a happy contrast +by selecting a subject of a different kind, by presenting +to our readers Mr. Layraud's fine picture, +which represents the gigantic power hammer used at +the St. Chamond Forges and Steel Works in the construction +of our naval guns. By the side of the machinery +gallery and the Eiffel tower this gigantic +apparatus is well in its place.</p> + +<div class="figcenter"> +<a href="./images/01_1.png"> +<img src="./images/01_1_th.png" width="600" height="362" alt="MARINE IRON AND STEEL WORKS AT SAINT CHAMOND" /> +</a> + +<p class="caption">UNIVERSAL EXPOSITION—BEAUX ARTS—MARINE +IRON AND STEEL WORKS AT SAINT CHAMOND—PRESENTATION OF A PIECE +OF ORDNANCE UNDER THE VERTICAL HAMMER.—PICTURE BY M. JOSEPH LAYRAUD.</p> +</div> + +<p>The following is the technical description that has +been given to us to accompany our engraving: In an +immense hall, measuring 260 ft. in length by 98 ft. in +width, a gang of workmen has just taken from the +furnace a 90 ton ingot for a large gun for an armor-clad +vessel. The piece is carried by a steam crane of +140 tons power, and the men grouped at the maneuvering +levers are directing this incandescent mass +under the power hammer which is to shape it. This +hammer, whose huge dimensions allow it to take +in the object treated, is one of the largest in existence. +Its striking mass is capable of reaching 100 tons, and +the height of the fall is 16 ft. To the left of the hammer +is seen a workman getting ready to set it in motion. +It takes but one man to maneuver this apparatus, and +this is one of the characteristic features of its construction.</p> + +<p>The beginning of this hammer's operation, as well as +the operations of the forge itself, which contains three +other hammers of less power, dates back to 1879. It is +with this great hammer that the largest cannons of +the naval artillery—those of 16 inches—have been +made (almost all of which have been manufactured at +St. Chamond), and those, too, of 14, 13, and 12 inches. +This is the hammer, too, that, a few months ago, was +the first to be set at work on the huge 13 in. guns of +new model, whose length is no less than 52 ft. in the +rough.</p> + +<p>Let us add a few more figures to this account in +order to emphasize the importance of the installations +which Mr. Layraud's picture recalls, and which our +great French industry has not hesitated to establish, +notwithstanding the great outlay that they necessitated. +This huge hammer required foundations extending +to a depth of 32 ft., and the amount of metal +used in its construction was 2,640,000 pounds. The +cost of establishing the works with all the apparatus +contained therein was $400,000.—<i>Le Monde Illustre.</i></p> + +<hr /> + + + + +<h2><a name="art02" id="art02"></a>FORGING A PROPELLER SHAFT.</h2> + + +<p>During the recent visit of the Shah of Persia to +England, he visited, among other places, the great +works of John Brown & Co., at Sheffield, and witnessed +the pressing of a propeller shaft for one of the +large ocean steamships. The operation is admirably +illustrated in our engraving, for which we are indebted +to the <i>Illustrated London News</i>.</p> + +<div class="figcenter"> +<a href="./images/02_1.png"> +<img src="./images/02_1_th.png" width="600" height="397" alt="PROPELLER SHAFT BEING PRESSED" /> +</a> + +<p class="caption">PROPELLER SHAFT BEING PRESSED AT MESSRS. JOHN +BROWN & CO.'S WORKS, SHEFFIELD.</p> +</div> + +<hr /> + + + + +<h2><a name="art03" id="art03"></a>CRANK AND SCREW SHAFTS OF THE MERCANTILE +MARINE.<a name="FNanchor_03_1" id="FNanchor_03_1"></a><a href="#Footnote_03_1"><sup>1</sup></a></h2> + +<h3>By <span class="sc">G. W. Manuel.</span></h3> + + + +<p>Being asked to read a paper before your institute, I +have chosen this subject, as I think no part of the +marine engine has given so much trouble and anxiety +to the seagoing engineer; and from the list of shipping +casualties in the daily papers, a large proportion seem +due to the shafting, causing loss to the shipowner, and +in some instances danger to the crew. My endeavor is +to put some of the causes of these casualties before you, +also some of the remedies that have tended to reduce +their number. Several papers have been read on this +subject, chiefly of a theoretical description, dealing with +the calculations relating to the twisting and bending +moments, effects of the angles of the cranks, and +length of stroke—notably that read by Mr. Milton before +the Institute of Naval Architects in 1881. The +only <i>practical</i> part of this paper dealt with the possibility +of the shafts getting out of line; and regarding +this contingency Dr. Kirk said that "if superintendent +engineers would only see that the bearings were +kept in line, broken crank and other shafts would not +be so much heard of." Of course this is one of those +statements made in discussions of this kind, for what +purpose I fail to see, and as far as my own experience +goes is <i>misleading</i>; for having taken charge of steamers +new from the builders' hands, when it is at least +expected that these shafts would <i>be in line</i>, the crank +shaft bearings heated very considerably, and <i>continued</i> +to do so, rendering the duration of life of the crank +shaft a short one; and though they were never what is +termed out of line, the bearings could <i>not</i> be kept cool +without the use of sea water, and occasionally the +engines had to be stopped to cool and smooth up the +bearing surfaces, causing delays, worry, and anxiety, +for which the engineer in charge was in no way responsible. +Happily this state of what I might call <i>uncertainties</i> +is being gradually remedied, thanks being +largely due to those engineers who have the skill to +suggest improvements and the patience to carry them +out against much opposition.</p> + +<p>These improvements in many instances pertain to +the engine builder's duties, and are questions which I +think have been treated lightly; notably that of insufficient +bearing surface, and one of the principal +causes of hot bearings, whereby the oil intended for +lubrication was squeezed out, and the metal surfaces +brought too close in contact; and when bearings had +a pressure of 200 lb. per square inch, it has been found +that not more than 120 lb. per square inch should be +exerted to keep them cool (this varies according to the +material of which the bearing is composed), without +having to use sea water and prevent them being ground +down, and thus getting out of line. I have known a +bearing in a new steamer, in spite of many gallons of +oil wasted on it, wear down one-eighth of an inch in a +voyage of only 6,000 miles, from insufficiency of bearing +surface.</p> + +<p>Several good rules are in use governing the strength of +shafts, which treat of the diameter of the bearings only +and angles of the cranks; and the engine builder, along +with the ship owner, has been chary of increasing the +surfaces by lengthening the bearings; for to do this +means increase of space taken up fore and aft the vessel, +besides additional weight of engine. Engine builders +all aim in competing to put their engines in less +space than their rivals, giving same power and sometimes +more. I think, however, this inducement is now +more carefully considered, as it has been found more +economical to give larger bearing surfaces than to have +steamers lying in port, refitting a crank shaft, along +with the consequences of heavy bills for salvage and +repairs, also the risk of losing the steamer altogether. +Proportioning the bearings to the weights and strains +they have to carry has also been an improvement. The +different bearings of marine engines were usually made +alike in surface, irrespective of the work each had to +do, with a view to economy in construction.</p> + +<p>In modern practice the after bearings have more surface +than the forward, except in cases where heavy +slide-valve gear has to be supported, so that the wear +down in the whole length of the shaft is equal, thus +avoiding those alternate bending strains at the top and +bottom of the stroke every revolution. Another improvement +that has been successfully introduced, adding +to the duration of life of crank shafts, is the use of +white bearing metal, such as Parson's white brass, on +which the shafts run smoothly with less friction and +tendency to heat, so that, along with well proportioned +surfaces, a number of crank shafts in the Peninsular +and Oriental Co.'s service have not required lining +up for eight years, and I hope with care may last till +new boilers are required. Large and powerful steamers +can be driven full speed from London to Australia and +back without having any water on the bearings, using +oil of only what is considered a moderate price, allowing +the engineer in charge to attend to the economical +working of both engines and boilers (as well as many +other engines of all kinds now placed on board a +large mail and passenger steamer), instead of getting +many a drenching with sea water, and worried by close +attention to one or two hot bearings all the watch. +Compare these results with the following: In the same +service in 1864, and with no blame to the engineer in +charge, the crank shaft bearings of a screw steamer +had to be lined up every five days at intermediate ports, +through insufficient bearing surfaces. Sea water had +continually to be used, resulting in frequent renewal +<ins class="correction" title="Transcriber's Note: so in original +(possible missing text after 'of')">of crank</ins> +shaft. Steamers can now run 25,000 miles without +having to lift a bearing, except for examination at +the end of the voyage. I would note here that the +form of the bearings on which the shafts work has also +been much improved. They are made more of a <i>solid +character</i>, the metal being more equally disposed +<i>round</i> the shaft, and the use of gun metal for the main +bearings is now fast disappearing. In large engines +the only metals used are cast iron and white brass, +an advantage also in reducing the amount of wear +on the recess by corrosion and grinding where sea +water was used often to a considerable extent.</p> + +<div class="figcenter"> +<a href="./images/03_1.png"> +<img src="./images/03_1_th.png" width="400" height="352" alt="Figures 1 and 2" /> +</a> +</div> + +<p>Figs. No. 1 and No. 2 show the design of the old and +new main bearings, and, I think, require but little explanation. +Most of you present will remember your +feelings when, after a hot bearing, the brasses were +found to be cracked at top and bottom, and the trouble +you had afterward to keep these brasses in position. +When a smoking hot bearing occurred, say in the heating +of a crank pin, it had the effect of damaging the material +of the shaft more or less, according to its original +soundness, generally at the fillets in the angles of the +cranks. For when the outer surface of the iron got +hot, cold water, often of a low temperature, was suddenly +poured on, and the hot iron, previously expanded, +was suddenly contracted, setting up strains +which in my opinion made a small tear transversely +where the metal was <i>solid</i>; and where what is termed +lamination flaws, due to construction, existed, these +were extended in their natural direction, and by a +repetition of this treatment these flaws became of such +a serious character that the shafts had to be condemned, +or actually gave way at sea. The introduction +of the triple expansion engine, with the three +cranks, gave better balance to the shaft, and the forces +acting in the path of the crank pin, being better divided, +caused more regular motion on the shaft, and +so to the propeller. This is specially noticeable in +screw steamers, and is taken advantage of by placing +the cabins further aft, nearer the propeller, the stern +having but little vibration; the dull and heavy surging +sound, due to unequal motions of the shaft in the two-crank +engines, is exchanged for a more regular sound +of less extent, and the power formerly wasted in vibrating +the stern is utilized in propelling the vessel. +In spite of all these improvements I have mentioned, +there remains the serious question of defects in the +material, due to variety of quality and the extreme +care that has to be exercised in all the stages during construction +of crank or other shafts built of iron. Many +shafts have given out at sea and been condemned, +through no other cause than <i>original defects</i> in their +construction and material.</p> + +<p>The process of welding and forging a crank shaft of +large diameter now is to make it up of so many small +<i>pieces</i>, the <i>best shafts</i> being made of what is termed +scrap, representing thousands of small pieces of selected +iron, such as cuttings of old iron boiler plates, cuttings +off forgings, old bolts, horseshoes, angle iron, etc., +all welded together, forged into billets, reheated, and +rolled into bars. It is then cut into lengths, piled, and +formed into slabs of suitable size for welding up into +the shafts. No doubt this method is preferable to the +old method of "fagoting," so called, as the iron bars +were placed side by side, resembling a bundle of fagots +of about 18 or 20 inches square.</p> + +<p>The result was that while the outside bars would be +welded, the inside would be improperly welded, or, +the hammer being weak, the blow would be insufficient +to secure the proper weld, and it was no uncommon +thing for a shaft to break and expose the internal bars, +showing them to be quite separate, or only partially +united. This danger has been much lessened in late +years by careful selection of the materials, improved +methods of cleaning the scrap, better furnaces, the use +of the most suitable fuels, and more powerful steam +hammers. Still, with all this care, I think I may say +there is not a shaft without flaws or defects, more or +less, and when these flaws are situated in line of the +greatest strains, and though you <i>may not</i> have a hot +bearing, they often extend until the shaft becomes unseaworthy.</p> + +<p>[Diagrams shown illustrated the various forms of +flaws.] These flaws were not observable when the +shafts were new, although carefully inspected. They +gradually increased under strain, came to the outside, +and were detected. Considerable loss fell upon the +owners of these vessels, who were in no way to blame; +nor could they recover any money from the makers of +the shafts, who were alone to blame. I am pleased to +state, and some of the members here present know, +that considerable improvement has been effected in +the use of better material than iron for crank shafts, +by the introduction of a special mild steel, by Messrs. +Vickers, Sons & Co., of Sheffield, and that instead of +having to record the old familiar defects found in iron +shafts, I can safely say no flaws have been observed, +when new or during eight years running, and there +are now twenty-two shafts of this mild steel in the +company's service.</p> + +<p>I may here state that steel was used for crank shafts +in this service in 1863, as then manufactured in Prussia +by Messrs. Krupp, and generally known as <i>Krupp's +steel</i>, the tensile strength of which was about 40 tons +per square inch, and though free from flaws, it was unable +to stand the fatigue, and broke, giving little warning. +It was of too brittle a nature, more resembling +chisel steel. It was broken again under a falling weight +of 10 cwt. with a 10 ft. drop = 12½ tons.</p> + +<p>The mild steel now used was first tried in 1880. It +possessed tensile strength of 24 to 25 tons per square +inch. It was then considered advisable not to exceed +this, and err rather on the safe side. This shaft has +been in use eight years, and no sign of any flaw has +been observed. Since then the tensile strength of mild +steel has gradually been increased by Messrs. Vickers, +the steel still retaining the elasticity and toughness +to endure fatigue. This has only been arrived at by +improvements in the manufacture and more powerful +and better adapted hammers to forge it down from +the large ingots to the size required. The amount of +work they are now able to subject the steel to renders +it more fit to sustain the fatigue such as that to be endured +by a crank shaft. These ingots of steel can be +cast up to 100 tons weight, and require powerful machines +to deal with them. For shafts say of 20 inches +diameter, the diameter of the ingot would be about 52 +inches. This allows sufficient work to be put on the +couplings, as well as the shaft. To make solid crank +shafts of this material, say of 19 inches diameter, the +ingot would weigh 42 tons, the forging, when completed, +17 tons, and the finished shaft 11¾ tons; so that +you see there is 25 tons wasted before any machining is +done, and 5¼ tons between the forging and finished +shaft. This makes it very expensive for solid shafts of +large size, and it is found better to make what is termed +a <i>built shaft</i>; the cranks are a little heavier, and +engine framings necessarily a little wider, a matter +comparatively of little moment. I give you a rough +drawing of the hydraulic hammer, or strictly speaking +a <i>press</i>, used by Messrs. Vickers in forging down the +ingots in shafts, guns, or other large work. This hammer +can give a squeeze of 3,000 tons. The steel seems +to yield under it like tough putty, and, unlike the +steam hammer, there is no <i>jarring</i> on the material, +and it is manipulated with the same ease as a small +hammer by hydraulics.</p> + +<p>The tensile strength of steel used for shafts having +increased from 24 to 30 tons, and in some cases 31 tons, +considering that this was 2 tons above that specified, +and that we were approaching what may be termed +<i>hard steel</i>, I proposed to the makers to test this material +beyond the usual tests, viz., tensile, extension, +and cold bending test. The latter, I considered, was +much too easy for this fine material, as a piece of fair +iron will bend cold to a radius of 1½ times its diameter +or thickness, without fracture; and I proposed a test +more resembling the fatigue that a crank shaft has +sometimes to stand, and more worthy of this material; +and in the event of its standing this successfully, I +would pass the material of 30 or 31 tons tensile strength. +Specimens of steel used in the shafts were cut off different +parts—crank pins and main bearings—(the shafts +being built shafts) and roughly planed to 1½ inches +square, and about 12 inches long. They were laid on +the block as shown, and a cast iron block, fitted with a +hammer head ½ ton weight, let suddenly fall 12 inches, +the block striking the bar with a blow of about 4 tons. +The steel bar was then turned upside down, and the +blow repeated, reversing the piece every time until +fracture was observed, and the bar ultimately broken. +The results were that this steel stood 58 blows before +showing signs of fracture, and was only broken after 77 +blows. It is noticeable how many blows it stood after +fracture. A bar of good wrought iron, undressed, of +same dimensions, was tried, and broke the first blow. +A bar cut from a piece of iron to form a large chain, +afterward forged down and only filed to same dimensions, +broke at 25 blows. I was well satisfied with the +results, and considered this material, though possessing +a high tensile strength, was in every way suitable for +the construction and endurance required in crank +shafts.</p> + +<p>Sheet No. 1 shows you some particulars of these +tests:</p> + +<table cellpadding="2" summary="Fatigue test A"> +<tr> +<td></td> +<td align="center" style="padding-right: 1em;">Tensile<br /> Tons.</td> +<td align="center" style="padding-right: 1em;">Elong.<br /> in 5"</td> +<td align="center" valign="bottom" style="padding-right: 1em;">Bend.</td> +<td align="center" style="padding-right: 1em;">Fractured<br /> Blows.</td> +<td align="center" style="padding-right: 1em;">Broke<br /> Blows.</td> +<td align="center" style="padding-right: 1em;">Fall<br /> In.</td> +</tr> +<tr> +<td align="center">A =</td> +<td align="center" style="padding-right: 1em;">30.5</td> +<td align="center" style="padding-right: 1em;">28 p. c.</td> +<td align="center" style="padding-right: 1em;">Good</td> +<td align="center" style="padding-right: 1em;">61</td> +<td align="center" style="padding-right: 1em;">78</td> +<td align="center" style="padding-right: 1em;">12</td> +</tr> +</table> + + +<p><a name="Page_11449" id="Page_11449"></a>In order to test the comparative value of steel of 24¾ +up to 35 tons tensile strength, I had several specimens +taken from shafts tested in the manner described, +which may be called a <i>fatigue</i> test. The results are +shown on the same sheet:</p> + +<table cellpadding="2" summary="Fatigue tests"> +<tr> +<td align="center" style="padding-right: .5em;">B =</td> +<td align="left" style="padding-right: 1em;">24½</td> +<td align="center" style="padding-right: 1em;"></td> +<td align="center" style="padding-right: 1em;">Good</td> +<td align="center" style="padding-right: 1em;">64</td> +<td align="center" style="padding-right: 1em;">72</td> +<td align="right" style="padding-right: 1em;">7</td> +</tr> +<tr> +<td align="left" style="padding-right: .5em;">B</td> +<td align="center" style="padding-right: 1em;">—</td> +<td align="center" style="padding-right: 1em;">—</td> +<td align="center" style="padding-right: 1em;">—</td> +<td align="center" style="padding-right: 1em;">48</td> +<td align="center" style="padding-right: 1em;">54</td> +<td align="center" style="padding-right: 1em;">12</td> +</tr> +<tr> +<td align="center" style="padding-right: .5em;">C =</td> +<td align="left" style="padding-right: 1em;">27</td> +<td align="center" style="padding-right: 1em;">25.9 p. c.</td> +<td align="center" style="padding-right: 1em;">Good</td> +<td align="center" style="padding-right: 1em;">76</td> +<td align="center" style="padding-right: 1em;">81</td> +<td align="center" style="padding-right: 1em;">12</td> +</tr> +<tr> +<td align="center" style="padding-right: .5em;">D =</td> +<td align="left" style="padding-right: 1em;">29.6</td> +<td align="center" style="padding-right: 1em;">28.4 p. c.</td> +<td align="center" style="padding-right: 1em;">Good</td> +<td align="center" style="padding-right: 1em;">71</td> +<td align="center" style="padding-right: 1em;">78</td> +<td align="center" style="padding-right: 1em;">12</td> +</tr> +<tr> +<td align="center" style="padding-right: .5em;">E =</td> +<td align="left" style="padding-right: 1em;">30.5</td> +<td align="center" style="padding-right: 1em;">28.9 p. c.</td> +<td align="center" style="padding-right: 1em;">Good</td> +<td align="center" style="padding-right: 1em;">58</td> +<td align="center" style="padding-right: 1em;">77</td> +<td align="center" style="padding-right: 1em;">12</td> +</tr> +<tr> +<td align="center" style="padding-right: .5em;">F =</td> +<td align="left" style="padding-right: 1em;">35.5</td> +<td align="center" style="padding-right: 1em;">20 p. c.</td> +<td align="center" style="padding-right: 1em;">Good</td> +<td align="center" style="padding-right: 1em;">80</td> +<td align="center" style="padding-right: 1em;">91</td> +<td align="center" style="padding-right: 1em;">12</td> +</tr> +</table> + +<p>The latter was very tough to break. Specimen marked +A shows one of these pieces of steel. I show you +also fresh broken specimens which will give you a +good idea of the beautiful quality of this material. +These specimens were cut out of shafts made of Steel +Co. of Scotland's steel. I also show you specimens +of cold bending:</p> + +<table summary="Fatigue tests B to I"> +<tr><td></td> +<td align="center" style="padding-right: 1em;">Tensile<br /> Tons.</td> +<td align="center" style="padding-right: 1em;">Elong.<br /> in. 5"</td> +<td align="center" valign="bottom" style="padding-right: 1em;">Bend.</td> +<td align="center" style="padding-right: 1em;">Fractured <br /> Blows.</td> +<td align="center" style="padding-right: 1em;">Broke<br /> Blows.</td> +<td align="center" style="padding-right: 1em;">Fall<br /> In.</td> +</tr> +<tr><td align="center">G =</td> +<td align="center" style="padding-right: 1em;">30.9</td> +<td align="center" style="padding-right: 1em;">27½ p. c.</td> +<td align="center" style="padding-right: 1em;">Good</td> +<td align="center" style="padding-right: 1em;">59</td> +<td align="center" style="padding-right: 1em;">66</td> +<td align="center" style="padding-right: 1em;">12</td> +</tr> +<tr><td align="center">H =</td> +<td align="center" style="padding-right: 1em;">29.3</td> +<td align="center" style="padding-right: 1em;">30 p. c.</td> +<td align="center" style="padding-right: 1em;">Good</td> +<td align="center" style="padding-right: 1em;">66</td> +<td align="center" style="padding-right: 1em;">90</td> +<td align="center" style="padding-right: 1em;">12</td> +</tr> +<tr><td align="center">I =</td> +<td align="center" style="padding-right: 1em;">28.9</td> +<td align="center" style="padding-right: 1em;">28.9 p. c.</td> +<td align="center" style="padding-right: 1em;">Good</td> +<td align="center" style="padding-right: 1em;">53</td> +<td align="center" style="padding-right: 1em;">68</td> +<td align="center" style="padding-right: 1em;">12</td> +</tr> +</table> + +<p>I think all of the above tests show that this material, +when carefully made and treated with sufficient mechanical +work on forging down from the ingot, is suitable +up to 34 tons for crank shafts; how much higher +it would be desirable to go is a question of superior excellence +in material and manufacture resting with the +makers. I would, however, remark that no allowance +has been made by the Board of Trade or Lloyds for +the excellence of this material above that of iron. I +was interested to know how the material in the best +iron shafts would stand this fatigue test compared +with steel, and had some specimens of same dimensions +cut out of iron shafts. The following are the results: +Best iron, three good qualities, rolled into flat bars, +cut and made into 4½ cwt. blooms.</p> + +<table summary="Fatigue test J"> +<tr><td align="center" style="padding-right: .5em;">J =</td> +<td align="center" style="padding-right: 1em;">18.6</td> +<td align="center" style="padding-right: 1em;">24.3 p. c.</td> +<td align="center" style="padding-right: 1em;">Good</td> +<td align="center" style="padding-right: 1em;">17</td> +<td align="center" style="padding-right: 1em;">18</td> +<td align="center" style="padding-right: 1em;">12</td> +</tr> +</table> + +<p>Made of best double rolled scrap, 4½ cwt. blooms.</p> + +<table summary="Fatigue test K"> +<tr><td align="center" style="padding-right: .5em;">K =</td> +<td align="center" style="padding-right: 1em;">22</td> +<td align="center" style="padding-right: 1em;">32½ p. c.</td> +<td align="center" style="padding-right: 1em;">Good</td> +<td align="center" style="padding-right: 1em;">21</td> +<td align="center" style="padding-right: 1em;">32</td> +<td align="center" style="padding-right: 1em;">12</td> +</tr> +</table> + +<p>You will see from these results that steel stood this +fatigue test, Vickers' 73 per cent. and Steel Co.'s 68 per +cent., better than iron of the best quality for crank +shafts; and I am of opinion that so long as we use +such material as these for crank shafts, along with the +present rules, and give ample <i>bearing surface</i>, there +will be few broken shafts to record.</p> + +<p>I omitted to mention that built shafts, both of steel +and iron, of large diameter, are now in general use, and +with the excellent machines, and under special mechanics, +are built up of five separate pieces in such a +rigid manner that they possess all the solidity necessary +for a crank shaft. The forgings of iron and steel +being much smaller are capable of more careful treatment +in the process of manufacture. These shafts, for +large mail steamers, when coupled up, are 35 feet long, +and weigh 45 tons. They require to be carefully coupled, +some makers finishing the bearings in the lathe, +others depend on the excellence of their work in each +piece, and finish each complete. To insure the correct +centering of these large shafts, I have had 6 in. dia. +recesses ¾ inch deep turned out of each coupling to +one gauge and made to fit one disk. Duplicate disks +are then fitted in each coupling, and the centering is +preserved, and should a spare piece be ever required, +there is no trouble to couple correctly on board the +steamer.</p> + +<p>The propeller shaft is generally made of iron, and if +made <i>not less</i> than the Board of Trade rules as regards +diameter, of the best iron, and the gun metal liners +carefully fitted, they have given little trouble; the +principal trouble has arisen from defective fitting of +the propeller boss. This shaft working in sea water, +though running in lignum vitæ bearings, has a considerable +wear down at the outer bearings in four or five +years, and the shaft gets out of line. This wear has +been lessened considerably by fitting the wood so that +the grain is endway to the shaft, and with sufficient +bearing surface these bearings have not required lining +up for nine years. It is, however, a shaft that cannot +be inspected except when in dry dock, and has to be +disconnected from the propeller, and drawn inside +for examination at periods suggested by experience. +Serious accidents have occurred through want of attention +to the examination of this shaft; when working in +salt water, with liners of gun metal, galvanic action +ensues, and extensive corrosion takes place in the iron +at the ends of the brass liners, more especially if they +are faced up at right angles to the shaft. Some engineers +have the uncovered part of the shaft between +the liners, inside the tube, protected against the sea +water by winding over it tarred line. As this may +give out and cause some trouble, by stopping the water +space, I have not adopted it, and shall be pleased +to have the experience of any seagoing engineer on +this important matter. A groove round the shaft is +formed, due to this action, and in some cases the shaft +has broken inside the stern tube, breaking not only it, +but tearing open the hull, resulting in the foundering of +the vessel. Steel has been used for screw shafts, but has +not been found so suitable, as it corrodes more rapidly +in the presence of salt water and gun metal than iron, +and unless protected by a solid liner for the most part +of its length, a mechanical feat which has not yet been +achieved in ordinary construction, as this liner would +require to be 20 ft. long. I find it exceedingly difficult +to get a liner of only 7 ft. long in one piece, and the +majority of 6 ft. liners are fitted <i>in two pieces</i>. The +joint of the two liners is rarely <i>watertight</i>, and many +shafts have been destroyed by this method of fitting +these liners.</p> + +<p>I trust that engine builders will make a step further +in the fitting of these liners on these shafts, as it is +against the interest of the <i>shipowner</i> to keep ships in +dry dock from such causes as defective liners, and I +think it will be only a matter of time when the screw +shaft will be completely protected from sea water, at +least inside the stern tube; and when this is done, I +would have no hesitation in using steel for screw shafts. +Though an easier forging than a crank shaft, these +shafts are often liable to flaws of a very serious character, +owing to the contraction of the <i>mass</i> of metal +forming the coupling; the outside cooling first tears +the center open, and when there is not much metal to +turn off the face of the coupling, it is sometimes undiscovered. +Having observed several of these cavities, +some only when the <i>last cut</i> was being taken off, I have +considered it advisable to have holes bored in the end +and center of each coupling, as far through as the +thickness of the flange; when the shafts are of large +size, this is sure to find these flaws out. Another flaw, +which has in many cases proved serious when allowed +to extend, is situated immediately abaft the gun metal +liner, in front of the propeller.</p> + +<p>This may be induced by corrosion, caused by the +presence of sea water, gun metal, and iron, assisted by +the rotation of the shaft. It may also be caused under +heavy strain, owing to the over-finishing of the shaft at +this part under the steam hammer.</p> + +<p>The forgemen, in these days of competition and low +prices, are instructed to so finish that there won't be +much weight to turn off when completing the shaft in +the lathe. This is effected by the use of half-round +blocks under the hammer, at a lower temperature than +the rest of the forging is done, along with the use of a +little water flung on from time to time; and it is remarkable +how near a forging is in truth when centered +in the lathe, and how little there is to come off. The +effect of this manipulation is to form a hard ring of +close grain about one inch thick from the circumference +of the shaft inward. The metal in this ring is much +harder than that in the rest of the shaft, and takes all +the strain the inner section gives; consequently, when +strain is brought on, either in heavy weather or should +the propeller strike any object at sea or in the Suez +canal, a fracture is caused at the circumference. This, +assisted by slight corrosion, has in my experience led +in the course of four months to a screw shaft being seriously +crippled.</p> + +<p>I show you a section of a screw shaft found to be +flawed, and which I had broken under the falling +weight of a steam hammer, when the decided difference +of the granules near the circumference from that in +the central part conveyed to me that it was weakened +by treatment I have referred to. I think more material +should be left on the forging, and the high finish +with a little cold water should be discontinued. Doing +away with the outer bearing in rudder post is an improvement, +provided the bearing in the outer end of +screw shaft in the stern tube is sufficiently large. It +allows the rudder post to have its own work to do +without bringing any strain on the screw shaft, and in +the event of the vessel's grounding and striking under +the rudder post, it does not throw any strain on the +screw shaft. It also tends to reduce weight at this +part, where all the weight is overhung from the stern +of the vessel.</p> + +<p><a name="Footnote_03_1" id="Footnote_03_1"></a><a href="#FNanchor_03_1">[1]</a></p> +<div class="note">A paper read before the Institute of Marine Engineers, Stratford, 1889.</div> + +<hr /> + + + + +<h2><a name="art04" id="art04"></a>EXPERIMENTAL AID IN THE DESIGN OF +HIGH SPEED STEAMSHIPS.</h2> + +<h3>By D. P.</h3> + + +<p>The achievement of one triumph after another in the +matter of high speed steamships, and especially the +confidence with which pledges of certain results are +given and accepted long before actual trials are made, +form one of the most convincing proofs of the important +part which scientific methods play in modern shipbuilding. +This is evident in the case of ships embodying +novel or hitherto untried features, and more especially +so in cases where shipbuilders, having no personal +practical experience or data, achieve such results. This +was notably illustrated in the case of the Fairfield Co. +undertaking some five years ago to build and engine a +huge craft of most phenomenal form and proportions, +and to propel the vessel at a given speed under conditions +which appeared highly impracticable to many +engaged in the same profession. The contract was proceeded +with, however, and the Czar of Russia's wonderful +yacht Livadia was the result, which (however much +she may have justified the professional strictures as to +form and proportions) entirely answered the designer's +anticipations as to speed. Equally remarkable and +far more interesting instances are the Inman liners +City of Paris and City of New York, in whose design +there was sufficient novelty to warrant the degree of +misgiving which undoubtedly existed regarding the +Messrs. Thomson's ability to attain the speed required. +In the case at least of the City of Paris, Messrs. Thomson's +intrepidity has been triumphantly justified. An +instance still more opposite to our present subject is +found in the now renowned Channel steamers Princess +Henrietta and Princess Josephine, built by Messrs. +Denny, of Dumbarton, for the Belgian government. +The speed stipulated for in this case was 20½ knots, +and although in one or two previous Channel steamers, +built by the Fairfield Co., a like speed had been +achieved, still the guaranteeing of this speed by Messrs. +Denny was remarkable, in so far as the firm had never +produced, or had to do with, any craft faster than 15 +or 16 knots. The attainment not only of the speed +guaranteed, but of the better part of a knot in excess +of that speed, was triumphant testimony to the skill +and care brought to bear upon the undertaking. In +this case, at least, the result was not one due to a previous +course of "trial and error" with actual ships, +but was distinctly due to superior practical skill, +backed and enhanced by knowledge and use of +specialized branches in the science of marine architecture. +Messrs. Denny are the only firm of private shipbuilders +possessing an experimental tank for recording +the speed and resistance of ships by means of miniature +reproductions of the actual vessels, and to this +fact may safely be ascribed their confidence in guaranteeing, +and their success in obtaining, a speed so +remarkable in itself and so much in excess of anything +they had previously had to do with. Confirmatory +evidence of their success with the Belgian steamers +is afforded by the fact that they have recently been +instructed to build for service between Stranraer +and Larne a paddle steamer guaranteed to steam 19 +knots, and have had inquiries as to other high speed +vessels.</p> + +<p>In estimating the power required for vessels of unusual +types or of abnormal speed, where empirical +formulæ do not apply, and where data for previous +ships are not available, the system of experimenting +with models is the only trustworthy expedient. In +the case of the Czar's extraordinary yacht, the Livadia, +already referred to, it may be remembered that previous +to the work of construction being proceeded with, +experiments were made with a small model of the +vessel by the late Dr. Tideman, at the government +tank at Amsterdam. On the strength of the data so +obtained, coupled with the results of trials made with +a miniature of the actual vessel on Loch Lomond, +those responsible for her stipulated speed were satisfied +that it could be attained. The actual results +amply justified the reliance placed upon such experiments.</p> + +<p>The design of many of her Majesty's ships has been +altered after trials with their models. This was notably +the case in connection with the design of the Medway +class of river gunboats. The Admiralty constructors +at first determined to make them 110 ft. long, by +only 26 ft. in breadth. A doubt arising in their minds, +the matter was referred to the late Mr. Froude, who +had models made of various breadths, with which he +experimented. The results satisfied the Admiralty +officers that a substantial gain, rather than a loss, +would follow from giving them much greater beam +than had been proposed, and this was amply verified +in the actual ships.</p> + +<p>So long ago as the last decade of last century, an +extended series of experiments with variously shaped +bodies, ships as well as other shapes, were conducted +by Colonel Beaufoy, in Greenland dock, London, under +the auspices of a society instituted to improve naval +architecture at that time. Robert Fulton, of America, +David Napier, of Glasgow, and other pioneers of the +steamship, are related to have carried out systematic +model experiments, although of a rude kind in modern +eyes, before entering on some of their ventures. About +1840 Mr. John Scott Russell carried on, on behalf of +the British Association, of which he was at that time +one of its most distinguished members, an elaborate +series of investigations into the form of least resistance +in vessels. For this purpose he leased the Virginia +House and grounds, a former residence of Rodger +Stewart, a famous Greenock shipowner of the early +part of the century, the house being used as offices, +while in the grounds an experimental tank was erected. +In it tests were made of the speed and resistance of +the various forms which Mr. Russell's ingenuity +evolved—notably those based on the well-known +<ins class="correction" title="Transcriber's Note: original reads 'steam'">stream</ins> +line theory—as possible types of the steam fleets of the +future. All the data derived from experiment was +tabulated, or shown graphically in the form of diagrams, +which, doubtless, proved of great interest to the +<i>savants</i> of the British Association of that day. Mr. +Russell returned to London in 1844, and the investigations +were discontinued.</p> + +<p>It will thus be seen that model experiments had +been made by investigators long before the time of the +late Dr. William Froude, of Torquay. It was not, however, +until this gentleman took the subject of resistance +of vessels in hand that designers were enabled to +render the results from model trials accurately applicable +to vessels of full size. This was principally due to +his enunciation and verification by experiment of what +is now known as the "law of comparison," or the law +by which one is enabled to refer accurately the resistance +of a model to one of larger size, or to that of a full +sized vessel. In effect, the law is this—for vessels of +the same proportional dimensions, or, as designers +say, of the same lines, there are speeds appropriate to +these vessels, which vary as the square roots of the +ratio of their dimensions, and at these appropriate +speeds the resistances will vary as the cubes of these +dimensions. The fundament upon which the law is +based has recently been shown to have found expression +in the works of F. Reech, a distinguished French +scientist who wrote early in the century. There are +no valid grounds for supposing that the discovery of +Reech was familiar to Froude; but even were this so, +it is abundantly evident that, although never claimed +by himself, there are the best of grounds for claiming +the law of comparison, as now established, to be an independent +discovery of Froude's.</p> + +<p>Dr. Froude began his investigations with ships' models +at the experimental tank at Torquay about 1872, +carrying it on uninterruptedly until his death in 1879. +Since his decease, the work of investigation has been +carried on by his son, Mr. R. E. Froude, who ably assisted +his father, and originated much of the existing +apparatus. At the beginning of 1886, the whole experimental +appliances and effects were removed from Torquay +to Haslar, near Portsmouth, where a large tank +and more commodious offices have been constructed, +with a view to entering more extensively upon the +work of experimental investigation. The dimensions +of the old tank were 280 ft. in length, 36 ft. in width, +and 10 ft. in depth. The new one is about 400 ft. long, +20 ft. wide, and 9 ft. deep. The new establishment is +more commodious and better equipped than the old, +and although the experiments are taken over a greater +length, the operators are enabled to turn out results +with as great dispatch as in the Torquay tank. The +adjacency of the new tank to the dockyard at Portsmouth +enables the Admiralty authorities to make fuller +and more frequent use of it than formerly. Since the +value of the work carried on for the British government +has become appreciated, several experimental establishments +of a similar character have been instituted +in other countries. The Dutch government in 1874 +formed one at Amsterdam which, up till his death in +1883, was under the superintendence of Dr. Tideman, +whose labors in this direction were second only to +those of the late Dr. Froude. In 1877 the French naval +authorities established an experimental tank in the +dockyard at Brest, and the Italian government have +just completed one on an elaborate scale in the naval +dockyard at Spezia. The Spezia tank, which is 500 +ft. in length by about 22 ft. in breadth, is fully equipped +with all the special and highly ingenious instruments +and appliances which the scientific skill of the +late Dr. Froude brought into existence, and have been +since his day improved upon by his son, Mr. R. E. +Froude, and other experts.</p> + +<p>Through the courtesy of our own Admiralty and of +Messrs. Denny, of Dumbarton, the Italians have been +permitted to avail themselves of the latest improvements +which experience has suggested, and the construction +of the special machinery and apparatus required +has been executed by firms in this country having +previous experience in this connection—Messrs. +Kelso & Co., of Commerce Street, Glasgow; and Mr. +Robert W. Munro, of London.</p> + +<p>Having briefly traced the origin and development of +the system of model experiment, it may now be of interest +to describe the <i>modus operandi</i> of such experiments, +and explain the way in which they are made +applicable to actual ships. The models with which +experiments are made in those establishments +conduct<a name="Page_11450" id="Page_11450"></a>ed on +the lines instituted by Mr. Froude are made of +paraffin wax, a material well adapted for the purpose, +being easily worked, impervious to water, and yielding +a fine smooth surface. Moreover, when done with, +the models may be remelted for further use and all +parings utilized. They are produced in the following +manner: A mould is formed in clay by means of cross +sections made somewhat larger than is actually required, +this allowance being made to admit of the cutting +and paring afterward required to bring the model to +the correct point. Into this mould a core is placed, +consisting of a light wooden framework covered with +calico and coated with a thick solution of clay to make +it impervious to the melted paraffin. This latter substance +is run into the space between the core and the +mould and allowed to cool. This space, forming the +thickness of the model, is usually from ¾ in. for a model +of 10 ft. long to 1¼ in. and 1½ in. for one of 16 ft. +and 18 ft. long. When cold, the model is floated out of +the mould by water pressure and placed bottom upward +on the bed of a shaping machine, an ingenious +piece of mechanism devised by the late Dr. Froude, to +aid in reducing the rough casting to the accurate form. +The bed of this machine, which travels automatically +while the machine is in operation, can be raised or +lowered to any desired level by adjusting screws. A +plan of water lines of the vessel to be modeled is placed +on a tablet geared to the machine, the travel of which +is a function of the travel of the bed containing the +model. With a pointer, which is connected by a system +of levers to the cutting tools, the operator traces +out the water lines upon the plan as the machine and +its bed are in motion, with the result that corresponding +lines are cut upon the model. The cutting tools +are swiftly revolving knives which work on vertical +spindles moved in a lateral direction (brought near or +removed from each other), according to the varying +breadth of the water lines throughout the length of the +model, as traced out by the operator's pointer. In this +way a series of longitudinal incisions are made on the +model at different levels corresponding to the water +lines of the vessel. The model is now taken from the +bed of the machine and the superfluous material or +projection between the incisions is removed by means +of a spokeshave or other sharp hand tool, and the whole +surface brought to the correct form, and made fair and +smooth.</p> + +<p>To test accuracy of form, the weight of model is carefully +taken, and the displacement at the intended trial +draught accurately determined from the plan of lines. +The difference between the weight of model and the +displacement at the draught intended is then put into +the bottom of the model in the form of small bags of +shot, and by unique and very delicately constructed instruments +for ascertaining the correct draught, the +smallest error can at once be detected and allowed for. +The models vary in size from about one-tenth to one-thirtieth +of the size of the actual ship. A model of the +largest size can be produced and its resistance determined +at a number of speeds in about two days or so. +The mode of procedure in arranging the model for the +resistance experiment, after the model is afloat in the +tank at the correct draught and trim, consists in attaching +to it a skillfully devised dynamometric apparatus +secured to a lightly constructed carriage. This carriage +traverses a railway which extends the whole length +of the tank about 15 in. or 18 in. above the water. The +floating model is carefully guided in its passage through +the water by a delicate device, keeping it from deviating +either to the right or left, but at the same time allowing +a free vertical and horizontal motion. The carriage +with the model attached is propelled by means of an +endless steel wire rope, passing at each end of the tank +around a drum, driven by a small stationary engine, +fitted with a very sensitive governor, capable of being +so adjusted that any required speed may be given to +the carriage and model. The resistance which the +model encounters in its passage through the water +is communicated to a spiral spring, and the extension +this spring undergoes is a measure of the model's +resistance. The amount of the extension is +recorded on a revolving cylinder to a much enlarged +scale through the medium of levers or bell +cranks supported by steel knife edges resting on rocking +pieces. On the same cylinder are registered +"time" and "distance" diagrams, by means of which +a correct measure of the speed is obtained. The +time diagram is recorded by means of a clock attached +to an electric circuit, making contact every half second, +and actuating a pen which forms an indent in what +would otherwise be a straight line on the paper. The +distance pen, by a similar arrangement, traces another +line on the cylinder in which are indents corresponding +to fixed distances of travel along the tank, the indents +being caused by small projections which strike a +trigger at the bottom of the carriage as it passes, and +make electric contact. From these time and distance +diagrams accurate account can be taken of the speed +at which the model and its supporting carriage have +been driven. Thus on the same cylinder is recorded +graphically the speed and resistance of the model. +The carriage may be driven at any assigned speed by +adjusting the governor of the driving engine already +alluded to, but the record of the speed by means of +the time and distance diagrams is more definite. When +the resistances of the model have been obtained at +several speeds, varying in some cases from 50 to 1,000 +feet per minute, the speeds are set off in suitable units +along a base line, and for every speed at which resistance +is measured, the resistance is set off to scale as an +ordinate value at those speeds. A line passing through +these spots forms the "curve of resistance," from which +the resistance experienced by the model at the given +trial speeds or any intermediate speed can be ascertained. +The resistance being known, the power required +to overcome resistance and drive the actual ship +at any given speed is easily deduced by applying the +rule before described as the law of comparison.—<i>The +Steamship.</i></p> + +<hr /> + + + + +<h2><a name="art05" id="art05"></a>THE SHIP IN THE NEW FRENCH BALLET +OF THE "TEMPEST."</h2> + + +<p>A new ballet, entitled the "Tempest," by Messrs. +Barbier and Thomas, has recently been put upon the +stage of the Opera at Paris with superb settings. One +of the most important of the several tableaux exhibited +is the last one of the third act, in which appears +a vessel of unusual dimensions for the stage, and which +leaves far behind it the celebrated ships of the "Corsaire" +and "L'Africaine." This vessel, starting from +the back of the stage, advances majestically, describes +a wide circle, and stops in front of the prompter's +box.</p> + +<div class="figcenter"> +<a href="./images/05_1.png"> +<img src="./images/05_1_th.png" width="549" height="400" alt="Figure 1." /> +</a> + +<p class="caption"><span class="sc">Fig. 1.</span>—SHIP OF +THE "TEMPEST," IN PROCESS OF CONSTRUCTION.</p> +</div> + +<div class="figleft" style="width: 250px;"> +<a href="./images/05_2.png"> +<img src="./images/05_2_th.png" width="250" height="276" alt="Figure 2." /> +</a> + +<p class="caption"><span class="sc">Fig. 2.</span>—SETTING OF THE SCENERY +BEFORE AND AFTER THE APPEARANCE OF THE SHIP.</p> +</div> + +<p>As the structure of this vessel and the mechanism +by which it is moved are a little out of the ordinary, +we shall give some details in regard to them. First, +the sea is represented by four parallel strips of water, +each formed of a vertical wooden frame entirely free +in its movements (Fig. 2). The ship (Figs. 1, 2, 3, 4 and +5) is carried by wheels that roll over the floor of the +stage. It is guided in its motion by two grooved +bronze wheels and by a rail formed of a simple reversed +T-iron which is fixed to the floor by bolts. In measure +as it advances, the strips of water open in the center +to allow it to pass, and, as the vessel itself is covered +up to the water line with painted canvas imitating the +sea, it has the appearance of cleaving the waves. As +soon as it has passed, the three strips of water in the +rear rise slightly. When the vessel reaches the first +of the strips, the three other strips, at first juxtaposed +against the preceding, spread out and thus increase +the extent of the sea, while the inclined plane of the +preceding tableau advances in order to make place for +the vessel. The shifting of this inclined place is effected +by simply pulling upon the carpet that covers it, +and which enters a groove in the floor in front of the +prompter's box. At this moment, the entire stage +seems to be in motion, and the effect is very striking.</p> + +<div class="figcenter"> +<a href="./images/05_3.png"> +<img src="./images/05_3_th.png" width="400" height="271" alt="Figure 3." /> +</a> + +<p class="caption"><span class="sc">Fig. 3.</span>—SHIP OF THE +NEW BALLET, THE "TEMPEST."</p> +</div> + +<p>We come now to the details of construction of the +vessel. It is not here a question of a ship represented +simply by means of frames and accessories, but of a +true ship in its entirety, performing its evolutions over +the whole stage. Now, a ship is not constructed at a +theater as in reality. It does not suffice to have it all +entire upon the stage, but it is necessary also to be +able to dismount it after every representation, and +that, too, in a large number of pieces that can be +easily stored away. Thus, the vessel of the Tempest, +which measures a dozen yards from stem to stern, and +is capable of carrying fifty persons, comes apart in +about 250 pieces of wood, without counting all the +iron work, bolts, etc. Nevertheless, it can be mounted +in less than two hours by ten skilled men.</p> + +<div class="figleft" style="width: 200px;"> +<a href="./images/05_4.png"> +<img src="./images/05_4_th.png" width="200" height="270" alt="Figure 4." /> +</a> + +<p class="caption"><span class="sc">Fig. 4.</span>—THE SHIP WITH ITS OCCUPANTS.</p> +</div> + +<p><a name="Page_11451" id="Page_11451"></a>The visible hull of the ship is placed upon a large +and very strong wooden framework, formed of twenty-six +trusses. In the center, there are two longitudinal +trusses about three feet in height by twenty-five in +length, upon which are assembled, perpendicularly, +seven other trusses. In the interior there are six +transverse pieces held by stirrup bolts, and at the extremity +of each of these is fixed a thirteen-inch iron +wheel. It is upon these twelve wheels that the entire +structure rolls.</p> + +<p>There are in addition the two bronze guide wheels +that we have already spoken of. In the rear there +are two large vertical trusses sixteen feet in height, +which are joined by ties and descend to the bottom of +the frame, to which they are bolted. These are worked +out into steps and constitute the skeleton of the immense +stern of the vessel. The skeleton of the prow +is formed of a large vertical truss which is bolted +to the front of the frame and is held within by a tie +bar. On each side of this truss are placed the <i>parallels</i> +(Figs. 1 and 3), which are formed of pieces of wood that +are set into the frame below and are provided above +with grooves for the passage of iron rods that support +the foot rests by means of which the supernumeraries +are lifted. As a whole, those rods constitute a jointed +parallelogram, so that the foot rest always remains +horizontal while describing a curve of five feet radius +from the top of the frame to the deck of the vessel. +They are actuated by a cable which winds around a +small windlass fixed in the interior of the frame.</p> + +<div class="figcenter"> +<a href="./images/05_5.png"> +<img src="./images/05_5_th.png" width="400" height="269" alt="Figure 5." /> +</a> + +<p class="caption"><span class="sc">Fig. 5.</span>—THE SHIP AS SEEN FROM THE STAGE.</p> +</div> + +<p>The large mast consists of a vertical sheath 10 ft. +high, which is set into the center of the frame, and in +the interior of which slides a wooden spar that exceeds +it by 5 ft. at first, and is capable of being drawn out +as many more feet for the final apotheosis. This +part of the mast carries three footboards and a platform +for the reception of "supers." It is actuated by +a windlass placed upon the frame.</p> + +<p>To form the skeleton of the vessel there are mounted +upon the frame a series of eight large vertical trusses +parallel with each other and cross-braced by small +trusses. The upper part of these supports the flooring +of the deck, and their exterior portion affects the +curve of a ship's sides. It is to these trusses that are +attached the panels covered with painted canvas that +represent the hull. These panels are nine in number on +each side. Above are placed those that simulate the +nettings and those that cover the prow or form its +crest.</p> + +<p>The turret that surrounds the large mast is formed +of vertical trusses provided with panels of painted +canvas and carrying a floor for the figurants to stand +upon.</p> + +<p>The bowsprit is in two parts, one sliding in the +other. The front portion is at first pulled back, in +order to hide the vessel entirely in the side scenes. +It begins to make its appearance before the vessel +<ins class="correction" title="Transcriber's Note: original reads 'itsself'">itself</ins> +gets under way. Light silken cordages connect +the mast, the bowsprit, and the small mast at the +stern.</p> + +<p>On each side of the vessel, there are bolted to the +frame that supports it five iron frames covered with +canvas (Fig. 3), which reach the level of the water line, +and upon which stand the "supers" representing the +naiads that are supposed to draw the ship upon the +beach. Finally at the bow there is fixed a frame which +supports a danseuse representing the living prow of +the vessel.</p> + +<p>The vessel is drawn to the middle of the stage by a +cable attached to its right side and passing around a +windlass placed in the side scenes to the left (Fig. 2). +It is at the same time pushed by machinists placed in +the interior of the framework. The latter, as above +stated, is entirely covered with painted canvas resembling +water.</p> + +<p>As the vessel, freighted with harmoniously grouped +spirits, and with naiads, sea fairies, and graceful genii +seeming to swim around it, sails in upon the stage, +puts about, and advances as if carried along by the +waves to the front of the stage, the effect is really +beautiful, and does great credit to the machinists of the +Opera.</p> + +<p>We are indebted to <i>Le Genie Civil</i> and <i>Le Monde +Illustré</i> for the description and engravings.</p> + +<hr /> + + + + +<h2><a name="art06" id="art06"></a>THE GIRARD HYDRAULIC RAILWAY.</h2> + + +<div class="figleft" style="width: 207px;"> +<img src="./images/06_1.png" width="207" height="221" alt="Figure 1." /> + +<p class="caption"><span class="sc">Fig. 1.</span></p> + +<img src="./images/06_2.png" width="203" height="138" alt="Figure 2." /> + +<p class="caption"><span class="sc">Fig. 2.</span></p> +</div> + +<p>We give herewith some illustrations of this railway +which has recently excited so much technical interest +in Europe and America, and which threatens to revolutionize +both the method and velocity of traveling, +if only the initial expense of laying the line can be +brought within moderate limits. A short line of railway +has been laid in Paris, and we have there examined +it, and traveled over the line more than once; so +that we can testify to the smoothness and ease of the +motion. Sir Edward Watkin examined the railway +recently, and we understand that a line two miles +long is to be laid in London, under his auspices. He +seems to think it might be used for the Channel tunnel, +being both smokeless and noiseless. It might also, +if it could be laid at a sufficiently low price, be useful +for the underground railways in London, of one of +which he is chairman. We are favorably impressed +by the experiments we have witnessed; our misgivings +are as to the cost. The railway is the invention of the +well known hydraulic engineer, Monsieur Girard, who, +as early as 1852, endeavored to replace the ordinary +steam traction on railways by hydraulic propulsion, +and in 1854 sought to diminish the resistance to the +movement of the wagons by removing the wheels, and +causing them to slide on broad rails. In order to test +the invention, Mons. Girard demanded, and at the end +of 1869 obtained, a concession for a short line from +Paris to Argenteuil, starting in front of the Palais de +l'Industrie, passing by Le Champ de Courses de Longchamps, +and crossing the Seine at Suresnes. Unfortunately, +the war of 1870-71 intervened, during which +the works were destroyed and Mons. Girard was killed. +After his death the invention was neglected for some +years. A short time ago, however, one of his former +colleagues, Mons. Barre, purchased the plans and +drawings of Mons. Girard from his family, and having +developed the invention, and taken out new patents, +formed a company to work them. The invention +may be divided into two parts, which are distinct, the +first relating to the mode of supporting the carriages +and the second to their propulsion. Each carriage is +carried by four or six shoes, shown in Figs. 3, 4, and 5; +and these shoes slide on a broad, flat rail, 8 in. or 10 in. +wide. The rail and shoe are shown in section in Fig. 1. +The rail is bolted to longitudinal wooden sleepers, and +the shoe is held on the rail by four pieces of metal, A, +two on each side, which project slightly below the top +of the rail. The bottom of the shoe which is in contact +with the rail is grooved or channeled, so as to hold +the water and keep a film between each shoe and the +rail. The carriage is supported by vertical rods, which +fit one into each shoe, a hole being formed for that +purpose; and the point of support being very low, +and quite close to the rail, great stability is insured. +It is proposed to make the rail of the form shown in +Fig. 2 in future, as this will avoid the plates, A, and +the flanges, B, will help to keep the water on the rail. +Figs. 3, 4, and 5 show the shoe in detail. Fig. 3 gives +a longitudinal section, Fig. 4 is a plan, and Fig. 5 is a +plan of the shoe inverted, showing the grooves in its +face. Fig. 3 shows the hollow shoe, into which water +at a pressure of ten atmospheres is forced by a pipe +from a tank on the tender. The water enters by the +pipe, C, and fills the whole of the chamber, D. The +water attempts to escape, and in doing so lifts the shoe +slightly, thus filling the first groove of the chamber. +The pressure again lifts the shoe, and the second chamber +is filled; and so on, until ultimately the water +escapes at the ends, E, and sides, F. Thus a film of +water is kept between the shoe and the rail, and on +this film the carriage is said to float. The water runs +away into the channels, H H (Fig. 6), and is collected +to be used over again. Fig. 3 also shows the means of +supporting the carriage on the shoe by means of K, +the point of support being very low. The system of +grooves on the lower face of the shoe is shown in Fig. +5. So much for the means by which wheels are dispensed +with, and the carriage enabled to slide along +the line.</p> + + +<div class="figcenter"> +<a href="./images/06_3.png"> +<img src="./images/06_3_th.png" width="400" height="187" alt="Figure 3." /> +</a> + +<p class="caption"><span class="sc">Fig. 3.</span></p> +</div> + +<div class="figcenter"> +<img src="./images/06_4.png" width="400" height="197" alt="Figure 4." /> + +<p class="caption"><span class="sc">Fig. 4.</span></p> +</div> + +<div class="figcenter"> +<img src="./images/06_5.png" width="345" height="183" alt="Figure 5." /> + +<p class="caption"><span class="sc">Fig. 5.</span></p> +</div> + +<div class="figcenter"> +<a href="./images/06_6.png"> +<img src="./images/06_6_th.png" width="400" height="303" alt="Figure 6." /> +</a> + +<p class="caption"><span class="sc">Fig. 6.</span></p> +</div> + +<p>The next point is the method of propulsion. Figs. 7 +and 8 give an elevation and plan of one of the experimental +carriages. Along the under side of each of the +carriages a straight turbine, L L, extends the whole +length, and water at high pressure impinges on the +blades of this turbine from a jet, M, and by this means +the carriage is moved along. A parabolic guide, which +can be moved in and out of gear by a lever, is placed +under the tender, and this on passing strikes the tappet, +S, and opens the valve which discharges the water from +the jet, M, and this process is repeated every few yards +along the whole line. The jets, M, must be placed at such +a distance apart that at least one will be able to operate +on the shortest train that can be used. In this turbine +there are two sets of blades, one above the other, placed +with their concave sides in opposite directions, so that +one set is used for propelling in one direction and the +other in the opposite direction. In Fig. 6 it is seen that +the jet, M, for one direction is just high enough to act +against the blades, Q, while the other jet is higher, and +acts on the blades, P, for propulsion in the opposite +direction. The valves, R, which are opened by the +tappet, S, are of peculiar construction, and we hope +soon to be able to give details of them. Reservoirs +(Fig. 6) holding water at high pressure must be placed +at intervals, and the pipe, T, carrying high pressure +water must run the whole length of the line. Fig. 6 +shows a cross section of the rail and carriage, and gives +a good idea of the general arrangements. The absence +of wheels and of greasing and lubricating arrangements +will alone effect a very great saving, as we are informed +that on the Lyons Railway, which is 800 kilometers +long, the cost of oil and grease exceeds £400,000 per annum. +As Sir Edward Watkin recently explained, all +the great railway companies have long tried to find a +substitute for wheels, and this railway appears to offer +a solution of that problem. Mons. Barre thinks that +a speed of 200 kilometers (or 120 miles) per hour may +be easily and safely attained.</p> + +<div class="figcenter"> +<a href="./images/06_7.png"> +<img src="./images/06_7_th.png" width="550" height="183" alt="Figure 7." /> +</a> + +<p class="caption"><span class="sc">Fig. 7.</span></p> +</div> + +<div class="figcenter"> +<a href="./images/06_8.png"> +<img src="./images/06_8_th.png" width="550" height="144" alt="Figure 8." /> +</a> + +<p class="caption"><span class="sc">Fig. 8.</span></p> +</div> + +<p>Of course, as there is no heavy locomotive, and as the +traction does not depend upon pressure on the rail, +the road may be made comparatively light. The force +required to move a wagon along the road is very small, +Mons. Barre stating, as the result of his experiments, +that an effort amounting to less than half a kilogramme +is sufficient to move one ton when suspended on a film +of water with his improved shoes. It is recommended +that the stations be placed at the summit of a double +incline, so that on going up one side of the incline the +motion of the train may be arrested, and on starting it +may be assisted. No brakes are required, as the friction +of the shoe against the rail, when the water under +pressure is not being forced through, is found to be +quite sufficient to bring the train to a standstill in a +very short distance. The same water is run into +troughs by the side of the line, and can be used over +and over again indefinitely, and in the case of long +journeys, the water required for the tender could be +taken up while the train is running. The principal +advantages claimed for the railway are: The absence +of vibration and of side rolling motion; the pleasure of +traveling is comparable to that of sleighing over a +surface of ice, there is no noise, and what is important +in town railways, no smoke; no dust is caused by the +motion of the train during the journey. It is not easy +<a name="Page_11452" id="Page_11452"></a>for the carriages to be thrown from the rails, since any +body getting on the rail is easily thrown off by the +shoe, and will not be liable to get underneath, as is the +case with wheels; the train can be stopped almost instantly, +very smoothly, and without shock. Very high +speed can be attained; with water at a pressure of 10 +kilogrammes, a speed of 140 kilometers per hour can be +attained; great facility in climbing up inclines and +turning round the curves; as fixed engines are employed +to obtain the pressure, there is great economy +in the use of coal and construction of boilers, and there +is a total absence of the expense of lubrication. It is, +however, difficult to see how the railway is to work +during a long and severe frost. We hope to give further +illustrations at an early date of this remarkable +invention.—<i>Industries.</i></p> + +<hr /> + + + + +<h2><a name="art07" id="art07"></a> +QUARTZ FIBERS.<a name="FNanchor_07_1" id="FNanchor_07_1"></a><a href="#Footnote_07_1"><sup>1</sup></a></h2> + + +<p>In almost all investigations which the physicist carries +out in the laboratory, he has to deal with and to +measure with accuracy those subtile and to our senses +inappreciable forces to which the so-called laws of +nature give rise. Whether he is observing by an electrometer +the behavior of electricity at rest or by a galvanometer +the action of electricity in motion, whether +in the tube of Crookes he is investigating the power of +radiant matter, or with the famous experiment of +Cavendish he is finding the mass of the earth—in these +and in a host of other cases he is bound to measure +with certainty and accuracy forces so small that in no +ordinary way could their existence be detected, while +disturbing causes which might seem to be of no particular +consequence must be eliminated if his experiments +are to have any value. It is not too much to say that +the very existence of the physicist depends upon the +power which he possesses of producing at will and by +artificial means forces against which he balances those +that he wishes to measure.</p> + +<p>I had better perhaps at once indicate in a general +way the magnitude of the forces with which we have +to deal.</p> + +<p>The weight of a single grain is not to our senses appreciable, +while the weight of a ton is sufficient to +crush the life out of any one in a moment. A ton is +about 15,000,000 grains. It is quite possible to measure +with unfailing accuracy forces which bear the same +relation to the weight of a grain that a grain bears to +a ton.</p> + +<p>To show how the torsion of wires or threads is made +use of in measuring forces, I have arranged what I can +hardly dignify by the name of an experiment. It is +simply a straw hung horizontally by a piece of wire. +Resting on the straw is a fragment of sheet iron weighing +ten grains. A magnet so weak that it cannot lift +the iron yet is able to pull the straw round through an +angle so great that the existence of the feeble attraction +is evident to every one in the room.</p> + +<p>Now it is clear that if, instead of a straw moving +over the table simply, we had here an arm in a glass +case and a mirror to read the motion of the arm, it +would be easy to observe a movement a hundred or +a thousand times less than that just produced, and +therefore to measure a force a hundred or a thousand +times less than that exerted by this feeble magnet.</p> + +<p>Again, if instead of wire as thick as an ordinary pin +I had used the finest wire that can be obtained, it +would have opposed the movement of the straw with +a far less force. It is possible to obtain wire ten times +finer than this stubborn material, but wire ten times +finer is much more than ten times more easily twisted. +It is ten thousand times more easily twisted. This is +because the torsion varies as the fourth power of the +diameter. So we say 10 × 10 = 100, 100 × 100 = 10,000. +Therefore, with the finest wire, forces 10,000 times +feebler still could be observed.</p> + +<p>It is therefore evident how great is the advantage of +reducing the size of a torsion wire. Even if it is only +halved, the torsion is reduced sixteenfold. To give a +better idea of the actual sizes of such wires and fibers +as are in use, I shall show upon the screen a series of +such photographs taken by Mr. Chapman, on each of +which a scale of thousandths of an inch has been +printed.</p> + +<div class="figcenter"> +<img src="./images/07_01.png" width="209" height="29" alt="Scale of 1000ths of an inch for Figs. 1 to 7." /> + +<p class="caption">Scale of 1000ths of an inch for Figs. 1 to 7. +The scale of Figs. 8 and 9 is much finer.</p> +</div> + +<table cellpadding="4" summary="Figures 1 and 2"> +<tr><td align="center" valign="bottom"> +<img src="./images/07_1.png" width="66" height="308" alt="Figure 1." /> +</td><td align="center" valign="bottom"> +<img src="./images/07_2.png" width="41" height="282" alt="Figure 2." /> +</td></tr> + +<tr> +<td align="center"><p class="caption"><span class="sc">Fig. 1.</span></p></td> +<td align="center"><p class="caption"><span class="sc">Fig. 2.</span></p></td></tr></table> + + +<div class="figleft" style="width: 145px;"> +<img src="./images/07_3.png" width="145" height="281" alt="Figure 3." /> + +<p class="caption"><span class="sc">Fig. 3.</span></p> +</div> + +<p>The first photograph (Fig. 1) is an ordinary hair—a +sufficiently familiar object, and one that is generally +spoken of as if it were rather fine. Much finer than +this is the specimen of copper wire now on the screen +(Fig. 2), which I recently obtained from Messrs. Nalder +Brothers. It is only a little over one-thousandth of an +inch in diameter. Ordinary spun glass, a most beautiful +material, is about one-thousandth of an inch in diameter, +and this would appear to be an ideal torsion thread +(Fig. 3). Owing to its fineness, its torsion would be extremely +small, and the more so because glass is more +easily deformed than metals. Owing to its very great +strength, it can carry heavier loads than would be expected +of it. I imagine many physicists must have +turned to this material in their endeavor to find a +really delicate torsion thread. I have so turned only +to be disappointed. It has every good quality but +one, and that is its imperfect elasticity. For instance, +a mirror hung by a piece of spun glass is casting an +image of a spot of light on the scale. If I turn the +mirror, by means of a fork, twice to the right, and +then turn it back again, the light does not come back +to its old point of rest, but oscillates about a point +on one side, which, however, is slowly changing, so +that it is impossible to say what the point of rest +really is. Further, if the glass is twisted one way first +and then the other way, the point of rest moves in a +manner which shows that it is not influenced by the last +deflection alone: the glass remembers what was done +to it previously. For this reason spun glass is quite +unsuitable as a torsion thread; it is impossible to say +what the twist is at any time, and therefore what is +the force developed.</p> + +<div class="figright"> +<img src="./images/07_4.png" width="31" height="301" alt="Figure 4." /> + +<p class="caption"><span class="sc">Fig. 4.</span></p> +</div> + +<p>So great has the difficulty been in finding a fine torsion +thread that the attempt has been given up, and +in all the most exact instruments silk has been used. +The natural cocoon fibers, as shown on the screen +(Fig. 4), consist of two irregular lines gummed together, +each about one two-thousandth of an inch in +diameter. These fibers must be separated from one +another and washed. Then each component will, according +to the experiment of Gray, carry nearly 60 +grains before breaking, and can be safely loaded with +15 grains. Silk is therefore very strong, carrying at +the rate of from 10 to 20 tons to the square inch. It is +further valuable in that its torsion is far less than that +of a fiber of the same size of metal or even of glass, if +such could be produced. The torsion of silk, though +exceedingly small, is quite sufficient to upset the working +of any delicate instrument, because it is never +constant. At one time the fiber twists one way and +another time in another, and the evil effect can only +be mitigated by using large apparatus in which strong +forces are developed. Any attempt that may be made +to increase the delicacy of apparatus by reducing their +dimensions is at once prevented by the relatively great +importance of the vagaries of the silk suspension.</p> + +<p>The result, then, is this. The smallness, the length +of period, and therefore delicacy, of the instruments at +the physicist's disposal have until lately been simply +limited by the behavior of silk. A more perfect suspension +means still more perfect instruments, and +therefore advance in knowledge.</p> + +<p>It was in this way that some improvements that I +was making in an instrument for measuring radiant +heat came to a deadlock about two years ago. I would +not use silk, and I could not find anything else that +would do. Spun glass, even, was far too coarse for +my purpose, it was a thousand times too stiff.</p> + +<div class="figleft" style="width: 184px;"> +<img src="./images/07_5.png" width="184" height="414" alt="Figure 5." /> + +<p class="caption"><span class="sc">Fig. 5.</span></p> +</div> + +<p>There is a material invented by Wollaston long ago, +which, however, I did not try because it is so easily +broken. It is platinum wire which has been drawn in +silver, and finally separated by the action of nitric +acid. A specimen about the size of a single line of silk +is now on the screen, showing the silver coating at one +end (Fig. 5).</p> + +<p>As nothing that I knew of could be obtained that +would be of use to me, I was driven to the necessity of +trying by experiment to find some new material. The +result of these experiments was the development of a +process of almost ridiculous simplicity which it may be +of interest for me to show.</p> + +<p>The apparatus consists of a small crossbow, and an +arrow made of straw with a needle point. To the tail +of the arrow is attached a fine rod of quartz which has +been melted and drawn out in the oxyhydrogen jet. I +have a piece of the same material in my hand, and +now after melting their ends and joining them together, +an operation which produces a beautiful and dazzling +light, all I have to do is to liberate the string of the +bow by pulling the trigger with one foot, and then if +all is well a fiber will have been drawn by the arrow, +the existence of which can be made evident by fastening +to it a piece of stamp paper.</p> + +<p>In this way threads can be produced of great length, +of almost any degree of fineness, of extraordinary uniformity, +and of enormous strength. I do not believe, +if any experimentalist had been promised by a good +fairy that he might have anything he desired, that he +would have ventured to ask for any one thing with so +many valuable properties as these fibers possess. I +hope in the course of this evening to show that I am +not exaggerating their merits.</p> + +<div class="figleft"> +<img src="./images/07_6.png" width="18" height="307" alt="Figure 6." /> +<p class="caption"><span class="sc">Fig. 6.</span></p> +</div> + +<div class="figleft" style="margin-top: 5px"> +<img src="./images/07_7.png" width="22" height="302" alt="Figure 7." /> + +<p class="caption"><span class="sc">Fig. 7.</span></p> +</div> + +<p>In the first place, let me say something about the degree +of fineness to which they can be drawn. There is +now projected upon the screen a quartz fiber one five-thousandth +of an inch in diameter (Fig. 6). This is +one which I had in constant use in an instrument +loaded with about 30 grains. It has a section only +one-sixth of that of a single line of silk, and it is just +as strong. Not being organic, it is in no way affected +by changes of moisture and temperature, and so it is +free from the vagaries of silk which give so much +trouble. The piece used in the instrument was about +16 inches long. Had it been necessary to employ spun +glass, which hitherto was the finest torsion material, +then, instead of 16 inches, I should have required a +piece 1,000 feet long, and an instrument as high as the +Eiffel tower to put it in.</p> + +<p>There is no difficulty in obtaining pieces as fine as +this yards long if required, or in spinning it very much +finer. There is upon the screen a single line made by +the small garden spider, and the size of this is perfectly +evident (Fig. 7). You now see a quartz fiber far +finer than this, or, rather, you see a diffraction phenomenon, +for no true image is formed at all; but even +this is a conspicuous object in comparison with the +tapering ends, which it is absolutely impossible to +trace in a microscope. The next two photographs, +taken by Mr. Nelson, whose skill and resources are so +famous, represent the extreme end of a tail of quartz, +and, though the scale is a great deal larger than that +used in the other photographs, the end will be visible +only to a few. Mr. Nelson has photographed here +what it is absolutely impossible to see. What the size +of these ends may be, I have no means of telling. Dr. +Royston Piggott has estimated some of them at less +than one-millionth of an inch, but, whatever they are, +they supply for the first time objects of extreme smallness +the form of which is certainly known, and, therefore, +I cannot help looking upon them as more satisfactory +tests for the microscope than diatoms and +other things of the real shape of which we know nothing +whatever.</p> + +<p>Since figures as large as a million cannot be realized +properly, it may be worth while to give an illustration +of what is meant by a fiber one-millionth of an inch +in diameter.</p> + +<p>A piece of quartz an inch long and an inch in diameter +would, if drawn out to this degree of fineness, +be sufficient to go all the way round the world 658 +times; or a grain of sand just visible—that is, one-hundredth +of an inch long and one hundredth of an +inch in diameter—would make one thousand miles of +such thread. Further, the pressure inside such a +thread due to a surface tension equal to that of water +would be 60 atmospheres.</p> + +<p>Going back to such threads as can be used in instruments, +I have made use of fibers one ten-thousandth +of an inch in diameter, and in these the torsion is 10,000 +times less than that of spun glass.</p> + +<p>As these fibers are made finer their strength increases +in proportion to their size, and surpasses that of ordinary +bar steel, reaching, to use the language of +engi<a name="Page_11453" id="Page_11453"></a>neers, +as high a figure as 80 tons to the inch. Fibers +of ordinary size have a strength of 50 tons to the inch.</p> + +<p>While it is evident that these fibers give us the +means of producing an exceedingly small torsion, and +one that is not affected by weather, it is not yet evident +that they may not show the same fatigue that +makes spun glass useless. I have, therefore, a duplicate +apparatus with a quartz fiber, and you will see +that the spot of light comes back to its true place on +the screen after the mirror has been twisted round +twice.</p> + +<p>I shall now for a moment draw your attention to +that peculiar property of melted quartz that makes +threads such as I have been describing a possibility. A +liquid cylinder, as Plateau has so beautifully shown, is +an unstable form. It can no more exist than can a +pencil stand on its point. It immediately breaks up +into a series of spheres. This is well illustrated in +that very ancient experiment of shooting threads of +resin electrically. When the resin is hot, the liquid +cylinders, which are projected in all directions, break +up into spheres, as you see now upon the screen. As +the resin cools, they begin to develop tails; and when +it is cool enough, <i>i.e.</i>, sufficiently viscous, the tails +thicken and the beads become less, and at last uniform +threads are the result. The series of photographs +show this well.</p> + +<div class="figleft"> +<a href="./images/07_8.png"> +<img src="./images/07_8_th.png" width="21" height="315" alt="Figure 8." /> +</a> + +<p class="caption"><span class="sc">Fig. 8.</span></p> +</div> + +<div class="figleft" style="margin-top: 20px"> +<img src="./images/07_9.png" width="23" height="295" alt="Figure 9." /> + +<p class="caption"><span class="sc">Fig. 9.</span></p> +</div> + +<p>There is a far more perfect illustration which we +have only to go into the garden to find. There we +may see in abundance what is now upon the screen—the +webs of those beautiful geometrical spiders. The +radial threads are smooth like the one you saw a few +minutes ago, but the threads that go round and round +are beaded. The spider draws these webs slowly, and +at the same time pours upon them a liquid, and still +further to obtain the effect of launching a liquid cylinder +in space he, or rather she, pulls it out like the +string of a bow, and lets it go with a jerk. The liquid +cylinder cannot exist, and the result is what you now +see upon the screen (Fig. 8). A more perfect illustration +of the regular breaking up of a liquid cylinder it +would be impossible to find. The beads are, as Plateau +showed they ought to be, alternately large and +small, and their regularity is marvelous. Sometimes +two still smaller beads are developed, as may be seen +in the second photograph, thus completely agreeing +with the results of Plateau's investigations.</p> + +<p>I have heard it maintained that the spider goes +round her web and places these beads there afterward. +But since a web with about 360,000 beads is completed +in an hour—that is at the rate of about 100 a second—this +does not seem likely. That what I have said is +true, is made more probable by the photograph of a +beaded web that I have made myself by simply stroking +a quartz fiber with a straw wetted with castor oil +(Fig. 9); it is rather larger than a spider line; but I +have made beaded threads, using a fine fiber, quite indistinguishable +from a real spider web, and they have +the further similarity that they are just as good for +catching flies.</p> + +<p>Now, going back to the melted quartz, it is evident +that if it ever became perfectly liquid, it could not exist +as a fiber for an instant. It is the extreme viscosity +of quartz, at the heat even of an electric arc, that +makes these fibers possible. The only difference between +quartz in the oxyhydrogen jet and quartz in the +arc is that in the first you make threads and in the second +are blown bubbles. I have in my hand some +microscopic bubbles of quartz showing all the perfection +of form and color that we are familiar with in the +soap bubble.</p> + +<p>An invaluable property of quartz is its power of insulating +perfectly, even in an atmosphere saturated +with water. The gold leaves now diverging were +charged some time before the lecture, and hardly show +any change, yet the insulator is a rod of quartz only +three-quarters of an inch long, and the air is kept +moist by a dish of water. The quartz may even be +dipped in the water and replaced with the water upon +it without any difference in the insulation being observed.</p> + +<p>Not only can fibers be made of extreme fineness, but +they are wonderfully uniform in diameter. So uniform +are they that they perfectly stand an optical test so +severe that irregularities invisible in any microscope +would immediately be made apparent. Every one +must have noticed when the sun is shining upon a border +of flowers and shrubs how the lines which spiders +use as railways to travel from place to place glisten +with brilliant colors. These colors are only produced +when the fibers are sufficiently fine. If you take one +of these webs and examine it in the sunlight, you will +find that the colors are variegated, and the effect, consequently, +is one of great beauty.</p> + +<p>A quartz fiber of about the same size shows colors in +the same way, but the tint is perfectly uniform on the +fiber. If the color of the fiber is examined with a +prism, the spectrum is found to consist of alternate +bright and dark bands. Upon the screen are photographs +taken by Mr. Briscoe, a student in the laboratory +at South Kensington, of the spectra of some of +these fibers at different angles of incidence. It will be +seen that coarse fibers have more bands than fine, +and that the number increases with the angle of incidence +of the light. There are peculiarities in the +march of the bands as the angle increases which I +cannot describe now. I may only say that they appear +to move not uniformly, but in waves, presenting +very much the appearance of a caterpillar walking.</p> + +<p>So uniform are the quartz fibers that the spectrum +from end to end consists of parallel bands. Occasionally +a fiber is found which presents a slight irregularity +here and there. A spider line is so irregular that +these bands are hardly observable; but, as the photograph +on the screen shows, it is possible to trace them +running up and down the spectrum when you know +what to look for.</p> + +<p>To show that these longitudinal bands are due to the +irregularities, I have drawn a taper piece of quartz by +hand, in which the two edges make with one another +an almost imperceptible angle, and the spectrum of +this shows the gradual change of diameter by the very +steep angle at which the bands run up the spectrum.</p> + +<p>Into the theory of the development of these bands I +am unable to enter; that is a subject on which your +professor of natural philosophy is best able to speak. +Perhaps I may venture to express the hope, as the experimental +investigation of this subject is now rendered +possible, that he may be induced to carry out a +research for which he is so eminently fitted.</p> + +<p>Though this is a subject which is altogether beyond +me, I have been able to use the results in a practical +way. When it is required to place into an instrument +a fiber of any particular size, all that has to be done is +to hold the frame of fibers toward a bright and distant +light, and look at them through a low-angled +prism. The banded spectra are then visible, and it is +the work of a moment to pick out one with the number +of bands that has been found to be given by a fiber +of the desired size. A coarse fiber may have a dozen +or more, while such fibers as I find most useful have +only two dark bands. Much finer ones exist, showing +the colors of the first order with one dark band; and +fibers so fine as to correspond to the white or even the +gray of Newton's scale are easily produced.</p> + +<p>Passing now from the most scientific test of the +uniformity of these fibers, I shall next refer to one +more homely. It is simply this: The common garden +spider, except when very young, cannot climb up one +of the same size as the web on which she displays such +activity. She is perfectly helpless, and slips down +with a run. After vainly trying to make any headway, +she finally puts her hands (or feet) into her mouth +and then tries again, with no better success. I may +mention that a male of the same species is able to run +up one of these with the greatest ease, a feat +which may perhaps save the lives of a few of these +unprotected creatures when quartz fibers are more +common.</p> + +<p>It is possible to make any quantity of very fine +quartz fiber without a bow and arrow at all, by simply +drawing out a rod of quartz over and over again +in a strong oxyhydrogen jet. Then, if a stand of any +sort has been placed a few feet in front of the jet, it +will be found covered with a maze of thread, of which +the photograph on the screen represents a sample. +This is hardly distinguishable from the web spun by +this magnificent spider in corners of greenhouses and +such places. By regulating the jet and the manipulation, +anything from one of these stranded cables to +a single ultro-microscope line may be developed.</p> + +<p>And now that I have explained that these fibers +have such valuable properties, it will no doubt be expected +that I should perform some feat with their aid +which, up to the present time, has been considered impossible, +and this I intend to do.</p> + +<p>Of all experiments, the one which has most excited +my admiration is the famous experiment of Cavendish, +of which I have a full size model before you. The object +of this experiment is to weigh the earth by comparing +directly the force with which it attracts things +with that due to large masses of lead. As is shown by +the model, any attraction which these large balls exert +on the small ones will tend to deflect this 6 ft. beam +in one direction, and then if the balls are reversed in +position, the deflection will be in the other direction. +Now, when it is considered how enormously greater +the earth is than these balls, it will be evident that +the attraction due to them must be in comparison excessively +small. To make this evident, the enormous +apparatus you see had to be constructed, and then, +using a fine torsion wire, a perfectly certain but small +effect was produced. The experiment, however, could +only be successfully carried out in cellars and underground +places, because changes of temperature produced +effects greater than those due to +gravity.<a name="FNanchor_07_2" id="FNanchor_07_2"></a><a href="#Footnote_07_2"><sup>2</sup></a></p> + +<p>Now I have in a hole in the wall an instrument no +bigger than a galvanometer, of which a model is on +the table. The balls of the Cavendish apparatus, +weighing several hundredweight each, are replaced by +balls weighing 1¾ pounds only. The smaller balls of +1¾ pounds are replaced by little weights of 15 grains +each. The 6 foot beam is replaced by one that will +swing round freely in a tube three-quarters of an inch +in diameter. The beam is, of course, suspended by a +quartz fiber. With this microscopic apparatus, not +only is the very feeble attraction observable, but I can +actually obtain an effect eighteen times as great as +that given by the apparatus of Cavendish, and what +is more important, the accuracy of observation is +enormously increased.</p> + +<p>The light from a lamp passes through a telescope +lens, and falls on the mirror of the instrument. It is +reflected back to the table, and thence by a fixed +mirror to the scale on the wall, where it comes to a +focus. If the mirror on the table were plane, the whole +movement of the light would be only about eight +inches, but the mirror is convex, and this magnifies +the motion nearly eight times. At the present moment +the attracting weights are in one extreme position, +and the line of light is quiet. I will now move +them to the other position, and you will see the result—the +light slowly begins to move, and slowly increases +in movement. In forty seconds it will have acquired +its highest velocity, and in forty more it will have +stopped at 5 feet 8½ inches from the starting point, +after which it will slowly move back again, oscillating +about its new position of rest.</p> + +<p>It is not possible at this hour to enter into any calculations; +I will only say that the motion you have +seen is the effect of a force of less than one ten-millionth +of the weight of a grain, and that with this +apparatus I can detect a force two thousand times +smaller still. There would be no difficulty even in +showing the attraction between two No. 5 shot.</p> + +<p>And now, in conclusion, I would only say that if +there is anything that is good in the experiments to +which I have this evening directed your attention, experiments +conducted largely with sticks, and string, +and straw and sealing wax, I may perhaps be pardoned +if I express my conviction that in these days we are too +apt to depart from the simple ways of our fathers, and +instead of following them, to fall down and worship +the brazen image which the instrument maker hath +set up.</p> + +<p><a name="Footnote_07_1" id="Footnote_07_1"></a><a href="#FNanchor_07_1">[1]</a></p> +<div class="note">Lecture delivered at the Royal Institution, on Friday, +June 14, by Mr. C. V. Boys, F.R.S.—<i>Nature.</i></div> + +<p><a name="Footnote_07_2" id="Footnote_07_2"></a><a href="#FNanchor_07_2">[2]</a></p> +<div class="note">Dr. Lodge has been able, by an elaborate arrangement +of screens, to make this attraction just evident to an audience.—C. V. B.</div> + +<hr /> + + + + +<h2><a name="art08" id="art08"></a>NATURE, COMPOSITION, AND TREATMENT +OF ANIMAL AND VEGETABLE FABRICS.</h2> + + +<p>The inseparable duties of studying the composition +of the various animal and vegetable fabrics, as also +their nature—when in contact with the various mineral, +vegetable, animal, and gaseous bodies applied in +the individual industries—should not devolve upon the +heads, chemists, or managers of firms alone. It is +most important that every intelligent workman, whom +we cannot expect to acquire a very extensive knowledge +of chemistry and perfect acquaintance of the +particular nature and component parts of fabrics, +should, at least, be able to thwart the possibility of the +majority of accidents brought about in regard to the +quality and aspect of materials treated by them.</p> + +<p>In the treatment of wool the first operations are of +no mean importance, and the whole subsequent operations +and final results, almost as a whole, depend on +the manner in which the fleece washing had been +effected. In presence of suintine, as also fatty matters, +as well as the countless kinds of acids deposited on the +wool through exudation from the body, etc., the +various agents and materials cannot act and deposit as +evenly as might be desired, and the complete obliteration +of the former, therefore, becomes an absolute +necessity.</p> + +<p>For vegetable fabrics a great technical and practical +knowledge is already requisite in their cultivation itself, +and before any operations are necessary at all. +One of the greatest points is the ripeness of the fibers. +It is almost an impossibility to produce delicate colors +on vegetable fabrics which were gathered inopportunely. +Numerous experiments have been made on cotton +containing smaller or larger quantities of unripe fibers, +and after the necessary preceding operations, have +been dyed in rose, purple, and blue colors, and the +beauty of the shades invariably differed in proportion +to the greater or lesser quantities of unripe fibers contained +in the samples, and by a careless admixture of +unripe and unseasoned fibers the most brilliant colors +have been completely spoiled in the presence of the +former. These deficiencies of unripe vegetable fibers +are so serious that the utmost precautions should be +taken, not only by planters to gather the fibers in a +ripe state, but the natural aspect of ripe and unripe +fibers and their respective differences should be known +to the operators of the individual branches in the cotton +industry themselves.</p> + +<p>The newest vegetable fabrics, as <i>ma</i> (China grass), +pina, <i>abaca</i>, or Manila hemp, <i>agave</i>, jute, and that obtained +from the palm tree, must be tended with equal +care to that of cotton. The <i>ma</i>, or China grass, is obtained +from the <i>Boehmeria nivea</i>, as also from the less +known <i>Boehmeria puya</i>. The fibers of this stalk, after +preparing and bleaching, have the whiteness of snow +and the brilliancy of silk. By a special process—the +description of which we must for the present leave in +abeyance—the China grass can be transformed into a +material greatly resembling the finest quality of wool. +The greatest advantage afforded in the application of +China grass is, moreover, that the tissues produced +with this fiber are much more easily washed than silks, +and in this operation they lose none of their beauty or +their quality.</p> + +<p>The <i>abaca</i> is produced from the fibrous parts of the +bark of the wild banana tree, found in the Philippines. +Its botanical denomination is <i>Musa troglodytarum</i>. +The <i>abaca</i> fiber is not spun or wrung, but is jointed +end to end. The threads are wound and subsequently +beaten for softening, and finally bleached by plunging +in lime water for twenty-four hours, and dried in the +sun.</p> + +<p>The <i>pina</i> is a fiber obtained from the leaf of the +anana tree (<i>Bromelias ananas</i>), and is prepared in the +same way as the abaca, but extreme care must in this +case be observed in culling the fibers, in order to sort +in accordance with their degree of fineness.</p> + +<p>The Arabs manufacture the stuff for their tents with +a mixture of camel's hair and the fibrous flocks (kind +of wadding) obtained from the stalks of the wafer +palm (the <i>Chamærops humilis</i>).</p> + +<p>The tissues used by the Arabs are coarse and colored, +but the palm fibers—when freed from gluten, which +makes them adhere more strongly—are susceptible to +divide in a most astonishing manner.</p> + +<p>The <i>Agave americana</i> is a coarse fiber, mostly used +in France for the manufacture of Gobelin carpets and +the production of ropes. Great efforts have been made +to bleach it in a satisfactory manner, as is done with +the <i>Phormium tenax</i>, but the former kind of fiber resists +the ordinary treatment with lyes, etc., and an appropriate +bleaching process has only been discovered +quite recently.</p> + +<p>Jute, which by many is confounded with <i>Phormium +tenax</i>, or New Zealand lint, is a fiber which can be +divided as finely as desired, and can be most beautifully +bleached.</p> + +<p>The jute or Indian <i>paat</i> is generally known as a +fibrous and textile fabric, obtained chiefly from Calcutta, +and is similar in nature to the <i>Corchorus capsularis</i>, +an Oriental species, known in Oriental India by +the name of <i>hatta jute</i> and <i>gheenatlapaat</i>. This fibrous +plant has the property of dividing into the finest parallel +fibers, which can be carded without difficulty, +and may be said to have the excellent properties of +linen, hemp, and cotton at once. When properly +bleached, it has an aspect which is as beautiful as that +of silk. A mixture of silk and jute can be easily +<a name="Page_11454" id="Page_11454"></a> +worked together, and can also be mixed with such +vegetable fibers as cotton and linen. An immense +quantity of flannel and other stuffs are now manufactured +and imitated with the different mixtures containing +jute.</p> + +<p>The <i>suun</i> is a fiber of a plant in the form of a cane +(<i>Crotalaria juncea</i>), and the paat or <i>suncheepaat</i> is the +thread of a species of spiral (<i>Corchorus olitarius</i>), sold +under the name of jute tissues.</p> + +<p>The cotton tissues lose about twenty-five per cent. of +their weight in bleaching, five per cent. of the substances +are dissolved through alkalies, and the other +twenty per cent., which are not attacked directly +through the alkalies, are removed through chlorine, +acids, and the water itself. The linen and hemp tissues +contain eighteen per cent. of substances which +are soluble in alkalies, and they lose from twenty-seven +to thirty per cent. of their weight when taken through +the consecutive bleaching operations.</p> + +<p>The substances do not alone include the substances +contained in the fabric originally, but also such as are +deposited in the preliminary treatment of the fabrics, +as dirt from the hands of the operator, and gluten +soluble in warm water; as also glue or gelatine, potash +or soda, starch, albumen, and sugar, used by +weavers, etc., and which are all soluble in water; further, +such as greasy matters, calcareous soap, coppery +soap, resinous or gummo-resinous matters, and the yellow +and green coloring matters contained in textile +fabrics, which are soluble in caustic soda; and finally, +the earthy constituents which are soluble in acids.</p> + +<p>The nature and composition of silk and wool is diametrically +opposed to that of the former. The silk is +more of a gummy nature, and is susceptible to decompose +into a kind +of <ins class="correction" title="Transcriber's Note: original reads 'galatinous'">gelatinous</ins> +mass if specially treated.</p> + +<p>The yellow coloring principle in silk was found only +to be contained in a very small proportion, and consisting +of several distinct bodies.</p> + +<p>The wool contains, first, a fatty matter which is +solid at an ordinary temperature, and perfectly liquid +at 60° C.; secondly, a fatty matter which is liquid at +15° C.; thirdly, a fibrous substance which essentially +constitutes the wool in the strict sense of the word.</p> + +<p>The wool at least contains three important principles, +as it will be known that the fibrous substance disengages +sulphur and hydro-sulphuric acid without losing +its peculiar properties; and it, therefore, appears probable +that the sulphur entered as an element in the +composition of a body which is perfectly distinct from +the fibrous substance aforementioned.</p> + +<p>In treating wool with nitric acid, and taking all possible +precautions to determine as accurately as possible +the quantity of sulphuric acid produced by the +contents of sulphur in the wool by the reaction with +chloride of barium, it will be found to contain from +1.53 to 1.87 per cent. of sulphur.—<i>Wool and Textile +Fabrics.</i></p> + +<hr /> + + + + +<h2><a name="art09" id="art09"></a> +THE PRODUCTION OF AMMONIA FROM COAL.<a name="FNanchor_09_1" id="FNanchor_09_1"></a><a href="#Footnote_09_1"><sup>1</sup></a></h2> + +<h3>By <span class="sc">Ludwig Mond.</span></h3> + + + +<p>As exemplifying to a certain extent the application +of methodical research to an industrial problem, I propose +to bring before you to-day an account of the work +I have been engaged in for many years in relation to +the procuring of new and abundant supplies of ammonia, +and to investigations connected therewith.</p> + +<p>Through the classic researches of Lawes and Gilbert, +who proved, in opposition to no less an authority than +Liebig, that ammonia is a most valuable manure which +enables us not only to maintain, but to multiply, the +yield of our fields, and thus to feed on the same area a +much larger number of inhabitants, the immense importance +of an abundant supply of ammonia, more +particularly for the Old World, with its teeming population +and worn-out soil, has been apparent to every +one.</p> + +<p>For many years Europe has paid to South America +millions upon millions of pounds for ammonia in the +shape of guano, and more recently, since the supply of +guano practically ceased, for nitrate of soda, which +effectually serves the same purpose as ammonia. During +the past year South America exported 750,000 tons +of nitrate, of which 650,000 went to Europe, representing +a value of not less than 6,500,000<i>l.</i></p> + +<p>The problem of saving this immense expenditure to +Europe, of making ourselves independent of a country +so far away for the supply of a material upon which +the prosperity of our agriculture—our most important +industry—depends, by supplying this ammonia from +sources at our own command, is certainly one of the +most important which our science has to solve.</p> + +<p>It is more than 100 years since Berthollet ascertained +that ammonia consists of nitrogen and hydrogen, two +elements which we have in great abundance at our +command, and innumerable attempts have been made +during this century to produce this valuable product +by the direct combination of the elements, as well as +by indirect means. It has been equally well known +that we are in possession of three abundant sources of +nitrogen:</p> + +<div class="ind"> +<p>(1.) In the shape of matter of animal origin.</p> + +<p>(2.) In the shape of matter of vegetable origin.</p> + +<p>(3.) In the atmosphere, which contains no less than +79 per cent. of uncombined nitrogen.</p> +</div> + +<p>In olden times ammonia was principally obtained +from animal matter, originally in Egypt by the distillation +of camel dung, later on from urine, and from +the distillation of bones and horn. The quantity so +obtained was very small and the products very expensive. +The introduction of coal gas for illumination +gave us a considerable and constantly increasing supply +of ammonia as a by-product of the gas manufacture, +and until recently all practical efforts to increase +our supply of ammonia were directed toward collecting +and utilizing in the best possible manner the ammonia +so obtained. The immense extension of the coal gas +industry all over the world has in this way put us into +possession of a very considerable amount of sulphate of +ammonia, amounting in Europe now to 140,000 tons +per annum. In recent years this has been augmented +by the ammonia obtained by the distillation of shale, +by the introduction of closed ovens for the manufacture +of coke, combined with apparatus for condensing the +ammonia formed in this manufacture, and also by the +condensation of the ammonia contained in the gases +from blast furnaces working with coal. But all these +new sources have so far added only about 40,000 tons +of sulphate of ammonia to our supply, making a total +of 180,000 tons per annum, of which about 120,000 are +produced in the United Kingdom, while we still import +650,000 tons of nitrate of soda, equivalent to +500,000 tons of sulphate of ammonia, to make up our +requirements.</p> + +<p>Many processes have from time to time been proposed +to obtain ammonia from other sources. The distillation +of turf, which contains upward of 3 per cent. of nitrogen, +has received much attention, and a large number +of inventors have endeavored to produce ammonia from +the nitrogen of the air; but none of these processes has +to my knowledge been successful on a manufacturing +scale.</p> + +<p>My attention was called to this subject at an early +part of my career. Already, as far back as 1861, I undertook +experiments to utilize, for the production of +ammonia, waste leather, a waste material of animal +origin at once abundant and very rich in nitrogen, +containing from 12 per cent. to 15 per cent. of this +element. Distillation in iron retorts yielded about +half the nitrogen of this material in the form of ammonia, +the carbon remaining in the retorts containing +still from 6 per cent. to 8 per cent. Distillation with a +moderate quantity of hydrate of lime increased the +yield of ammonia only by 1 per cent. to 1½ per cent. +A rather better result was obtained by distilling the +ground residual carbon with hydrate of lime, but this +operation proceeded very slowly, and the total yield of +ammonia still remained very far below the quantity +theoretically obtainable, so that I came to the conclusion +that it was more rational to utilize the leather, +reduced to powder by mechanical means, by mixing it +directly with other manures.</p> + +<p>A few years later I became connected with a large +animal charcoal works, in which sulphate of ammonia +was obtained as a by-product. Here again I was met +with the fact that the yield of ammonia by no means +corresponded with the nitrogen in the raw material +and that the charcoal remaining in the retorts contained +still about half as much nitrogen as had been +present in the bones used.</p> + +<p>From this time forward my attention was for many +years given exclusively to the soda manufacture, and +it was only in 1879 that I again took up the question +of ammonia. I then determined to submit the various +processes which had been proposed for obtaining +ammonia from the nitrogen of the air to a searching +investigation, and engaged Mr. Joseph Hawliczek to +carry out the experimental work.</p> + +<p>These processes may be broadly divided into three +classes:</p> + +<div class="ind"> +<p>(1.) Processes which propose to combine nascent hydrogen +with nitrogen at high temperatures or +by electricity, with or without the presence of acid +gases.</p> + +<p>(2.) Processes in which nitrides are first formed, from +which ammonia is obtained by the action of hydrogen +or steam.</p> + +<p>(3.) Processes in which cyanides are first formed and +the ammonia obtained from these by the action of +steam.</p> +</div> + +<p>We began with an investigation of those processes +in which a mixture of steam and nitrogen or of steam +and air is made to act upon coke at a high temperature, +sometimes in the presence of lime, baryta, or an alkali, +sometimes in the presence of hydrochloric acid.</p> + +<p>Very numerous patents have been taken out in this +direction and there is no doubt that ammonia has been +obtained by these processes by many inventors, but as +I was aware that coke contains a considerable quantity +of nitrogen, frequently as much as 1.5 per cent., which +might be the source of the ammonia obtained, I determined +to carry on the investigation in such a way as +to make quite certain whether we obtained the ammonia +from the coke or from the nitrogen of the atmosphere, +or from both. For this purpose we made for +every experiment carried on by a mixture of nitrogen +or air with steam another experiment with steam alone, +carefully excluding nitrogen from the apparatus. A +very large number of experiments carried on at carefully +determined temperatures, ranging from 500° to +1,200°C., and in which the directions given by the various +inventors were most carefully observed, all led to +the same result, viz., that the quantities of ammonia +obtained were the same whether nitrogen was introduced +into the apparatus with the steam or whether +steam alone was used, thus proving conclusively that +the ammonia obtained was derived from the nitrogen +contained in the coke.</p> + +<p>Further, on carefully determining the nitrogen in +the coke used, it was found that the quantity of +ammonia we had obtained in burning coke in a current +of nitrogen and steam very nearly corresponded with +the total nitrogen in the coke, so that we subsequently +made our nitrogen determinations in the coke by simply +burning it in a current of steam.</p> + +<p>A process belonging to this class, proposed by Hugo +Fleck, in which a mixture of carbonic oxide, steam, +and nitrogen is made to pass over lime at a moderate +red heat in order to obtain ammonia, was also carefully +tried. It was claimed for this process that it produced +nascent hydrogen at temperatures at which the +ammonia is not dissociated, and for this reason succeeded +where others had failed. We found that a considerable +amount of hydrogen was obtained in this way at +a temperature not exceeding 350°C., and that the reaction +was nearly complete at 500°C.; but although we +tried many experiments over a great range of temperatures, +we never obtained a trace of ammonia by this +process.</p> + +<p>Among experiments with processes of the second +class, based upon the formation of nitrides and their +subsequent decomposition, the nitrides of boron and +titanium had received most attention from inventors. +The nitride of boron, which is obtained by treating +boracic acid with carbon in the presence of nitrogen, +when acted upon by steam, forms boracic acid again +and yields the whole of its nitrogen in the form of +ammonia, but the high temperature at which the first +reaction takes place, and the volatility of boracic acid +in a current of steam, make it impossible to utilize this +reaction industrially.</p> + +<p>There seemed to be a better chance for a process +patented by M. Tessier du Mothay, who proposed to +bring a mixture of nitrogen and hydrogen into contact +with titanium nitride and thus to form ammonia continuously. +Titanium is the only element of which +we know at present several combinations with nitrogen, +and the higher of these does, on being acted upon +by a current of hydrogen at an elevated temperature, +produce ammonia and a lower nitride of titanium; but +this lower nitride does not absorb nitrogen under any +of the conditions under which we tried it, which explains +the fact that if we passed a current of hydrogen +and nitrogen over the higher nitride, we at first obtained +a quantity of ammonia corresponding to the +quantity which the nitride would give with hydrogen +alone, but that the formation of ammonia then ceased +completely.</p> + +<p>Thus far we had quite failed to get the nitrogen of +the air into action.</p> + +<p>With the third class of processes, however, based +upon the formation in the first instance of cyanides, +we found by our very first experiments that the nitrogen +of the atmosphere can be easily led into combination. +A few experiments showed that the cyanide of +barium was much more readily formed than any other +cyanide; so we gave our full attention from this time +to the process for obtaining ammonia by means of +cyanide of barium invented by MM. Margueritte and +Sourdeval. This process consists in heating a mixture +of carbonate of barium with carbon in the presence of +nitrogen, and subsequently treating the cyanide of +barium produced with steam, thus producing ammonia +and regenerating the carbonate of barium. A +great difficulty in this process is that the carbonate of +barium fuses at high temperatures, and when fused +attacks fireclay goods very powerfully.</p> + +<p>We found that this can be overcome by mixing the +carbonate of barium with a sufficient quantity of carbon +and a small quantity of pitch, and that in this +way balls can be made which will not fuse, so that +they can be treated in a continuous apparatus in which +the broken briquettes can be charged from the top, +and after treatment can be withdrawn from the +bottom.</p> + +<p>We found that the formation of cyanides required a +temperature of at least 1,200° C., and proceeded most +readily at 1,400° C., temperatures which, although difficult +to attain, are still quite within the range of practical +working, and we found no difficulty in obtaining a +product containing 30 per cent. of barium cyanide, +corresponding to a conversion into cyanide of 40 per +cent. of the barium present.</p> + +<p>We found, however, that the cyanide when exposed +to the atmosphere at a temperature above 300° C. is +readily destroyed under reformation of carbonate of +barium, so that it is absolutely necessary to cool it +down to this temperature before exposing it to the +atmosphere, a fact of great importance that had +hitherto been overlooked.</p> + +<p>The operation for producing ammonia and regenerating +the carbonate of barium by acting upon the +cyanide with steam offers no difficulty whatever, and +if the temperature is not allowed to exceed 500° C., the +results are quantitative. The regenerated carbonate +of barium acts actually better than the ground witherite +used in the first instance, and if care is taken that +no impurities are introduced by the pitch which is +used to remake the briquettes and to replace the small +amount of carbon consumed at each operation, I see +no reason why it should not continue to act for a very +long time.</p> + +<p>The cyanide is not acted on by carbonic oxide, but +carbonic acid destroys it at high temperatures, so that +it is not possible to produce it by heating the briquettes +directly in a flame free from oxygen, but containing +carbonic acid. The process has, therefore, to +be carried out in closed vessels, and I designed for this +purpose the following apparatus:</p> + +<p>Clay retorts of moderate dimensions and thin walls +are placed vertically in a furnace, passing through the +hearth as well as through the arch of the furnace. +These are joined at the bottom to cast iron retorts of +the same shape as the earthenware retort. Through a +cast iron mouthpiece on the top of the retort the material +was introduced, while in the cast iron retort below +the material was cooled to the necessary temperature +by radiation and by the cold nitrogen gas introduced +into the bottom of it. The lower end of the cast iron +retort was furnished with an arrangement for taking +out from time to time small quantities of the material, +while fresh material was in the same proportion fed in +at the top. As a source of nitrogen I used the gases +escaping from the carbonating towers of the ammonia-soda +process. The formation of cyanide of barium +from barium carbonate, carbon, and nitrogen absorbs +a very large amount of heat—no less than 97,000 calories +per equivalent of the cyanide formed—which heat +has to be transmitted through the walls of the retort. +I therefore considered it necessary to use retorts with +very thin walls, but I did not succeed in obtaining +retorts of this description which would resist the very +high temperatures which the process requires, and for +this reason I abandoned these experiments. I was at +that time not acquainted with the excellent quality of +clay retorts used in zinc works, with which I have +since experimented for a different purpose. I have no +doubt that with such retorts the production of cyanides +by this process can be carried out without great +difficulty.</p> + +<p>I believe that the process will prove remunerative +for the manufacture of cyanogen products, which, if +produced more cheaply, may in the future play an important +role in organic synthesis, in the extraction of +noble metals, and possibly other chemical and metallurgical +operations.</p> + +<p>The process certainly also offers a solution of the +problem of obtaining ammonia from the nitrogen of +the atmosphere, but whether this can be done with +satisfactory commercial results is a question I cannot at +present answer, as I have not been able to secure the +data for making the necessary calculations.</p> + +<p>I am the more doubtful about this point, as in the +course of our investigations I have found means to produce +ammonia at small cost and in great abundance +from the immense store of combined nitrogen which we +possess in our coal fields.</p> + +<p>Among the processes for obtaining ammonia from the +nitrogen of the air which we investigated, was one apparently +of great simplicity, patented by Messrs. Rickman +and Thompson. These gentlemen state that by +passing air and steam through a deep coal fire, the +nitrogen so passed through is to a certain extent converted +into ammonia. In investigating this statement +we found that the process described certainly yields a +considerable quantity of ammonia, but when we +burned the same coal at a moderate temperature by +<a name="Page_11455" id="Page_11455"></a> +means of steam alone in a tube heated from the outside, +we obtained twice as much ammonia as we had done +by burning it with a mixture of air and steam, proving +in this case, as in all others, the source of the ammonia +to have been the nitrogen contained in the coal. The +quantity of ammonia obtained was, however, so large +that I determined to follow up this experience, and at +once commenced experiments on a semi-manufacturing +scale to ascertain whether they would lead to practical +and economic results.</p> + +<p>I came to the conclusion that burning coal by steam +alone at a temperature at which the ammonia formed +should not be dissociated, although it yielded more +ammonia, would not lead to an economic process, because +it would require apparatus heated from the outside, +of great complication, bulk, and costliness, on account +of the immense quantity of raw material to be +treated for a small amount of ammonia obtainable.</p> + +<p>On the other hand, if the coal could be burned in +gas producers by a mixture of air and steam, the plant +and working of it would be simple and inexpensive, the +gas obtained could be utilized in the same way as ordinary +producer gas, and would pay to a large extent +for the coal used in the operation, so that although +only one-half of the ammonia would be obtained, it +seemed probable that the result would be economical.</p> + +<p>I consequently constructed gas producers and absorbing +plant of various designs and carried on experiments +for a number of years. These experiments were +superintended by Mr. G. H. Beckett, Dr. Carl Markel, +and, during the last four years, by Dr. Adolf Staub, to +whose zeal and energy I am much indebted for the success +that has been achieved. The object of these experiments +was to determine the most favorable conditions +for the economic working of the process with +respect to both the cost of manufacture as well as the +first cost and simplicity of plant. The cost of manufacture +depends mainly upon the yield of ammonia, as +the expenses remain almost the same whether a large +or a small amount of ammonia is obtained; the only +other item of importance is the quantity of steam used +in the process. We found the yield of ammonia to +vary with the temperature at which the producer was +working, and to be highest when the producer was +worked as cool as was compatible with a good combustion +of the fuel. The temperature again depended upon +the amount of steam introduced into the producer, +and of course decreased the more steam increased. We +obtained the best practical results by introducing +about two tons of steam for every ton of fuel consumed. +We experimented upon numerous kinds of +fuel, common slack and burgy of the Lancashire, Staffordshire, +and Nottinghamshire districts. We found +not much difference in the amount of nitrogen contained +in these fuels, which varied between 1.2 and 1.6 +per cent., nor did we find much difference in the ammonia +obtained from these fuels if worked under similar +conditions. Employing the quantity of steam just +named we recovered about half the nitrogen in the form +of ammonia, yielding on an average 0.8 per cent. of ammonia, +equal to 32 kilos, of sulphate per ton of fuel. +In order to obtain regular results we found it necessary +to work with a great depth of fuel in the producers, so +that slight irregularities in the working would not +affect results. Open burning kinds of slack do of +course work with the greater ease, but there is no +difficulty in using a caking fuel, as the low temperature +at which the producers work prevents clinkering and +diminishes the tendency of such fuels to cake together.</p> + +<p>The quantity of steam thus required to obtain a +good yield of ammonia is rather considerable, and +threatened to become a serious item of expense. Only +one-third of this steam is decomposed, in its passage +through the producer, and two-thirds remain mixed +with the gases which leave the producer. My endeavors +were consequently directed toward finding means +to recover this steam, and to return it to the producers, +and also to utilize the heat of the gases which leave the +producers with a temperature of 450° to 500° C., for +raising steam for the same purpose. The difficulties in +the way of attaining this end and at the same time of +recovering, in a simple manner, the small amount of +ammonia contained in the immense volume of gas we +have to deal with, were very great. We obtain from +one ton of coal 160,000 cubic feet of dry gas at 0° C. and +atmospheric pressure. The steam mixed with this gas +as it leaves the producer adds another 80,000 cubic feet +to this, and the large amount of latent heat in this +quantity of steam makes the problem still more difficult. +The application of cooling arrangements, such +as have been successfully applied to blast furnace gases, +in which there is no steam present, and which depend +upon the cooling through the metallic sides of the apparatus, +is here practically out of the question. After +trying a number of different kinds of apparatus, I have +succeeded in solving the problem in the following +way:</p> + +<p>The gases issuing from the producers are led through +a rectangular chamber partly filled with water, which +is thrown up in a fine spray by revolving beaters so as +to fill the whole area of the chamber. This water, of +course, becomes hot; a certain quantity of it evaporates, +the spray produced washes all dust and soot out +of the gases, and also condenses the fixed ammonia. +The water thus becomes, to a certain degree, saturated +with ammonia salts, and a certain portion of it is regularly +removed from the chamber and distilled with lime +to recover the ammonia.</p> + +<div class="figcenter"> +<a href="./images/09_1.png"> +<img src="./images/09_1_th.png" width="542" height="400" alt="Longitudinal Section of Plant for obtaining Ammonia from Gas Producers. Cross Section through Gas Producers." /> +</a> + +<p class="caption">Longitudinal Section of Plant for obtaining Ammonia +from Gas Producers.<br /> +Cross Section through Gas Producers.</p> +</div> + +<p>This chamber is provided with water lutes, through +which the tar condensed in it is from time to time removed. +From this chamber the gases, which are now +cooled down to about 100° C., and are loaded with a +large amount of water vapor, are passed through a +scrubber filled with perforated bricks, in which the +ammonia contained in the gases is absorbed by sulphuric +acid. In this scrubber a fairly concentrated +solution of sulphate of ammonia containing 36 to 38 +per cent. is used, to which a small quantity of sulphuric +acid is added, so that the liquid leaving the +scrubber contains only 2.5 per cent. of free acid. This +is necessary, as a liquid containing more acid would +act upon the tarry matter and produce a very dark-colored +solution. The liquid running from the scrubber +is passed through a separator in which the solution +of sulphate of ammonia separates from the tar. The +greater portion of the clear liquid is, after adding a +fresh quantity of acid to it, pumped back through the +scrubber. A certain portion of it is, after treatment +with a small quantity of heavy tar oils, which take +the tarry matter dissolved in it out, evaporated in conical +lead-lined pans furnished with lead steam coils, and +which are kept constantly filled by the addition of +fresh liquor until the whole mass is thick. This is then +run out on a strainer and yields, after draining and +washing with a little water, a sulphate of ammonia of +very fair quality, which finds a ready sale. The +mother liquor, which contains all the free acid, is +pumped back to the scrubber.</p> + +<p>The gas on entering this scrubber contains only 0.13 +volume per cent. of ammonia, and on leaving the scrubber +it contains not more than one-tenth of this quantity. +Its temperature has been reduced to 80° C., and +is fully saturated with moisture, so that practically no +condensation of water takes place in the scrubber. +The gas is next passed through a second scrubber filled +with perforated wood blocks. In this it meets with a +current of cold water which condenses the steam, the +water being thereby heated to about 78° C. In this +scrubber the gas is cooled down to about 40°-50° C., +and passes from it to the gas main leading to the various +places where it is to be consumed. The hot water +obtained in this second scrubber is passed through a +vessel suitably constructed for separating the tar which +is mixed with it, and is then pumped through a third +scrubber, through which, in an opposite direction to +the hot water, cold air is passed. This is forced by +means of a Roots blower through the scrubber into the +producer.</p> + +<p>The air gets heated to about 76° C. and saturated +with moisture at that temperature by its contact with +the hot water, and the water leaves this third scrubber +cold enough to be pumped back through the second +scrubber. The same quantity of water is thus constantly +used for condensing the water vapor in one +scrubber and giving it up to the air in the other. In +this way we recover and return to the producer fully +two-thirds of the steam which has been originally introduced, +so that we have to add to the air, which has +thus been loaded with moisture, an additional quantity +of steam equal to only one-third of the total quantity +required before it enters the producer. This additional +quantity of steam, which amounts to 0.6 ton of +steam for every ton of fuel burnt, we obtain as exhaust +steam from the engines driving the blowers and pumps +required for working the plant.</p> + +<p>The gas producers which I prefer to use are of rectangular +shape, so that a number of them can be put into +a row. They are six feet wide and 12 feet long inside. +The air is introduced and the ashes removed at the +two small sides of the producer which taper toward +the middle and are closed at the bottom by a water +lute of sufficient depth for the pressure under which +the air is forced in, equal to about 4 inches of water. +The ashes are taken out from underneath the water, +the producers having no grate or fire bars at all. The +<a name="Page_11456" id="Page_11456"></a> +air enters just above the level of the water through a +pipe connected with the blower. These small sides of +the producer rest upon cast iron plates lined to a certain +height with brickwork, and this brickwork is carried +by horizontal cast iron plates above the air entrance. +In this way a chamber is formed of triangular +shape, one side of which is closed by the ashes, and +thus the air is distributed over the whole width of the +producer.</p> + +<p>The gas is taken out in the middle of the top of the +producer by an iron pipe, and fuel charged in by hoppers +on both sides of this pipe. Between the pipe +and the hoppers two hanging arches are put into +the producers a certain distance down, and the fuel is +kept above the bottom level of these hanging arches. +This compels the products of distillation, produced +when fresh fuel is charged in, to pass through the incandescent +fuel between the two hanging arches, whereby +the tarry products are to a considerable extent converted +into permanent gas, and the coal dust arising +from the charging is kept back in the producer.</p> + +<p>The details of construction of this plant will be easily +understood by reference to the diagrams before you.</p> + +<p>The fuel we use is a common kind of slack, and contains, +on an average, 33.5 per cent. of volatile matter, +including water, and 11.5 per cent. of ashes, leaving 55 +per cent. of non-volatile carbon.</p> + +<p>The cinders which we take out of the producer contain, +on an average, 33 per cent. of carbon. Of this we +recover about one-half by riddling or picking, which +we return to the producer. The amount of unburnt +carbon lost in the cinders is thus not more than 3 per +cent. to 4 per cent. on the weight of fuel used.</p> + +<p>The gas we obtain contains, in a dry state, on an +average, 15 per cent. of carbonic acid, 10 per cent. of +carbonic oxide, 23 per cent. of hydrogen, 3 per cent. of +hydrocarbons, and 49 per cent. of nitrogen.</p> + +<p>The caloric value of this gas is very nearly equal to +73 per cent. of the caloric value of the fuel used, but in +using this gas for heating purposes, such as raising +steam or making salt, we utilize the heat it can give +very much better than in burning fuel, as we can completely +burn it with almost the theoretical quantity of +air, so that the products of combustion resulting do +not contain more than 1 to 2 per cent. of free oxygen. +Consequently the heat escaping into the chimney is +very much less than when fuel is burnt direct, and we +arrive at evaporating, by means of the gas, 85 per cent. +of the water that we would evaporate by burning the +fuel direct, in ordinary fireplaces.</p> + +<p>We have, however, to use a certain quantity of steam +in the producers and in evaporating the sulphate of +ammonia liquors, which has to be deducted from the +steam that can be raised by the gas in order to get at +the quantity of available steam therefrom obtainable. +The former amounts, as already stated, to 0.6 ton, the +latter to 0.1 ton of steam per ton of fuel burnt, making +a total of 0.7 ton. The gas obtained from one ton +of fuel evaporates 5.8 tons of water in good steam boilers, +working at a rate of evaporation of 50 to 55 tons +per 24 hours under 90 lb. pressure. Deducting from +this the 0.7 ton necessary for working the plant leaves +an available amount of steam raised by the gas from +one ton of fuel of 5.1 tons, equal to 75 per cent. of the +steam that we can obtain from the same fuel by hand +firing.</p> + +<p>In addition to the gas, we obtain about 3 per cent. of +tar from the fuel. This tar is very thick, and of little +commercial value. It contains only 4 per cent. of oils +volatile below 200° C., and 38 per cent. of oils of a higher +boiling point, consisting mostly of creosote oils very +similar to those obtained from blast furnaces; and only +small quantities of anthracene and paraffin wax.</p> + +<p>I have made no attempts to utilize this tar except as +fuel. It evaporates nearly twice as much water as its +weight of coal, and we have thus to add its evaporative +efficiency to that of the gas given above, leading to a +total of about 80 per cent. of the evaporative efficiency +of the fuel used in the producers. The loss involved in +gasifying the fuel to recover the ammonia therefrom +amounts thus to 20 per cent. of the fuel used. This +means that, where we have now to burn 100 tons of fuel, +we shall have to burn 125 tons in the producers in order +to obtain ammonia equal to about half the nitrogen +contained therein. Our actual yield of ammonia on a +large scale amounting on an average to 32 kilos., equal +to 70.6 lb. per ton of fuel, 125 tons of fuel will turn out +4 tons of sulphate of ammonia. We thus consume +6.25 tons of fuel for every ton of sulphate obtained, or +nearly the same quantity as is used in producing a ton +of caustic soda by the Le Blanc process—a product not +more than half the value of ammonium sulphate. At +present prices in Northwich this fuel represents a value +of 35<i>s.</i> If we add to this the extra cost of labor over +and above the cost of burning fuel in ordinary fireplaces, +the cost of sulphuric acid, bags, etc., we come to +a total of 4<i>l.</i> 10<i>s.</i> to 5<i>l.</i> per ton of sulphate of ammonia, +which at the present selling price of this article, say +12<i>l.</i> per ton, leaves, after a liberal allowance for wear +and tear of plant, an ample margin of profit. With a +rise in the price of fuel, this margin, however, rapidly +decreases, and the working of the process will, of course, +be much more expensive on a small scale, as will also +be the cost of the plant, which under all circumstances +is very considerable. The great advantages incidental +to this process over and above the profit arising from +the manufacture of sulphate of ammonia, viz., the absolute +impossibility of producing smoke and the great +regularity of the heating resulting from the use of gas, +are, therefore, as far as I can see for the present, only +available for large consumers of cheap fuel.</p> + +<p>We have tried many experiments to produce hydrochloric +acid in the producers, with the hope of thereby +increasing the yield of ammonia, as it is well known +that ammonium chloride vapor, although it consists of +a mixture of ammonia gas and hydrochloric acid gas, +is not at all dissociated at temperatures at which the +dissociation of ammonia alone has already taken place +to a considerable extent.</p> + +<p>I had also hoped that I might in this way produce +the acid necessary to combine with the ammonia at +very small cost. For this purpose we moistened the +fuel used with concentrated brine, and also with the +waste liquors from the ammonia soda manufacture, +consisting mainly of chloride of calcium; and we also +introduced with the fuel balls made by mixing very +concentrated chloride of calcium solution with clay, +which allowed us to produce a larger quantity of +hydrochloric acid in the producer than by the other +methods.</p> + +<p>We did in this way succeed in producing hydrochloric +acid sometimes less and sometimes more than +was necessary to combine with the ammonia, but we +did not succeed in producing with regularity the exact +amount of acid necessary to neutralize the ammonia. +When the ammonia was in excess, we had therefore +to use sulphuric acid as before to absorb this excess, +and we were never certain that sometimes the hydrochloric +acid might not be in excess, which would +have necessitated to construct the whole plant so that +it could have resisted the action of weak hydrochloric +acid—a difficulty which I have not ventured to attack. +The yield of ammonia was not in any case increased +by the presence of the hydrochloric acid. This +explains itself if we consider that there is only a very +small amount of ammonia and hydrochloric acid diffused +through a very large volume of other gases, so +that the very peculiar protective action which the +hydrochloric acid does exercise in retarding the dissociation +of ammonia in ammonium chloride vapor, +where an atom of ammonia is always in contact with +an atom of hydrochloric acid, will be diminished almost +to zero in such a dilute gas where the atoms of +hydrochloric acid and ammonia will only rarely come +into immediate contact with each other.</p> + +<p>When we burnt coke by a mixture of air and steam +in presence of a large excess of hydrochloric acid, the +yield of ammonia certainly was thereby considerably +increased, but such a large excess cannot be used on +an industrial scale. I have therefore for the present +to rest satisfied with obtaining only half the nitrogen +contained in the fuel in the form of ammonia.</p> + +<p>The enormous consumption of fuel in this country—amounting +to no less than 150 million tons per annum—would +at this rate yield as much as five million tons +of sulphate of ammonia a year, so that if only one-tenth +of this fuel would be treated by the process, +England alone could supply the whole of the nitrogenous +compounds, sulphate of ammonia, and nitrate +of soda at present consumed by the Old World. As +the process is especially profitable for large consumers +of fuel situated in districts where fuel is cheap, it +seems to me particularly suitable to be adopted in +this country. It promises to give England the privilege +of supplying the Old World with this all-important +fertilizer, and while yielding a fair profit to the invested +capital and finding employment for a considerable +number of men, to make us, last not least, independent +of the New World for our supply of so indispensable a +commodity.</p> + +<p>Before leaving my subject, I will, if you will allow +me, give you in a few words a description of two other +inventions which have been the outcome of this research. +While looking one day at the beautiful, almost +colorless, flame of the producer gas burning under +one of our boilers, it occurred to me that a gas so +rich in hydrogen might be turned to better use, and +that it might be possible to convert it direct into electricity +by means of a gas battery.</p> + +<p>You all know that Lord Justice Grove showed, now +fifty years ago, that two strips of platinum partly immersed +in dilute sulphuric acid, one of which is in contact +with hydrogen and the other with oxygen, produce +electricity. I will not detain you with the many and +varied forms of gas batteries which Dr. Carl Langer +(to whom I intrusted this investigation) has made and +tried during the last four years, in order to arrive at +the construction of a gas battery which would give a +practical result, but I will call your attention to the +battery before me on the table, which is the last result +of our extended labors in this direction, and which we +hope will mark a great step in advance in the economic +production of electricity.</p> + +<p>The distinguishing feature of this battery is that the +electrolyte is not employed as a mobile liquid, but in a +quasi-solid form, and it is, therefore, named dry gas +battery. It consists of a number of elements, which +are formed of a porous diaphragm of a non-conducting +material (in this instance plaster of Paris), which is impregnated +with dilute sulphuric acid. Both sides of +this diaphragm are covered with very fine platinum leaf +perforated with very numerous small holes, and over +this a thin film of platinum black. Both these coatings +are in contact with frameworks of lead and antimony, +insulated one from the other, which conduct the electricity +to the poles of the battery.</p> + +<p>A number of these elements are placed side by side, +with non-conducting frames intervening, so as to form +chambers through which the hydrogen gas is passed +along one side of the element and air along the other.</p> + +<p>This peculiar construction allows us to get a very +large amount of duty from a very small amount of +platinum. One of the batteries before you, consisting +of seven elements, with a total effective surface of half +a square meter, contains 2½ grammes of platinum leaf +and 7 grammes of platinum black, a total of 9½ grammes +of platinum, and produces a current of 2 amperes +and 5 volts, or 10 watts, when the outer resistance is +properly adjusted. This current is equal to nearly 50 +per cent. of the total energy obtainable from the hydrogen +absorbed in the battery.</p> + +<p>In order to maintain a constant current, we have +from time to time (say once an hour) to interchange +the gases, so as to counteract the disturbing influence +produced by the transport of the sulphuric acid gas +from one side of the diaphragm to the other. This +operation can easily be performed automatically by a +commutator worked by a clock.</p> + +<p>The water produced in the battery by the oxidation +of the hydrogen is carried off by the inert gas mixed +with the hydrogen, and by the air, of which we use a +certain excess for this purpose. This is important, as +if the platinum black becomes wet, it loses its absorbing +power for the gases almost completely and stops +the work of the battery. To avoid this was in fact +the great difficulty in designing a powerful gas battery, +and all previous constructions which employed the +electrolyte as a mobile liquid failed in consequence.</p> + +<p>The results obtained by our battery are practically +the same whether pure oxygen and hydrogen or air +and gases containing 25 per cent. of hydrogen are used; +but we found that the latter gases must be practically +free from carbonic oxide and hydrocarbons, which both +interfere very much with the absorbing power of the +platinum black.</p> + +<p>We had thus to find a cheap method of eliminating +these two gases from the producer gas, and converting +them at the same time into their equivalent of hydrogen. +The processes hitherto known for this purpose, +viz., passing a mixture of such gases with steam over +lime (which I mentioned some time ago) or over oxide +of iron or manganese, require high temperatures, which +render them expensive, and the latter do not effect the +reaction to a sufficient extent for our purpose.</p> + +<p>We have succeeded in attaining our object at a temperature +below that at which the gases leave my producers, +viz., at 350° C. to 450° C., by passing the producer +gases, still containing a considerable excess +of steam, over metallic nickel or cobalt. These metals +have the extraordinary property of decomposing +almost completely, even at the low temperature +named, carbonic oxide into carbon and carbonic acid +and hydrocarbons into carbon and hydrogen.</p> + +<p>In order to carry the process out with small quantities +of nickel and cobalt, we impregnate pumice stone +or similar material with a salt of nickel or cobalt, and +reduce this by means of hydrogen or producer gas. +These pieces of pumice stone are filled into a retort or +chamber and the hot gases passed through them. As +the reaction produces heat, it is not necessary to heat +the chambers or retorts from the outside when the +necessary temperature has once been attained. This +process has not yet been carried out on a large scale, +but the laboratory experiments have been so satisfactory +that we have no doubt as to its complete success. +It will enable us to obtain gases containing 36 per cent. +to 40 per cent. of hydrogen and practically free from +carbonic oxide and hydrocarbons from producer gas at +a very small cost, and thus to make the latter suitable +for the production of electricity by our gas battery. +We obtain, as stated before, 50 per cent. of the energy +in the hydrogen absorbed in the battery in the form of +electricity, while, if the same gas was consumed under +steam boilers to make steam, which, as I have shown +before, could in this way be raised cheaper than by +burning fuel direct, and if this steam was turned into +motive power by first-rate steam engines, and the +motive power converted into electricity by a dynamo, +the yield of electricity would in the most favorable case +not exceed 8 per cent. of the energy in the gas. I hope +that this kind of battery will one day enable us to perform +chemical operations by electricity on the largest +scale, and to press this potent power into the service of +the chemical industries.</p> + +<p>The statement is frequently made that "Necessity is +the mother of invention." If this has been the case in +the past, I think it is no longer so in our days, since +science has made us acquainted with the correlation of +forces, teaching us what amount of energy we utilize +and how much we waste in our various methods for +attaining certain objects, and indicating to us where +and in what direction and how far improvement is +possible; and since the increase in our knowledge of +the properties of matter enables us to form an opinion +beforehand as to the substances we have available for +obtaining a desired result.</p> + +<p>We can now foresee, in most cases, in what direction +progress in technology will move, and in consequence +the inventor is now frequently in advance of the wants +of his time. He may even create new wants, to my +mind a distinct step in the development of human +culture. It can then no longer be stated that "Necessity +is the mother of invention;" but I think it may +truly be said that the steady, methodical investigation +of natural phenomena is the father of industrial progress.</p> + +<p>Sir Lowthian Bell, Bart., F.R.S., in moving a vote +of thanks, said that the meeting had had the privilege +of listening to a description of results obtained by a +man of exceptional intelligence and learning, supplemented +by that devotion of mind which qualified him +to pursue his work with great energy and perseverance. +The importance of the president's address could not +possibly be overrated. At various periods different +substances had been put forward as indications of +the civilization of the people. He remembered hearing +from Dr. Ure that he considered the consumption of +sulphuric acid to be the most accurate measure of the +civilization of the people.</p> + +<p>In course of time sulphuric acid gave way to soap, +the consumption of which was probably still regarded +as the great exponent of civilization by such of his fellow +citizens as had thereby made their name. From +what he had heard that morning, however, he should +be inclined to make soap yield to ammonia, as sulphuric +acid had in its time succumbed to soap. For +not only was ammonia of great importance to us as a +manufacturing nation, but it almost appeared to be a +condition of our existence. England had a large population +concentrated on an area so small as to make it +almost a matter of apprehension whether the surface +could maintain the people upon it.</p> + +<p>We were now importing almost as much food as we +consumed, and were thus more and more dependent +on the foreigner. Under certain conditions this would +become a very serious matter, and thus any one who +showed how to produce plenty of ammonia at a cheap +rate was a benefactor to his country. Mr. Mond's process +seemed to come nearer to success than any which +had preceded it, and it needed no words from him to +induce the meeting to accord a hearty vote of thanks +to the president for his admirable paper.</p> + +<p>Mr. J. C. Stevenson, M.P., in seconding the motion, +said that no paper could be more interesting and valuable +to the society than that delivered by the president. +It opened out a future for the advancement of chemical +industry which almost overcame one by the greatness +of its possibilities. Mr. Mond had performed an +invaluable service by investigating the various methods +proposed for the manufacture of ammonia, and +clearing the decks of those processes supposed by their +inventors to be valuable, but proved by him to be delusive. +It gave him hearty pleasure therefore to second +the vote of thanks proposed by Sir Lowthian Bell.</p> + +<p>The vote having been put and carried by acclamation, +after a brief reply from the president:</p> + +<p>The secretary read the report of the scrutators, +which showed that 158 ballot papers had been sent in, +154 voting for the proposed list intact, and four substituting +other names. The gentlemen nominated in +the list issued by the Council were therefore declared +elected.</p> + +<p><a name="Footnote_09_1" id="Footnote_09_1"></a><a href="#FNanchor_09_1">[1]</a></p> +<div class="note">A paper read at the annual general meeting of +the Society of Chemical Industry, London, July 10, 1889.</div> + +<hr /> + + + +<p><a name="art10" id="art10"></a>In his brief report for the year ending May 1, 1889, +the director of the Pasteur Institute, Paris, announces +the treatment of 1,673 subjects, of whom 6 were seized +with rabies during and 4 within a fortnight after the +process. But 3 only succumbed after the treatment +had been completely carried out, making 1 death in +554, or, including all cases, 1 in 128.</p> + + +<hr /> + + + + +<h2><a name="Page_11457" id="Page_11457"></a><a name="art11" id="art11"></a>ALKALI MANUFACTORIES.</h2> + + +<p>When the alkali, etc., Works Regulation Act was +passed in 1881, it was supposed that the result would +be that the atmosphere in the districts where such +works are situated would be considerably improved, +and, consequently, that vegetation would have a +better chance in the struggle for existence, and the +sanitary conditions of human dwellings would be advanced. +In all these respects the act has been a success. +But perhaps the most notable result is the effect +which the act and those which have preceded it have +had upon the manufactures which they control.</p> + +<p>This was not anticipated by manufacturers, but now +one of the principal of them (Mr. A. M. Chance) has +stated that "Government inspection has not only led +to material improvement in the general management +of chemical works, but it has also been in reality a +distinct benefit to, rather than a tax upon, the owners +of such works."</p> + +<p>This expression of opinion is substantiated by the +chief inspector under the act, whose report for last +year has recently been laid before the local government +board.</p> + +<p>There are 1,057 works in the United Kingdom which +are visited by the inspectors, and in only two of these +during 1888 did the neglect to carry out the inspectors' +warnings become so flagrant as to call for legal interference; +viz., in the case of Thomas Farmer & Co. +(limited), Victoria Docks, E., who were fined 20<i>l.</i> and +costs for failing to use the "best practicable means" +for preventing the escape of acid gas from manure +plant; and in the case of Joseph Fison & Co., Bramford, +who were fined 50<i>l.</i> and costs for excessive escape +of acid gas from sulphuric acid plant. There were +seven other cases, but these were simply for failure to +register under the act.</p> + +<p>It is very evident, therefore, that from a public +point of view the act is splendidly successful, and from +the practical or scientific side it is no less satisfactory.</p> + +<p>Of the total number of chemical works (1,057) 866 are +registered in England, 131 in Scotland, and 44 in Ireland—a +decrease in the case of Scotland of 8, and in +Ireland of 2 from the previous year, while England has +increased by 1. This must not, however, be taken as +a sign of diminished production, because there is a +tendency for the larger works to increase in size and +for the smaller ones to close their operations. The +principal nuisances which the inspectors have to prevent +are the escape of hydrochloric acid gas from alkali +works and of sulphurous gas from vitriol and manure +works.</p> + +<p>The alkali act forbids the manufacturer to allow +the escape of more than 5 per cent. of the hydrochloric +acid which he produces, or that that acid must not +exist to a greater extent than 0.2 grain in 1 cubic foot +of air, steam, or chimney gas which accompanies. The +inspectors' figures for last year show that the percentage +of the acid which escaped amounted to only +1.96 of the total produced, which is equal to 0.089 grain +per cubic foot, and much below the figures for previous +years. The figures in regard to sulphurous gas are +equally satisfactory. The act allows 4 grains of sulphuric +anhydride (SO<sub>3</sub>) per cubic foot to escape into the +air, and last year's average was only 0.737 grain, or less +than a fifth of the limit.</p> + +<p>Of course it is now the aim of the Leblanc alkali +manufacturers to reduce the escape of hydrochloric +acid to the lowest possible amount, as their profits depend +solely upon the sale of chlorine products, soda +products being sold at a loss. In this connection it is +interesting to note that the amount of common salt +manufactured in the United Kingdom in 1888 was +2,039,867 tons, and of this nearly 600,000 tons were taken +by Leblanc soda makers, and over 200,000 tons by the +ammonia-soda makers. The figures are very largely +in excess of previous years, and indicate a gratifying +growth in trade.</p> + +<p>The salt used in the Leblanc process yields the +hydrochloric acid, and that in the ammonia-soda +method none, so that we may put down the theoretical +production of acid as 380,000 tons, 7,600 tons of which +was allowed to escape.</p> + +<p>What was a mere trace in the chimney gases +amounts, therefore, to a good round figure at the end +of a year, and if it were converted into bleaching powder +it would be worth nearly 150,000<i>l.</i> These figures are, it +should be understood, based on theory, but they serve +to show to what importance a gas has now reached +which twenty-five years ago was a perfect incubus to +the manufacturers, and wrought desolation in the +country sides miles and miles around the producing +works. There has long been an expectation that the +ammonia-soda makers would add the manufacture of +bleaching powder to their process, but they appear to +be as far as ever from that result, and meanwhile the +Leblanc makers are honestly striving to utilize every +atom of the valuable material which they handle. +Hence the eagerness to recover the sulphur from tank +waste by one or other of the few workable processes +which have been proposed.</p> + +<p>This waste contains from 11 to 15 per cent. of sulphur, +and when it is stated that the total amount of +tank waste produced yearly is about 750,000 tons, containing +about 100,000 tons of sulphur, it will be seen +how large is the reward held out to the successful +manipulator. Moreover, the value of the sulphur that +might possibly be saved is not the only prize held out +to those who can successfully deal with the waste, for +this material is not only thrown away as useless, but +much expense is incurred in the throwing.</p> + +<p>In Lancashire and in other inland districts land +must be found on which to deposit it, and the act of +depositing is costly, for unless it is beaten together so +as to exclude the air, an intolerable nuisance arises +from it. The cost of haulage and deposit on land +varies, according to the district, from 1s. to 1s. 6d. a +ton. In Widnes it is about 1s.</p> + +<p>In the Newcastle district the practice is to carry this +material out to sea at a cost of about 4d. a ton.</p> + +<p>Mr. Chance's process for the recovery of sulphur from +the waste signalizes the centenary of the Leblanc process; +Parnell and Simpson are following in his wake, +and lately Mr. F. Gossage, of Widnes, has been working +on a process for the production of alkali, which +enables him to save the sulphur of the sulphuric acid. +In his process a mixture of 70 parts Leblanc salt cake +(sulphate of soda) and 30 parts common salt is mixed +with coal and heated in a furnace, and so reduced to +sulphide of sodium. The resulting "ash" is then dissolved +in water and exposed to the action of carbonic +acid, when sulphureted hydrogen is given off, to be +dealt with as in Mr. Chance's sulphur process, while +bicarbonate of soda is formed and separates by precipitation +from the solution of undecomposed common +salt.</p> + +<p>Ere long it is expected this new method will be in +active operation in some Leblanc works, the plant of +which will, in all probability, be utilized. It has these +great advantages: The absence of lime, the recovery +of the sulphur used in the first instance and the consequent +absence of the objectionable tank waste. Thus +a bright promise is held out that the days of alkali +waste are numbered, and that the air in certain parts +of Lancashire will be more balmy than it has been in +the memory of the oldest inhabitant.—<i>Chemist and +Druggist.</i></p> + +<hr /> + + + + +<h2><a name="art12" id="art12"></a>THE FUELS OF THE FUTURE.</h2> + + +<p>It is undeniable that in this country, at least, we are +accustomed to regard coal as the chief, and, indeed, +the only substance which falls to be considered under +the name of fuel. In other countries, however, the +case is different. Various materials, ranging from +wood to oil, come within the category of material for +the production of heat. The question of fuel, it may +be remarked, has a social, an antiquarian, and a chemical +interest. In the first place, the inquiry whether or +not our supplies of coal will hold out for say the next +hundred thousand years, or for a much more limited +period only, has been very often discussed by sociologists +and by geological authorities.</p> + +<p>Again, it is clear that as man advances in the practice +of civilized arts, his dependence upon fuel becomes +of more and more intimate character. He not merely +demands fire wherewith to cook his food, and to raise +his own temperature or that of his dwelling, but requires +fuel for the thousand and one manufacturing +operations in which he is perpetually engaged. It is +obvious that without fuel civilized life would practically +come to an end. We cannot take the shortest +journey by rail or steamboat without a tacit dependence +upon a fuel supply; and the failure of this supply +would therefore mean and imply the extinction of all the +comforts and conveniences on which we are accustomed +to rely as aids to easy living in these latter days. Again, +socially regarded, man is the only animal that practices +the fire-making habit. Even the highest apes, who +will sit round the fire which a traveler has just left, +and enjoy the heat, do not appear to have developed +any sense or idea of keeping up the fire by casting fresh +fuel upon it. It seems fairly certain, then, that we +may define man as being a "fuel-employing animal," +and in so doing be within the bounds of certitude. He +may be, and often is, approached by other animals in +respect of many of his arts and practices. Birds weave +nest materials, ants make—and maul—slaves, beavers +build dams, and other animals show the germs and beginnings +of human contrivances for aiding the processes +of life, but as yet no animal save man lights and +maintains a fire. That the fire-making habit must +have dawned very early in human history appears to +be proved by the finding of ashes and other evidences +of the presence of fire among the remains and traces +of primitive man.</p> + +<p>All we know, also, concerning the history of savage +tribes teaches us that humanity is skillful, even in very +rude stages of its progress, in the making of fire. The +contrivances for obtaining fire are many and curious +in savage life, while, once attained, this art seems to +have not only formed a constant accompaniment but +probably also a determining cause in the evolution of +civilization. Wood, the fat of animals, and even the +oils expressed from plants, probably all became known +to man as convenient sources of fuel in prehistoric times. +From the incineration of wood to the use of peat and +coal would prove an easy stage in the advance toward +present day practices, and with the attainment of coal +as a fuel the first great era in man's fire-making habits +may be said to end.</p> + +<p>Beyond the coal stage, however, lies the more or less +distinctively modern one of the utilization of gas and +oil for fuel. The existence of great natural centers, +or underground stores, of gas and oil is probably no +new fact. We read in the histories of classic chroniclers +of the blazing gases which were wont to issue from the +earth, and to inspire feelings of superstitious awe in the +minds of beholders. Only within a few years, however, +have geologists been able to tell us much or anything +regarding these reservoirs of natural fuel which +have become famous in America and in the Russian +province of Baku.</p> + +<p>For example, it is now known that three products—gas, +oil, and salt or brine—lie within natural receptacles +formed by the rock strata in the order of their weight. +This law, as has well been said, forms the foundation +of all successful boring experiments, and the search for +natural fuel, therefore, becomes as easy and as reliable +a duty as that for artesian water or for coal. The +great oil fever of the West was attended at first, as +Professor M'Gee tells us, with much waste of the product. +Wells were sunk everywhere, and the oil overflowed +the land, tainting the rivers, poisoning the air, +and often driving out the prospectors from the field of +discovery. In Baku accidents and catastrophes have, +similarly, been of frequent occurrence. We read of +petroleum flowing from the ground in jets 200 feet +high, and as thick as a man's body; we learn how it +swept away the huge cranes and other machinery, +and how, as it flowed away from the orifices, its +course was marked by the formation of rivers of oil +many miles in length.</p> + +<p>In America the pressure of rock gas has burst open +stills weighing over a ton, and has rushed through +huge iron tanks and split open the pipes wherewith it +was sought to control its progress. The roar of this +great stream of natural gas was heard for miles around +as it escaped from the outlet, and when it was ignited +the pillar of flame illumined the surrounding country +over a radius extending in some cases to forty miles. It +is clear that man having tapped the earth's stores of +natural fuel, stood in danger of having unloosed a +monster whose power he seemed unable to control. +Yet, as the sequel will show, science has been able to +tackle with success the problems of mastering the +force and of utilizing the energy which are thus locked +up within the crust of the globe.</p> + +<p>As regards the chemistry of rock gas, we may remark +in the first place that this natural product ranks +usually as light carbureted hydrogen gas. In this +respect it is not unlike the marsh gas with which +everyone is familiar, which is found bubbling up from +swamps and morasses, and which constitutes the "will +o' the wisp" of romance. In rock gas, marsh gas itself +is actually found in the proportion of about 93 per +cent. The composition of marsh gas is very simple. +It consists of the two elements carbon and hydrogen +united in certain proportions, indicated chemically +by the symbol CH<sub>4</sub>. We find, in fact, that rock +gas possesses a close relationship, chemically speaking, +with many familiar carbon compounds, and of these +latter, petroleum itself, asphaltum, coal, jet, graphite +or plumbago, and even the diamond itself—which is +only crystallized carbon after all—are excellent examples.</p> + +<p>The differences between these substances really +consist in the degree of fixing of the carbon or solid +portion of the product, as it were, which exists. Thus +in coal and jet the carbon is of stable character, such +as we might expect to result from the slow decomposition +of vegetable matter, and the products of this +action are not volatile or liable to be suddenly dissociated +or broken up. On the other hand, when we +deal with the <i>hydrocarbons</i> as they are called, in the +shape of rock gas, naphtha, petroleum, tar, asphaltum, +and similar substances, we see how the carbon has become +subordinated to the hydrogen part of the compounds, +with the result of rendering them more or +less unstable in their character. As Professor M'Gee +has shown us, there is in truth a graduated series +leading us from the marsh gas and rock gas as the +lightest members of this class of compounds onward +through the semi-gaseous naphtha to the fluid petroleum, +the semi-fluid tar, the solid asphaltum, and +the rigid and brittle substance known as albertite, +with other and allied products. Having said so much +regarding the chemistry of the fuels of the future, we +may now pass to consider their geological record. A +somewhat curious distribution awaits the man of +science in this latter respect. Most readers are aware +that the geologists are accustomed to classify rocks, +according to their relative age, into three great groups, +known respectively as the primary, secondary, and +tertiary periods. In the secondary period we do not +appear to meet with the fuels of the future, but as far +back as the Devonian or old Red Sandstone period, +and in the still older Silurian rocks, stores of gas and +petroleum abound. In the latest or tertiary period, +again, we come upon nearly all the forms of fuels we +have already specified.</p> + +<p>The meaning of this geological distribution of the +fuels is entirely fortuitous. Dr. M'Gee tells us that as +their formation depended on local conditions (such as +plant growth), and as we have no means of judging +why such local conditions occurred within any given +area, so must we regard the existence of fuel products +in particular regions as beyond explanation. Of one +point, however, we are well assured, namely that the +volume of the fuels of the future is developed in an inverse +proportion to their geological age. The proportionate +volume, as it has been expressed, diminishes +progressively as the geological scale is descended. +Again, the weight of the fuels varies directly with +their age; for it is in the older formation of any series +that we come upon the oils and tars and asphaltum, +while the marsh gas exists in later and more recently +formed deposits. Further geological research shows +us that the American gas fields exist each as an inverted +trough or dome, a conformation due, of course, to +the bending and twisting of the rocks by the great underground +heat forces of the world. The porous part +of the dome may be sandstone or limestone, and above +this portion lie shales, which are the opposite of porous +in texture. The dome, further, contains gas above, +naphtha in the middle, and petroleum below, while last +of all comes water, which is usually very salt. In the +Indiana field, however, we are told that the oils lie near +the springing or foundation of the arch of the dome, +and at its crown gas exists, and overlies brine.</p> + +<p>A very important inquiry, in relation to the statement +that upon the products whose composition and +history have just been described the fuel supply of the +future will depend, consists in the question of the extent +and duration of these natural gas and oil reservoirs. +If we are beginning to look forward to a time +when our coal supply will have been worked out, it +behooves us to ask whether or not the supply of natural +gas and oil is practically illimitable. The geologist +will be able to give the coming man some degree of +comfort on this point, by informing him that there +seems to be no limit to the formation of the fuel of +the future.</p> + +<p>Natural gas is being manufactured to-day by nature +on a big scale. Wherever plant material has been entombed +in the rock formations, and wherever its decomposition +proceeds, as proceed it must, there natural +gas is being made. So that with the prospect of coal +becoming as rare as the dodo itself, the world, we are +told by scientists, may still regard with complacency +the failure of our ordinary carbon supply. The natural +gases and oils of the world will provide the human +race with combustible material for untold ages—such +at least is the opinion of those who are best informed +on the subject. For one thing, we are reminded that +gas is found to be the most convenient and most +economical of fuels. Rock gas is being utilized abroad +even now in manufacturing processes. Dr. M'Gee says +that even if the natural supply of rock gas were exhausted +to-morrow, manufacturers of glass, certain +grades of iron, and other products would substitute an +artificial gas for the natural product rather than return +to coal. He adds that "enormous waste would +thereby be prevented, the gas by which the air of +whole counties in coke-burning regions is contaminated +would be utilized, and the carbon of the dense +smoke clouds by which manufacturing cities are +overshadowed would be turned to good account." So +that, as regards the latter point, even Mr. Ruskin +with his horror of the black smoke of to-day and of +the disfigurement of sky and air might become a warm +ally of the fuel of the future. The chemist in his +laudation of rock gas and allied products is only re-echoing, +when all is said and done, the modern eulogy +pronounced on ordinary coal gas as a cooking and +heating medium.</p> + +<p>We are within the mark when we say that the past +five years alone have witnessed a wonderful extension in +the use of gas in the kitchen and elsewhere. It would +be singular, indeed, if we should happen to be already +<a name="Page_11458" id="Page_11458"></a> +anticipating the fuel of the future by such a practice. +Whether or not this is the case, it is at least satisfactory +for mankind to know that the mother earth will +not fail him when he comes to demand a substitute for +coal. I may be too early even to think of the day of +extinction; but we may regard that evil day with +complacency in face of the stores of fuel husbanded for +us within the rock foundations of our planet.—<i>Glasgow +Herald.</i></p> + +<hr /> + + + + +<h2><a name="art13" id="art13"></a>PORTABLE ELECTRIC LIGHT.</h2> + + +<p>The famous house of MM. Sautter, Lemonnier & +Co. takes a conspicuous part in the Paris exhibition, +and from the wide range of its specialties exhibits +largely in three important branches of industry: mechanics, +electricity, and the optics of lighthouses and +projectors. In these three branches MM. Sautter, Lemonnier +& Co. occupy a leading position in all parts +of the world.</p> + +<p>The invention of the aplanetic projector, due to Col. +Mangin, was a clever means of overcoming difficulties, +practically insurmountable, that were inseparable from +the construction of parabolic mirrors; this contributed +chiefly to the success of MM. Sautter, Lemonnier & Co. +in this direction. The firm has produced more than +1,500 of these apparatus, representing a value of nearly +£500,000, for the French and other governments.</p> + +<p>Besides the great projector, which forms the central +and crowning object of the exhibit of MM. Sautter, +Lemonnier & Co. in the machinery hall, the firm exhibits +a projector 90 centimeters in diameter mounted +on a crane traveling on wheels, in the pavilion of the +War Department. The lamp used for this apparatus +has a luminous value of 6,000 carcels, with a current of +100 amperes; the amplifying power of the mirror is +2,025, which gives an intensity of ten millions to twelve +millions of carcels to the beam.</p> + +<p>Projectors used for field work are mounted on a portable +carriage, which also contains the electric generator +and the motor driving it.</p> + +<div class="figcenter"> +<a href="./images/13_1.png"> +<img src="./images/13_1_th.png" width="412" height="400" alt="MILITARY PORTABLE ELECTRIC LIGHT AT THE PARIS EXHIBITION." /> +</a> + +<p class="caption">MILITARY PORTABLE ELECTRIC LIGHT AT THE PARIS EXHIBITION.</p> +</div> + +<p>It consists of a tubular boiler (Dion, Bouton & Trepardoux +system). This generator is easily taken to +pieces, cleaned, and repaired, and steam can be raised +to working pressure in 20 minutes. The mechanical +and electrical part of the apparatus consists of a Parsons +turbo-motor, of which MM. Sautter, Lemonnier +& Co. possess the license in France for application to +military and naval purposes. The speed of the motor +is 9,000 revolutions per minute, and the dynamo is +driven direct from it; at this speed it gives a current +of 100 amperes with and from 55 to 70 volts; the intensity +of the light is from 5,500 to 6,000 carcels. The +carriage upon which the whole of this apparatus is +mounted is carried on four wheels, made of wood with +gun metal mountings. These are more easy to repair +when in service than if they were wholly of iron. The +weight of the carriage is three tons.—<i>Engineering.</i></p> + +<hr /> + + + + +<h2><a name="art14" id="art14"></a>ELECTRIC MOTOR FOR ALTERNATING +CURRENTS.</h2> + + +<p>Prof. Galileo Ferraris, of Turin, who has carefully +studied alternating currents and secondary transformers, +has constructed a little motor based upon an +entirely new principle, which is as follows: If we take +two inductive fields developed by two bobbins, the +axes of which cut each other at right angles, and a pole +placed at the vertex of the angle, this pole will be subjected +to the simultaneous action of the two bobbins, +and the resultant of the magnetic actions will be represented +in magnitude and direction by the diagonal of +the parallelogram, two consecutive sides of which have +for their length the intensity of the two fields, and +for their direction the axes of the two bobbins.</p> + +<p>If into each of these bobbins we send alternating currents +having between one bobbin and the other a difference +of phase of 90°, the extremity of the resultant will +describe a circle having for its center the vertex of the +right angle.</p> + +<p>If, instead of a fixed pole, we use a metal cylinder +movable on its axis, we shall obtain a continuous rotatory +motion of this part, and the direction of the movement +will change when we interchange the difference +of phase in the exciting currents. This rotatory movement +is not due to the Foucault currents, for the metal +cylinder may consist of plates of iron insulated from +each other.</p> + +<p>In order to realize the production of these fields, several +means can be employed: The current is sent from +an alternating current machine into the primary circuit +of a transformer and thence into one of the bobbins, +the other being supplied by means of the secondary +current of the transformer. A resistance introduced +into the circuit will produce the required difference of +phase, and the equality of the intensities of the fields +will be obtained by multiplying the number of turns +of the secondary wire on the bobbin. Moreover, the +two bobbins may be supplied by the secondary current +of a transformer by producing the difference of phase, +as in the first case.</p> + +<p>In the motor constructed by Prof. Ferraris the armature +consisted of a copper cylinder measuring 7 centimeters +in diameter and 15 centimeters in length, movable +on its axis. The inductors were formed of two groups +of two bobbins. The bobbins which branched off from +the primary circuit of a Gaulard transformer, and were +connected in series, comprised 196 spirals with a resistance +of 13 ohms; the bobbins comprising the secondary +circuit were coupled in parallel, and had 504 spirals +with 3.43 ohms resistance. In order to produce the difference +of phase, a resistance of 17 ohms was introduced +into the second circuit, when the dynamo produced a +current of 9 amperes with 80 inversions per second. +Under these conditions the available work measured +on the axis of the motor was found for different speeds: +Revolutions per minute: 262—400—546—650—722—770. +Watts measured at the brake: 1.32—2.12—2.55—2.77—2.55—2.40. +The maximum rendering corresponds to a +speed of rotation of 650 revolutions, and Prof. Ferraris +attributes the loss of work for higher speeds to the vibrations +to which the machine is exposed. At present +the apparatus is but a laboratory one.—<i>Bulletin International +de l'Electricite.</i></p> + +<hr /> + + + + +<h2><a name="art15" id="art15"></a>THE ELECTRIC AGE.</h2> + +<h3>By <span class="sc">Charles Carleton Coffin.</span></h3> + + +<p>The application of electricity for our convenience +and comfort is one of the marvels of the age. Never +in the history of the world has there been so rapid a +development of an occult science. Prior to 1819 very +little was known in regard to magnetism and electricity. +During that year Oersted discovered that an +electric current would deflect a magnetic needle, thus +showing that there was some relationship between +electric and magnetic force. A few months later, Arago +and Sir Humphry Davy, independently of each other, +discovered that by coiling a wire around a piece of +iron, and passing an electric current through it, the +iron would possess for the time being all the properties +of a magnet. In 1825 William Sturgeon, of London, +bent a piece of wire in the form of the letter U, wound +a second wire around it, and, upon connecting it with +a galvanic battery, discovered that the first wire became +magnetic, but lost its magnetic property the +moment the battery was disconnected. The idea of a +telegraphic signal came to him, but the electric impulse, +through his rude apparatus, faded out at a distance of +fifty feet. In 1830 Prof. Joseph Henry, of this country, +constructed a line of wire, one and a half miles in +length, and sent a current of electricity through it, ringing +a bell at the farther end. The following year Professor +Faraday discovered magnetic induction. This, in +brief, is the genesis of magnetic electricity, which is +the basis of all that has been accomplished in electrical +science.</p> + +<p>The first advance after these discoveries was in the +development of the electric telegraph—the discovery in +1837, by the philosopher Steinhill, that the earth could +serve as a conductor, thus requiring but one wire in +the employment of an electric current. Simultaneously +came Morse's invention of the mechanism for the +telegraph in 1844, foreshadowed by Henry in the ringing +of bells, thus transmitting intelligence by sound. +Four years later, in 1848, Prof. M. G. Farmer, still living +in Eliot, Me., attached an electro-magnet to clockwork +for the striking of bells to give an alarm of fire. +The same idea came to William F. Channing. The +mechanism, constructed simply to illustrate the idea by +Professor Farmer, was placed upon the roof of the +Court House in Boston, and connected with the telegraph +wire leading to New York, and an alarm rung +by the operator in that city. The application of electricity +for giving definite information to firemen was +first made in Boston, and it was my privilege to give +the first alarm on the afternoon of April 12, 1852.</p> + +<p>At the close of the last century, Benjamin Thompson, +born in Woburn, Mass., known to the world as Count +Rumford, was in the workshop of the military arsenal +of the King of Bavaria in Munich, superintending the +boring of a cannon. The machinery was worked by +two horses. He was surprised at the amount of heat +which was generated, for when he threw the borings +into a tumbler filled with cold water, it was set to boiling, +greatly to the astonishment of the workmen. +Whence came the heat? What was heat? The old +philosopher said that it was an element. By experiment +he discovered that a horse working two hours +and twenty minutes with the boring machinery would +heat nineteen pounds of water to the boiling point. +He traced the heat to the horse, but with all his acumen +he did not go on with the induction to the hay +and oats, to the earth, the sunshine and rain, and +so get back to the sun. One hundred years ago there +was no chemical science worthy of the name, no knowledge +of the constitution of plants or the properties of +light and heat. The old philosophers considered light +and heat to be fluids, which passed out of substances +when they were too full. Count Rumford showed that +motion was convertible into heat, but did not trace the +motion to its source, so far as we know, in the sun.</p> + +<p>It is only forty-six years since Professor Joule first +demonstrated the mutual relations of all the manifestations +of nature's energy. Thirty-nine years only have +passed since he announced the great law of the convertibility +of force. He constructed a miniature churn +which held one pound of water, and connected the revolving +paddle of the churn with a wheel moved by a +pound weight, wound up the weight, and set the paddle +in motion. A thermometer detected the change of +temperature and a graduated scale marked the distance +traversed by the descending weight. Repeated experiments +showed that a pound weight falling 772 feet +would raise the temperature of water one degree, and +that this was an unvarying law. This was transferring +gravitation to heat, and the law held good when applied +to electricity, magnetism, and chemical affinity, +leading to the conclusion that they were severally +manifestations of one universal power.—<i>Congregationalist.</i></p> + +<hr /> + + + + +<h2><a name="art16" id="art16"></a>EARLY ELECTRIC LIGHTING.</h2> + + +<p>The opening of the new station of the Electric +Lighting Co., of Salem, Mass., was recently celebrated +with appropriate festivities.</p> + +<p>Among the letters of regret from those unable to +attend the opening was the following from Prof. Moses +G. Farmer:</p> + +<p class="letter">"<span class="sc">Eliot</span>, Me., Aug. 5, 1889.</p> + +<p>"<i>To the Salem Electric Lighting Company, Charles H. +Price, President</i>:</p> + +<p>"<span class="sc">Gentlemen</span>: It would give me great pleasure to +accept your kind invitation to be present at the opening +of your new station in Salem on the 8th of this +present August.</p> + +<p>"It is now thirty years since the first dwelling house +in Salem was lighted by electricity. That little obscure +dwelling, 11 Pearl Street, formerly owned by +'Pa' Webb, had the honor to be illuminated by the +effulgent electric beam during every evening of July, +1859, as some of your honored residents, perhaps, well +remember. Mr. George D. Phippen can doubtless testify +to one or more evenings; Mr. Wm. H. Mendell, of +Boston, can also add his testimony; dozens of others +could also do the same, had not some of them already +passed to the 'great beyond,' among whom I well recollect +the interest taken by the late and honored +Henry L. Williams, Mr. J. G. Felt, and I do not know +how many others. I well remember reading some +of the very finest print standing with my back to the +front wall and reading by the light of a 32 candle +power lamp on the northernmost end of the mantel +piece in the parlor; very possibly the hole in which +the lamp was fastened remains to this day. In a +little closet in the rear sleeping room was a switch +which could be turned in one direction and give a +beautiful glow light, while if turned in the other direction, +it instantly gave as beautiful a dark. My then 12 +year old daughter used to surprise and please her +visitors by suddenly turning on and off the 'glim.' It +is not well to despise the day of small things, for although +the dynamo had not at that date put in an +appearance, and though I used thirty-six Smee cells of +six gallons capacity each, yet I demonstrated then +and there that the incandescent electric light was a +possibility, and although I innocently remarked to the +late Samuel W. Bates, of Boston, who with his partner, +Mr. Chauncey Smith, furnished so generously in +the interest of science, not wholly without hope of +return, the funds for the experiment, that it 'did not +take much zinc,' and though Mr. Bates as naively replied, +'I notice that it takes some silver, though,' still +<a name="Page_11459" id="Page_11459"></a> +it was then and there heralded as the coming grand +illuminant for the dwelling. I am thankful to have +lived to see my predictions partly fulfilled.</p> + +<p>"During the early fifties I published a statement +something like this: 'One pound of coal will furnish +gas enough to maintain a candle light for fifteen hours. +One pound of gas (the product of five pounds of coal) +will, in a good fishtail gas burner, furnish one candle +light for seventy-five hours. One pound of coal burned +in a good furnace, under a good boiler, driving a +good steam engine, turning a good magneto-electric +machine, will give a candle light for one thousand +hours. But if all the energy locked up in one pound +of pure carbon could be wholly converted into light, +it would maintain one candle light for more than one +and a half years.'</p> + +<p>"So, gentlemen, <i>nil desperandum</i>; there is still +room for improvement. Let your motto be 'Excelsior.' +Possibly you may have already extracted from one-fifteenth +to one-twelfth of the energy stored in the pound +of carbon, but hardly more. Go on, go on, and bring +it so cheap as to reach the humblest dwelling when you +shall celebrate the centennial of the opening of your +new station.</p> + +<p>"I do most sincerely regret that I cannot be with +you in the flesh. I am, like Ixion of old, confined to a +wheel (chair in my case), cannot walk, cannot even +stand; hence, owing to the impairment of my understanding +(???), I must wish you all the enjoyments of +the evening, and gladly content myself that you have +made so much possible.</p> + +<p class="letter">"Very truly yours, <span class="sc">Moses G. Farmer</span>."</p> + +<hr /> + + + + +<h2><a name="art17" id="art17"></a> +THE MODERN THEORY OF LIGHT.<a name="FNanchor_17_1" id="FNanchor_17_1"></a><a href="#Footnote_17_1"><sup>1</sup></a></h2> + +<h3>By Prof. <span class="sc">Oliver Lodge</span>.</h3> + + + +<p>To persons occupied in other branches of learning, +and not directly engaged in the study of physical science, +some rumor must probably have traveled of the +stir and activity manifest at the present time among +the votaries of that department of knowledge.</p> + +<p>It may serve a useful purpose if I try and explain to +outsiders what this stir is mainly about, and why it +exists. There is a proximate and there is an ultimate +cause. The proximate cause is certain experiments exhibiting +in a marked and easily recognizable way the +already theoretically predicted connection between +electricity and light. The ultimate cause is that we +begin to feel inklings and foretastes of theories, wider +than that of gravitation, more fundamental than any +theories which have yet been advanced; theories +which if successfully worked out will carry the banner +of physical science far into the dark continent of metaphysics, +and will illuminate with a clear philosophy +much that is at present only dimly guessed. More explicitly, +we begin to perceive chinks of insight into the +natures of electricity, of ether, of elasticity, and even +of matter itself. We begin to have a kinetic theory of +the physical universe.</p> + +<p>We are living, not in a Newtonian, but at the beginning +of a perhaps still greater Thomsonian era. +Greater, not because any one man is probably greater +than Newton,<a name="FNanchor_17_2" id="FNanchor_17_2"></a><a href="#Footnote_17_2"><sup>2</sup></a> but +because of the stupendousness of +the problems now waiting to be solved. There are a +dozen men of great magnitude, either now living or +but recently deceased, to whom what we now know +toward these generalizations is in some measure due, +and the epoch of complete development may hardly be +seen by those now alive. It is proverbially rash to attempt +prediction, but it seems to me that it may well +take a period of fifty years for these great strides to be +fully accomplished. If it does, and if progress goes on +at anything like its present rate, the aspect of physical +science bequeathed to the latter half of the twentieth +century will indeed excite admiration, and when the +populace are sufficiently educated to appreciate it, will +form a worthy theme for poetry, for oratorios, and for +great works of art.</p> + + +<p>To attempt to give any idea of the drift of progress +in all the directions which I have hastily mentioned, +to attempt to explain the beginnings of the theories of +elasticity and of matter, would take too long, and +might only result in confusion. I will limit myself +chiefly to giving some notion of what we have gained +in knowledge concerning electricity, ether, and light. +Even that is far too much. I find I must confine myself +principally to light, and only treat of the others as +incidental to that.</p> + +<p>For now well nigh a century we have had a wave +theory of light; and a wave theory of light is quite +certainly true. It is directly demonstrable that light +consists of waves of some kind or other, and that these +waves travel at a certain well-known velocity, seven +times the circumference of the earth per second, taking +eight minutes on the journey from the sun to the +earth. This propagation in time of an undulatory disturbance +necessarily involves a medium. If waves +setting out from the sun exist in space eight minutes +before striking our eyes, there must necessarily be in +space some medium in which they exist and which +conveys them. Waves we cannot have unless they be +waves in something.</p> + +<p>No ordinary medium is competent to transmit waves +at anything like the speed of light; hence the luminiferous +medium must be a special kind of substance, +and it is called the ether. The <i>luminiferous</i> ether it +used to be called, because the conveyance of light was +all it was then known to be capable of; but now that +it is known to do a variety of other things also, the +qualifying adjective may be dropped.</p> + +<p>Wave motion in ether, light certainly is; but what +does one mean by the term wave? The popular notion +is, I suppose, of something heaving up and down, or, +perhaps, of something breaking on the shore in which +it is possible to bathe. But if you ask a mathematician +what he means by a wave, he will probably reply +that the simplest wave is</p> + +<p class="center"><i>y</i> = <i>a</i> sin (<i>p</i> <i>t</i> - <i>n</i> <i>x</i>),</p> + +<p>and he might possibly refuse to give any other answer.</p> + +<p>And in refusing to give any other answer than this, +or its equivalent in ordinary words, he is entirely justified; +that is what is meant by the term wave, and +nothing less general would be all-inclusive.</p> + +<p>Translated into ordinary English the phrase signifies +"a disturbance periodic both in space and time." Anything +thus doubly periodic is a wave; and all waves, +whether in air as sound waves, or in ether as light +waves, or on the surface of water as ocean waves, are +comprehended in the definition.</p> + +<p>What properties are essential to a medium capable +of transmitting wave motion? Roughly we may say +two—<i>elasticity</i> and <i>inertia</i>. Elasticity in some form, +or some equivalent of it, in order to be able to store up +energy and effect recoil; inertia, in order to enable the +disturbed substance to overshoot the mark and oscillate +beyond its place of equilibrium to and fro. Any +medium possessing these two properties can transmit +waves, and unless a medium possesses these properties +in some form or other, or some equivalent for +them, it may be said with moderate security to be incompetent +to transmit waves. But if we make this latter +statement, one must be prepared to extend to the +terms elasticity and inertia their very largest and +broadest signification, so as to include any possible +kind of restoring force and any possible kind of persistence +of motion respectively.</p> + +<p>These matters may be illustrated in many ways, but +perhaps a simple loaded lath or spring in a vise will +serve well enough. Pull aside one end, and its elasticity +tends to make it recoil; let it go, and its inertia +causes it to overshoot its normal position; both causes +together cause it to swing to and fro till its energy is +exhausted. A regular series of such springs at equal +intervals in space, set going at regular intervals of time +one after the other, gives you at once a wave motion +and appearance which the most casual observer must +recognize as such. A series of pendulums will do just +as well. Any wave-transmitting medium must similarly +possess some form of elasticity and of inertia.</p> + +<p>But now proceed to ask what is this ether which in +the case of light is thus vibrating? What corresponds +to the elastic displacement and recoil of the spring or +pendulum? What corresponds to the inertia whereby +it overshoots its mark? Do we know these properties +in the ether in any other way?</p> + +<p>The answer, given first by Clerk Maxwell, and now +reiterated and insisted on by experiments performed in +every important laboratory in the world, is:</p> + +<p>The elastic displacement corresponds to electrostatic +charge (roughly speaking, to electricity).</p> + +<p>The inertia corresponds to magnetism.</p> + +<p>This is the basis of the modern electro-magnetic theory +of light. Now let me illustrate electrically how +this can be.</p> + +<p>The old and familiar operation of charging a Leyden +jar—the storing up of energy in a strained dielectric, +any electrostatic charging whatever—is quite analogous +to the drawing aside of our flexible spring. It is +making use of the elasticity of the ether to produce a +tendency to recoil. Letting go the spring is analogous +to permitting a discharge of the jar—permitting the +strained dielectric to recover itself, the electrostatic +disturbance to subside.</p> + +<p>In nearly all the experiments of electrostatics, ethereal +elasticity is manifest.</p> + +<p>Next consider inertia. How would one illustrate the +fact that water, for instance, possesses inertia—the +power of persisting in motion against obstacles—the +power of possessing kinetic energy? The most direct +way would be to take a stream of water and try suddenly +to stop it. Open a water tap freely and then +suddenly shut it. The impetus or momentum of the +stopped water makes itself manifest by a violent shock +to the pipe, with which everybody must be familiar. +The momentum of water is utilized by engineers in the +"water ram."</p> + +<p>A precisely analogous experiment in electricity is +what Faraday called "the extra current." Send a current +through a coil of wire round a piece of iron, or +take any other arrangement for developing powerful +magnetism, and then suddenly stop the current by +breaking the circuit. A violent flash occurs if the +stoppage is sudden enough, a flash which means the +bursting of the insulating air partition by the accumulated +electro-magnetic momentum.</p> + +<p>Briefly, we may say that nearly all electro-magnetic +experiments illustrate the fact of ethereal inertia.</p> + +<p>Now return to consider what happens when a charged +conductor (say a Leyden jar) is discharged. The recoil +of the strained dielectric causes a current, the inertia +of this current causes it to overshoot the mark, +and for an instant the charge of the jar is reversed; +the current now flows backward and charges the jar +up as at first; back again flows the current, and so on, +charging and reversing the charge with rapid oscillations +until the energy is all dissipated into heat. The +operation is precisely analogous to the release of a +strained spring or to the plucking of a stretched +string.</p> + +<p>But the discharging body thus thrown into strong +electrical vibration is embedded in the all-pervading +ether, and we have just seen that the ether possesses +the two properties requisite for the generation and +transmission of waves—viz., elasticity and inertia or +density; hence, just as a tuning fork vibrating in air +excites aerial waves or sound, so a discharging Leyden +jar in ether excites ethereal waves or light.</p> + +<p>Ethereal waves can therefore be actually produced +by direct electrical means. I discharge here a jar, and +the room is for an instant filled with light. With +light, I say, though you can see nothing. You can see +and hear the spark indeed—but that is a mere secondary +disturbance we can for the present ignore—I do not +mean any secondary disturbance. I mean the true +ethereal waves emitted by the electric oscillation going +on in the neighborhood of this recoiling dielectric. +You pull aside the prong of a tuning fork and let it go; +vibration follows and sound is produced. You charge +a Leyden jar and let it discharge; vibration follows +and light is excited.</p> + +<p>It is light just as good as any other light. It travels +at the same pace, it is reflected and refracted according +to the same laws; every experiment known to optics +can be performed with this ethereal radiation electrically +produced, and yet you cannot see it. Why not? +For no fault of the light; the fault (if there be a fault) +is in the eye. The retina is incompetent to respond to +these vibrations—they are too slow. The vibrations +set up when this large jar is discharged are from a +hundred thousand to a million per second, but that is +too slow for the retina. It responds only to vibrations +between 4,000 billions and 7,000 billions per second. +The vibrations are too quick for the ear, which responds +only to vibrations between 40 and 40,000 per second. +Between the highest audible and the lowest visible +vibrations there has been hitherto a great gap, +which these electric oscillations go far to fill up. There +has been a great gap simply because we have no intermediate +sense organ to detect rates of vibration between +40,000 and 4,000,000,000,000,000 per second. It +was, therefore, an unexplored territory. Waves have +been there all the time in any quantity, but we have +not thought about them nor attended to them.</p> + +<p>It happens that I have myself succeeded in getting +electric oscillations so slow as to be audible. The lowest +I have got at present are 125 per second, and for +some way above this the sparks emit a musical note; +but no one has yet succeeded in directly making electric +oscillations which are visible, though indirectly +every one does it when they light a candle.</p> + +<p>Here, however, is an electric oscillator, which vibrates +300 million times a second, and emits ethereal +waves a yard long. The whole range of vibrations between +musical tones and some thousand million per +second is now filled up.</p> + +<p>These electro-magnetic waves have long been known +on the side of theory, but interest in them has been +immensely quickened by the discovery of a receiver or +detector for them. The great though simple discovery +by Hertz of an "electric eye," as Sir W. Thomson calls +it, makes experiments on these waves for the first time +easy or even possible. We have now a sort of artificial +sense organ for their appreciation—an electric arrangement +which can virtually "see" these intermediate +rates of vibration.</p> + +<p>The Hertz receiver is the simplest thing in the world—nothing +but a bit of wire or a pair of bits of wire adjusted +so that when immersed in strong electric radiation +they give minute sparks across a microscopic air +gap.</p> + +<p>The receiver I have here is adapted for the yard-long +waves emitted from this small oscillator; but for the +far longer waves emitted by a discharging Leyden jar +an excellent receiver is a gilt wall paper or other interrupted +metallic surface. The waves falling upon the +metallic surface are reflected, and in the act of reflection +excite electric currents, which cause sparks. +Similarly, gigantic solar waves may produce auroræ; +and minute waves from a candle do electrically disturb +the retina.</p> + +<p>The smaller waves are, however, far the most interesting +and the most tractable to ordinary optical experiments. +From a small oscillator, which may be a +couple of small cylinders kept sparking into each other +end to end by an induction coil, waves are emitted on +which all manner of optical experiments can be performed.</p> + +<p>They can be reflected by plain sheets of metal, concentrated +by parabolic reflectors, refracted by prisms, +concentrated by lenses. I have at the college a large +lens of pitch, weighing over three hundredweight, for +concentrating them to a focus. They can be made to +show the phenomenon of interference, and thus have +their wave length accurately measured. They are stopped +by all conductors and transmitted by all insulators. +Metals are opaque, but even imperfect insulators +such as wood or stone are strikingly transparent, and +waves may be received in one room from a source in +another, the door between the two being shut.</p> + +<p>The real nature of metallic opacity and of transparency +has long been clear in Maxwell's theory of light, +and these electrically produced waves only illustrate +and bring home the well known facts. The experiments +of Hertz are in fact the apotheosis of that +theory.</p> + +<p>Thus, then, in every way Maxwell's 1865 brilliant +perception of the real nature of light is abundantly +justified; and for the first time we have a true theory +of light, no longer based upon analogy with sound, nor +upon a hypothetical jelly or elastic solid.</p> + +<p>Light is an electro-magnetic disturbance of the ether. +Optics is a branch of electricity. Outstanding problems +in optics are being rapidly solved now that we +have the means of definitely exciting light with a full +perception of what we are doing and of the precise +mode of its vibration.</p> + +<p>It remains to find out how to shorten down the waves—to +hurry up the vibration until the light becomes visible. +Nothing is wanted but quicker modes of vibrations. +Smaller oscillators must be used—very much smaller—oscillators +not much bigger than molecules. In all +probability—one may almost say certainly—ordinary +light is the result of electric oscillation in the molecules +of hot bodies, or sometimes of bodies not hot—as +in the phenomenon of phosphorescence.</p> + +<p>The direct generation of <i>visible</i> light by electric +means, so soon as we have learnt how to attain the +necessary frequency of vibration, will have most important +practical consequences.</p> + +<p>Speaking in this university, it is happily quite unnecessary +for me to bespeak interest in a subject by +any reference to possible practical applications. But +any practical application of what I have dealt with +this evening is apparently so far distant as to be free +from any sordid gloss of competition and company promotion, +and is interesting in itself as a matter of pure +science.</p> + +<p>For consider our present methods of making artificial +light; they are both wasteful and ineffective.</p> + +<p>We want a certain range of oscillation, between 7,000 +and 4,000 billion vibrations per second; no other is +useful to us, because no other has any effect upon our +retina; but we do not know how to produce vibrations +of this rate. We can produce a definite vibration of +one or two hundred or thousand per second; in other +words, we can excite a pure tone of definite pitch; and +we can demand any desired range of such tones continuously +by means of bellows and a keyboard. We +can also (though the fact is less well known) excite +momentarily definite ethereal vibrations of some million +per second, as I have explained at length; but we +do not at present seem to know how to maintain this +rate quite continuously. To get much faster rates of +vibration than this we have to fall back upon atoms. +We know how to make atoms vibrate; it is done by +what we call "heating" the substance, and if we could +deal with individual atoms unhampered by others, it +is possible that we might get a pure and simple mode +of vibration from them. It is possible, but unlikely; +for atoms, even when isolated, have a multitude of +modes of vibration special to themselves, of which only +a few are of practical use to us, and we do not know +how to excite some without also the others. However, +<a name="Page_11460" id="Page_11460"></a> +we do not at present even deal with individual atoms; +we treat them crowded together in a compact mass, so +that their modes of vibration are really infinite.</p> + +<p>We take a lump of matter, say a carbon filament or +a piece of quicklime, and by raising its temperature we +impress upon its atoms higher and higher modes of +vibration, not transmuting the lower into the higher, +but superposing the higher upon the lower, until at +length we get such rates of vibration as our retina is +constructed for, and we are satisfied. But how wasteful +and indirect and empirical is the process. We want +a small range of rapid vibrations, and we know no +better than to make the whole series leading up to +them. It is as though, in order to sound some little +shrill octave of pipes in an organ, we are obliged to +depress every key and every pedal, and to blow a +young hurricane.</p> + +<p>I have purposely selected as examples the more perfect +methods of obtaining artificial light, wherein the +waste radiation is only useless and not noxious. But +the old-fashioned plan was cruder even than this; it +consisted simply in setting something burning; +whereby not the fuel but the air was consumed, +whereby also a most powerful radiation was produced, +in the waste waves of which we were content to sit +stewing, for the sake of the minute—almost infinitesimal—fraction +of it which enabled us to see.</p> + +<p>Every one knows now, however, that combustion +is not a pleasant or healthy mode of obtaining light; +but every one does not realize that neither is incandescence +a satisfactory and unwasteful method which +is likely to be practiced for more than a few decades, +or perhaps a century.</p> + +<p>Look at the furnaces and boilers of a great steam +engine driving a group of dynamos, and estimate the +energy expended; and then look at the incandescent +filaments of the lamps excited by them, and estimate +how much of their radiated energy is of real service to +the eye. It will be as the energy of a pitch pipe to an +entire orchestra.</p> + +<p>It is not too much to say that a boy turning a handle +could, if his energy were properly directed, produce +quite as much real light as is produced by all this mass +of mechanism and consumption of material. There +might, perhaps, be something contrary to the laws of +nature in thus hoping to get and utilize some specific +kind of radiation without the rest, but Lord Rayleigh +has shown in a short communication to the British +Association at York that it is not so, and that, therefore, +we have a right to try to do it.</p> + +<p>We do not yet know how, it is true, but it is one of +the things we have got to learn.</p> + +<p>Any one looking at a common glow-worm must be +struck with the fact that not by ordinary combustion, +nor yet on the steam engine and dynamo principle, is +that easy light produced. Very little waste radiation +is there from phosphorescent things in general. Light +of the kind able to affect the retina is directly emitted; +and for this, for even a large supply of this, a modicum +of energy suffices.</p> + +<p>Solar radiation consists of waves of all sizes, it is +true; but then solar radiation has innumerable things +to do besides making things visible. The whole of its +energy is useful. In artificial lighting nothing but +light is desired; when heat is wanted it is best obtained +separately by combustion. And so soon as we clearly +recognize that light is an electric vibration, so soon +shall we begin to beat about for some mode of exciting +and maintaining an electrical vibration of any required +degree of rapidity. When this has been accomplished +the problem of artificial lighting will have been solved.</p> + +<p><a name="Footnote_17_1" id="Footnote_17_1"></a><a href="#FNanchor_17_1">[1]</a></p> +<div class="note">Being the general substance of a lecture to +the Ashmolean Society in the University of Oxford, on Monday, June 3, +1889. [Reprinted from the <i>Liverpool University College Magazine</i>.]</div> + +<p><a name="Footnote_17_2" id="Footnote_17_2"></a><a href="#FNanchor_17_2">[2]</a></p> +<div class="note">Though, indeed, a century hence it may be premature +to offer an opinion on such a point.</div> + +<hr /> + + + + +<h2><a name="art18" id="art18"></a>ON PURIFICATION OF AIR BY OZONE—WITH +AN ACCOUNT OF A NEW METHOD.<a name="FNanchor_18_1" id="FNanchor_18_1"></a><a href="#Footnote_18_1"><sup>1</sup></a></h2> + +<h3>By Dr. <span class="sc">B. W. Richardson</span>.</h3> + + + +<p>During the time when I was engaged in my preliminary +medical studies—for I never admit to this day of +being anything less than a medical student—the substance +called ozone became the topic of much conversation +and speculation. I cannot say that ozone was a +discovery of that date, for in the early part of the century +Von Marum had observed that when electrical +discharges were made through oxygen in a glass cylinder +inverted over water, the water rose in the cylinder +as if something had either been taken away from the +gas, or as if the gas itself had been condensed, and was +therefore occupying a smaller space. It had also been +observed by many electricians that during a passage of +the electric spark through air or oxygen, there was a +peculiar emanation or odor which some compared to +fresh sea air, others to the air after a thunderstorm, +when the sky has become very clear, the firmament +blue, and the stars, if visible, extremely bright.</p> + +<p>But it was not until the time, or about the time, of +which I have spoken, 1846-49, that these discovered but +unexplained phenomena received proper recognition. +The distinguished physicist Schonbein first, if I may +so say, isolated the substance which yielded the phenomena, +and gave to it the name, by which it has since +generally been known, of <i>ozone</i>, which means, to emit +an odor; a name, I have always thought, not particularly +happy, but which has become, practically, so +fully recognized and understood, that it would be +wrong now to disturb it.</p> + +<p>Schonbein made ozone by the action of the electric +spark on oxygen. He collected it, he tested its chemical +properties, he announced it to be oxygen in a modified +form, and he traced its action as an active oxidizer +of various substances, and especially of organic substances, +even when they were in a state of decomposition.</p> + +<p>But Schonbein went further than this. He argued +that ozone was a natural part of the atmosphere, and +that in places where there was no decomposition, that +is to say, in places away from great towns, ozone was +present. On the high tower of a cathedral in a big +city he discovered ozone; in the city, at the foot of the +tower, he found no ozone at the same time. He argued, +therefore, that the ozone above was used up in +purifying the town below, and so suggested quite a +new explanation of the purification of air.</p> + +<p>The subject was very soon taken up by English observers, +and I remember well a lecture upon it by +Michael Faraday, in which that illustrious philosopher, +confirming Schonbein, stated that he had discovered +ozone freely on the Brighton Downs, and had found the +evidence of it diminishing as he approached Brighton, +until it was lost altogether in the town itself.</p> + +<p>Such was the beginning of our knowledge of ozone, +the precise nature of which has not yet been completely +made out. At the present time it is held to be oxygen +condensed. To use a chemical phrase, the molecule +of oxygen, which in the ordinary state is composed +of two atoms, is condensed, in ozone, as three atoms. +By the electric spark discharged in dry oxygen as much +as 15 per cent. may, under proper conditions, be turned +into ozone. Ozone has also been found to be heavier +than air. Professor Zinno says, that compared with +an equal volume of air its density is equal to 1,658, and +that it is forty-eight times heavier than hydrogen. +Heat decomposes it; at the temperature of boiling +water it begins to decompose. In water it is much less +soluble than oxygen, and indeed is practically insoluble; +when made to bubble through boiling water, it +ceases to be ozone. The oxidizing power of ozone is +very much greater than that of oxygen, and, according +to Saret, when ozone is decomposed, one part of it enters +into combination, the other remains simply as +oxygen.</p> + +<p>It is remarkable that some substances, like turpentine +and cinnamon, absorb ozone and combine with it, +a simple fact of much greater importance than has ever +been attached to it. I found, for instance, that cinnamon +which by exposure to the air has been made odorless +and, as it is said, "spoiled," can be made to reabsorb +ozone and gain a kind of freshness. It is certain +also that some substances which are supposed to +have disinfecting properties owe what virtues they +possess to the presence of ozone.</p> + +<p>On some grand scale ozone is formed in the air, and +my former friend and colleague, the late Dr. Moffatt, +of Hawarden, with whom I wrote a paper on "Meteorology +and Disease," read before the Epidemiological +Society in 1852-53, described what he designated ozone +periods of the atmosphere, connecting these with +storms. When the atmospheric pressure is decreasing, +when with that there is increasing warmth and moisture, +and when south and southwesterly winds prevail, +then ozone is active; but when the atmospheric pressure +is increasing, when the air is becoming dry and +cold, and north and northeasterly winds prevail, then +the presence of ozone is less active. These facts have +also been put in another way, namely, that the maximum +period of ozone occurs when there is greatest +evaporation of water from the earth, and the minimum +when there is greatest condensation of water on the +earth; a theory which tallies well with the idea that +ozone is most freely present when electricity is being +produced, least present when electricity is in smallest +quantity. Mr. Buchan, reporting on the observations +of the Scottish Meteorological Society, records that +ozone is most abundant from February to June, when +the average amount is 6.0; and least from July to +January, when the average is 5.7; the maximum, 6.2, +being reached in May, and the minimum, 5.3, in November. +This same excellent observer states that +"ozone is more abundant on the sea coast than inland; +in the west than the east of Great Britain; in elevated +than in low situations; with southwest than with northeast +winds; in the country than in towns; and on the +windward than the leeward side of towns."</p> + +<p>Recently a very singular hypothesis has been broached +in regard to the blue color of the firmament and +ozone. It has been observed that when a tube is filled +with ozone, the light transmitted through it is of a blue +color; from which fact it is assumed that the blue color +of the sky is due to the presence of this body in the higher +atmospheric strata. The hypothesis is in entire accord +with the suggestion of Professor Dove, to which +Moffatt always paid the greatest respect, viz., that the +source of ozone for the whole of the planet is equatorial, +and that the point of development of ozone is where +the terrestrial atmosphere raised to its highest altitude, +at the equator, expands out north and south in opposite +directions toward the two poles, to return to the +equator over the earth as the trade winds.</p> + +<p>It is necessary for all who would understand the applications +of ozone for any purpose, whether for bleaching +purposes or pure chemical purposes, or for medical +or sanitary purposes, to understand these preliminary +facts concerning it, facts which bring me to the +particular point to which I wish to refer to-day.</p> + +<p>In my essay describing the model city, Hygeiopolis, +it was suggested that in every town there should be a +building like a gas house, in which ozone should be +made and stored, and from which it should be dispensed +to every street or house at pleasure. This suggestion +was made as the final result of observations +which had been going on since I first began to work +at the subject in 1852. It occurred to me from the +moment when I first made ozone by Schonbein's method, +that the value of it in a hygienic point of view +was incalculable.</p> + +<p>To my then young and enthusiastic mind it seemed +that in ozone we had a means of stopping all putrefaction, +of destroying all infectious substances, and of +actually commanding and destroying the causes which +produced the great spreading diseases; and, although +increase of years and greater experience have toned +down the enthusiasm, I still believe that here one of +the most useful fields for investigation remains almost +unexplored.</p> + +<p>In my first experiments I subjected decomposing +blood to ozone, and found that the products of decomposition +were instantly destroyed, and that the fluid +was rendered odorless and sweet. I discovered that +the red corpuscles of fresh blood decomposed ozone, +and that coagulated blood underwent a degree of solution +through its action. I put dead birds and pieces +of animal substances that had undergone extreme decomposition +into atmospheres containing ozone, and +observed the rapidity with which the products of decomposition +were neutralized and rendered harmless. +I employed ozone medicinally, by having it inhaled +by persons who were suffering from fœtor of the breath, +and with remarkable success, and I began to employ +it and have employed it ever since (that is to say, for +thirty-seven years), for purposes of disinfection and +deodorization, in close rooms, closets, and the like. +I should have used it much more largely but for one +circumstance, namely, the almost impracticable difficulty +of making it with sufficient ease and in sufficient +quantities to meet the necessities of sanitary practice. +We are often obstructed in this way. We know of +something exceedingly useful, but we cannot utilize +it. This was the case with ozone. I hope now that +difficulty is overcome. If it is, we shall start from this +day on a new era in regard to ozone as an instrument +of sanitation.</p> + +<p>As we have seen, ozone was originally made by +charging dry oxygen or common dry air with electricity +from sparks or points. Afterward Faraday showed +that it could be made by holding a warm glass rod in +vapor of ether. Again he showed that it could be +made by passing air over bright phosphorus half immersed +in water. Then Siemens modified the electric +process by inventing his well known ozone tube, which +consists of a wide glass tube coated with tinfoil on its +outside, and holding within it a smaller glass tube +coated with tinfoil on its surface. When a current of +dry air or oxygen was passed in current between these +two tubes, and the electric spark from a Ruhmkorf +coil was discharged by the terminal wires connected +with tinfoil surfaces, ozone was freely produced, and +this was no doubt the best method, for by means of a +double-acting hand bellows currents of ozone could be +driven over very freely. One of these tubes with hand +bellows attached, which I have had in use for twenty-four +years, is before the meeting, and answers as well +as ever. The practical difficulty lies in the requirement +of a battery, a large coil, and a separate bellows +as well as the tube.</p> + +<p>My dear and most distinguished friend, the late Professor +Polli, of Milan, tried to overcome the difficulties +arising from the use of the coil by making ozone chemically, +namely, by the decomposition of permanganate +of potassa with strong sulphuric acid. He placed the +permanganate in glass vessels, moistened it gradually +with the acid, and then allowed the ozone, which is +formed, to diffuse into the air. In this way he endeavored, +as I had done, to purify the air of rooms, especially +those vitiated by the breaths of many people. +When he visited me, not very long before his death, he +was enthusiastic as to the success that must attend the +utilization of ozone for purification, and when I expressed +a practical doubt, he rallied me by saying I +must not desert my own child. At the theater La +Scala, on the occasion of an unusually full attendance, +Polli collected the condensible part of the exhaled organic +matter, by means of a large glass bell filled with +ice and placed over the circular opening in the roof, +which corresponds with the large central light. The +deposit on this bell was liquid and had a mouldy smell; +was for some few days limpid, but then became very +thick and had a nauseous odor. When mixed with a +solution of one part glucose to four parts of water, and +kept at a temperature of from 20° to 24° C., this liquid +underwent a slow fermentation, with the formation, +on the superficies, of green must; during the same +period of time, and placed under the same conditions, +a similar glucose solution underwent no change whatever.</p> + +<p>By the use of his ozone bottles Polli believed that he +had supplied a means most suitable for directly destroying +in the air miasmatic principles, without otherwise +interfering with the respiratory functions. The +ozonized air had neither a powerful nor an offensive +smell, and it might be easily and economically made. +The smell of ozone was scarcely perceptible, and was +far less disagreeable than chlorine, bromine, and iodine, +while it was more efficacious than either of these; if, +therefore, its application as a purifier of a vitiated air +succeeded, it would probably supply all the exigences +of defective ventilation in crowded atmospheres. In +confined places vessels might be placed containing +mixtures of permanganate of potassa or soda and acid +in proper quantities, and of which the duration of the +action was known; or sulphuric acid could be dropped +upon the permanganate.</p> + +<p>This idea of applying ozone was no doubt very ingenious, +and in the bottles before us on the table, +which have been prepared in Hastings by Mr. Rossiter, +we see it in operation. The disadvantages of the plan +are that manipulation with strong sulphuric acid is +never an agreeable or safe process, and that the ozone +evolved cannot be on a large scale without considerable +trouble.</p> + +<p>In 1875 Dr. Lender published a process for the production +of ozone. In this process he used equal parts +of manganese, permanganate of potash, and oxalic +acid. When this mixture is placed in contact with +water, ozone is quickly generated. For a room of +medium size two spoonfuls of this powder, placed in a +dish and occasionally diluted with water, would be +<ins class="correction" title="Transcriber's Note: original reads 'sufficent'">sufficient</ins>. +As the ozone is developed, it disinfects the +surrounding air without producing cough.</p> + +<p>Lender's process is very useful when ozone is wanted +on a limited scale. We have some of it here prepared +by Mr. Rossiter, and it answers exceedingly well; but it +would be impossible to generate sufficient ozone by this +plan for the large application that would be required +should it come into general use. The process deserves +to be remembered, and the physician may find it +valuable as a means by which ozone may be medically +applied, to wounds, or by inhalation when there are +fœtid exhalations from the mouth or nostrils.</p> + + +<h3>A NEW METHOD.</h3> + +<p>For the past ten or fifteen years the manufacture of +ozone, for the reasons related above, has remained in +abeyance, and it is to a new mode, which will, I trust, +mark another stage of advancement, that I now wish +to direct attention. Some years since, Mr. Wimshurst, +a most able electrician, invented the electrical +machine which goes by his name. The machine, as +will be seen from the specimen of it on the table, looks +something like the old electrical machine, but differs +in that there is no friction, and that the plates of glass +with their metal sectors, separated a little distance +from each other, revolve, when the handle of the machine +is turned, in opposite directions. The machine +when it is in good working order (and it is very easily +kept in good working order) produces electricity +abundantly, and in working it I observed that ozone +was so freely generated, that more than once the air +of my laboratory became charged with ozone to an +oppressive degree. The fact led me to use this machine +for the production of ozone on a large scale, in +the following way.</p> + +<p>From the terminals of the machine two wires are carried +and are conducted, by their terminals, to an ozone +generator formed somewhat after the manner of +Siemens', but with this difference, that the discharge +is made through a series of fine points within the +cylinders. The machine is placed on a table with the +<a name="Page_11461" id="Page_11461"></a> +ozone generator at the back of it, and can be so arranged +that with the turning of the handle which +works the machine a blast of air is carried through the +generator. Thus by one action electricity is generated, +sparks are discharged in the ozone generator, air is +driven through, and ozone is delivered over freely.</p> + +<p>If it be wished to use pure oxygen instead of common +air, nothing more is required than to use compressed +oxygen and to allow a gentle current to pass through +the ozone generator in place of air. For this purpose +Brin's compressed oxygen is the purest and best; but +for ordinary service atmospheric air is +sufficient.<a name="FNanchor_18_2" id="FNanchor_18_2"></a><a href="#Footnote_18_2"><sup>2</sup></a></p> + + +<p>The advantages of this apparatus are as follows:</p> + +<p>1. With care it is always ready for use, and as no +battery is required nor anything more than the turning +of a handle, any person can work it.</p> + +<p>2. It can be readily moved about from one part of a +room or ward to another part.</p> + +<p>3. If required for the sick it can be wheeled near the +bedside and, by a tube, the ozone it emits can be +brought into action in any way desired by the physician.</p> + +<p>I refer in the above to the minor uses of ozone by +this method, but I should add that it admits of application +on a much grander scale. It would now be +quite easy in any public institution to have a room in +which a large compound Wimshurst could be worked +with a gas engine, and from which, with the additional +apparatus named, ozone could be distributed at +pleasure into any part of the building. On a still +larger scale ozone could be supplied to towns by this +method, as suggested in Hygeiopolis, the model city.</p> + +<p>It will occur, I doubt not, to the learned president +of this section, and to others of our common profession, +that care will have to be taken in the application +of ozone that it be used with discretion. This is true. +It has been observed in regard to diseases, that in the +presence of some diseases ozone is absent in the atmosphere, +but that with other diseases ozone is present +in abundance. During epidemics of cholera, ozone is +at a minimum. During other epidemics, like influenza, +it has been at a maximum. In our paper Dr. Moffatt +and I classified diseases under both conditions, and the +difference must never be forgotten, since in some +diseases we might by the use of ozone do mischief instead +of good. Moreover, as my published experiments +have shown, prolonged inhalation of ozone produces +headache, coryza, soreness of the eyes, soreness +of the throat, general malaise, and all the symptoms of +severe influenza cold. Warm-blooded animals, also, +exposed to it in full charge, suffer from congestion of +the lungs, which may prove rapidly fatal. With care, +however, these dangers are easily avoided, the point of +practice being never to charge the air with ozone too +abundantly or too long.</p> + +<p>A simple test affords good evidence as to presence of +ozone. If into twenty ounces of water there be put +one ounce of starch and forty grains of potassium iodide, +and the whole be boiled together, a starch will be +made which can be used as a test for ozone. If ozone +be passed through this starch the potassium is oxidized, +and the iodine, set free, strikes a blue color with the +starch. Or bibulous paper can be dipped in the starch, +dried and cut into slips, and these slips being placed in +the air will indicate when ozone is present. In disinfecting +or purifying the air of a room with ozone, there +is no occasion to stop until the test paper, by change +of color, shows that the ozone has done its work of +destroying the organic matter which is the cause of +impurity or danger. For my own part, I have never +seen the slightest risk from the use of ozone in an impure +air. The difficulty has always been to obtain +sufficient ozone to remove the impurity, and it is this +difficulty which I hope now to have conquered.—<i>The +Asclepiad.</i></p> + +<p><a name="Footnote_18_1" id="Footnote_18_1"></a><a href="#FNanchor_18_1">[1]</a></p> +<div class="note">Paper read in Section C, Domestic Health, at +the Hastings Health Congress, on Friday, May 3, 1889.</div> + +<p><a name="Footnote_18_2" id="Footnote_18_2"></a><a href="#FNanchor_18_2">[2]</a></p> +<div class="note">For illustration to-day, Messrs Mayfield, the +electrical engineers of Queen Victoria Street, E. C., have +been good enough to lend me a machine fitted up on the plan named. +It works so effectively that I can make the ozone given off from +it detectable in every part of this large hall.</div> + +<hr /> + + + + +<h2><a name="art19" id="art19"></a>HEAT IN MAN.</h2> + + +<p>At a recent meeting of the Physiological Society of +Berlin, Prof. Zuntz spoke on heat regulation in man, +basing his remarks on experiments made by Dr. +Loewy. The store of heat in the human body at any +one time is very large, equal, in fact, to nearly all the +heat produced by the body during twenty hours, hence +the heat given off to a calorimeter during a given period +cannot be taken as a measure of the heat production. +This determination must be based rather upon +the amount of oxygen consumed and of carbonic acid +gas given off. The purpose of the experiments was to +ascertain what alteration the gaseous interchange of the +body undergoes by the application of cold, inasmuch +as existing data on this point are largely contradictory.</p> + +<p>The observations were made on a number of men +whose respiratory gases were compared, during complete +rest, when they were at one time clothed, at another +time naked, at temperatures from 12° to 15° C., +and in warm and cold baths. Each experiment lasted +from half an hour to an hour, during which period the +gases were repeatedly analyzed. As a result of fifty-five +experiments, twenty showed no alteration of oxygen +consumption as the result of cooling, nine gave a +lessened consumption, while the remaining twenty-six +showed an increased using up of oxygen. This diversity +of result is explicable on the basis of observations +made by Prof. Zuntz, who was himself experimented +upon, as to his subjective heat sensations during the +experiments. He found that after the first impression +due to the application of cold is overcome, it was quite +easy to maintain himself in a perfectly passive condition; +subsequently it required a distinct effort of the +will to refrain from shivering and throwing the muscles +into activity, and finally even this became no longer +possible, and involuntary shivering and muscular contraction +supervened, as soon as the body temperature +(<i>in ano</i>) had fallen ½° to 1° C. During the first stage +of cooling, Zuntz's oxygen consumption showed a uniform +diminution; during the period also in which +shivering was repressed by an effort of the will, cooling +led to no increased consumption of oxygen, but as +soon as shivering became involuntary there was at once +an increased using up of oxygen and excretion of carbonic +acid.</p> + +<p>This explains the differences in the results of Dr. +Loewy's experiments, and may be taken to show that +in man, and presumably in <i>large</i> animals, heat regulation +as directly dependent upon alteration (fall) in +temperature of the surrounding medium does not exist; +the increased heat production is rather the outcome of +the movements resulting from the application of cold +to the body. In <i>small</i> animals, on the other hand, +there undoubtedly exists a heat regulation dependent +upon an increased activity of chemical changes in the +tissues set up by the application of cold to the surface +of the body, and in this case the thermotaxic centers +in the brain most probably play some part.—Dr. Herter +gave an account of experiments made by Dr. Popoff +on the artificial digestion of various and variously +cooked meats. Lean beef and the flesh of eels and +flounders were digested in artificial gastric juice; the +amount of raw flesh thus peptonized was in all cases +greater than that of cooked meat similarly treated. +The flesh was shredded and heated by steam to 100° C. +The result was the same for beef as for fish. When +compared with each other, beef was, on the whole, the +most digestible, but the amount of fish flesh which +was peptonized was sufficiently great to do away with +the evil repute which fish still has in Germany as a +proteid food. Smoked meat differed in no essential +extent from raw meat as regards its digestibility.</p> + +<hr /> + + + + +<h2><a name="art20" id="art20"></a>PRESERVATION OF SPIDERS FOR THE +CABINET.</h2> + + +<p>For several years past, I have devoted a portion of +my leisure time to the arrangement of the collection of +Arachnidæ of the Natural History Museum of the +University of Gand. This collection, which is partially +a result of my own captures, is quite a large one, for +a university museum, since it comprises more than six +hundred European and foreign specimens. Each +group of individuals of the small forms and each +individual of the large forms is contained in a bottle +of alcohol closed with a ground glass stopper, and, +whenever possible, the specimens have been spread +out and fixed upon strips of glass.</p> + +<p>The loss of alcohol through evaporation is almost +entirely prevented by paraffining the stoppers and +tying a piece of bladder over them.</p> + +<p>Properly labeled, the series has a very satisfactory +aspect, and is easily consulted for study. The reader, +however, will readily understand how much time and +patience such work requires, and can easily imagine +how great an amount of space the collection occupies, +it being at least twenty times greater than that that +would be taken up by a collection of an equal number +of insects mounted in the ordinary way on pins and +kept in boxes.</p> + +<p>These inconveniences led me to endeavor to find out +whether there was not some way of preserving spiders, +properly so called, in a dry state, and without distortion +or notable modification of their colors.</p> + +<p>Experience long ago taught me that pure and simple +desiccation, after a more or less prolonged immersion +in alcohol, gives passable results only with scorpions, +galeodes, phrynes, and mygales, and consequently with +arachnides having thick integuments, while it is entirely +unsuccessful with most of the spiders. The +abdomen of these shrivels, the characteristic colors +disappear in great part, and the animals become unrecognizable.</p> + +<p>Something else was therefore necessary, and I +thought of carbolated glycerine. My process, which +I have tried only upon the common species of the +country—<i>Tegenaria domestica</i>, <i>Epeira cucurbitina</i>, +<i>Zilla inclinata</i>, etc., having furnished me with preparations +that were generally satisfactory. I think I +shall be doing collectors a service by publishing it in +the <i>Naturaliste</i>.</p> + +<p>The specimens should first be deprived of moisture, +that is to say, they should be allowed to remain eight +or ten days in succession in 50 per cent. alcohol and in +pure commercial alcohol. Absolute alcohol is not +necessary.</p> + +<p>After being taken from the alcohol, and allowed to +drain, the specimens are immersed in a mixture compound +of</p> + +<ul> +<li>Pure glycerine 2 volumes,</li> +<li>Pure carbolic acid in crystals 1 volume.</li> +</ul> + +<p>In this they ought to remain at least a week, but +there will be no harm if they are left therein indefinitely, +so that the collections of summer may be +mounted during winter evenings.</p> + +<p>What follows is a little more delicate, although very +easy. After being removed from the carbolated glycerine, +the spiders are placed upon several folds of white +filtering paper, and are changed from time to time +until the greatest part of the liquid has been absorbed. +An insect pin is then passed through the cephalothorax +of each individual and is inserted in the support upon +which the final desiccation is to take place. This support +consists of a piece of sheet cork tacked or glued +at the edges to a piece of wood at least one inch in +thickness. Upon the cork are placed four or five folds +of filtering paper, so that the ventral surface of the pinned +spider is in contact with this absorbing surface. +For the rest, the legs, palpi, spinnerets, etc., are spread +out by means of fine pins, precisely as would be done +in the case of coleoptera.</p> + +<div class="figcenter"> +<img src="./images/20_1.png" width="400" height="239" alt="SETTING BOARD FOR SPIDERS." /> + +<p class="caption">SETTING BOARD FOR SPIDERS.<br /> +A. Absorbent papers. B. Sheet cork. C. Wooden support.</p> +</div> + +<p>The setting board is put for two or three months in +a very dry place under cover from dust.</p> + +<p>The spiders thus treated will scarcely have changed +in appearance, the abdomen of the largest Epeiras will +have preserved its form, the hairs will in nowise have +become agglutinated, and a person would never suspect +that glycerine had performed the role.</p> + +<p>The forms with a large abdomen require a special +precaution; it is necessary to pass the mounting pin +through a piece of thin cardboard or of gelatine prolonged +behind under the abdomen, because the latter +is heavy, and the pedicel that connects it with the +cephalothorax easily breaks.</p> + +<p>The specimens are mounted in boxes lined with cork, +just as insects are.</p> + +<p>As there is nothing simpler than to have in one's laboratory +three bottles, two of them containing alcohol and +the other containing carbolated glycerine, and as it is +easy to make setting boards capable of holding from +twenty to thirty individuals at once, it will be seen +that, with a little practice, the method is scarcely +any more complicated than the one daily employed +for coleoptera and orthoptera, which latter, too, must +pass through alcohol, and be pinned, spread out, and +dried. There are but two additional elements, carbolated +glycerine and absorbent paper. I do not estimate +the time necessary for desiccation as being very +long, since the zoologist can occupy himself with other +subjects while the specimens are drying. Let us add +that the process renders the preservation indefinite, +and that destructive insects are not to be feared. Some +vertebrates, such as monkeys, that I preserved in the +flesh ten years ago, by a nearly identical method, are +still intact—<i>F. Plateau, in Le Naturaliste.</i></p> + +<hr /> + + + + +<h2><a name="art21" id="art21"></a>DRIED WINE GRAPES.</h2> + + +<p>According to a report of the Committee of the Grape +Growers' and Wine Maker's Association of California, +the drying of wine grapes on a large scale was begun +during the vintage season of 1887, in which season +about eight carloads in all were made and sold, the +bulk of which came from the vicinity of Fresno; that +year, the committee are informed, the growers netted +about three and a half cents per pound. During the +season of 1888 about 112 carloads were dried, packed, +and sold, netting the growers from two and a half to +three and a half cents per pound, depending on the +quality of the fruit. The great bulk of that year's +product has entered into consumption, but there yet +remains unsold to consumers, we are informed, about +ten carloads, which, it is expected, will be sold during +the next three months. It has been observed by those +handling this product that the largest sales of dried +wine grapes in 1888 and 1889 took place at those points +to which the first lots were shipped in 1887, which +would show that as the product becomes better known +it finds a readier market.</p> + +<p>Dried wine grapes are prepared in a similar manner +to raisins; that is they are dried in the sun, but do not +require the same care in handling that are given to +raisins. Wooden trays 2 × 3 are sometimes used, but +it is by no means necessary to go to the expense of +procuring trays, as it has been found that a good quality +of coarse brown paper will answer every purpose, +and this, with care, may be made to last two or three +seasons. The drying was last season principally done +on the bare ground, but there is much loss by shelling, +as those dried are required to be turned; a pitchfork +is used for that purpose. Brown building paper can be +procured of city paper dealers in large rolls at four and +a half cents per pound; according to the thickness, it +will cost from one and three-quarters to three and a +half cents per square yard. A thin, tough, waterproof +paper is also made in rolls at about six cents a square +yard. Wine grapes dry in from ten days to three weeks, +according to variety and weather, and with the exception +of Malvoisie, Rose of Peru, and Black Hamburg, +from three and a half to four and a half tons of the +green fruit are required to make one of the dried; +these three varieties, however, being large, meaty, and +a firm pulp, do not require more than from three to +three and a half tons of the green fruit to produce one +ton of dried, and are, therefore, the most profitable for +drying; they also command better values in the market. +The grapes are sufficiently dried when, on being +rolled between the thumb and finger, no moisture exudes, +and also when the stems are found to be dry and +brittle, so that they can be separated readily from the +berries. After the grapes have reached the proper +state of dryness, they are taken in boxes or sacks to +the packing house, where they are +<ins class="correction" title="Transcriber's Note: original reads 'steamed'">stemmed</ins> and cleaned, +after which they are packed in white cotton sacks, +holding from fifty to seventy-five pounds each, and +when marked are ready for shipment.</p> + +<p>The stemming and cleaning of the dried grapes is +done by special machines designed for that purpose, +which leaves the fruit in a bright, clean condition attractive +to purchasers. These machines are at present +built only by James Porteous, Fresno, and are operated +either by hand or power. The cost of a stemmer +and cleaner complete is $80, f. o. b. cars at Fresno. +Where several producers can do so, it would be advisable +to club together and get the machine in this way. +Much extra expense could be avoided and one set of +machinery would serve several vineyards, possibly an +entire district where time was not a great object; or +some one person in a district could purchase an outfit +and do the work by contract, going from place to place. +The capacity of the stemmer and cleaner is from five +to eight tons per day, when the grapes are in proper +condition; and the cost or charge for stemming, cleaning, +sacking, and sewing up the sacks is from four to +five dollars per ton when the producer furnishes the +sacks. Good cotton sacks, holding about seventy-five +pounds, cost from eight to ten cents each, including +the necessary twine. Last year dried grapes were generally +sold for cash, f. o. b., but it is probable that +other markets could be secured by selling on consignment.</p> + +<p>As to the advisability of such a course, each producer +must himself be the judge. It is, however, quite certain +that until consumers have an opportunity to try +this product, the sales will necessarily be more or less +limited, unless vigorously pushed by merchants and +others interested in extending the markets for California +products in the Eastern cities not yet tried. The +varieties most suitable and profitable for drying, and +especially for consumption in the Eastern markets, are +the Malvoisie, Rose of Peru, Black Hamburg, Mission, +Zinfandel, Charbono, Grenache, and in some localities +the Carignan, of the dark varieties, and the Feher +<a name="Page_11462" id="Page_11462"></a> +Zagos and Golden Chasselas of the white grapes; there +are many other white grapes that are excellent when +dried, but are too valuable for wine-making purposes, +or are too small or deficient in sugar for use as dried +grapes.</p> + +<p>The same is true of the dark grapes, some of which +ripen so late that it would be impossible to dry them +in the sun, and the use of artificial heat is, at present +prices, too expensive. Therefore, the varieties mentioned, +which generally mature early, are found to be +the most suitable for this purpose. This product is +sold by dealers in the Eastern cities for cooking purposes, +and as a substitute for dried fruits, such as +peaches, apples, apricots, etc., in comparison with +which it is usually much cheaper; while for stewing +and for puddings and pies it answers the same purpose. +The demand for this product will probably be gauged +by the Eastern fruit crop; that is, the quantity that +can be disposed of will depend upon the quantity of +Eastern fruit in the market, and the prices will be +largely dependent upon that of dried fruit.</p> + +<hr /> + + + + +<h2><a name="art22" id="art22"></a>WALNUT OIL.</h2> + +<h3>By <span class="sc">Thomas T. P. Bruce Warren.</span></h3> + + +<p>This oil, which I obtained from the fully ripened +nut of the <i>Jugluns regia</i>, has so many excellent properties, +especially for mixing with artists' colors for fine +art work, that I am surprised at the small amount of +information available on this interesting oil.</p> + +<p>Walnut oil is largely used for adulterating olive oil, +and to compensate for its high iodine absorption it is +mixed with pure lard oil olein, which also retards the +thickening effect due to oxidation. The marc left on +expression of the oil is said to be largely used in the +manufacture of chocolate. Many people, I am told, +prefer walnut oil to olive oil for cooking purposes.</p> + +<p>The value of this oil for out-door work has been given +me by a friend who used it for painting the verandas +and jalousies of his house (near Como, Italy) some +twenty years ago, and which have not required painting +since. In this country, at least, walnut oil is beyond +the reach of the general painter, and I do not +know that the pure oil is to be obtained as a commercial +article, even on a small scale.</p> + +<p>It was in examining the properties of this and other +oils, used as adulterants of olive oil, that I was obliged +to prepare them so as to be sure of getting them in a +reliable condition as regards purity. The walnuts +were harvested in the autumn of 1887, and kept in a +dry airy room until the following March. The kernels +had shrunk up and contracted a disagreeable acrid +taste, so familiar with old olive oil in which this has +been used as an adulterant. Most oxidized oils, especially +cotton seed oil, reveal a similar acrid taste, but +walnut oil has, in addition, an unmistakable increase +in viscosity. The nuts were opened and the kernels +thrown into warm water, so as to loosen the epidermis; +they were then rubbed in a coarse towel, so as to +blanch them. The decorticated nuts were wiped dry +and rubbed to a smooth paste in a marble mortar. +The paste was first digested in CS<sub>2</sub>, then placed in a +percolator and exhausted with the same solvent, which +was evaporated off. The yield of oil was small, but +probably, if the nuts had been left to fully ripen on the +trees without knocking them off, the yield might have +been greater. It is by no means improbable that oxidation +may have rendered a portion of the oil insoluble. +The decorticated kernels gave a perfectly sweet, inodorous, +and almost colorless oil, which rapidly thickens to +an almost colorless, transparent, and perfectly elastic +skin or film, which does not darken or crack easily by +age. These are properties which, for fine art painting, +might be of great value in preserving the tinctorial +purity and freshness of pigments.</p> + +<p>Sulphur chloride gives a perfectly white product +with the fresh oil, but, when oxidized, the product is +very dark, almost black. The iodine absorption of the +fresh oil thus obtained is very high, but falls rapidly +by oxidation or blowing. A curious fact has been disclosed +with reference to the oxidation of this and similar +oils. If such an oil be mixed with lard oil, olive oil, +or sperm oil, it thickens by oxidation, but is perfectly +soluble. Such a mixture is largely used in weaving or +spinning. Commercial samples of linseed oil, when +cold-drawn, have a much higher iodine absorption, +probably due to the same cause. Oils extracted by CS<sub>2</sub> +are very much higher than the same oils, especially if +hot-pressed.—<i>Chem. News.</i></p> + +<hr /> + + + + +<h2><a name="art23" id="art23"></a>THE PYRO DEVELOPER WITH METABISULPHITE +OF POTASH.</h2> + +<h3>By Dr. <span class="sc">J. M. Eder.</span></h3> + + +<p>Lately I called attention to the metabisulphite of +potassium as an addition to the pyro solution for +development, and can give now some of my experiences +with this salt.</p> + +<p>The metabisulphite of potassium, which was introduced +into the market by Dr. Schuchardt, and whose +correct analysis is not known yet, is a white crystal, +which in a solid condition, as well as in an aqueous +solution, has a strong smell of sulphurous acid. An +aqueous 2 per cent. solution of this salt dissolves pyrogallic +acid to a weak yellowish color, being distinguished +from the more light brown solution of sulphite +of soda and pyro. The solution kept very +well for four weeks in half-filled bottles, and showed a +better preservation than the usual solution of pyro and +sulphite of soda. More than 2 per cent. of the metabisulphite +of potassium is without any advantage. If +this solution is mixed with soda, a picture will develop +rapidly, but the same will show a strongly yellow coloration +in the gelatine film. Sulphite of soda has to be +added to the soda <ins class="correction" title="Transcriber's Note: original reads 'sulution'">solution</ins> +to obtain an agreeable +brownish or black tone in the negatives.</p> + +<p>If the contents of metabisulphite and pyro-soda developer +are increased, it will act very slowly; larger +quantities of the metabisulphite of potassium, therefore, +act like a strong retarder. In small quantities +there is no injurious retarding action, but it will have +the effect that the plates obtain very clear shadows +in this developer, and that the picture appears slower, +and will strengthen more slowly. The strongly retarding +action of larger quantities of metabisulphite might +be accounted for in that the bisulphite will give, with +the carbonate of soda, monosulphite and soda bicarbonate, +which latter is not a strong enough alkali to +develop the bromide of silver strongly with pyro. An +increase of soda compensates this retarding action of +the metabisulphite of potassium.</p> + +<p>Good results were obtained by me with this salt +after several tests, by producing the following solutions:</p> + +<table cellpadding="2" summary="Pyro solution A"> +<tr> +<td colspan="3" align="center">A.</td> +</tr> +<tr> +<td align="left" style="padding-right: 1em;">Pyrogallic acid</td> +<td align="right">4</td> +<td>grammes.</td> +</tr> +<tr> +<td align="left" style="padding-right: 1em;">Metabisulphite of potassium</td> +<td align="right">1½</td> +<td align="center">"</td> +</tr> +<tr> +<td align="left" style="padding-right: 1em;">Water</td> +<td align="right">100</td> +<td align="left">c. c.</td> +</tr> +</table> + +<p>This solution keeps for weeks in corked bottles.</p> + +<table cellpadding="2" summary="Soda solution B"> +<tr> +<td colspan="3" align="center">B.</td> +</tr> +<tr> +<td align="left" style="padding-right: 1em;">Crystallized soda</td> +<td align="right">10</td> +<td>grammes.</td> +</tr> +<tr> +<td align="left" style="padding-right: 1em;">Neutral sulphite of soda</td> +<td align="right">15</td> +<td align="center">"</td> +</tr> +<tr> +<td align="left" style="padding-right: 1em;">Water</td> +<td align="right">100</td> +<td align="left">c. c.</td> +</tr> +</table> + +<p>Before using mix—</p> + +<table cellpadding="2" summary="Mixture of A and B"> +<tr> +<td align="left" style="padding-right: 1em;">Pyro solution A</td> +<td align="right">20</td> +<td>c. c.</td> +</tr> +<tr> +<td align="left" style="padding-right: 1em;">Soda solution B</td> +<td align="right">20</td> +<td align="center">"</td> +</tr> +<tr> +<td align="left" style="padding-right: 1em;">Water</td> +<td align="right">20</td> +<td align="center">"</td> +</tr> +</table> + +<p>The developer acts about one and a half times slower +than the ordinary pyro soda developer, approaching +to the latter pretty nearly, and gives to the negatives +an agreeable color and softness, with clear shadows. +If the negatives are to be thinner, more water, say +30 to 40 c. c., is taken. If denser, then the soda is increased, +and the water in the developer is reduced. An +alum bath before fixing is to be recommended.</p> + +<p>An advantage of this development is the great durability +of the pyro-meta sulphite solution. The cost +price is about the same as that of the ordinary pyro +developer. At all events, it is worth while to make +further investigation with the metabisulphite of potassium, +the same being also a good preservative for +hydroquinone solutions.—<i>Photographische Correspondenz; +Reported in the Photo. News.</i></p> + +<hr /> + + + + +<h2>A New Catalogue of Valuable Papers</h2> + + +<p>Contained in <span class="sc">Scientific American Supplement</span> +during the past ten years, sent <i>free of charge</i> to any +address.</p> + +<p class="address">MUNN & CO., 361 Broadway, New York.</p> + +<hr /> + + + + +<h2>THE SCIENTIFIC AMERICAN</h2> + +<h2>Architects and Builders Edition.</h2> + +<h3>$2.50 a Year. 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You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Scientific American Supplement, No. 717, September 28, 1889 + +Author: Various + +Release Date: February 12, 2006 [EBook #17755] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN *** + + + + +Produced by Amy Cunningham, Juliet Sutherland and the +Online Distributed Proofreading Team at http://www.pgdp.net + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 717 + + + + +NEW YORK, SEPTEMBER 28, 1889. + +Scientific American Supplement. Vol. XXVIII., No. 717. + +Scientific American established 1845. + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + * * * * * + + + + +TABLE OF CONTENTS. + + +I. CIVIL ENGINEERING.--The Girard Hydraulic Railway.--One of + the great curiosities of the Paris exposition, the almost + frictionless railway, with sectional illustrations of its + structure.--8 illustrations. 11451 + +II. ELECTRICITY.--Early Electric Lighting.--Electric lighting in + Salem in 1859, a very curious piece of early history. 11458 + + Electric Motor for Alternating Currents.--A motor on an + entirely new principle for the application of the alternating + current with results obtained, and the economic outlook of + the invention. 11458 + + Portable Electric Light.--A lamp for military and other use, + in which the prime motor, including the boiler and the lamp + itself, are carried on one carriage.--1 illustration. 11458 + + The Electric Age.--By CHARLES CARLETON COFFIN.--A short + _resume_ of the initial achievements of modern + electricity. 11458 + +III. GEOLOGY.--The Fuels of the Future.--A prognosis of the future + prospect of the world as regards a fuel supply, with a + special reference to the use of natural gas. 11457 + +IV. MISCELLANEOUS.--Preservation of Spiders for the Cabinet.--A + method of setting up spiders for preservation in the cabinet, + with formulae of solutions used and full details of the + manipulation.--1 illustration. 11461 + + The Ship in the New French Ballet of the "Tempest."--A + curious example of modern scenic perfection, giving the + construction and use of an appliance of the modern ballet.--5 + illustrations. 11450 + +V. NAVAL ENGINEERING.--Crank and Screw Shafts of the Mercantile + Marine.--By G. W. MANUEL.--This all-important subject of + modern naval engineering treated in detail, illustrating the + progress of the present day, the superiority of material and + method of using it, with interesting practical examples.--1 + illustration. 11448 + + Experimental Aid in the Design of High Speed Steamships.--By + D. P.--A plea for the experimental determination of the + probable speed of ships, with examples of its application in + practice. 11449 + + Forging a Propeller Shaft.--How large steamer shafts are + forged, with example of the operation as exhibited to the + Shah of Persia at Brown & Co.'s works, Sheffield, England.--1 + illustration. 11447 + + The Naval Forges and Steel Works at St. Chamond.--The forging + of a piece of ordnance from a 90 ton ingot of steel, an + artistic presentation of the subject.--1 illustration. 11447 + +VI. PHOTOGRAPHY.--The Pyro Developer with Metabisulphite of + Potash.--By Dr. J. M. EDER.--A new addition to the pyro + developer, with formulae and results. 11462 + +VII. PHYSICS.--Quartz Fibers.--A lecture by Mr. C. V. BOYS on his + famous experiments of the production of microscopic fibers, + with enlarged illustrations of the same, and a graphic + account of the entire subject.--7 illustrations. 11452 + + The Modern Theory of Light.--By Prof. OLIVER LODGE.--An + abstract of a lecture by the eminent investigator and + expositor of Prof. Hertz's experiments, giving a brief review + of the present aspect of this absorbing question. 11459 + +VIII. PHYSIOLOGY.--Heat in Man.--Experiments recently made by Dr. + Loewy on the heat of the human system.--Described and + commented on by Prof. ZUNTZ. 11461 + +IX. SANITATION.--On Purification of Air by Ozone--with an Account + of a New Method.--By Dr. B. W. RICHARDSON.--A very important + subject treated in full, giving the past attempts in the + utilization of ozone and a method now available. 11460 + +X. TECHNOLOGY.--Alkali Manufactories.--Present aspect of the + Leblanc process and the new process for the recovery of + sulphur from its waste. 11457 + + Dried Wine Grapes.--The preparation of the above wine on a + large scale in California, with full details of the process + adopted. 11461 + + The Production of Ammonia from Coal.--By LUDWIG MOND.--A + valuable review of this important industry, with actual + working results obtained in carrying out a retort process.--2 + illustrations. 11454 + + Nature, Composition, and Treatment of Animal and Vegetable + Fabrics.--The history of fabrics and fibers in the vegetable + and animal world, their sources, applications, and + treatments. 11453 + + Walnut Oil.--By Thomas T. P. BRUCE WARREN.--An excellent oil + for painters' use, with description of a simple method for + preparing it on a small scale. 11462 + + * * * * * + + + + +THE NAVAL FORGES AND STEEL WORKS AT ST. CHAMOND. + + +With the idyls and historic or picturesque subjects that the Universal +Exposition gives us the occasion to publish, we thought we would make +a happy contrast by selecting a subject of a different kind, by +presenting to our readers Mr. Layraud's fine picture, which represents +the gigantic power hammer used at the St. Chamond Forges and Steel +Works in the construction of our naval guns. By the side of the +machinery gallery and the Eiffel tower this gigantic apparatus is well +in its place. + +[Illustration: UNIVERSAL EXPOSITION--BEAUX ARTS--MARINE IRON AND STEEL +WORKS AT SAINT CHAMOND--PRESENTATION OF A PIECE OF ORDNANCE UNDER THE +VERTICAL HAMMER.--PICTURE BY M. JOSEPH LAYRAUD.] + +The following is the technical description that has been given to us +to accompany our engraving: In an immense hall, measuring 260 ft. in +length by 98 ft. in width, a gang of workmen has just taken from the +furnace a 90 ton ingot for a large gun for an armor-clad vessel. The +piece is carried by a steam crane of 140 tons power, and the men +grouped at the maneuvering levers are directing this incandescent mass +under the power hammer which is to shape it. This hammer, whose huge +dimensions allow it to take in the object treated, is one of the +largest in existence. Its striking mass is capable of reaching 100 +tons, and the height of the fall is 16 ft. To the left of the hammer +is seen a workman getting ready to set it in motion. It takes but one +man to maneuver this apparatus, and this is one of the characteristic +features of its construction. + +The beginning of this hammer's operation, as well as the operations of +the forge itself, which contains three other hammers of less power, +dates back to 1879. It is with this great hammer that the largest +cannons of the naval artillery--those of 16 inches--have been made +(almost all of which have been manufactured at St. Chamond), and +those, too, of 14, 13, and 12 inches. This is the hammer, too, that, a +few months ago, was the first to be set at work on the huge 13 in. +guns of new model, whose length is no less than 52 ft. in the rough. + +Let us add a few more figures to this account in order to emphasize +the importance of the installations which Mr. Layraud's picture +recalls, and which our great French industry has not hesitated to +establish, notwithstanding the great outlay that they necessitated. +This huge hammer required foundations extending to a depth of 32 ft., +and the amount of metal used in its construction was 2,640,000 pounds. +The cost of establishing the works with all the apparatus contained +therein was $400,000.--_Le Monde Illustre._ + + * * * * * + + + + +FORGING A PROPELLER SHAFT. + + +During the recent visit of the Shah of Persia to England, he visited, +among other places, the great works of John Brown & Co., at Sheffield, +and witnessed the pressing of a propeller shaft for one of the large +ocean steamships. The operation is admirably illustrated in our +engraving, for which we are indebted to the _Illustrated London News_. + +[Illustration: PROPELLER SHAFT BEING PRESSED AT MESSRS. JOHN BROWN & +CO.'S WORKS, SHEFFIELD.] + + * * * * * + + + + +CRANK AND SCREW SHAFTS OF THE MERCANTILE MARINE.[1] + +By G. W. MANUEL. + + [Footnote 1: A paper read before the Institute of Marine + Engineers, Stratford, 1889.] + + +Being asked to read a paper before your institute, I have chosen this +subject, as I think no part of the marine engine has given so much +trouble and anxiety to the seagoing engineer; and from the list of +shipping casualties in the daily papers, a large proportion seem due +to the shafting, causing loss to the shipowner, and in some instances +danger to the crew. My endeavor is to put some of the causes of these +casualties before you, also some of the remedies that have tended to +reduce their number. Several papers have been read on this subject, +chiefly of a theoretical description, dealing with the calculations +relating to the twisting and bending moments, effects of the angles of +the cranks, and length of stroke--notably that read by Mr. Milton +before the Institute of Naval Architects in 1881. The only _practical_ +part of this paper dealt with the possibility of the shafts getting +out of line; and regarding this contingency Dr. Kirk said that "if +superintendent engineers would only see that the bearings were kept in +line, broken crank and other shafts would not be so much heard of." Of +course this is one of those statements made in discussions of this +kind, for what purpose I fail to see, and as far as my own experience +goes is _misleading_; for having taken charge of steamers new from the +builders' hands, when it is at least expected that these shafts would +_be in line_, the crank shaft bearings heated very considerably, and +_continued_ to do so, rendering the duration of life of the crank +shaft a short one; and though they were never what is termed out of +line, the bearings could _not_ be kept cool without the use of sea +water, and occasionally the engines had to be stopped to cool and +smooth up the bearing surfaces, causing delays, worry, and anxiety, +for which the engineer in charge was in no way responsible. Happily +this state of what I might call _uncertainties_ is being gradually +remedied, thanks being largely due to those engineers who have the +skill to suggest improvements and the patience to carry them out +against much opposition. + +These improvements in many instances pertain to the engine builder's +duties, and are questions which I think have been treated lightly; +notably that of insufficient bearing surface, and one of the principal +causes of hot bearings, whereby the oil intended for lubrication was +squeezed out, and the metal surfaces brought too close in contact; and +when bearings had a pressure of 200 lb. per square inch, it has been +found that not more than 120 lb. per square inch should be exerted to +keep them cool (this varies according to the material of which the +bearing is composed), without having to use sea water and prevent them +being ground down, and thus getting out of line. I have known a +bearing in a new steamer, in spite of many gallons of oil wasted on +it, wear down one-eighth of an inch in a voyage of only 6,000 miles, +from insufficiency of bearing surface. + +Several good rules are in use governing the strength of shafts, which +treat of the diameter of the bearings only and angles of the cranks; +and the engine builder, along with the ship owner, has been chary of +increasing the surfaces by lengthening the bearings; for to do this +means increase of space taken up fore and aft the vessel, besides +additional weight of engine. Engine builders all aim in competing to +put their engines in less space than their rivals, giving same power +and sometimes more. I think, however, this inducement is now more +carefully considered, as it has been found more economical to give +larger bearing surfaces than to have steamers lying in port, refitting +a crank shaft, along with the consequences of heavy bills for salvage +and repairs, also the risk of losing the steamer altogether. +Proportioning the bearings to the weights and strains they have to +carry has also been an improvement. The different bearings of marine +engines were usually made alike in surface, irrespective of the work +each had to do, with a view to economy in construction. + +In modern practice the after bearings have more surface than the +forward, except in cases where heavy slide-valve gear has to be +supported, so that the wear down in the whole length of the shaft is +equal, thus avoiding those alternate bending strains at the top and +bottom of the stroke every revolution. Another improvement that has +been successfully introduced, adding to the duration of life of crank +shafts, is the use of white bearing metal, such as Parson's white +brass, on which the shafts run smoothly with less friction and +tendency to heat, so that, along with well proportioned surfaces, a +number of crank shafts in the Peninsular and Oriental Co.'s service +have not required lining up for eight years, and I hope with care may +last till new boilers are required. Large and powerful steamers can be +driven full speed from London to Australia and back without having any +water on the bearings, using oil of only what is considered a moderate +price, allowing the engineer in charge to attend to the economical +working of both engines and boilers (as well as many other engines of +all kinds now placed on board a large mail and passenger steamer), +instead of getting many a drenching with sea water, and worried by +close attention to one or two hot bearings all the watch. Compare +these results with the following: In the same service in 1864, and +with no blame to the engineer in charge, the crank shaft bearings of a +screw steamer had to be lined up every five days at intermediate +ports, through insufficient bearing surfaces. Sea water had +continually to be used, resulting in frequent renewal of crank shaft. +Steamers can now run 25,000 miles without having to lift a bearing, +except for examination at the end of the voyage. I would note here +that the form of the bearings on which the shafts work has also been +much improved. They are made more of a _solid character_, the metal +being more equally disposed _round_ the shaft, and the use of gun +metal for the main bearings is now fast disappearing. In large engines +the only metals used are cast iron and white brass, an advantage also +in reducing the amount of wear on the recess by corrosion and grinding +where sea water was used often to a considerable extent. + +[Illustration: Fig. 1 + Fig. 2] + +Figs. No. 1 and No. 2 show the design of the old and new main +bearings, and, I think, require but little explanation. Most of you +present will remember your feelings when, after a hot bearing, the +brasses were found to be cracked at top and bottom, and the trouble +you had afterward to keep these brasses in position. When a smoking +hot bearing occurred, say in the heating of a crank pin, it had the +effect of damaging the material of the shaft more or less, according +to its original soundness, generally at the fillets in the angles of +the cranks. For when the outer surface of the iron got hot, cold +water, often of a low temperature, was suddenly poured on, and the hot +iron, previously expanded, was suddenly contracted, setting up strains +which in my opinion made a small tear transversely where the metal was +_solid_; and where what is termed lamination flaws, due to +construction, existed, these were extended in their natural direction, +and by a repetition of this treatment these flaws became of such a +serious character that the shafts had to be condemned, or actually +gave way at sea. The introduction of the triple expansion engine, with +the three cranks, gave better balance to the shaft, and the forces +acting in the path of the crank pin, being better divided, caused more +regular motion on the shaft, and so to the propeller. This is +specially noticeable in screw steamers, and is taken advantage of by +placing the cabins further aft, nearer the propeller, the stern having +but little vibration; the dull and heavy surging sound, due to unequal +motions of the shaft in the two-crank engines, is exchanged for a more +regular sound of less extent, and the power formerly wasted in +vibrating the stern is utilized in propelling the vessel. In spite of +all these improvements I have mentioned, there remains the serious +question of defects in the material, due to variety of quality and the +extreme care that has to be exercised in all the stages during +construction of crank or other shafts built of iron. Many shafts have +given out at sea and been condemned, through no other cause than +_original defects_ in their construction and material. + +The process of welding and forging a crank shaft of large diameter now +is to make it up of so many small _pieces_, the _best shafts_ being +made of what is termed scrap, representing thousands of small pieces +of selected iron, such as cuttings of old iron boiler plates, +cuttings off forgings, old bolts, horseshoes, angle iron, etc., all +welded together, forged into billets, reheated, and rolled into bars. +It is then cut into lengths, piled, and formed into slabs of suitable +size for welding up into the shafts. No doubt this method is +preferable to the old method of "fagoting," so called, as the iron +bars were placed side by side, resembling a bundle of fagots of about +18 or 20 inches square. + +The result was that while the outside bars would be welded, the inside +would be improperly welded, or, the hammer being weak, the blow would +be insufficient to secure the proper weld, and it was no uncommon +thing for a shaft to break and expose the internal bars, showing them +to be quite separate, or only partially united. This danger has been +much lessened in late years by careful selection of the materials, +improved methods of cleaning the scrap, better furnaces, the use of +the most suitable fuels, and more powerful steam hammers. Still, with +all this care, I think I may say there is not a shaft without flaws or +defects, more or less, and when these flaws are situated in line of +the greatest strains, and though you _may not_ have a hot bearing, +they often extend until the shaft becomes unseaworthy. + +[Diagrams shown illustrated the various forms of flaws.] These flaws +were not observable when the shafts were new, although carefully +inspected. They gradually increased under strain, came to the outside, +and were detected. Considerable loss fell upon the owners of these +vessels, who were in no way to blame; nor could they recover any money +from the makers of the shafts, who were alone to blame. I am pleased +to state, and some of the members here present know, that considerable +improvement has been effected in the use of better material than iron +for crank shafts, by the introduction of a special mild steel, by +Messrs. Vickers, Sons & Co., of Sheffield, and that instead of having +to record the old familiar defects found in iron shafts, I can safely +say no flaws have been observed, when new or during eight years +running, and there are now twenty-two shafts of this mild steel in the +company's service. + +I may here state that steel was used for crank shafts in this service +in 1863, as then manufactured in Prussia by Messrs. Krupp, and +generally known as _Krupp's steel_, the tensile strength of which was +about 40 tons per square inch, and though free from flaws, it was +unable to stand the fatigue, and broke, giving little warning. It was +of too brittle a nature, more resembling chisel steel. It was broken +again under a falling weight of 10 cwt. with a 10 ft. drop = 121/2 tons. + +The mild steel now used was first tried in 1880. It possessed tensile +strength of 24 to 25 tons per square inch. It was then considered +advisable not to exceed this, and err rather on the safe side. This +shaft has been in use eight years, and no sign of any flaw has been +observed. Since then the tensile strength of mild steel has gradually +been increased by Messrs. Vickers, the steel still retaining the +elasticity and toughness to endure fatigue. This has only been arrived +at by improvements in the manufacture and more powerful and better +adapted hammers to forge it down from the large ingots to the size +required. The amount of work they are now able to subject the steel to +renders it more fit to sustain the fatigue such as that to be endured +by a crank shaft. These ingots of steel can be cast up to 100 tons +weight, and require powerful machines to deal with them. For shafts +say of 20 inches diameter, the diameter of the ingot would be about 52 +inches. This allows sufficient work to be put on the couplings, as +well as the shaft. To make solid crank shafts of this material, say of +19 inches diameter, the ingot would weigh 42 tons, the forging, when +completed, 17 tons, and the finished shaft 113/4 tons; so that you see +there is 25 tons wasted before any machining is done, and 51/4 tons +between the forging and finished shaft. This makes it very expensive +for solid shafts of large size, and it is found better to make what is +termed a _built shaft_; the cranks are a little heavier, and engine +framings necessarily a little wider, a matter comparatively of little +moment. I give you a rough drawing of the hydraulic hammer, or +strictly speaking a _press_, used by Messrs. Vickers in forging down +the ingots in shafts, guns, or other large work. This hammer can give +a squeeze of 3,000 tons. The steel seems to yield under it like tough +putty, and, unlike the steam hammer, there is no _jarring_ on the +material, and it is manipulated with the same ease as a small hammer +by hydraulics. + +The tensile strength of steel used for shafts having increased from 24 +to 30 tons, and in some cases 31 tons, considering that this was 2 +tons above that specified, and that we were approaching what may be +termed _hard steel_, I proposed to the makers to test this material +beyond the usual tests, viz., tensile, extension, and cold bending +test. The latter, I considered, was much too easy for this fine +material, as a piece of fair iron will bend cold to a radius of 11/2 +times its diameter or thickness, without fracture; and I proposed a +test more resembling the fatigue that a crank shaft has sometimes to +stand, and more worthy of this material; and in the event of its +standing this successfully, I would pass the material of 30 or 31 tons +tensile strength. Specimens of steel used in the shafts were cut off +different parts--crank pins and main bearings--(the shafts being built +shafts) and roughly planed to 11/2 inches square, and about 12 inches +long. They were laid on the block as shown, and a cast iron block, +fitted with a hammer head 1/2 ton weight, let suddenly fall 12 inches, +the block striking the bar with a blow of about 4 tons. The steel bar +was then turned upside down, and the blow repeated, reversing the +piece every time until fracture was observed, and the bar ultimately +broken. The results were that this steel stood 58 blows before showing +signs of fracture, and was only broken after 77 blows. It is +noticeable how many blows it stood after fracture. A bar of good +wrought iron, undressed, of same dimensions, was tried, and broke the +first blow. A bar cut from a piece of iron to form a large chain, +afterward forged down and only filed to same dimensions, broke at 25 +blows. I was well satisfied with the results, and considered this +material, though possessing a high tensile strength, was in every way +suitable for the construction and endurance required in crank shafts. + +Sheet No. 1 shows you some particulars of these tests: + + Tensile Elong. Fractured Broke Fall + Tons. in 5" Bend. Blows. Blows. In. + A = 30.5 28 p. c. Good 61 78 12 + +In order to test the comparative value of steel of 243/4 up to 35 tons +tensile strength, I had several specimens taken from shafts tested in +the manner described, which may be called a _fatigue_ test. The +results are shown on the same sheet: + + B = 241/2 Good 64 72 7 + B -- -- -- 48 54 12 + C = 27 25.9 p. c. Good 76 81 12 + D = 29.6 28.4 p. c. Good 71 78 12 + E = 30.5 28.9 p. c. Good 58 77 12 + F = 35.5 20 p. c. Good 80 91 12 + +The latter was very tough to break. Specimen marked A shows one of +these pieces of steel. I show you also fresh broken specimens which +will give you a good idea of the beautiful quality of this material. +These specimens were cut out of shafts made of Steel Co. of Scotland's +steel. I also show you specimens of cold bending: + + Tensile Elong. Fractured Broke Fall + Tons. in. 5" Bend. Blows. Blows. In. + G = 30.9 271/2 p. c. Good 59 66 12 + H = 29.3 30 p. c. Good 66 90 12 + I = 28.9 28.9 p. c. Good 53 68 12 + +I think all of the above tests show that this material, when carefully +made and treated with sufficient mechanical work on forging down from +the ingot, is suitable up to 34 tons for crank shafts; how much higher +it would be desirable to go is a question of superior excellence in +material and manufacture resting with the makers. I would, however, +remark that no allowance has been made by the Board of Trade or Lloyds +for the excellence of this material above that of iron. I was +interested to know how the material in the best iron shafts would +stand this fatigue test compared with steel, and had some specimens of +same dimensions cut out of iron shafts. The following are the results: +Best iron, three good qualities, rolled into flat bars, cut and made +into 41/2 cwt. blooms. + + J = 18.6 24.3 p. c. Good 17 18 12 + +Made of best double rolled scrap, 41/2 cwt. blooms. + + K = 22 321/2 p. c. Good 21 32 12 + +You will see from these results that steel stood this fatigue test, +Vickers' 73 per cent. and Steel Co.'s 68 per cent., better than iron +of the best quality for crank shafts; and I am of opinion that so long +as we use such material as these for crank shafts, along with the +present rules, and give ample _bearing surface_, there will be few +broken shafts to record. + +I omitted to mention that built shafts, both of steel and iron, of +large diameter, are now in general use, and with the excellent +machines, and under special mechanics, are built up of five separate +pieces in such a rigid manner that they possess all the solidity +necessary for a crank shaft. The forgings of iron and steel being much +smaller are capable of more careful treatment in the process of +manufacture. These shafts, for large mail steamers, when coupled up, +are 35 feet long, and weigh 45 tons. They require to be carefully +coupled, some makers finishing the bearings in the lathe, others +depend on the excellence of their work in each piece, and finish each +complete. To insure the correct centering of these large shafts, I +have had 6 in. dia. recesses 3/4 inch deep turned out of each coupling +to one gauge and made to fit one disk. Duplicate disks are then fitted +in each coupling, and the centering is preserved, and should a spare +piece be ever required, there is no trouble to couple correctly on +board the steamer. + +The propeller shaft is generally made of iron, and if made _not less_ +than the Board of Trade rules as regards diameter, of the best iron, +and the gun metal liners carefully fitted, they have given little +trouble; the principal trouble has arisen from defective fitting of +the propeller boss. This shaft working in sea water, though running in +lignum vitae bearings, has a considerable wear down at the outer +bearings in four or five years, and the shaft gets out of line. This +wear has been lessened considerably by fitting the wood so that the +grain is endway to the shaft, and with sufficient bearing surface +these bearings have not required lining up for nine years. It is, +however, a shaft that cannot be inspected except when in dry dock, and +has to be disconnected from the propeller, and drawn inside for +examination at periods suggested by experience. Serious accidents have +occurred through want of attention to the examination of this shaft; +when working in salt water, with liners of gun metal, galvanic action +ensues, and extensive corrosion takes place in the iron at the ends of +the brass liners, more especially if they are faced up at right angles +to the shaft. Some engineers have the uncovered part of the shaft +between the liners, inside the tube, protected against the sea water +by winding over it tarred line. As this may give out and cause some +trouble, by stopping the water space, I have not adopted it, and shall +be pleased to have the experience of any seagoing engineer on this +important matter. A groove round the shaft is formed, due to this +action, and in some cases the shaft has broken inside the stern tube, +breaking not only it, but tearing open the hull, resulting in the +foundering of the vessel. Steel has been used for screw shafts, but +has not been found so suitable, as it corrodes more rapidly in the +presence of salt water and gun metal than iron, and unless protected +by a solid liner for the most part of its length, a mechanical feat +which has not yet been achieved in ordinary construction, as this +liner would require to be 20 ft. long. I find it exceedingly difficult +to get a liner of only 7 ft. long in one piece, and the majority of 6 +ft. liners are fitted _in two pieces_. The joint of the two liners is +rarely _watertight_, and many shafts have been destroyed by this +method of fitting these liners. + +I trust that engine builders will make a step further in the fitting +of these liners on these shafts, as it is against the interest of the +_shipowner_ to keep ships in dry dock from such causes as defective +liners, and I think it will be only a matter of time when the screw +shaft will be completely protected from sea water, at least inside the +stern tube; and when this is done, I would have no hesitation in using +steel for screw shafts. Though an easier forging than a crank shaft, +these shafts are often liable to flaws of a very serious character, +owing to the contraction of the _mass_ of metal forming the coupling; +the outside cooling first tears the center open, and when there is not +much metal to turn off the face of the coupling, it is sometimes +undiscovered. Having observed several of these cavities, some only +when the _last cut_ was being taken off, I have considered it +advisable to have holes bored in the end and center of each coupling, +as far through as the thickness of the flange; when the shafts are of +large size, this is sure to find these flaws out. Another flaw, which +has in many cases proved serious when allowed to extend, is situated +immediately abaft the gun metal liner, in front of the propeller. + +This may be induced by corrosion, caused by the presence of sea water, +gun metal, and iron, assisted by the rotation of the shaft. It may +also be caused under heavy strain, owing to the over-finishing of the +shaft at this part under the steam hammer. + +The forgemen, in these days of competition and low prices, are +instructed to so finish that there won't be much weight to turn off +when completing the shaft in the lathe. This is effected by the use of +half-round blocks under the hammer, at a lower temperature than the +rest of the forging is done, along with the use of a little water +flung on from time to time; and it is remarkable how near a forging is +in truth when centered in the lathe, and how little there is to come +off. The effect of this manipulation is to form a hard ring of close +grain about one inch thick from the circumference of the shaft inward. +The metal in this ring is much harder than that in the rest of the +shaft, and takes all the strain the inner section gives; consequently, +when strain is brought on, either in heavy weather or should the +propeller strike any object at sea or in the Suez canal, a fracture is +caused at the circumference. This, assisted by slight corrosion, has +in my experience led in the course of four months to a screw shaft +being seriously crippled. + +I show you a section of a screw shaft found to be flawed, and which I +had broken under the falling weight of a steam hammer, when the +decided difference of the granules near the circumference from that in +the central part conveyed to me that it was weakened by treatment I +have referred to. I think more material should be left on the forging, +and the high finish with a little cold water should be discontinued. +Doing away with the outer bearing in rudder post is an improvement, +provided the bearing in the outer end of screw shaft in the stern tube +is sufficiently large. It allows the rudder post to have its own work +to do without bringing any strain on the screw shaft, and in the event +of the vessel's grounding and striking under the rudder post, it does +not throw any strain on the screw shaft. It also tends to reduce +weight at this part, where all the weight is overhung from the stern +of the vessel. + + * * * * * + + + + +EXPERIMENTAL AID IN THE DESIGN OF HIGH SPEED STEAMSHIPS. + +By D. P. + + +The achievement of one triumph after another in the matter of high +speed steamships, and especially the confidence with which pledges of +certain results are given and accepted long before actual trials are +made, form one of the most convincing proofs of the important part +which scientific methods play in modern shipbuilding. This is evident +in the case of ships embodying novel or hitherto untried features, and +more especially so in cases where shipbuilders, having no personal +practical experience or data, achieve such results. This was notably +illustrated in the case of the Fairfield Co. undertaking some five +years ago to build and engine a huge craft of most phenomenal form and +proportions, and to propel the vessel at a given speed under +conditions which appeared highly impracticable to many engaged in the +same profession. The contract was proceeded with, however, and the +Czar of Russia's wonderful yacht Livadia was the result, which +(however much she may have justified the professional strictures as to +form and proportions) entirely answered the designer's anticipations +as to speed. Equally remarkable and far more interesting instances are +the Inman liners City of Paris and City of New York, in whose design +there was sufficient novelty to warrant the degree of misgiving which +undoubtedly existed regarding the Messrs. Thomson's ability to attain +the speed required. In the case at least of the City of Paris, Messrs. +Thomson's intrepidity has been triumphantly justified. An instance +still more opposite to our present subject is found in the now +renowned Channel steamers Princess Henrietta and Princess Josephine, +built by Messrs. Denny, of Dumbarton, for the Belgian government. The +speed stipulated for in this case was 201/2 knots, and although in one +or two previous Channel steamers, built by the Fairfield Co., a like +speed had been achieved, still the guaranteeing of this speed by +Messrs. Denny was remarkable, in so far as the firm had never +produced, or had to do with, any craft faster than 15 or 16 knots. The +attainment not only of the speed guaranteed, but of the better part of +a knot in excess of that speed, was triumphant testimony to the skill +and care brought to bear upon the undertaking. In this case, at least, +the result was not one due to a previous course of "trial and error" +with actual ships, but was distinctly due to superior practical skill, +backed and enhanced by knowledge and use of specialized branches in +the science of marine architecture. Messrs. Denny are the only firm of +private shipbuilders possessing an experimental tank for recording the +speed and resistance of ships by means of miniature reproductions of +the actual vessels, and to this fact may safely be ascribed their +confidence in guaranteeing, and their success in obtaining, a speed so +remarkable in itself and so much in excess of anything they had +previously had to do with. Confirmatory evidence of their success with +the Belgian steamers is afforded by the fact that they have recently +been instructed to build for service between Stranraer and Larne a +paddle steamer guaranteed to steam 19 knots, and have had inquiries as +to other high speed vessels. + +In estimating the power required for vessels of unusual types or of +abnormal speed, where empirical formulae do not apply, and where data +for previous ships are not available, the system of experimenting with +models is the only trustworthy expedient. In the case of the Czar's +extraordinary yacht, the Livadia, already referred to, it may be +remembered that previous to the work of construction being proceeded +with, experiments were made with a small model of the vessel by the +late Dr. Tideman, at the government tank at Amsterdam. On the strength +of the data so obtained, coupled with the results of trials made with +a miniature of the actual vessel on Loch Lomond, those responsible for +her stipulated speed were satisfied that it could be attained. The +actual results amply justified the reliance placed upon such +experiments. + +The design of many of her Majesty's ships has been altered after +trials with their models. This was notably the case in connection with +the design of the Medway class of river gunboats. The Admiralty +constructors at first determined to make them 110 ft. long, by only 26 +ft. in breadth. A doubt arising in their minds, the matter was +referred to the late Mr. Froude, who had models made of various +breadths, with which he experimented. The results satisfied the +Admiralty officers that a substantial gain, rather than a loss, would +follow from giving them much greater beam than had been proposed, and +this was amply verified in the actual ships. + +So long ago as the last decade of last century, an extended series of +experiments with variously shaped bodies, ships as well as other +shapes, were conducted by Colonel Beaufoy, in Greenland dock, London, +under the auspices of a society instituted to improve naval +architecture at that time. Robert Fulton, of America, David Napier, of +Glasgow, and other pioneers of the steamship, are related to have +carried out systematic model experiments, although of a rude kind in +modern eyes, before entering on some of their ventures. About 1840 Mr. +John Scott Russell carried on, on behalf of the British Association, +of which he was at that time one of its most distinguished members, an +elaborate series of investigations into the form of least resistance +in vessels. For this purpose he leased the Virginia House and grounds, +a former residence of Rodger Stewart, a famous Greenock shipowner of +the early part of the century, the house being used as offices, while +in the grounds an experimental tank was erected. In it tests were made +of the speed and resistance of the various forms which Mr. Russell's +ingenuity evolved--notably those based on the well-known stream line +theory--as possible types of the steam fleets of the future. All the +data derived from experiment was tabulated, or shown graphically in +the form of diagrams, which, doubtless, proved of great interest to +the _savants_ of the British Association of that day. Mr. Russell +returned to London in 1844, and the investigations were discontinued. + +It will thus be seen that model experiments had been made by +investigators long before the time of the late Dr. William Froude, of +Torquay. It was not, however, until this gentleman took the subject of +resistance of vessels in hand that designers were enabled to render +the results from model trials accurately applicable to vessels of full +size. This was principally due to his enunciation and verification by +experiment of what is now known as the "law of comparison," or the law +by which one is enabled to refer accurately the resistance of a model +to one of larger size, or to that of a full sized vessel. In effect, +the law is this--for vessels of the same proportional dimensions, or, +as designers say, of the same lines, there are speeds appropriate to +these vessels, which vary as the square roots of the ratio of their +dimensions, and at these appropriate speeds the resistances will vary +as the cubes of these dimensions. The fundament upon which the law is +based has recently been shown to have found expression in the works of +F. Reech, a distinguished French scientist who wrote early in the +century. There are no valid grounds for supposing that the discovery +of Reech was familiar to Froude; but even were this so, it is +abundantly evident that, although never claimed by himself, there are +the best of grounds for claiming the law of comparison, as now +established, to be an independent discovery of Froude's. + +Dr. Froude began his investigations with ships' models at the +experimental tank at Torquay about 1872, carrying it on +uninterruptedly until his death in 1879. Since his decease, the work +of investigation has been carried on by his son, Mr. R. E. Froude, who +ably assisted his father, and originated much of the existing +apparatus. At the beginning of 1886, the whole experimental appliances +and effects were removed from Torquay to Haslar, near Portsmouth, +where a large tank and more commodious offices have been constructed, +with a view to entering more extensively upon the work of experimental +investigation. The dimensions of the old tank were 280 ft. in length, +36 ft. in width, and 10 ft. in depth. The new one is about 400 ft. +long, 20 ft. wide, and 9 ft. deep. The new establishment is more +commodious and better equipped than the old, and although the +experiments are taken over a greater length, the operators are enabled +to turn out results with as great dispatch as in the Torquay tank. The +adjacency of the new tank to the dockyard at Portsmouth enables the +Admiralty authorities to make fuller and more frequent use of it than +formerly. Since the value of the work carried on for the British +government has become appreciated, several experimental establishments +of a similar character have been instituted in other countries. The +Dutch government in 1874 formed one at Amsterdam which, up till his +death in 1883, was under the superintendence of Dr. Tideman, whose +labors in this direction were second only to those of the late Dr. +Froude. In 1877 the French naval authorities established an +experimental tank in the dockyard at Brest, and the Italian government +have just completed one on an elaborate scale in the naval dockyard at +Spezia. The Spezia tank, which is 500 ft. in length by about 22 ft. in +breadth, is fully equipped with all the special and highly ingenious +instruments and appliances which the scientific skill of the late Dr. +Froude brought into existence, and have been since his day improved +upon by his son, Mr. R. E. Froude, and other experts. + +Through the courtesy of our own Admiralty and of Messrs. Denny, of +Dumbarton, the Italians have been permitted to avail themselves of the +latest improvements which experience has suggested, and the +construction of the special machinery and apparatus required has been +executed by firms in this country having previous experience in this +connection--Messrs. Kelso & Co., of Commerce Street, Glasgow; and Mr. +Robert W. Munro, of London. + +Having briefly traced the origin and development of the system of +model experiment, it may now be of interest to describe the _modus +operandi_ of such experiments, and explain the way in which they are +made applicable to actual ships. The models with which experiments are +made in those establishments conducted on the lines instituted by Mr. +Froude are made of paraffin wax, a material well adapted for the +purpose, being easily worked, impervious to water, and yielding a fine +smooth surface. Moreover, when done with, the models may be remelted +for further use and all parings utilized. They are produced in the +following manner: A mould is formed in clay by means of cross sections +made somewhat larger than is actually required, this allowance being +made to admit of the cutting and paring afterward required to bring +the model to the correct point. Into this mould a core is placed, +consisting of a light wooden framework covered with calico and coated +with a thick solution of clay to make it impervious to the melted +paraffin. This latter substance is run into the space between the core +and the mould and allowed to cool. This space, forming the thickness +of the model, is usually from 3/4 in. for a model of 10 ft. long to 11/4 +in. and 11/2 in. for one of 16 ft. and 18 ft. long. When cold, the model +is floated out of the mould by water pressure and placed bottom upward +on the bed of a shaping machine, an ingenious piece of mechanism +devised by the late Dr. Froude, to aid in reducing the rough casting +to the accurate form. The bed of this machine, which travels +automatically while the machine is in operation, can be raised or +lowered to any desired level by adjusting screws. A plan of water +lines of the vessel to be modeled is placed on a tablet geared to the +machine, the travel of which is a function of the travel of the bed +containing the model. With a pointer, which is connected by a system +of levers to the cutting tools, the operator traces out the water +lines upon the plan as the machine and its bed are in motion, with the +result that corresponding lines are cut upon the model. The cutting +tools are swiftly revolving knives which work on vertical spindles +moved in a lateral direction (brought near or removed from each +other), according to the varying breadth of the water lines throughout +the length of the model, as traced out by the operator's pointer. In +this way a series of longitudinal incisions are made on the model at +different levels corresponding to the water lines of the vessel. The +model is now taken from the bed of the machine and the superfluous +material or projection between the incisions is removed by means of a +spokeshave or other sharp hand tool, and the whole surface brought to +the correct form, and made fair and smooth. + +To test accuracy of form, the weight of model is carefully taken, and +the displacement at the intended trial draught accurately determined +from the plan of lines. The difference between the weight of model and +the displacement at the draught intended is then put into the bottom +of the model in the form of small bags of shot, and by unique and very +delicately constructed instruments for ascertaining the correct +draught, the smallest error can at once be detected and allowed for. +The models vary in size from about one-tenth to one-thirtieth of the +size of the actual ship. A model of the largest size can be produced +and its resistance determined at a number of speeds in about two days +or so. The mode of procedure in arranging the model for the resistance +experiment, after the model is afloat in the tank at the correct +draught and trim, consists in attaching to it a skillfully devised +dynamometric apparatus secured to a lightly constructed carriage. This +carriage traverses a railway which extends the whole length of the +tank about 15 in. or 18 in. above the water. The floating model is +carefully guided in its passage through the water by a delicate +device, keeping it from deviating either to the right or left, but at +the same time allowing a free vertical and horizontal motion. The +carriage with the model attached is propelled by means of an endless +steel wire rope, passing at each end of the tank around a drum, driven +by a small stationary engine, fitted with a very sensitive governor, +capable of being so adjusted that any required speed may be given to +the carriage and model. The resistance which the model encounters in +its passage through the water is communicated to a spiral spring, and +the extension this spring undergoes is a measure of the model's +resistance. The amount of the extension is recorded on a revolving +cylinder to a much enlarged scale through the medium of levers or bell +cranks supported by steel knife edges resting on rocking pieces. On +the same cylinder are registered "time" and "distance" diagrams, by +means of which a correct measure of the speed is obtained. The time +diagram is recorded by means of a clock attached to an electric +circuit, making contact every half second, and actuating a pen which +forms an indent in what would otherwise be a straight line on the +paper. The distance pen, by a similar arrangement, traces another line +on the cylinder in which are indents corresponding to fixed distances +of travel along the tank, the indents being caused by small +projections which strike a trigger at the bottom of the carriage as it +passes, and make electric contact. From these time and distance +diagrams accurate account can be taken of the speed at which the model +and its supporting carriage have been driven. Thus on the same +cylinder is recorded graphically the speed and resistance of the +model. The carriage may be driven at any assigned speed by adjusting +the governor of the driving engine already alluded to, but the record +of the speed by means of the time and distance diagrams is more +definite. When the resistances of the model have been obtained at +several speeds, varying in some cases from 50 to 1,000 feet per +minute, the speeds are set off in suitable units along a base line, +and for every speed at which resistance is measured, the resistance is +set off to scale as an ordinate value at those speeds. A line passing +through these spots forms the "curve of resistance," from which the +resistance experienced by the model at the given trial speeds or any +intermediate speed can be ascertained. The resistance being known, the +power required to overcome resistance and drive the actual ship at any +given speed is easily deduced by applying the rule before described as +the law of comparison.--_The Steamship._ + + * * * * * + + + + +THE SHIP IN THE NEW FRENCH BALLET OF THE "TEMPEST." + + +A new ballet, entitled the "Tempest," by Messrs. Barbier and Thomas, +has recently been put upon the stage of the Opera at Paris with superb +settings. One of the most important of the several tableaux exhibited +is the last one of the third act, in which appears a vessel of unusual +dimensions for the stage, and which leaves far behind it the +celebrated ships of the "Corsaire" and "L'Africaine." This vessel, +starting from the back of the stage, advances majestically, describes +a wide circle, and stops in front of the prompter's box. + +[Illustration: FIG. 1.--SHIP OF THE "TEMPEST," IN PROCESS OF +CONSTRUCTION.] + +[Illustration: FIG. 2.--SETTING OF THE SCENERY BEFORE AND AFTER THE +APPEARANCE OF THE SHIP.] + +As the structure of this vessel and the mechanism by which it is moved +are a little out of the ordinary, we shall give some details in regard +to them. First, the sea is represented by four parallel strips of +water, each formed of a vertical wooden frame entirely free in its +movements (Fig. 2). The ship (Figs. 1, 2, 3, 4 and 5) is carried by +wheels that roll over the floor of the stage. It is guided in its +motion by two grooved bronze wheels and by a rail formed of a simple +reversed T-iron which is fixed to the floor by bolts. In measure as it +advances, the strips of water open in the center to allow it to pass, +and, as the vessel itself is covered up to the water line with painted +canvas imitating the sea, it has the appearance of cleaving the waves. +As soon as it has passed, the three strips of water in the rear rise +slightly. When the vessel reaches the first of the strips, the three +other strips, at first juxtaposed against the preceding, spread out +and thus increase the extent of the sea, while the inclined plane of +the preceding tableau advances in order to make place for the vessel. +The shifting of this inclined place is effected by simply pulling upon +the carpet that covers it, and which enters a groove in the floor in +front of the prompter's box. At this moment, the entire stage seems to +be in motion, and the effect is very striking. + +[Illustration: FIG. 3.--SHIP OF THE NEW BALLET, THE "TEMPEST."] + +We come now to the details of construction of the vessel. It is not +here a question of a ship represented simply by means of frames and +accessories, but of a true ship in its entirety, performing its +evolutions over the whole stage. Now, a ship is not constructed at a +theater as in reality. It does not suffice to have it all entire upon +the stage, but it is necessary also to be able to dismount it after +every representation, and that, too, in a large number of pieces that +can be easily stored away. Thus, the vessel of the Tempest, which +measures a dozen yards from stem to stern, and is capable of carrying +fifty persons, comes apart in about 250 pieces of wood, without +counting all the iron work, bolts, etc. Nevertheless, it can be +mounted in less than two hours by ten skilled men. + +[Illustration: FIG. 4.--THE SHIP WITH ITS OCCUPANTS.] + +The visible hull of the ship is placed upon a large and very strong +wooden framework, formed of twenty-six trusses. In the center, there +are two longitudinal trusses about three feet in height by twenty-five +in length, upon which are assembled, perpendicularly, seven other +trusses. In the interior there are six transverse pieces held by +stirrup bolts, and at the extremity of each of these is fixed a +thirteen-inch iron wheel. It is upon these twelve wheels that the +entire structure rolls. + +There are in addition the two bronze guide wheels that we have already +spoken of. In the rear there are two large vertical trusses sixteen +feet in height, which are joined by ties and descend to the bottom of +the frame, to which they are bolted. These are worked out into steps +and constitute the skeleton of the immense stern of the vessel. The +skeleton of the prow is formed of a large vertical truss which is +bolted to the front of the frame and is held within by a tie bar. On +each side of this truss are placed the _parallels_ (Figs. 1 and 3), +which are formed of pieces of wood that are set into the frame below +and are provided above with grooves for the passage of iron rods that +support the foot rests by means of which the supernumeraries are +lifted. As a whole, those rods constitute a jointed parallelogram, so +that the foot rest always remains horizontal while describing a curve +of five feet radius from the top of the frame to the deck of the +vessel. They are actuated by a cable which winds around a small +windlass fixed in the interior of the frame. + +[Illustration: FIG. 5.--THE SHIP AS SEEN FROM THE STAGE.] + +The large mast consists of a vertical sheath 10 ft. high, which is set +into the center of the frame, and in the interior of which slides a +wooden spar that exceeds it by 5 ft. at first, and is capable of being +drawn out as many more feet for the final apotheosis. This part of the +mast carries three footboards and a platform for the reception of +"supers." It is actuated by a windlass placed upon the frame. + +To form the skeleton of the vessel there are mounted upon the frame a +series of eight large vertical trusses parallel with each other and +cross-braced by small trusses. The upper part of these supports the +flooring of the deck, and their exterior portion affects the curve of +a ship's sides. It is to these trusses that are attached the panels +covered with painted canvas that represent the hull. These panels are +nine in number on each side. Above are placed those that simulate the +nettings and those that cover the prow or form its crest. + +The turret that surrounds the large mast is formed of vertical trusses +provided with panels of painted canvas and carrying a floor for the +figurants to stand upon. + +The bowsprit is in two parts, one sliding in the other. The front +portion is at first pulled back, in order to hide the vessel entirely +in the side scenes. It begins to make its appearance before the vessel +itself gets under way. Light silken cordages connect the mast, the +bowsprit, and the small mast at the stern. + +On each side of the vessel, there are bolted to the frame that +supports it five iron frames covered with canvas (Fig. 3), which reach +the level of the water line, and upon which stand the "supers" +representing the naiads that are supposed to draw the ship upon the +beach. Finally at the bow there is fixed a frame which supports a +danseuse representing the living prow of the vessel. + +The vessel is drawn to the middle of the stage by a cable attached to +its right side and passing around a windlass placed in the side scenes +to the left (Fig. 2). It is at the same time pushed by machinists +placed in the interior of the framework. The latter, as above stated, +is entirely covered with painted canvas resembling water. + +As the vessel, freighted with harmoniously grouped spirits, and with +naiads, sea fairies, and graceful genii seeming to swim around it, +sails in upon the stage, puts about, and advances as if carried along +by the waves to the front of the stage, the effect is really +beautiful, and does great credit to the machinists of the Opera. + +We are indebted to _Le Genie Civil_ and _Le Monde Illustre_ for the +description and engravings. + + * * * * * + + + + +THE GIRARD HYDRAULIC RAILWAY. + + +[Illustration: FIG. 1.] + +[Illustration: FIG. 2.] + +We give herewith some illustrations of this railway which has recently +excited so much technical interest in Europe and America, and which +threatens to revolutionize both the method and velocity of traveling, +if only the initial expense of laying the line can be brought within +moderate limits. A short line of railway has been laid in Paris, and +we have there examined it, and traveled over the line more than once; +so that we can testify to the smoothness and ease of the motion. Sir +Edward Watkin examined the railway recently, and we understand that a +line two miles long is to be laid in London, under his auspices. He +seems to think it might be used for the Channel tunnel, being both +smokeless and noiseless. It might also, if it could be laid at a +sufficiently low price, be useful for the underground railways in +London, of one of which he is chairman. We are favorably impressed by +the experiments we have witnessed; our misgivings are as to the cost. +The railway is the invention of the well known hydraulic engineer, +Monsieur Girard, who, as early as 1852, endeavored to replace the +ordinary steam traction on railways by hydraulic propulsion, and in +1854 sought to diminish the resistance to the movement of the wagons +by removing the wheels, and causing them to slide on broad rails. In +order to test the invention, Mons. Girard demanded, and at the end of +1869 obtained, a concession for a short line from Paris to Argenteuil, +starting in front of the Palais de l'Industrie, passing by Le Champ de +Courses de Longchamps, and crossing the Seine at Suresnes. +Unfortunately, the war of 1870-71 intervened, during which the works +were destroyed and Mons. Girard was killed. After his death the +invention was neglected for some years. A short time ago, however, one +of his former colleagues, Mons. Barre, purchased the plans and +drawings of Mons. Girard from his family, and having developed the +invention, and taken out new patents, formed a company to work them. +The invention may be divided into two parts, which are distinct, the +first relating to the mode of supporting the carriages and the second +to their propulsion. Each carriage is carried by four or six shoes, +shown in Figs. 3, 4, and 5; and these shoes slide on a broad, flat +rail, 8 in. or 10 in. wide. The rail and shoe are shown in section in +Fig. 1. The rail is bolted to longitudinal wooden sleepers, and the +shoe is held on the rail by four pieces of metal, A, two on each side, +which project slightly below the top of the rail. The bottom of the +shoe which is in contact with the rail is grooved or channeled, so as +to hold the water and keep a film between each shoe and the rail. The +carriage is supported by vertical rods, which fit one into each shoe, +a hole being formed for that purpose; and the point of support being +very low, and quite close to the rail, great stability is insured. It +is proposed to make the rail of the form shown in Fig. 2 in future, as +this will avoid the plates, A, and the flanges, B, will help to keep +the water on the rail. Figs. 3, 4, and 5 show the shoe in detail. Fig. +3 gives a longitudinal section, Fig. 4 is a plan, and Fig. 5 is a plan +of the shoe inverted, showing the grooves in its face. Fig. 3 shows +the hollow shoe, into which water at a pressure of ten atmospheres is +forced by a pipe from a tank on the tender. The water enters by the +pipe, C, and fills the whole of the chamber, D. The water attempts to +escape, and in doing so lifts the shoe slightly, thus filling the +first groove of the chamber. The pressure again lifts the shoe, and +the second chamber is filled; and so on, until ultimately the water +escapes at the ends, E, and sides, F. Thus a film of water is kept +between the shoe and the rail, and on this film the carriage is said +to float. The water runs away into the channels, H H (Fig. 6), and is +collected to be used over again. Fig. 3 also shows the means of +supporting the carriage on the shoe by means of K, the point of +support being very low. The system of grooves on the lower face of the +shoe is shown in Fig. 5. So much for the means by which wheels are +dispensed with, and the carriage enabled to slide along the line. + +[Illustration: FIG. 3.] + +[Illustration: FIG. 4.] + +[Illustration: FIG. 5.] + +[Illustration: FIG. 6.] + +The next point is the method of propulsion. Figs. 7 and 8 give an +elevation and plan of one of the experimental carriages. Along the +under side of each of the carriages a straight turbine, L L, extends +the whole length, and water at high pressure impinges on the blades of +this turbine from a jet, M, and by this means the carriage is moved +along. A parabolic guide, which can be moved in and out of gear by a +lever, is placed under the tender, and this on passing strikes the +tappet, S, and opens the valve which discharges the water from the +jet, M, and this process is repeated every few yards along the whole +line. The jets, M, must be placed at such a distance apart that at +least one will be able to operate on the shortest train that can be +used. In this turbine there are two sets of blades, one above the +other, placed with their concave sides in opposite directions, so that +one set is used for propelling in one direction and the other in the +opposite direction. In Fig. 6 it is seen that the jet, M, for one +direction is just high enough to act against the blades, Q, while the +other jet is higher, and acts on the blades, P, for propulsion in the +opposite direction. The valves, R, which are opened by the tappet, S, +are of peculiar construction, and we hope soon to be able to give +details of them. Reservoirs (Fig. 6) holding water at high pressure +must be placed at intervals, and the pipe, T, carrying high pressure +water must run the whole length of the line. Fig. 6 shows a cross +section of the rail and carriage, and gives a good idea of the general +arrangements. The absence of wheels and of greasing and lubricating +arrangements will alone effect a very great saving, as we are informed +that on the Lyons Railway, which is 800 kilometers long, the cost of +oil and grease exceeds L400,000 per annum. As Sir Edward Watkin +recently explained, all the great railway companies have long tried to +find a substitute for wheels, and this railway appears to offer a +solution of that problem. Mons. Barre thinks that a speed of 200 +kilometers (or 120 miles) per hour may be easily and safely attained. + +[Illustration: FIG. 7.] + +[Illustration: FIG. 8.] + +Of course, as there is no heavy locomotive, and as the traction does +not depend upon pressure on the rail, the road may be made +comparatively light. The force required to move a wagon along the road +is very small, Mons. Barre stating, as the result of his experiments, +that an effort amounting to less than half a kilogramme is sufficient +to move one ton when suspended on a film of water with his improved +shoes. It is recommended that the stations be placed at the summit of +a double incline, so that on going up one side of the incline the +motion of the train may be arrested, and on starting it may be +assisted. No brakes are required, as the friction of the shoe against +the rail, when the water under pressure is not being forced through, is +found to be quite sufficient to bring the train to a standstill in a +very short distance. The same water is run into troughs by the side of +the line, and can be used over and over again indefinitely, and in the +case of long journeys, the water required for the tender could be taken +up while the train is running. The principal advantages claimed for +the railway are: The absence of vibration and of side rolling motion; +the pleasure of traveling is comparable to that of sleighing over a +surface of ice, there is no noise, and what is important in town +railways, no smoke; no dust is caused by the motion of the train during +the journey. It is not easy for the carriages to be thrown from the +rails, since any body getting on the rail is easily thrown off by the +shoe, and will not be liable to get underneath, as is the case with +wheels; the train can be stopped almost instantly, very smoothly, and +without shock. Very high speed can be attained; with water at a +pressure of 10 kilogrammes, a speed of 140 kilometers per hour can be +attained; great facility in climbing up inclines and turning round the +curves; as fixed engines are employed to obtain the pressure, there is +great economy in the use of coal and construction of boilers, and +there is a total absence of the expense of lubrication. It is, +however, difficult to see how the railway is to work during a long and +severe frost. We hope to give further illustrations at an early date +of this remarkable invention.--_Industries._ + + * * * * * + + + + +QUARTZ FIBERS.[1] + + [Footnote 1: Lecture delivered at the Royal Institution, on + Friday, June 14, by Mr. C. V. Boys, F.R.S.--_Nature._] + + +In almost all investigations which the physicist carries out in the +laboratory, he has to deal with and to measure with accuracy those +subtile and to our senses inappreciable forces to which the so-called +laws of nature give rise. Whether he is observing by an electrometer +the behavior of electricity at rest or by a galvanometer the action of +electricity in motion, whether in the tube of Crookes he is +investigating the power of radiant matter, or with the famous +experiment of Cavendish he is finding the mass of the earth--in these +and in a host of other cases he is bound to measure with certainty and +accuracy forces so small that in no ordinary way could their existence +be detected, while disturbing causes which might seem to be of no +particular consequence must be eliminated if his experiments are to +have any value. It is not too much to say that the very existence of +the physicist depends upon the power which he possesses of producing +at will and by artificial means forces against which he balances those +that he wishes to measure. + +I had better perhaps at once indicate in a general way the magnitude +of the forces with which we have to deal. + +The weight of a single grain is not to our senses appreciable, while +the weight of a ton is sufficient to crush the life out of any one in +a moment. A ton is about 15,000,000 grains. It is quite possible to +measure with unfailing accuracy forces which bear the same relation to +the weight of a grain that a grain bears to a ton. + +To show how the torsion of wires or threads is made use of in +measuring forces, I have arranged what I can hardly dignify by the +name of an experiment. It is simply a straw hung horizontally by a +piece of wire. Resting on the straw is a fragment of sheet iron +weighing ten grains. A magnet so weak that it cannot lift the iron yet +is able to pull the straw round through an angle so great that the +existence of the feeble attraction is evident to every one in the +room. + +Now it is clear that if, instead of a straw moving over the table +simply, we had here an arm in a glass case and a mirror to read the +motion of the arm, it would be easy to observe a movement a hundred or +a thousand times less than that just produced, and therefore to +measure a force a hundred or a thousand times less than that exerted +by this feeble magnet. + +Again, if instead of wire as thick as an ordinary pin I had used the +finest wire that can be obtained, it would have opposed the movement +of the straw with a far less force. It is possible to obtain wire ten +times finer than this stubborn material, but wire ten times finer is +much more than ten times more easily twisted. It is ten thousand times +more easily twisted. This is because the torsion varies as the fourth +power of the diameter. So we say 10 x 10 = 100, 100 x 100 = 10,000. +Therefore, with the finest wire, forces 10,000 times feebler still +could be observed. + +It is therefore evident how great is the advantage of reducing the +size of a torsion wire. Even if it is only halved, the torsion is +reduced sixteenfold. To give a better idea of the actual sizes of such +wires and fibers as are in use, I shall show upon the screen a series +of such photographs taken by Mr. Chapman, on each of which a scale of +thousandths of an inch has been printed. + +[Illustration: Scale of 1000ths of an inch for Figs. 1 to 7. The scale +of Figs. 8 and 9 is much finer.] + +[Illustration: FIG. 1.] + +[Illustration: FIG. 2.] + +[Illustration: FIG. 3.] + +The first photograph (Fig. 1) is an ordinary hair--a sufficiently +familiar object, and one that is generally spoken of as if it were +rather fine. Much finer than this is the specimen of copper wire now +on the screen (Fig. 2), which I recently obtained from Messrs. Nalder +Brothers. It is only a little over one-thousandth of an inch in +diameter. Ordinary spun glass, a most beautiful material, is about +one-thousandth of an inch in diameter, and this would appear to be an +ideal torsion thread (Fig. 3). Owing to its fineness, its torsion +would be extremely small, and the more so because glass is more easily +deformed than metals. Owing to its very great strength, it can carry +heavier loads than would be expected of it. I imagine many physicists +must have turned to this material in their endeavor to find a really +delicate torsion thread. I have so turned only to be disappointed. It +has every good quality but one, and that is its imperfect elasticity. +For instance, a mirror hung by a piece of spun glass is casting an +image of a spot of light on the scale. If I turn the mirror, by means +of a fork, twice to the right, and then turn it back again, the light +does not come back to its old point of rest, but oscillates about a +point on one side, which, however, is slowly changing, so that it is +impossible to say what the point of rest really is. Further, if the +glass is twisted one way first and then the other way, the point of +rest moves in a manner which shows that it is not influenced by the +last deflection alone: the glass remembers what was done to it +previously. For this reason spun glass is quite unsuitable as a +torsion thread; it is impossible to say what the twist is at any time, +and therefore what is the force developed. + +[Illustration: FIG. 4.] + +So great has the difficulty been in finding a fine torsion thread that +the attempt has been given up, and in all the most exact instruments +silk has been used. The natural cocoon fibers, as shown on the screen +(Fig. 4), consist of two irregular lines gummed together, each about +one two-thousandth of an inch in diameter. These fibers must be +separated from one another and washed. Then each component will, +according to the experiment of Gray, carry nearly 60 grains before +breaking, and can be safely loaded with 15 grains. Silk is therefore +very strong, carrying at the rate of from 10 to 20 tons to the square +inch. It is further valuable in that its torsion is far less than that +of a fiber of the same size of metal or even of glass, if such could +be produced. The torsion of silk, though exceedingly small, is quite +sufficient to upset the working of any delicate instrument, because it +is never constant. At one time the fiber twists one way and another +time in another, and the evil effect can only be mitigated by using +large apparatus in which strong forces are developed. Any attempt that +may be made to increase the delicacy of apparatus by reducing their +dimensions is at once prevented by the relatively great importance of +the vagaries of the silk suspension. + +The result, then, is this. The smallness, the length of period, and +therefore delicacy, of the instruments at the physicist's disposal +have until lately been simply limited by the behavior of silk. A more +perfect suspension means still more perfect instruments, and therefore +advance in knowledge. + +It was in this way that some improvements that I was making in an +instrument for measuring radiant heat came to a deadlock about two +years ago. I would not use silk, and I could not find anything else +that would do. Spun glass, even, was far too coarse for my purpose, it +was a thousand times too stiff. + +[Illustration: FIG. 5.] + +There is a material invented by Wollaston long ago, which, however, I +did not try because it is so easily broken. It is platinum wire which +has been drawn in silver, and finally separated by the action of +nitric acid. A specimen about the size of a single line of silk is now +on the screen, showing the silver coating at one end (Fig. 5). + +As nothing that I knew of could be obtained that would be of use to +me, I was driven to the necessity of trying by experiment to find some +new material. The result of these experiments was the development of a +process of almost ridiculous simplicity which it may be of interest +for me to show. + +The apparatus consists of a small crossbow, and an arrow made of straw +with a needle point. To the tail of the arrow is attached a fine rod +of quartz which has been melted and drawn out in the oxyhydrogen jet. +I have a piece of the same material in my hand, and now after melting +their ends and joining them together, an operation which produces a +beautiful and dazzling light, all I have to do is to liberate the +string of the bow by pulling the trigger with one foot, and then if +all is well a fiber will have been drawn by the arrow, the existence +of which can be made evident by fastening to it a piece of stamp +paper. + +In this way threads can be produced of great length, of almost any +degree of fineness, of extraordinary uniformity, and of enormous +strength. I do not believe, if any experimentalist had been promised +by a good fairy that he might have anything he desired, that he would +have ventured to ask for any one thing with so many valuable +properties as these fibers possess. I hope in the course of this +evening to show that I am not exaggerating their merits. + +[Illustration: FIG. 6.] + +[Illustration: FIG. 7.] + +In the first place, let me say something about the degree of fineness +to which they can be drawn. There is now projected upon the screen a +quartz fiber one five-thousandth of an inch in diameter (Fig. 6). This +is one which I had in constant use in an instrument loaded with about +30 grains. It has a section only one-sixth of that of a single line of +silk, and it is just as strong. Not being organic, it is in no way +affected by changes of moisture and temperature, and so it is free +from the vagaries of silk which give so much trouble. The piece used +in the instrument was about 16 inches long. Had it been necessary to +employ spun glass, which hitherto was the finest torsion material, +then, instead of 16 inches, I should have required a piece 1,000 feet +long, and an instrument as high as the Eiffel tower to put it in. + +There is no difficulty in obtaining pieces as fine as this yards long +if required, or in spinning it very much finer. There is upon the +screen a single line made by the small garden spider, and the size of +this is perfectly evident (Fig. 7). You now see a quartz fiber far +finer than this, or, rather, you see a diffraction phenomenon, for no +true image is formed at all; but even this is a conspicuous object in +comparison with the tapering ends, which it is absolutely impossible +to trace in a microscope. The next two photographs, taken by Mr. +Nelson, whose skill and resources are so famous, represent the extreme +end of a tail of quartz, and, though the scale is a great deal larger +than that used in the other photographs, the end will be visible only +to a few. Mr. Nelson has photographed here what it is absolutely +impossible to see. What the size of these ends may be, I have no means +of telling. Dr. Royston Piggott has estimated some of them at less +than one-millionth of an inch, but, whatever they are, they supply for +the first time objects of extreme smallness the form of which is +certainly known, and, therefore, I cannot help looking upon them as +more satisfactory tests for the microscope than diatoms and other +things of the real shape of which we know nothing whatever. + +Since figures as large as a million cannot be realized properly, it +may be worth while to give an illustration of what is meant by a fiber +one-millionth of an inch in diameter. + +A piece of quartz an inch long and an inch in diameter would, if drawn +out to this degree of fineness, be sufficient to go all the way round +the world 658 times; or a grain of sand just visible--that is, +one-hundredth of an inch long and one hundredth of an inch in +diameter--would make one thousand miles of such thread. Further, the +pressure inside such a thread due to a surface tension equal to that +of water would be 60 atmospheres. + +Going back to such threads as can be used in instruments, I have made +use of fibers one ten-thousandth of an inch in diameter, and in these +the torsion is 10,000 times less than that of spun glass. + +As these fibers are made finer their strength increases in proportion +to their size, and surpasses that of ordinary bar steel, reaching, to +use the language of engineers, as high a figure as 80 tons to the +inch. Fibers of ordinary size have a strength of 50 tons to the inch. + +While it is evident that these fibers give us the means of producing +an exceedingly small torsion, and one that is not affected by weather, +it is not yet evident that they may not show the same fatigue that +makes spun glass useless. I have, therefore, a duplicate apparatus +with a quartz fiber, and you will see that the spot of light comes +back to its true place on the screen after the mirror has been twisted +round twice. + +I shall now for a moment draw your attention to that peculiar property +of melted quartz that makes threads such as I have been describing a +possibility. A liquid cylinder, as Plateau has so beautifully shown, +is an unstable form. It can no more exist than can a pencil stand on +its point. It immediately breaks up into a series of spheres. This is +well illustrated in that very ancient experiment of shooting threads +of resin electrically. When the resin is hot, the liquid cylinders, +which are projected in all directions, break up into spheres, as you +see now upon the screen. As the resin cools, they begin to develop +tails; and when it is cool enough, i.e., sufficiently viscous, the +tails thicken and the beads become less, and at last uniform threads +are the result. The series of photographs show this well. + +[Illustration: FIG. 8.] + +[Illustration: FIG. 9.] + +There is a far more perfect illustration which we have only to go into +the garden to find. There we may see in abundance what is now upon the +screen--the webs of those beautiful geometrical spiders. The radial +threads are smooth like the one you saw a few minutes ago, but the +threads that go round and round are beaded. The spider draws these +webs slowly, and at the same time pours upon them a liquid, and still +further to obtain the effect of launching a liquid cylinder in space +he, or rather she, pulls it out like the string of a bow, and lets it +go with a jerk. The liquid cylinder cannot exist, and the result is +what you now see upon the screen (Fig. 8). A more perfect illustration +of the regular breaking up of a liquid cylinder it would be impossible +to find. The beads are, as Plateau showed they ought to be, +alternately large and small, and their regularity is marvelous. +Sometimes two still smaller beads are developed, as may be seen in the +second photograph, thus completely agreeing with the results of +Plateau's investigations. + +I have heard it maintained that the spider goes round her web and +places these beads there afterward. But since a web with about 360,000 +beads is completed in an hour--that is at the rate of about 100 a +second--this does not seem likely. That what I have said is true, is +made more probable by the photograph of a beaded web that I have made +myself by simply stroking a quartz fiber with a straw wetted with +castor oil (Fig. 9); it is rather larger than a spider line; but I +have made beaded threads, using a fine fiber, quite indistinguishable +from a real spider web, and they have the further similarity that they +are just as good for catching flies. + +Now, going back to the melted quartz, it is evident that if it ever +became perfectly liquid, it could not exist as a fiber for an instant. +It is the extreme viscosity of quartz, at the heat even of an electric +arc, that makes these fibers possible. The only difference between +quartz in the oxyhydrogen jet and quartz in the arc is that in the +first you make threads and in the second are blown bubbles. I have in +my hand some microscopic bubbles of quartz showing all the perfection +of form and color that we are familiar with in the soap bubble. + +An invaluable property of quartz is its power of insulating perfectly, +even in an atmosphere saturated with water. The gold leaves now +diverging were charged some time before the lecture, and hardly show +any change, yet the insulator is a rod of quartz only three-quarters +of an inch long, and the air is kept moist by a dish of water. The +quartz may even be dipped in the water and replaced with the water +upon it without any difference in the insulation being observed. + +Not only can fibers be made of extreme fineness, but they are +wonderfully uniform in diameter. So uniform are they that they +perfectly stand an optical test so severe that irregularities +invisible in any microscope would immediately be made apparent. Every +one must have noticed when the sun is shining upon a border of flowers +and shrubs how the lines which spiders use as railways to travel from +place to place glisten with brilliant colors. These colors are only +produced when the fibers are sufficiently fine. If you take one of +these webs and examine it in the sunlight, you will find that the +colors are variegated, and the effect, consequently, is one of great +beauty. + +A quartz fiber of about the same size shows colors in the same way, +but the tint is perfectly uniform on the fiber. If the color of the +fiber is examined with a prism, the spectrum is found to consist of +alternate bright and dark bands. Upon the screen are photographs +taken by Mr. Briscoe, a student in the laboratory at South Kensington, +of the spectra of some of these fibers at different angles of +incidence. It will be seen that coarse fibers have more bands than +fine, and that the number increases with the angle of incidence of the +light. There are peculiarities in the march of the bands as the angle +increases which I cannot describe now. I may only say that they appear +to move not uniformly, but in waves, presenting very much the +appearance of a caterpillar walking. + +So uniform are the quartz fibers that the spectrum from end to end +consists of parallel bands. Occasionally a fiber is found which +presents a slight irregularity here and there. A spider line is so +irregular that these bands are hardly observable; but, as the +photograph on the screen shows, it is possible to trace them running +up and down the spectrum when you know what to look for. + +To show that these longitudinal bands are due to the irregularities, I +have drawn a taper piece of quartz by hand, in which the two edges +make with one another an almost imperceptible angle, and the spectrum +of this shows the gradual change of diameter by the very steep angle +at which the bands run up the spectrum. + +Into the theory of the development of these bands I am unable to +enter; that is a subject on which your professor of natural philosophy +is best able to speak. Perhaps I may venture to express the hope, as +the experimental investigation of this subject is now rendered +possible, that he may be induced to carry out a research for which he +is so eminently fitted. + +Though this is a subject which is altogether beyond me, I have been +able to use the results in a practical way. When it is required to +place into an instrument a fiber of any particular size, all that has +to be done is to hold the frame of fibers toward a bright and distant +light, and look at them through a low-angled prism. The banded spectra +are then visible, and it is the work of a moment to pick out one with +the number of bands that has been found to be given by a fiber of the +desired size. A coarse fiber may have a dozen or more, while such +fibers as I find most useful have only two dark bands. Much finer ones +exist, showing the colors of the first order with one dark band; and +fibers so fine as to correspond to the white or even the gray of +Newton's scale are easily produced. + +Passing now from the most scientific test of the uniformity of these +fibers, I shall next refer to one more homely. It is simply this: The +common garden spider, except when very young, cannot climb up one of +the same size as the web on which she displays such activity. She is +perfectly helpless, and slips down with a run. After vainly trying to +make any headway, she finally puts her hands (or feet) into her mouth +and then tries again, with no better success. I may mention that a +male of the same species is able to run up one of these with the +greatest ease, a feat which may perhaps save the lives of a few of +these unprotected creatures when quartz fibers are more common. + +It is possible to make any quantity of very fine quartz fiber without +a bow and arrow at all, by simply drawing out a rod of quartz over and +over again in a strong oxyhydrogen jet. Then, if a stand of any sort +has been placed a few feet in front of the jet, it will be found +covered with a maze of thread, of which the photograph on the screen +represents a sample. This is hardly distinguishable from the web spun +by this magnificent spider in corners of greenhouses and such places. +By regulating the jet and the manipulation, anything from one of these +stranded cables to a single ultro-microscope line may be developed. + +And now that I have explained that these fibers have such valuable +properties, it will no doubt be expected that I should perform some +feat with their aid which, up to the present time, has been considered +impossible, and this I intend to do. + +Of all experiments, the one which has most excited my admiration is +the famous experiment of Cavendish, of which I have a full size model +before you. The object of this experiment is to weigh the earth by +comparing directly the force with which it attracts things with that +due to large masses of lead. As is shown by the model, any attraction +which these large balls exert on the small ones will tend to deflect +this 6 ft. beam in one direction, and then if the balls are reversed +in position, the deflection will be in the other direction. Now, when +it is considered how enormously greater the earth is than these balls, +it will be evident that the attraction due to them must be in +comparison excessively small. To make this evident, the enormous +apparatus you see had to be constructed, and then, using a fine +torsion wire, a perfectly certain but small effect was produced. The +experiment, however, could only be successfully carried out in cellars +and underground places, because changes of temperature produced +effects greater than those due to gravity.[2] + + [Footnote 2: Dr. Lodge has been able, by an elaborate + arrangement of screens, to make this attraction just evident to + an audience.--C. V. B.] + +Now I have in a hole in the wall an instrument no bigger than a +galvanometer, of which a model is on the table. The balls of the +Cavendish apparatus, weighing several hundredweight each, are replaced +by balls weighing 13/4 pounds only. The smaller balls of 13/4 pounds are +replaced by little weights of 15 grains each. The 6 foot beam is +replaced by one that will swing round freely in a tube three-quarters +of an inch in diameter. The beam is, of course, suspended by a quartz +fiber. With this microscopic apparatus, not only is the very feeble +attraction observable, but I can actually obtain an effect eighteen +times as great as that given by the apparatus of Cavendish, and what +is more important, the accuracy of observation is enormously +increased. + +The light from a lamp passes through a telescope lens, and falls on +the mirror of the instrument. It is reflected back to the table, and +thence by a fixed mirror to the scale on the wall, where it comes to a +focus. If the mirror on the table were plane, the whole movement of +the light would be only about eight inches, but the mirror is convex, +and this magnifies the motion nearly eight times. At the present +moment the attracting weights are in one extreme position, and the +line of light is quiet. I will now move them to the other position, +and you will see the result--the light slowly begins to move, and +slowly increases in movement. In forty seconds it will have acquired +its highest velocity, and in forty more it will have stopped at 5 +feet 81/2 inches from the starting point, after which it will slowly +move back again, oscillating about its new position of rest. + +It is not possible at this hour to enter into any calculations; I will +only say that the motion you have seen is the effect of a force of +less than one ten-millionth of the weight of a grain, and that with +this apparatus I can detect a force two thousand times smaller still. +There would be no difficulty even in showing the attraction between +two No. 5 shot. + +And now, in conclusion, I would only say that if there is anything +that is good in the experiments to which I have this evening directed +your attention, experiments conducted largely with sticks, and string, +and straw and sealing wax, I may perhaps be pardoned if I express my +conviction that in these days we are too apt to depart from the simple +ways of our fathers, and instead of following them, to fall down and +worship the brazen image which the instrument maker hath set up. + + * * * * * + + + + +NATURE, COMPOSITION, AND TREATMENT OF ANIMAL AND VEGETABLE FABRICS. + + +The inseparable duties of studying the composition of the various +animal and vegetable fabrics, as also their nature--when in contact +with the various mineral, vegetable, animal, and gaseous bodies +applied in the individual industries--should not devolve upon the +heads, chemists, or managers of firms alone. It is most important that +every intelligent workman, whom we cannot expect to acquire a very +extensive knowledge of chemistry and perfect acquaintance of the +particular nature and component parts of fabrics, should, at least, be +able to thwart the possibility of the majority of accidents brought +about in regard to the quality and aspect of materials treated by +them. + +In the treatment of wool the first operations are of no mean +importance, and the whole subsequent operations and final results, +almost as a whole, depend on the manner in which the fleece washing +had been effected. In presence of suintine, as also fatty matters, as +well as the countless kinds of acids deposited on the wool through +exudation from the body, etc., the various agents and materials cannot +act and deposit as evenly as might be desired, and the complete +obliteration of the former, therefore, becomes an absolute necessity. + +For vegetable fabrics a great technical and practical knowledge is +already requisite in their cultivation itself, and before any +operations are necessary at all. One of the greatest points is the +ripeness of the fibers. It is almost an impossibility to produce +delicate colors on vegetable fabrics which were gathered +inopportunely. Numerous experiments have been made on cotton +containing smaller or larger quantities of unripe fibers, and after +the necessary preceding operations, have been dyed in rose, purple, +and blue colors, and the beauty of the shades invariably differed in +proportion to the greater or lesser quantities of unripe fibers +contained in the samples, and by a careless admixture of unripe and +unseasoned fibers the most brilliant colors have been completely +spoiled in the presence of the former. These deficiencies of unripe +vegetable fibers are so serious that the utmost precautions should be +taken, not only by planters to gather the fibers in a ripe state, but +the natural aspect of ripe and unripe fibers and their respective +differences should be known to the operators of the individual +branches in the cotton industry themselves. + +The newest vegetable fabrics, as _ma_ (China grass), pina, _abaca_, or +Manila hemp, _agave_, jute, and that obtained from the palm tree, must +be tended with equal care to that of cotton. The _ma_, or China grass, +is obtained from the _Boehmeria nivea_, as also from the less known +_Boehmeria puya_. The fibers of this stalk, after preparing and +bleaching, have the whiteness of snow and the brilliancy of silk. By a +special process--the description of which we must for the present +leave in abeyance--the China grass can be transformed into a material +greatly resembling the finest quality of wool. The greatest advantage +afforded in the application of China grass is, moreover, that the +tissues produced with this fiber are much more easily washed than +silks, and in this operation they lose none of their beauty or their +quality. + +The _abaca_ is produced from the fibrous parts of the bark of the wild +banana tree, found in the Philippines. Its botanical denomination is +_Musa troglodytarum_. The _abaca_ fiber is not spun or wrung, but is +jointed end to end. The threads are wound and subsequently beaten for +softening, and finally bleached by plunging in lime water for +twenty-four hours, and dried in the sun. + +The _pina_ is a fiber obtained from the leaf of the anana tree +(_Bromelias ananas_), and is prepared in the same way as the abaca, +but extreme care must in this case be observed in culling the fibers, +in order to sort in accordance with their degree of fineness. + +The Arabs manufacture the stuff for their tents with a mixture of +camel's hair and the fibrous flocks (kind of wadding) obtained from +the stalks of the wafer palm (the _Chamaerops humilis_). + +The tissues used by the Arabs are coarse and colored, but the palm +fibers--when freed from gluten, which makes them adhere more +strongly--are susceptible to divide in a most astonishing manner. + +The _Agave americana_ is a coarse fiber, mostly used in France for the +manufacture of Gobelin carpets and the production of ropes. Great +efforts have been made to bleach it in a satisfactory manner, as is +done with the _Phormium tenax_, but the former kind of fiber resists +the ordinary treatment with lyes, etc., and an appropriate bleaching +process has only been discovered quite recently. + +Jute, which by many is confounded with _Phormium tenax_, or New +Zealand lint, is a fiber which can be divided as finely as desired, +and can be most beautifully bleached. + +The jute or Indian _paat_ is generally known as a fibrous and textile +fabric, obtained chiefly from Calcutta, and is similar in nature to +the _Corchorus capsularis_, an Oriental species, known in Oriental +India by the name of _hatta jute_ and _gheenatlapaat_. This fibrous +plant has the property of dividing into the finest parallel fibers, +which can be carded without difficulty, and may be said to have the +excellent properties of linen, hemp, and cotton at once. When properly +bleached, it has an aspect which is as beautiful as that of silk. A +mixture of silk and jute can be easily worked together, and can also +be mixed with such vegetable fibers as cotton and linen. An immense +quantity of flannel and other stuffs are now manufactured and imitated +with the different mixtures containing jute. + +The _suun_ is a fiber of a plant in the form of a cane (_Crotalaria +juncea_), and the paat or _suncheepaat_ is the thread of a species of +spiral (_Corchorus olitarius_), sold under the name of jute tissues. + +The cotton tissues lose about twenty-five per cent. of their weight in +bleaching, five per cent. of the substances are dissolved through +alkalies, and the other twenty per cent., which are not attacked +directly through the alkalies, are removed through chlorine, acids, +and the water itself. The linen and hemp tissues contain eighteen per +cent. of substances which are soluble in alkalies, and they lose from +twenty-seven to thirty per cent. of their weight when taken through +the consecutive bleaching operations. + +The substances do not alone include the substances contained in the +fabric originally, but also such as are deposited in the preliminary +treatment of the fabrics, as dirt from the hands of the operator, and +gluten soluble in warm water; as also glue or gelatine, potash or +soda, starch, albumen, and sugar, used by weavers, etc., and which are +all soluble in water; further, such as greasy matters, calcareous +soap, coppery soap, resinous or gummo-resinous matters, and the yellow +and green coloring matters contained in textile fabrics, which are +soluble in caustic soda; and finally, the earthy constituents which +are soluble in acids. + +The nature and composition of silk and wool is diametrically opposed +to that of the former. The silk is more of a gummy nature, and is +susceptible to decompose into a kind of gelatinous mass if specially +treated. + +The yellow coloring principle in silk was found only to be contained +in a very small proportion, and consisting of several distinct bodies. + +The wool contains, first, a fatty matter which is solid at an ordinary +temperature, and perfectly liquid at 60 deg. C.; secondly, a fatty matter +which is liquid at 15 deg. C.; thirdly, a fibrous substance which +essentially constitutes the wool in the strict sense of the word. + +The wool at least contains three important principles, as it will be +known that the fibrous substance disengages sulphur and +hydro-sulphuric acid without losing its peculiar properties; and it, +therefore, appears probable that the sulphur entered as an element in +the composition of a body which is perfectly distinct from the fibrous +substance aforementioned. + +In treating wool with nitric acid, and taking all possible precautions +to determine as accurately as possible the quantity of sulphuric acid +produced by the contents of sulphur in the wool by the reaction with +chloride of barium, it will be found to contain from 1.53 to 1.87 per +cent. of sulphur.--_Wool and Textile Fabrics._ + + * * * * * + + + + +THE PRODUCTION OF AMMONIA FROM COAL.[1] + +By LUDWIG MOND. + + [Footnote 1: A paper read at the annual general meeting of the + Society of Chemical Industry, London, July 10, 1889.] + + +As exemplifying to a certain extent the application of methodical +research to an industrial problem, I propose to bring before you +to-day an account of the work I have been engaged in for many years in +relation to the procuring of new and abundant supplies of ammonia, and +to investigations connected therewith. + +Through the classic researches of Lawes and Gilbert, who proved, in +opposition to no less an authority than Liebig, that ammonia is a most +valuable manure which enables us not only to maintain, but to +multiply, the yield of our fields, and thus to feed on the same area a +much larger number of inhabitants, the immense importance of an +abundant supply of ammonia, more particularly for the Old World, with +its teeming population and worn-out soil, has been apparent to every +one. + +For many years Europe has paid to South America millions upon millions +of pounds for ammonia in the shape of guano, and more recently, since +the supply of guano practically ceased, for nitrate of soda, which +effectually serves the same purpose as ammonia. During the past year +South America exported 750,000 tons of nitrate, of which 650,000 went +to Europe, representing a value of not less than 6,500,000l. + +The problem of saving this immense expenditure to Europe, of making +ourselves independent of a country so far away for the supply of a +material upon which the prosperity of our agriculture--our most +important industry--depends, by supplying this ammonia from sources at +our own command, is certainly one of the most important which our +science has to solve. + +It is more than 100 years since Berthollet ascertained that ammonia +consists of nitrogen and hydrogen, two elements which we have in great +abundance at our command, and innumerable attempts have been made +during this century to produce this valuable product by the direct +combination of the elements, as well as by indirect means. It has been +equally well known that we are in possession of three abundant sources +of nitrogen: + + (1.) In the shape of matter of animal origin. + + (2.) In the shape of matter of vegetable origin. + + (3.) In the atmosphere, which contains no less than 79 per cent. + of uncombined nitrogen. + +In olden times ammonia was principally obtained from animal matter, +originally in Egypt by the distillation of camel dung, later on from +urine, and from the distillation of bones and horn. The quantity so +obtained was very small and the products very expensive. The +introduction of coal gas for illumination gave us a considerable and +constantly increasing supply of ammonia as a by-product of the gas +manufacture, and until recently all practical efforts to increase our +supply of ammonia were directed toward collecting and utilizing in the +best possible manner the ammonia so obtained. The immense extension of +the coal gas industry all over the world has in this way put us into +possession of a very considerable amount of sulphate of ammonia, +amounting in Europe now to 140,000 tons per annum. In recent years +this has been augmented by the ammonia obtained by the distillation of +shale, by the introduction of closed ovens for the manufacture of +coke, combined with apparatus for condensing the ammonia formed in +this manufacture, and also by the condensation of the ammonia +contained in the gases from blast furnaces working with coal. But all +these new sources have so far added only about 40,000 tons of +sulphate of ammonia to our supply, making a total of 180,000 tons per +annum, of which about 120,000 are produced in the United Kingdom, +while we still import 650,000 tons of nitrate of soda, equivalent to +500,000 tons of sulphate of ammonia, to make up our requirements. + +Many processes have from time to time been proposed to obtain ammonia +from other sources. The distillation of turf, which contains upward of +3 per cent. of nitrogen, has received much attention, and a large +number of inventors have endeavored to produce ammonia from the +nitrogen of the air; but none of these processes has to my knowledge +been successful on a manufacturing scale. + +My attention was called to this subject at an early part of my career. +Already, as far back as 1861, I undertook experiments to utilize, for +the production of ammonia, waste leather, a waste material of animal +origin at once abundant and very rich in nitrogen, containing from 12 +per cent. to 15 per cent. of this element. Distillation in iron +retorts yielded about half the nitrogen of this material in the form +of ammonia, the carbon remaining in the retorts containing still from +6 per cent. to 8 per cent. Distillation with a moderate quantity of +hydrate of lime increased the yield of ammonia only by 1 per cent. to +11/2 per cent. A rather better result was obtained by distilling the +ground residual carbon with hydrate of lime, but this operation +proceeded very slowly, and the total yield of ammonia still remained +very far below the quantity theoretically obtainable, so that I came +to the conclusion that it was more rational to utilize the leather, +reduced to powder by mechanical means, by mixing it directly with +other manures. + +A few years later I became connected with a large animal charcoal +works, in which sulphate of ammonia was obtained as a by-product. Here +again I was met with the fact that the yield of ammonia by no means +corresponded with the nitrogen in the raw material and that the +charcoal remaining in the retorts contained still about half as much +nitrogen as had been present in the bones used. + +From this time forward my attention was for many years given +exclusively to the soda manufacture, and it was only in 1879 that I +again took up the question of ammonia. I then determined to submit the +various processes which had been proposed for obtaining ammonia from +the nitrogen of the air to a searching investigation, and engaged Mr. +Joseph Hawliczek to carry out the experimental work. + +These processes may be broadly divided into three classes: + + (1.) Processes which propose to combine nascent hydrogen with + nitrogen at high temperatures or by electricity, with or without + the presence of acid gases. + + (2.) Processes in which nitrides are first formed, from which + ammonia is obtained by the action of hydrogen or steam. + + (3.) Processes in which cyanides are first formed and the ammonia + obtained from these by the action of steam. + +We began with an investigation of those processes in which a mixture +of steam and nitrogen or of steam and air is made to act upon coke at +a high temperature, sometimes in the presence of lime, baryta, or an +alkali, sometimes in the presence of hydrochloric acid. + +Very numerous patents have been taken out in this direction and there +is no doubt that ammonia has been obtained by these processes by many +inventors, but as I was aware that coke contains a considerable +quantity of nitrogen, frequently as much as 1.5 per cent., which might +be the source of the ammonia obtained, I determined to carry on the +investigation in such a way as to make quite certain whether we +obtained the ammonia from the coke or from the nitrogen of the +atmosphere, or from both. For this purpose we made for every +experiment carried on by a mixture of nitrogen or air with steam +another experiment with steam alone, carefully excluding nitrogen from +the apparatus. A very large number of experiments carried on at +carefully determined temperatures, ranging from 500 deg. to 1,200 deg.C., and +in which the directions given by the various inventors were most +carefully observed, all led to the same result, viz., that the +quantities of ammonia obtained were the same whether nitrogen was +introduced into the apparatus with the steam or whether steam alone +was used, thus proving conclusively that the ammonia obtained was +derived from the nitrogen contained in the coke. + +Further, on carefully determining the nitrogen in the coke used, it +was found that the quantity of ammonia we had obtained in burning coke +in a current of nitrogen and steam very nearly corresponded with the +total nitrogen in the coke, so that we subsequently made our nitrogen +determinations in the coke by simply burning it in a current of steam. + +A process belonging to this class, proposed by Hugo Fleck, in which a +mixture of carbonic oxide, steam, and nitrogen is made to pass over +lime at a moderate red heat in order to obtain ammonia, was also +carefully tried. It was claimed for this process that it produced +nascent hydrogen at temperatures at which the ammonia is not +dissociated, and for this reason succeeded where others had failed. We +found that a considerable amount of hydrogen was obtained in this way +at a temperature not exceeding 350 deg.C., and that the reaction was +nearly complete at 500 deg.C.; but although we tried many experiments over +a great range of temperatures, we never obtained a trace of ammonia by +this process. + +Among experiments with processes of the second class, based upon the +formation of nitrides and their subsequent decomposition, the nitrides +of boron and titanium had received most attention from inventors. The +nitride of boron, which is obtained by treating boracic acid with +carbon in the presence of nitrogen, when acted upon by steam, forms +boracic acid again and yields the whole of its nitrogen in the form of +ammonia, but the high temperature at which the first reaction takes +place, and the volatility of boracic acid in a current of steam, make +it impossible to utilize this reaction industrially. + +There seemed to be a better chance for a process patented by M. +Tessier du Mothay, who proposed to bring a mixture of nitrogen and +hydrogen into contact with titanium nitride and thus to form ammonia +continuously. Titanium is the only element of which we know at present +several combinations with nitrogen, and the higher of these does, on +being acted upon by a current of hydrogen at an elevated temperature, +produce ammonia and a lower nitride of titanium; but this lower +nitride does not absorb nitrogen under any of the conditions under +which we tried it, which explains the fact that if we passed a current +of hydrogen and nitrogen over the higher nitride, we at first obtained +a quantity of ammonia corresponding to the quantity which the nitride +would give with hydrogen alone, but that the formation of ammonia then +ceased completely. + +Thus far we had quite failed to get the nitrogen of the air into +action. + +With the third class of processes, however, based upon the formation +in the first instance of cyanides, we found by our very first +experiments that the nitrogen of the atmosphere can be easily led into +combination. A few experiments showed that the cyanide of barium was +much more readily formed than any other cyanide; so we gave our full +attention from this time to the process for obtaining ammonia by means +of cyanide of barium invented by MM. Margueritte and Sourdeval. This +process consists in heating a mixture of carbonate of barium with +carbon in the presence of nitrogen, and subsequently treating the +cyanide of barium produced with steam, thus producing ammonia and +regenerating the carbonate of barium. A great difficulty in this +process is that the carbonate of barium fuses at high temperatures, +and when fused attacks fireclay goods very powerfully. + +We found that this can be overcome by mixing the carbonate of barium +with a sufficient quantity of carbon and a small quantity of pitch, +and that in this way balls can be made which will not fuse, so that +they can be treated in a continuous apparatus in which the broken +briquettes can be charged from the top, and after treatment can be +withdrawn from the bottom. + +We found that the formation of cyanides required a temperature of at +least 1,200 deg. C., and proceeded most readily at 1,400 deg. C., temperatures +which, although difficult to attain, are still quite within the range +of practical working, and we found no difficulty in obtaining a +product containing 30 per cent. of barium cyanide, corresponding to a +conversion into cyanide of 40 per cent. of the barium present. + +We found, however, that the cyanide when exposed to the atmosphere at +a temperature above 300 deg. C. is readily destroyed under reformation of +carbonate of barium, so that it is absolutely necessary to cool it +down to this temperature before exposing it to the atmosphere, a fact +of great importance that had hitherto been overlooked. + +The operation for producing ammonia and regenerating the carbonate of +barium by acting upon the cyanide with steam offers no difficulty +whatever, and if the temperature is not allowed to exceed 500 deg. C., the +results are quantitative. The regenerated carbonate of barium acts +actually better than the ground witherite used in the first instance, +and if care is taken that no impurities are introduced by the pitch +which is used to remake the briquettes and to replace the small amount +of carbon consumed at each operation, I see no reason why it should +not continue to act for a very long time. + +The cyanide is not acted on by carbonic oxide, but carbonic acid +destroys it at high temperatures, so that it is not possible to +produce it by heating the briquettes directly in a flame free from +oxygen, but containing carbonic acid. The process has, therefore, to +be carried out in closed vessels, and I designed for this purpose the +following apparatus: + +Clay retorts of moderate dimensions and thin walls are placed +vertically in a furnace, passing through the hearth as well as through +the arch of the furnace. These are joined at the bottom to cast iron +retorts of the same shape as the earthenware retort. Through a cast +iron mouthpiece on the top of the retort the material was introduced, +while in the cast iron retort below the material was cooled to the +necessary temperature by radiation and by the cold nitrogen gas +introduced into the bottom of it. The lower end of the cast iron +retort was furnished with an arrangement for taking out from time to +time small quantities of the material, while fresh material was in the +same proportion fed in at the top. As a source of nitrogen I used the +gases escaping from the carbonating towers of the ammonia-soda +process. The formation of cyanide of barium from barium carbonate, +carbon, and nitrogen absorbs a very large amount of heat--no less than +97,000 calories per equivalent of the cyanide formed--which heat has +to be transmitted through the walls of the retort. I therefore +considered it necessary to use retorts with very thin walls, but I did +not succeed in obtaining retorts of this description which would +resist the very high temperatures which the process requires, and for +this reason I abandoned these experiments. I was at that time not +acquainted with the excellent quality of clay retorts used in zinc +works, with which I have since experimented for a different purpose. I +have no doubt that with such retorts the production of cyanides by +this process can be carried out without great difficulty. + +I believe that the process will prove remunerative for the manufacture +of cyanogen products, which, if produced more cheaply, may in the +future play an important role in organic synthesis, in the extraction +of noble metals, and possibly other chemical and metallurgical +operations. + +The process certainly also offers a solution of the problem of +obtaining ammonia from the nitrogen of the atmosphere, but whether +this can be done with satisfactory commercial results is a question I +cannot at present answer, as I have not been able to secure the data +for making the necessary calculations. + +I am the more doubtful about this point, as in the course of our +investigations I have found means to produce ammonia at small cost and +in great abundance from the immense store of combined nitrogen which +we possess in our coal fields. + +Among the processes for obtaining ammonia from the nitrogen of the air +which we investigated, was one apparently of great simplicity, +patented by Messrs. Rickman and Thompson. These gentlemen state that +by passing air and steam through a deep coal fire, the nitrogen so +passed through is to a certain extent converted into ammonia. In +investigating this statement we found that the process described +certainly yields a considerable quantity of ammonia, but when we +burned the same coal at a moderate temperature by means of steam +alone in a tube heated from the outside, we obtained twice as much +ammonia as we had done by burning it with a mixture of air and steam, +proving in this case, as in all others, the source of the ammonia to +have been the nitrogen contained in the coal. The quantity of ammonia +obtained was, however, so large that I determined to follow up this +experience, and at once commenced experiments on a semi-manufacturing +scale to ascertain whether they would lead to practical and economic +results. + +I came to the conclusion that burning coal by steam alone at a +temperature at which the ammonia formed should not be dissociated, +although it yielded more ammonia, would not lead to an economic +process, because it would require apparatus heated from the outside, +of great complication, bulk, and costliness, on account of the immense +quantity of raw material to be treated for a small amount of ammonia +obtainable. + +On the other hand, if the coal could be burned in gas producers by a +mixture of air and steam, the plant and working of it would be simple +and inexpensive, the gas obtained could be utilized in the same way as +ordinary producer gas, and would pay to a large extent for the coal +used in the operation, so that although only one-half of the ammonia +would be obtained, it seemed probable that the result would be +economical. + +I consequently constructed gas producers and absorbing plant of +various designs and carried on experiments for a number of years. +These experiments were superintended by Mr. G. H. Beckett, Dr. Carl +Markel, and, during the last four years, by Dr. Adolf Staub, to whose +zeal and energy I am much indebted for the success that has been +achieved. The object of these experiments was to determine the most +favorable conditions for the economic working of the process with +respect to both the cost of manufacture as well as the first cost and +simplicity of plant. The cost of manufacture depends mainly upon the +yield of ammonia, as the expenses remain almost the same whether a +large or a small amount of ammonia is obtained; the only other item of +importance is the quantity of steam used in the process. We found the +yield of ammonia to vary with the temperature at which the producer +was working, and to be highest when the producer was worked as cool as +was compatible with a good combustion of the fuel. The temperature +again depended upon the amount of steam introduced into the producer, +and of course decreased the more steam increased. We obtained the best +practical results by introducing about two tons of steam for every ton +of fuel consumed. We experimented upon numerous kinds of fuel, common +slack and burgy of the Lancashire, Staffordshire, and Nottinghamshire +districts. We found not much difference in the amount of nitrogen +contained in these fuels, which varied between 1.2 and 1.6 per cent., +nor did we find much difference in the ammonia obtained from these +fuels if worked under similar conditions. Employing the quantity of +steam just named we recovered about half the nitrogen in the form of +ammonia, yielding on an average 0.8 per cent. of ammonia, equal to 32 +kilos, of sulphate per ton of fuel. In order to obtain regular results +we found it necessary to work with a great depth of fuel in the +producers, so that slight irregularities in the working would not +affect results. Open burning kinds of slack do of course work with the +greater ease, but there is no difficulty in using a caking fuel, as +the low temperature at which the producers work prevents clinkering +and diminishes the tendency of such fuels to cake together. + +The quantity of steam thus required to obtain a good yield of ammonia +is rather considerable, and threatened to become a serious item of +expense. Only one-third of this steam is decomposed, in its passage +through the producer, and two-thirds remain mixed with the gases which +leave the producer. My endeavors were consequently directed toward +finding means to recover this steam, and to return it to the +producers, and also to utilize the heat of the gases which leave the +producers with a temperature of 450 deg. to 500 deg. C., for raising steam for +the same purpose. The difficulties in the way of attaining this end +and at the same time of recovering, in a simple manner, the small +amount of ammonia contained in the immense volume of gas we have to +deal with, were very great. We obtain from one ton of coal 160,000 +cubic feet of dry gas at 0 deg. C. and atmospheric pressure. The steam +mixed with this gas as it leaves the producer adds another 80,000 +cubic feet to this, and the large amount of latent heat in this +quantity of steam makes the problem still more difficult. The +application of cooling arrangements, such as have been successfully +applied to blast furnace gases, in which there is no steam present, +and which depend upon the cooling through the metallic sides of the +apparatus, is here practically out of the question. After trying a +number of different kinds of apparatus, I have succeeded in solving +the problem in the following way: + +The gases issuing from the producers are led through a rectangular +chamber partly filled with water, which is thrown up in a fine spray +by revolving beaters so as to fill the whole area of the chamber. This +water, of course, becomes hot; a certain quantity of it evaporates, +the spray produced washes all dust and soot out of the gases, and also +condenses the fixed ammonia. The water thus becomes, to a certain +degree, saturated with ammonia salts, and a certain portion of it is +regularly removed from the chamber and distilled with lime to recover +the ammonia. + +[Illustration: Longitudinal Section of Plant for obtaining Ammonia +from Gas Producers. + +Cross Section through Gas Producers.] + +This chamber is provided with water lutes, through which the tar +condensed in it is from time to time removed. From this chamber the +gases, which are now cooled down to about 100 deg. C., and are loaded with +a large amount of water vapor, are passed through a scrubber filled +with perforated bricks, in which the ammonia contained in the gases is +absorbed by sulphuric acid. In this scrubber a fairly concentrated +solution of sulphate of ammonia containing 36 to 38 per cent. is used, +to which a small quantity of sulphuric acid is added, so that the +liquid leaving the scrubber contains only 2.5 per cent. of free acid. +This is necessary, as a liquid containing more acid would act upon the +tarry matter and produce a very dark-colored solution. The liquid +running from the scrubber is passed through a separator in which the +solution of sulphate of ammonia separates from the tar. The greater +portion of the clear liquid is, after adding a fresh quantity of acid +to it, pumped back through the scrubber. A certain portion of it is, +after treatment with a small quantity of heavy tar oils, which take +the tarry matter dissolved in it out, evaporated in conical lead-lined +pans furnished with lead steam coils, and which are kept constantly +filled by the addition of fresh liquor until the whole mass is thick. +This is then run out on a strainer and yields, after draining and +washing with a little water, a sulphate of ammonia of very fair +quality, which finds a ready sale. The mother liquor, which contains +all the free acid, is pumped back to the scrubber. + +The gas on entering this scrubber contains only 0.13 volume per cent. +of ammonia, and on leaving the scrubber it contains not more than +one-tenth of this quantity. Its temperature has been reduced to +80 deg. C., and is fully saturated with moisture, so that practically no +condensation of water takes place in the scrubber. The gas is next +passed through a second scrubber filled with perforated wood blocks. +In this it meets with a current of cold water which condenses the +steam, the water being thereby heated to about 78 deg. C. In this scrubber +the gas is cooled down to about 40 deg.-50 deg. C., and passes from it to the +gas main leading to the various places where it is to be consumed. The +hot water obtained in this second scrubber is passed through a vessel +suitably constructed for separating the tar which is mixed with it, +and is then pumped through a third scrubber, through which, in an +opposite direction to the hot water, cold air is passed. This is +forced by means of a Roots blower through the scrubber into the +producer. + +The air gets heated to about 76 deg. C. and saturated with moisture at +that temperature by its contact with the hot water, and the water +leaves this third scrubber cold enough to be pumped back through the +second scrubber. The same quantity of water is thus constantly used +for condensing the water vapor in one scrubber and giving it up to the +air in the other. In this way we recover and return to the producer +fully two-thirds of the steam which has been originally introduced, so +that we have to add to the air, which has thus been loaded with +moisture, an additional quantity of steam equal to only one-third of +the total quantity required before it enters the producer. This +additional quantity of steam, which amounts to 0.6 ton of steam for +every ton of fuel burnt, we obtain as exhaust steam from the engines +driving the blowers and pumps required for working the plant. + +The gas producers which I prefer to use are of rectangular shape, so +that a number of them can be put into a row. They are six feet wide +and 12 feet long inside. The air is introduced and the ashes removed +at the two small sides of the producer which taper toward the middle +and are closed at the bottom by a water lute of sufficient depth for +the pressure under which the air is forced in, equal to about 4 inches +of water. The ashes are taken out from underneath the water, the +producers having no grate or fire bars at all. The air enters just +above the level of the water through a pipe connected with the blower. +These small sides of the producer rest upon cast iron plates lined to +a certain height with brickwork, and this brickwork is carried by +horizontal cast iron plates above the air entrance. In this way a +chamber is formed of triangular shape, one side of which is closed by +the ashes, and thus the air is distributed over the whole width of the +producer. + +The gas is taken out in the middle of the top of the producer by an +iron pipe, and fuel charged in by hoppers on both sides of this pipe. +Between the pipe and the hoppers two hanging arches are put into the +producers a certain distance down, and the fuel is kept above the +bottom level of these hanging arches. This compels the products of +distillation, produced when fresh fuel is charged in, to pass through +the incandescent fuel between the two hanging arches, whereby the +tarry products are to a considerable extent converted into permanent +gas, and the coal dust arising from the charging is kept back in the +producer. + +The details of construction of this plant will be easily understood by +reference to the diagrams before you. + +The fuel we use is a common kind of slack, and contains, on an +average, 33.5 per cent. of volatile matter, including water, and 11.5 +per cent. of ashes, leaving 55 per cent. of non-volatile carbon. + +The cinders which we take out of the producer contain, on an average, +33 per cent. of carbon. Of this we recover about one-half by riddling +or picking, which we return to the producer. The amount of unburnt +carbon lost in the cinders is thus not more than 3 per cent. to 4 per +cent. on the weight of fuel used. + +The gas we obtain contains, in a dry state, on an average, 15 per +cent. of carbonic acid, 10 per cent. of carbonic oxide, 23 per cent. +of hydrogen, 3 per cent. of hydrocarbons, and 49 per cent. of +nitrogen. + +The caloric value of this gas is very nearly equal to 73 per cent. of +the caloric value of the fuel used, but in using this gas for heating +purposes, such as raising steam or making salt, we utilize the heat it +can give very much better than in burning fuel, as we can completely +burn it with almost the theoretical quantity of air, so that the +products of combustion resulting do not contain more than 1 to 2 per +cent. of free oxygen. Consequently the heat escaping into the chimney +is very much less than when fuel is burnt direct, and we arrive at +evaporating, by means of the gas, 85 per cent. of the water that we +would evaporate by burning the fuel direct, in ordinary fireplaces. + +We have, however, to use a certain quantity of steam in the producers +and in evaporating the sulphate of ammonia liquors, which has to be +deducted from the steam that can be raised by the gas in order to get +at the quantity of available steam therefrom obtainable. The former +amounts, as already stated, to 0.6 ton, the latter to 0.1 ton of steam +per ton of fuel burnt, making a total of 0.7 ton. The gas obtained +from one ton of fuel evaporates 5.8 tons of water in good steam +boilers, working at a rate of evaporation of 50 to 55 tons per 24 +hours under 90 lb. pressure. Deducting from this the 0.7 ton necessary +for working the plant leaves an available amount of steam raised by +the gas from one ton of fuel of 5.1 tons, equal to 75 per cent. of the +steam that we can obtain from the same fuel by hand firing. + +In addition to the gas, we obtain about 3 per cent. of tar from the +fuel. This tar is very thick, and of little commercial value. It +contains only 4 per cent. of oils volatile below 200 deg. C., and 38 per +cent. of oils of a higher boiling point, consisting mostly of creosote +oils very similar to those obtained from blast furnaces; and only +small quantities of anthracene and paraffin wax. + +I have made no attempts to utilize this tar except as fuel. It +evaporates nearly twice as much water as its weight of coal, and we +have thus to add its evaporative efficiency to that of the gas given +above, leading to a total of about 80 per cent. of the evaporative +efficiency of the fuel used in the producers. The loss involved in +gasifying the fuel to recover the ammonia therefrom amounts thus to 20 +per cent. of the fuel used. This means that, where we have now to burn +100 tons of fuel, we shall have to burn 125 tons in the producers in +order to obtain ammonia equal to about half the nitrogen contained +therein. Our actual yield of ammonia on a large scale amounting on an +average to 32 kilos., equal to 70.6 lb. per ton of fuel, 125 tons of +fuel will turn out 4 tons of sulphate of ammonia. We thus consume 6.25 +tons of fuel for every ton of sulphate obtained, or nearly the same +quantity as is used in producing a ton of caustic soda by the Le Blanc +process--a product not more than half the value of ammonium sulphate. +At present prices in Northwich this fuel represents a value of 35s. If +we add to this the extra cost of labor over and above the cost of +burning fuel in ordinary fireplaces, the cost of sulphuric acid, bags, +etc., we come to a total of 4l. 10s. to 5l. per ton of sulphate of +ammonia, which at the present selling price of this article, say 12l. +per ton, leaves, after a liberal allowance for wear and tear of plant, +an ample margin of profit. With a rise in the price of fuel, this +margin, however, rapidly decreases, and the working of the process +will, of course, be much more expensive on a small scale, as will also +be the cost of the plant, which under all circumstances is very +considerable. The great advantages incidental to this process over and +above the profit arising from the manufacture of sulphate of ammonia, +viz., the absolute impossibility of producing smoke and the great +regularity of the heating resulting from the use of gas, are, +therefore, as far as I can see for the present, only available for +large consumers of cheap fuel. + +We have tried many experiments to produce hydrochloric acid in the +producers, with the hope of thereby increasing the yield of ammonia, +as it is well known that ammonium chloride vapor, although it consists +of a mixture of ammonia gas and hydrochloric acid gas, is not at all +dissociated at temperatures at which the dissociation of ammonia alone +has already taken place to a considerable extent. + +I had also hoped that I might in this way produce the acid necessary +to combine with the ammonia at very small cost. For this purpose we +moistened the fuel used with concentrated brine, and also with the +waste liquors from the ammonia soda manufacture, consisting mainly of +chloride of calcium; and we also introduced with the fuel balls made +by mixing very concentrated chloride of calcium solution with clay, +which allowed us to produce a larger quantity of hydrochloric acid in +the producer than by the other methods. + +We did in this way succeed in producing hydrochloric acid sometimes +less and sometimes more than was necessary to combine with the +ammonia, but we did not succeed in producing with regularity the exact +amount of acid necessary to neutralize the ammonia. When the ammonia +was in excess, we had therefore to use sulphuric acid as before to +absorb this excess, and we were never certain that sometimes the +hydrochloric acid might not be in excess, which would have +necessitated to construct the whole plant so that it could have +resisted the action of weak hydrochloric acid--a difficulty which I +have not ventured to attack. The yield of ammonia was not in any case +increased by the presence of the hydrochloric acid. This explains +itself if we consider that there is only a very small amount of +ammonia and hydrochloric acid diffused through a very large volume of +other gases, so that the very peculiar protective action which the +hydrochloric acid does exercise in retarding the dissociation of +ammonia in ammonium chloride vapor, where an atom of ammonia is always +in contact with an atom of hydrochloric acid, will be diminished +almost to zero in such a dilute gas where the atoms of hydrochloric +acid and ammonia will only rarely come into immediate contact with +each other. + +When we burnt coke by a mixture of air and steam in presence of a +large excess of hydrochloric acid, the yield of ammonia certainly was +thereby considerably increased, but such a large excess cannot be used +on an industrial scale. I have therefore for the present to rest +satisfied with obtaining only half the nitrogen contained in the fuel +in the form of ammonia. + +The enormous consumption of fuel in this country--amounting to no less +than 150 million tons per annum--would at this rate yield as much as +five million tons of sulphate of ammonia a year, so that if only +one-tenth of this fuel would be treated by the process, England alone +could supply the whole of the nitrogenous compounds, sulphate of +ammonia, and nitrate of soda at present consumed by the Old World. As +the process is especially profitable for large consumers of fuel +situated in districts where fuel is cheap, it seems to me particularly +suitable to be adopted in this country. It promises to give England +the privilege of supplying the Old World with this all-important +fertilizer, and while yielding a fair profit to the invested capital +and finding employment for a considerable number of men, to make us, +last not least, independent of the New World for our supply of so +indispensable a commodity. + +Before leaving my subject, I will, if you will allow me, give you in a +few words a description of two other inventions which have been the +outcome of this research. While looking one day at the beautiful, +almost colorless, flame of the producer gas burning under one of our +boilers, it occurred to me that a gas so rich in hydrogen might be +turned to better use, and that it might be possible to convert it +direct into electricity by means of a gas battery. + +You all know that Lord Justice Grove showed, now fifty years ago, that +two strips of platinum partly immersed in dilute sulphuric acid, one +of which is in contact with hydrogen and the other with oxygen, +produce electricity. I will not detain you with the many and varied +forms of gas batteries which Dr. Carl Langer (to whom I intrusted this +investigation) has made and tried during the last four years, in order +to arrive at the construction of a gas battery which would give a +practical result, but I will call your attention to the battery before +me on the table, which is the last result of our extended labors in +this direction, and which we hope will mark a great step in advance in +the economic production of electricity. + +The distinguishing feature of this battery is that the electrolyte is +not employed as a mobile liquid, but in a quasi-solid form, and it is, +therefore, named dry gas battery. It consists of a number of elements, +which are formed of a porous diaphragm of a non-conducting material +(in this instance plaster of Paris), which is impregnated with dilute +sulphuric acid. Both sides of this diaphragm are covered with very +fine platinum leaf perforated with very numerous small holes, and over +this a thin film of platinum black. Both these coatings are in contact +with frameworks of lead and antimony, insulated one from the other, +which conduct the electricity to the poles of the battery. + +A number of these elements are placed side by side, with +non-conducting frames intervening, so as to form chambers through +which the hydrogen gas is passed along one side of the element and air +along the other. + +This peculiar construction allows us to get a very large amount of +duty from a very small amount of platinum. One of the batteries before +you, consisting of seven elements, with a total effective surface of +half a square meter, contains 21/2 grammes of platinum leaf and 7 +grammes of platinum black, a total of 91/2 grammes of platinum, and +produces a current of 2 amperes and 5 volts, or 10 watts, when the +outer resistance is properly adjusted. This current is equal to nearly +50 per cent. of the total energy obtainable from the hydrogen absorbed +in the battery. + +In order to maintain a constant current, we have from time to time +(say once an hour) to interchange the gases, so as to counteract the +disturbing influence produced by the transport of the sulphuric acid +gas from one side of the diaphragm to the other. This operation can +easily be performed automatically by a commutator worked by a clock. + +The water produced in the battery by the oxidation of the hydrogen is +carried off by the inert gas mixed with the hydrogen, and by the air, +of which we use a certain excess for this purpose. This is important, +as if the platinum black becomes wet, it loses its absorbing power for +the gases almost completely and stops the work of the battery. To +avoid this was in fact the great difficulty in designing a powerful +gas battery, and all previous constructions which employed the +electrolyte as a mobile liquid failed in consequence. + +The results obtained by our battery are practically the same whether +pure oxygen and hydrogen or air and gases containing 25 per cent. of +hydrogen are used; but we found that the latter gases must be +practically free from carbonic oxide and hydrocarbons, which both +interfere very much with the absorbing power of the platinum black. + +We had thus to find a cheap method of eliminating these two gases from +the producer gas, and converting them at the same time into their +equivalent of hydrogen. The processes hitherto known for this purpose, +viz., passing a mixture of such gases with steam over lime (which I +mentioned some time ago) or over oxide of iron or manganese, require +high temperatures, which render them expensive, and the latter do not +effect the reaction to a sufficient extent for our purpose. + +We have succeeded in attaining our object at a temperature below that +at which the gases leave my producers, viz., at 350 deg. C. to 450 deg. C., by +passing the producer gases, still containing a considerable excess of +steam, over metallic nickel or cobalt. These metals have the +extraordinary property of decomposing almost completely, even at the +low temperature named, carbonic oxide into carbon and carbonic acid +and hydrocarbons into carbon and hydrogen. + +In order to carry the process out with small quantities of nickel and +cobalt, we impregnate pumice stone or similar material with a salt of +nickel or cobalt, and reduce this by means of hydrogen or producer +gas. These pieces of pumice stone are filled into a retort or chamber +and the hot gases passed through them. As the reaction produces heat, +it is not necessary to heat the chambers or retorts from the outside +when the necessary temperature has once been attained. This process +has not yet been carried out on a large scale, but the laboratory +experiments have been so satisfactory that we have no doubt as to its +complete success. It will enable us to obtain gases containing 36 per +cent. to 40 per cent. of hydrogen and practically free from carbonic +oxide and hydrocarbons from producer gas at a very small cost, and +thus to make the latter suitable for the production of electricity by +our gas battery. We obtain, as stated before, 50 per cent. of the +energy in the hydrogen absorbed in the battery in the form of +electricity, while, if the same gas was consumed under steam boilers +to make steam, which, as I have shown before, could in this way be +raised cheaper than by burning fuel direct, and if this steam was +turned into motive power by first-rate steam engines, and the motive +power converted into electricity by a dynamo, the yield of electricity +would in the most favorable case not exceed 8 per cent. of the energy +in the gas. I hope that this kind of battery will one day enable us to +perform chemical operations by electricity on the largest scale, and +to press this potent power into the service of the chemical +industries. + +The statement is frequently made that "Necessity is the mother of +invention." If this has been the case in the past, I think it is no +longer so in our days, since science has made us acquainted with the +correlation of forces, teaching us what amount of energy we utilize +and how much we waste in our various methods for attaining certain +objects, and indicating to us where and in what direction and how far +improvement is possible; and since the increase in our knowledge of +the properties of matter enables us to form an opinion beforehand as +to the substances we have available for obtaining a desired result. + +We can now foresee, in most cases, in what direction progress in +technology will move, and in consequence the inventor is now +frequently in advance of the wants of his time. He may even create new +wants, to my mind a distinct step in the development of human culture. +It can then no longer be stated that "Necessity is the mother of +invention;" but I think it may truly be said that the steady, +methodical investigation of natural phenomena is the father of +industrial progress. + +Sir Lowthian Bell, Bart., F.R.S., in moving a vote of thanks, said +that the meeting had had the privilege of listening to a description +of results obtained by a man of exceptional intelligence and learning, +supplemented by that devotion of mind which qualified him to pursue +his work with great energy and perseverance. The importance of the +president's address could not possibly be overrated. At various +periods different substances had been put forward as indications of +the civilization of the people. He remembered hearing from Dr. Ure +that he considered the consumption of sulphuric acid to be the most +accurate measure of the civilization of the people. + +In course of time sulphuric acid gave way to soap, the consumption of +which was probably still regarded as the great exponent of +civilization by such of his fellow citizens as had thereby made their +name. From what he had heard that morning, however, he should be +inclined to make soap yield to ammonia, as sulphuric acid had in its +time succumbed to soap. For not only was ammonia of great importance +to us as a manufacturing nation, but it almost appeared to be a +condition of our existence. England had a large population +concentrated on an area so small as to make it almost a matter of +apprehension whether the surface could maintain the people upon it. + +We were now importing almost as much food as we consumed, and were +thus more and more dependent on the foreigner. Under certain +conditions this would become a very serious matter, and thus any one +who showed how to produce plenty of ammonia at a cheap rate was a +benefactor to his country. Mr. Mond's process seemed to come nearer to +success than any which had preceded it, and it needed no words from +him to induce the meeting to accord a hearty vote of thanks to the +president for his admirable paper. + +Mr. J. C. Stevenson, M.P., in seconding the motion, said that no paper +could be more interesting and valuable to the society than that +delivered by the president. It opened out a future for the advancement +of chemical industry which almost overcame one by the greatness of its +possibilities. Mr. Mond had performed an invaluable service by +investigating the various methods proposed for the manufacture of +ammonia, and clearing the decks of those processes supposed by their +inventors to be valuable, but proved by him to be delusive. It gave +him hearty pleasure therefore to second the vote of thanks proposed by +Sir Lowthian Bell. + +The vote having been put and carried by acclamation, after a brief +reply from the president: + +The secretary read the report of the scrutators, which showed that 158 +ballot papers had been sent in, 154 voting for the proposed list +intact, and four substituting other names. The gentlemen nominated in +the list issued by the Council were therefore declared elected. + + * * * * * + + +In his brief report for the year ending May 1, 1889, the director of +the Pasteur Institute, Paris, announces the treatment of 1,673 +subjects, of whom 6 were seized with rabies during and 4 within a +fortnight after the process. But 3 only succumbed after the treatment +had been completely carried out, making 1 death in 554, or, including +all cases, 1 in 128. + + * * * * * + + + + +ALKALI MANUFACTORIES. + + +When the alkali, etc., Works Regulation Act was passed in 1881, it was +supposed that the result would be that the atmosphere in the districts +where such works are situated would be considerably improved, and, +consequently, that vegetation would have a better chance in the +struggle for existence, and the sanitary conditions of human dwellings +would be advanced. In all these respects the act has been a success. +But perhaps the most notable result is the effect which the act and +those which have preceded it have had upon the manufactures which they +control. + +This was not anticipated by manufacturers, but now one of the +principal of them (Mr. A. M. Chance) has stated that "Government +inspection has not only led to material improvement in the general +management of chemical works, but it has also been in reality a +distinct benefit to, rather than a tax upon, the owners of such +works." + +This expression of opinion is substantiated by the chief inspector +under the act, whose report for last year has recently been laid +before the local government board. + +There are 1,057 works in the United Kingdom which are visited by the +inspectors, and in only two of these during 1888 did the neglect to +carry out the inspectors' warnings become so flagrant as to call for +legal interference; viz., in the case of Thomas Farmer & Co. +(limited), Victoria Docks, E., who were fined 20l. and costs for +failing to use the "best practicable means" for preventing the escape +of acid gas from manure plant; and in the case of Joseph Fison & Co., +Bramford, who were fined 50l. and costs for excessive escape of acid +gas from sulphuric acid plant. There were seven other cases, but these +were simply for failure to register under the act. + +It is very evident, therefore, that from a public point of view the +act is splendidly successful, and from the practical or scientific +side it is no less satisfactory. + +Of the total number of chemical works (1,057) 866 are registered in +England, 131 in Scotland, and 44 in Ireland--a decrease in the case of +Scotland of 8, and in Ireland of 2 from the previous year, while +England has increased by 1. This must not, however, be taken as a sign +of diminished production, because there is a tendency for the larger +works to increase in size and for the smaller ones to close their +operations. The principal nuisances which the inspectors have to +prevent are the escape of hydrochloric acid gas from alkali works and +of sulphurous gas from vitriol and manure works. + +The alkali act forbids the manufacturer to allow the escape of more +than 5 per cent. of the hydrochloric acid which he produces, or that +that acid must not exist to a greater extent than 0.2 grain in 1 cubic +foot of air, steam, or chimney gas which accompanies. The inspectors' +figures for last year show that the percentage of the acid which +escaped amounted to only 1.96 of the total produced, which is equal to +0.089 grain per cubic foot, and much below the figures for previous +years. The figures in regard to sulphurous gas are equally +satisfactory. The act allows 4 grains of sulphuric anhydride (SO3) per +cubic foot to escape into the air, and last year's average was only +0.737 grain, or less than a fifth of the limit. + +Of course it is now the aim of the Leblanc alkali manufacturers to +reduce the escape of hydrochloric acid to the lowest possible amount, +as their profits depend solely upon the sale of chlorine products, +soda products being sold at a loss. In this connection it is +interesting to note that the amount of common salt manufactured in the +United Kingdom in 1888 was 2,039,867 tons, and of this nearly 600,000 +tons were taken by Leblanc soda makers, and over 200,000 tons by the +ammonia-soda makers. The figures are very largely in excess of +previous years, and indicate a gratifying growth in trade. + +The salt used in the Leblanc process yields the hydrochloric acid, and +that in the ammonia-soda method none, so that we may put down the +theoretical production of acid as 380,000 tons, 7,600 tons of which +was allowed to escape. + +What was a mere trace in the chimney gases amounts, therefore, to a +good round figure at the end of a year, and if it were converted into +bleaching powder it would be worth nearly 150,000l. These figures are, +it should be understood, based on theory, but they serve to show to +what importance a gas has now reached which twenty-five years ago was +a perfect incubus to the manufacturers, and wrought desolation in the +country sides miles and miles around the producing works. There has +long been an expectation that the ammonia-soda makers would add the +manufacture of bleaching powder to their process, but they appear to +be as far as ever from that result, and meanwhile the Leblanc makers +are honestly striving to utilize every atom of the valuable material +which they handle. Hence the eagerness to recover the sulphur from +tank waste by one or other of the few workable processes which have +been proposed. + +This waste contains from 11 to 15 per cent. of sulphur, and when it is +stated that the total amount of tank waste produced yearly is about +750,000 tons, containing about 100,000 tons of sulphur, it will be +seen how large is the reward held out to the successful manipulator. +Moreover, the value of the sulphur that might possibly be saved is not +the only prize held out to those who can successfully deal with the +waste, for this material is not only thrown away as useless, but much +expense is incurred in the throwing. + +In Lancashire and in other inland districts land must be found on +which to deposit it, and the act of depositing is costly, for unless +it is beaten together so as to exclude the air, an intolerable +nuisance arises from it. The cost of haulage and deposit on land +varies, according to the district, from 1s. to 1s. 6d. a ton. In +Widnes it is about 1s. + +In the Newcastle district the practice is to carry this material out +to sea at a cost of about 4d. a ton. + +Mr. Chance's process for the recovery of sulphur from the waste +signalizes the centenary of the Leblanc process; Parnell and Simpson +are following in his wake, and lately Mr. F. Gossage, of Widnes, has +been working on a process for the production of alkali, which enables +him to save the sulphur of the sulphuric acid. In his process a +mixture of 70 parts Leblanc salt cake (sulphate of soda) and 30 parts +common salt is mixed with coal and heated in a furnace, and so reduced +to sulphide of sodium. The resulting "ash" is then dissolved in water +and exposed to the action of carbonic acid, when sulphureted hydrogen +is given off, to be dealt with as in Mr. Chance's sulphur process, +while bicarbonate of soda is formed and separates by precipitation +from the solution of undecomposed common salt. + +Ere long it is expected this new method will be in active operation in +some Leblanc works, the plant of which will, in all probability, be +utilized. It has these great advantages: The absence of lime, the +recovery of the sulphur used in the first instance and the consequent +absence of the objectionable tank waste. Thus a bright promise is held +out that the days of alkali waste are numbered, and that the air in +certain parts of Lancashire will be more balmy than it has been in the +memory of the oldest inhabitant.--_Chemist and Druggist._ + + * * * * * + + + + +THE FUELS OF THE FUTURE. + + +It is undeniable that in this country, at least, we are accustomed to +regard coal as the chief, and, indeed, the only substance which falls +to be considered under the name of fuel. In other countries, however, +the case is different. Various materials, ranging from wood to oil, +come within the category of material for the production of heat. The +question of fuel, it may be remarked, has a social, an antiquarian, +and a chemical interest. In the first place, the inquiry whether or +not our supplies of coal will hold out for say the next hundred +thousand years, or for a much more limited period only, has been very +often discussed by sociologists and by geological authorities. + +Again, it is clear that as man advances in the practice of civilized +arts, his dependence upon fuel becomes of more and more intimate +character. He not merely demands fire wherewith to cook his food, and +to raise his own temperature or that of his dwelling, but requires +fuel for the thousand and one manufacturing operations in which he is +perpetually engaged. It is obvious that without fuel civilized life +would practically come to an end. We cannot take the shortest journey +by rail or steamboat without a tacit dependence upon a fuel supply; +and the failure of this supply would therefore mean and imply the +extinction of all the comforts and conveniences on which we are +accustomed to rely as aids to easy living in these latter days. Again, +socially regarded, man is the only animal that practices the +fire-making habit. Even the highest apes, who will sit round the fire +which a traveler has just left, and enjoy the heat, do not appear to +have developed any sense or idea of keeping up the fire by casting +fresh fuel upon it. It seems fairly certain, then, that we may define +man as being a "fuel-employing animal," and in so doing be within the +bounds of certitude. He may be, and often is, approached by other +animals in respect of many of his arts and practices. Birds weave nest +materials, ants make--and maul--slaves, beavers build dams, and other +animals show the germs and beginnings of human contrivances for aiding +the processes of life, but as yet no animal save man lights and +maintains a fire. That the fire-making habit must have dawned very +early in human history appears to be proved by the finding of ashes +and other evidences of the presence of fire among the remains and +traces of primitive man. + +All we know, also, concerning the history of savage tribes teaches us +that humanity is skillful, even in very rude stages of its progress, +in the making of fire. The contrivances for obtaining fire are many +and curious in savage life, while, once attained, this art seems to +have not only formed a constant accompaniment but probably also a +determining cause in the evolution of civilization. Wood, the fat of +animals, and even the oils expressed from plants, probably all became +known to man as convenient sources of fuel in prehistoric times. From +the incineration of wood to the use of peat and coal would prove an +easy stage in the advance toward present day practices, and with the +attainment of coal as a fuel the first great era in man's fire-making +habits may be said to end. + +Beyond the coal stage, however, lies the more or less distinctively +modern one of the utilization of gas and oil for fuel. The existence +of great natural centers, or underground stores, of gas and oil is +probably no new fact. We read in the histories of classic chroniclers +of the blazing gases which were wont to issue from the earth, and to +inspire feelings of superstitious awe in the minds of beholders. Only +within a few years, however, have geologists been able to tell us much +or anything regarding these reservoirs of natural fuel which have +become famous in America and in the Russian province of Baku. + +For example, it is now known that three products--gas, oil, and salt +or brine--lie within natural receptacles formed by the rock strata in +the order of their weight. This law, as has well been said, forms the +foundation of all successful boring experiments, and the search for +natural fuel, therefore, becomes as easy and as reliable a duty as +that for artesian water or for coal. The great oil fever of the West +was attended at first, as Professor M'Gee tells us, with much waste of +the product. Wells were sunk everywhere, and the oil overflowed the +land, tainting the rivers, poisoning the air, and often driving out +the prospectors from the field of discovery. In Baku accidents and +catastrophes have, similarly, been of frequent occurrence. We read of +petroleum flowing from the ground in jets 200 feet high, and as thick +as a man's body; we learn how it swept away the huge cranes and other +machinery, and how, as it flowed away from the orifices, its course +was marked by the formation of rivers of oil many miles in length. + +In America the pressure of rock gas has burst open stills weighing +over a ton, and has rushed through huge iron tanks and split open the +pipes wherewith it was sought to control its progress. The roar of +this great stream of natural gas was heard for miles around as it +escaped from the outlet, and when it was ignited the pillar of flame +illumined the surrounding country over a radius extending in some +cases to forty miles. It is clear that man having tapped the earth's +stores of natural fuel, stood in danger of having unloosed a monster +whose power he seemed unable to control. Yet, as the sequel will show, +science has been able to tackle with success the problems of mastering +the force and of utilizing the energy which are thus locked up within +the crust of the globe. + +As regards the chemistry of rock gas, we may remark in the first place +that this natural product ranks usually as light carbureted hydrogen +gas. In this respect it is not unlike the marsh gas with which +everyone is familiar, which is found bubbling up from swamps and +morasses, and which constitutes the "will o' the wisp" of romance. In +rock gas, marsh gas itself is actually found in the proportion of +about 93 per cent. The composition of marsh gas is very simple. It +consists of the two elements carbon and hydrogen united in certain +proportions, indicated chemically by the symbol CH4. We find, in fact, +that rock gas possesses a close relationship, chemically speaking, +with many familiar carbon compounds, and of these latter, petroleum +itself, asphaltum, coal, jet, graphite or plumbago, and even the +diamond itself--which is only crystallized carbon after all--are +excellent examples. + +The differences between these substances really consist in the degree +of fixing of the carbon or solid portion of the product, as it were, +which exists. Thus in coal and jet the carbon is of stable character, +such as we might expect to result from the slow decomposition of +vegetable matter, and the products of this action are not volatile or +liable to be suddenly dissociated or broken up. On the other hand, +when we deal with the _hydrocarbons_ as they are called, in the shape +of rock gas, naphtha, petroleum, tar, asphaltum, and similar +substances, we see how the carbon has become subordinated to the +hydrogen part of the compounds, with the result of rendering them more +or less unstable in their character. As Professor M'Gee has shown us, +there is in truth a graduated series leading us from the marsh gas and +rock gas as the lightest members of this class of compounds onward +through the semi-gaseous naphtha to the fluid petroleum, the +semi-fluid tar, the solid asphaltum, and the rigid and brittle +substance known as albertite, with other and allied products. Having +said so much regarding the chemistry of the fuels of the future, we +may now pass to consider their geological record. A somewhat curious +distribution awaits the man of science in this latter respect. Most +readers are aware that the geologists are accustomed to classify +rocks, according to their relative age, into three great groups, known +respectively as the primary, secondary, and tertiary periods. In the +secondary period we do not appear to meet with the fuels of the +future, but as far back as the Devonian or old Red Sandstone period, +and in the still older Silurian rocks, stores of gas and petroleum +abound. In the latest or tertiary period, again, we come upon nearly +all the forms of fuels we have already specified. + +The meaning of this geological distribution of the fuels is entirely +fortuitous. Dr. M'Gee tells us that as their formation depended on +local conditions (such as plant growth), and as we have no means of +judging why such local conditions occurred within any given area, so +must we regard the existence of fuel products in particular regions as +beyond explanation. Of one point, however, we are well assured, namely +that the volume of the fuels of the future is developed in an inverse +proportion to their geological age. The proportionate volume, as it +has been expressed, diminishes progressively as the geological scale +is descended. Again, the weight of the fuels varies directly with +their age; for it is in the older formation of any series that we come +upon the oils and tars and asphaltum, while the marsh gas exists in +later and more recently formed deposits. Further geological research +shows us that the American gas fields exist each as an inverted trough +or dome, a conformation due, of course, to the bending and twisting of +the rocks by the great underground heat forces of the world. The +porous part of the dome may be sandstone or limestone, and above this +portion lie shales, which are the opposite of porous in texture. The +dome, further, contains gas above, naphtha in the middle, and +petroleum below, while last of all comes water, which is usually very +salt. In the Indiana field, however, we are told that the oils lie +near the springing or foundation of the arch of the dome, and at its +crown gas exists, and overlies brine. + +A very important inquiry, in relation to the statement that upon the +products whose composition and history have just been described the +fuel supply of the future will depend, consists in the question of the +extent and duration of these natural gas and oil reservoirs. If we are +beginning to look forward to a time when our coal supply will have +been worked out, it behooves us to ask whether or not the supply of +natural gas and oil is practically illimitable. The geologist will be +able to give the coming man some degree of comfort on this point, by +informing him that there seems to be no limit to the formation of the +fuel of the future. + +Natural gas is being manufactured to-day by nature on a big scale. +Wherever plant material has been entombed in the rock formations, and +wherever its decomposition proceeds, as proceed it must, there natural +gas is being made. So that with the prospect of coal becoming as rare +as the dodo itself, the world, we are told by scientists, may still +regard with complacency the failure of our ordinary carbon supply. The +natural gases and oils of the world will provide the human race with +combustible material for untold ages--such at least is the opinion of +those who are best informed on the subject. For one thing, we are +reminded that gas is found to be the most convenient and most +economical of fuels. Rock gas is being utilized abroad even now in +manufacturing processes. Dr. M'Gee says that even if the natural +supply of rock gas were exhausted to-morrow, manufacturers of glass, +certain grades of iron, and other products would substitute an +artificial gas for the natural product rather than return to coal. He +adds that "enormous waste would thereby be prevented, the gas by which +the air of whole counties in coke-burning regions is contaminated +would be utilized, and the carbon of the dense smoke clouds by which +manufacturing cities are overshadowed would be turned to good +account." So that, as regards the latter point, even Mr. Ruskin with +his horror of the black smoke of to-day and of the disfigurement of +sky and air might become a warm ally of the fuel of the future. The +chemist in his laudation of rock gas and allied products is only +re-echoing, when all is said and done, the modern eulogy pronounced on +ordinary coal gas as a cooking and heating medium. + +We are within the mark when we say that the past five years alone have +witnessed a wonderful extension in the use of gas in the kitchen and +elsewhere. It would be singular, indeed, if we should happen to be +already anticipating the fuel of the future by such a practice. +Whether or not this is the case, it is at least satisfactory for +mankind to know that the mother earth will not fail him when he comes +to demand a substitute for coal. I may be too early even to think of +the day of extinction; but we may regard that evil day with +complacency in face of the stores of fuel husbanded for us within the +rock foundations of our planet.--_Glasgow Herald._ + + * * * * * + + + + +PORTABLE ELECTRIC LIGHT. + + +The famous house of MM. Sautter, Lemonnier & Co. takes a conspicuous +part in the Paris exhibition, and from the wide range of its +specialties exhibits largely in three important branches of industry: +mechanics, electricity, and the optics of lighthouses and projectors. +In these three branches MM. Sautter, Lemonnier & Co. occupy a leading +position in all parts of the world. + +The invention of the aplanetic projector, due to Col. Mangin, was a +clever means of overcoming difficulties, practically insurmountable, +that were inseparable from the construction of parabolic mirrors; this +contributed chiefly to the success of MM. Sautter, Lemonnier & Co. in +this direction. The firm has produced more than 1,500 of these +apparatus, representing a value of nearly L500,000, for the French and +other governments. + +Besides the great projector, which forms the central and crowning +object of the exhibit of MM. Sautter, Lemonnier & Co. in the machinery +hall, the firm exhibits a projector 90 centimeters in diameter mounted +on a crane traveling on wheels, in the pavilion of the War Department. +The lamp used for this apparatus has a luminous value of 6,000 +carcels, with a current of 100 amperes; the amplifying power of the +mirror is 2,025, which gives an intensity of ten millions to twelve +millions of carcels to the beam. + +Projectors used for field work are mounted on a portable carriage, +which also contains the electric generator and the motor driving it. + +[Illustration: MILITARY PORTABLE ELECTRIC LIGHT AT THE PARIS +EXHIBITION.] + +It consists of a tubular boiler (Dion, Bouton & Trepardoux system). +This generator is easily taken to pieces, cleaned, and repaired, and +steam can be raised to working pressure in 20 minutes. The mechanical +and electrical part of the apparatus consists of a Parsons +turbo-motor, of which MM. Sautter, Lemonnier & Co. possess the license +in France for application to military and naval purposes. The speed of +the motor is 9,000 revolutions per minute, and the dynamo is driven +direct from it; at this speed it gives a current of 100 amperes with +and from 55 to 70 volts; the intensity of the light is from 5,500 to +6,000 carcels. The carriage upon which the whole of this apparatus is +mounted is carried on four wheels, made of wood with gun metal +mountings. These are more easy to repair when in service than if they +were wholly of iron. The weight of the carriage is three +tons.--_Engineering._ + + * * * * * + + + + +ELECTRIC MOTOR FOR ALTERNATING CURRENTS. + + +Prof. Galileo Ferraris, of Turin, who has carefully studied +alternating currents and secondary transformers, has constructed a +little motor based upon an entirely new principle, which is as +follows: If we take two inductive fields developed by two bobbins, the +axes of which cut each other at right angles, and a pole placed at the +vertex of the angle, this pole will be subjected to the simultaneous +action of the two bobbins, and the resultant of the magnetic actions +will be represented in magnitude and direction by the diagonal of the +parallelogram, two consecutive sides of which have for their length +the intensity of the two fields, and for their direction the axes of +the two bobbins. + +If into each of these bobbins we send alternating currents having +between one bobbin and the other a difference of phase of 90 deg., the +extremity of the resultant will describe a circle having for its +center the vertex of the right angle. + +If, instead of a fixed pole, we use a metal cylinder movable on its +axis, we shall obtain a continuous rotatory motion of this part, and +the direction of the movement will change when we interchange the +difference of phase in the exciting currents. This rotatory movement +is not due to the Foucault currents, for the metal cylinder may +consist of plates of iron insulated from each other. + +In order to realize the production of these fields, several means can +be employed: The current is sent from an alternating current machine +into the primary circuit of a transformer and thence into one of the +bobbins, the other being supplied by means of the secondary current of +the transformer. A resistance introduced into the circuit will produce +the required difference of phase, and the equality of the intensities +of the fields will be obtained by multiplying the number of turns of +the secondary wire on the bobbin. Moreover, the two bobbins may be +supplied by the secondary current of a transformer by producing the +difference of phase, as in the first case. + +In the motor constructed by Prof. Ferraris the armature consisted of a +copper cylinder measuring 7 centimeters in diameter and 15 centimeters +in length, movable on its axis. The inductors were formed of two +groups of two bobbins. The bobbins which branched off from the primary +circuit of a Gaulard transformer, and were connected in series, +comprised 196 spirals with a resistance of 13 ohms; the bobbins +comprising the secondary circuit were coupled in parallel, and had 504 +spirals with 3.43 ohms resistance. In order to produce the difference +of phase, a resistance of 17 ohms was introduced into the second +circuit, when the dynamo produced a current of 9 amperes with 80 +inversions per second. Under these conditions the available work +measured on the axis of the motor was found for different speeds: +Revolutions per minute: 262--400--546--650--722--770. Watts measured +at the brake: 1.32--2.12--2.55--2.77--2.55--2.40. The maximum +rendering corresponds to a speed of rotation of 650 revolutions, and +Prof. Ferraris attributes the loss of work for higher speeds to the +vibrations to which the machine is exposed. At present the apparatus +is but a laboratory one.--_Bulletin International de l'Electricite._ + + * * * * * + + + + +THE ELECTRIC AGE. + +By CHARLES CARLETON COFFIN. + + +The application of electricity for our convenience and comfort is one +of the marvels of the age. Never in the history of the world has there +been so rapid a development of an occult science. Prior to 1819 very +little was known in regard to magnetism and electricity. During that +year Oersted discovered that an electric current would deflect a +magnetic needle, thus showing that there was some relationship between +electric and magnetic force. A few months later, Arago and Sir Humphry +Davy, independently of each other, discovered that by coiling a wire +around a piece of iron, and passing an electric current through it, +the iron would possess for the time being all the properties of a +magnet. In 1825 William Sturgeon, of London, bent a piece of wire in +the form of the letter U, wound a second wire around it, and, upon +connecting it with a galvanic battery, discovered that the first wire +became magnetic, but lost its magnetic property the moment the battery +was disconnected. The idea of a telegraphic signal came to him, but +the electric impulse, through his rude apparatus, faded out at a +distance of fifty feet. In 1830 Prof. Joseph Henry, of this country, +constructed a line of wire, one and a half miles in length, and sent a +current of electricity through it, ringing a bell at the farther end. +The following year Professor Faraday discovered magnetic induction. +This, in brief, is the genesis of magnetic electricity, which is the +basis of all that has been accomplished in electrical science. + +The first advance after these discoveries was in the development of +the electric telegraph--the discovery in 1837, by the philosopher +Steinhill, that the earth could serve as a conductor, thus requiring +but one wire in the employment of an electric current. Simultaneously +came Morse's invention of the mechanism for the telegraph in 1844, +foreshadowed by Henry in the ringing of bells, thus transmitting +intelligence by sound. Four years later, in 1848, Prof. M. G. Farmer, +still living in Eliot, Me., attached an electro-magnet to clockwork +for the striking of bells to give an alarm of fire. The same idea came +to William F. Channing. The mechanism, constructed simply to +illustrate the idea by Professor Farmer, was placed upon the roof of +the Court House in Boston, and connected with the telegraph wire +leading to New York, and an alarm rung by the operator in that city. +The application of electricity for giving definite information to +firemen was first made in Boston, and it was my privilege to give the +first alarm on the afternoon of April 12, 1852. + +At the close of the last century, Benjamin Thompson, born in Woburn, +Mass., known to the world as Count Rumford, was in the workshop of the +military arsenal of the King of Bavaria in Munich, superintending the +boring of a cannon. The machinery was worked by two horses. He was +surprised at the amount of heat which was generated, for when he threw +the borings into a tumbler filled with cold water, it was set to +boiling, greatly to the astonishment of the workmen. Whence came the +heat? What was heat? The old philosopher said that it was an element. +By experiment he discovered that a horse working two hours and twenty +minutes with the boring machinery would heat nineteen pounds of water +to the boiling point. He traced the heat to the horse, but with all +his acumen he did not go on with the induction to the hay and oats, to +the earth, the sunshine and rain, and so get back to the sun. One +hundred years ago there was no chemical science worthy of the name, no +knowledge of the constitution of plants or the properties of light and +heat. The old philosophers considered light and heat to be fluids, +which passed out of substances when they were too full. Count Rumford +showed that motion was convertible into heat, but did not trace the +motion to its source, so far as we know, in the sun. + +It is only forty-six years since Professor Joule first demonstrated +the mutual relations of all the manifestations of nature's energy. +Thirty-nine years only have passed since he announced the great law of +the convertibility of force. He constructed a miniature churn which +held one pound of water, and connected the revolving paddle of the +churn with a wheel moved by a pound weight, wound up the weight, and +set the paddle in motion. A thermometer detected the change of +temperature and a graduated scale marked the distance traversed by the +descending weight. Repeated experiments showed that a pound weight +falling 772 feet would raise the temperature of water one degree, and +that this was an unvarying law. This was transferring gravitation to +heat, and the law held good when applied to electricity, magnetism, +and chemical affinity, leading to the conclusion that they were +severally manifestations of one universal power.--_Congregationalist._ + + * * * * * + + + + +EARLY ELECTRIC LIGHTING. + + +The opening of the new station of the Electric Lighting Co., of Salem, +Mass., was recently celebrated with appropriate festivities. + +Among the letters of regret from those unable to attend the opening +was the following from Prof. Moses G. Farmer: + + "ELIOT, Me., Aug. 5, 1889. + +"_To the Salem Electric Lighting Company, Charles H. Price, +President_: + +"GENTLEMEN: It would give me great pleasure to accept your kind +invitation to be present at the opening of your new station in Salem +on the 8th of this present August. + +"It is now thirty years since the first dwelling house in Salem was +lighted by electricity. That little obscure dwelling, 11 Pearl Street, +formerly owned by 'Pa' Webb, had the honor to be illuminated by the +effulgent electric beam during every evening of July, 1859, as some of +your honored residents, perhaps, well remember. Mr. George D. Phippen +can doubtless testify to one or more evenings; Mr. Wm. H. Mendell, of +Boston, can also add his testimony; dozens of others could also do the +same, had not some of them already passed to the 'great beyond,' among +whom I well recollect the interest taken by the late and honored Henry +L. Williams, Mr. J. G. Felt, and I do not know how many others. I well +remember reading some of the very finest print standing with my back +to the front wall and reading by the light of a 32 candle power lamp +on the northernmost end of the mantel piece in the parlor; very +possibly the hole in which the lamp was fastened remains to this day. +In a little closet in the rear sleeping room was a switch which could +be turned in one direction and give a beautiful glow light, while if +turned in the other direction, it instantly gave as beautiful a dark. +My then 12 year old daughter used to surprise and please her visitors +by suddenly turning on and off the 'glim.' It is not well to despise +the day of small things, for although the dynamo had not at that date +put in an appearance, and though I used thirty-six Smee cells of six +gallons capacity each, yet I demonstrated then and there that the +incandescent electric light was a possibility, and although I +innocently remarked to the late Samuel W. Bates, of Boston, who with +his partner, Mr. Chauncey Smith, furnished so generously in the +interest of science, not wholly without hope of return, the funds for +the experiment, that it 'did not take much zinc,' and though Mr. Bates +as naively replied, 'I notice that it takes some silver, though,' +still it was then and there heralded as the coming grand illuminant +for the dwelling. I am thankful to have lived to see my predictions +partly fulfilled. + +"During the early fifties I published a statement something like this: +'One pound of coal will furnish gas enough to maintain a candle light +for fifteen hours. One pound of gas (the product of five pounds of +coal) will, in a good fishtail gas burner, furnish one candle light +for seventy-five hours. One pound of coal burned in a good furnace, +under a good boiler, driving a good steam engine, turning a good +magneto-electric machine, will give a candle light for one thousand +hours. But if all the energy locked up in one pound of pure carbon +could be wholly converted into light, it would maintain one candle +light for more than one and a half years.' + +"So, gentlemen, _nil desperandum_; there is still room for +improvement. Let your motto be 'Excelsior.' Possibly you may have +already extracted from one-fifteenth to one-twelfth of the energy +stored in the pound of carbon, but hardly more. Go on, go on, and +bring it so cheap as to reach the humblest dwelling when you shall +celebrate the centennial of the opening of your new station. + +"I do most sincerely regret that I cannot be with you in the flesh. I +am, like Ixion of old, confined to a wheel (chair in my case), cannot +walk, cannot even stand; hence, owing to the impairment of my +understanding (???), I must wish you all the enjoyments of the +evening, and gladly content myself that you have made so much +possible. + + "Very truly yours, MOSES G. FARMER." + + * * * * * + + + + +THE MODERN THEORY OF LIGHT.[1] + + [Footnote 1: Being the general substance of a lecture to the + Ashmolean Society in the University of Oxford, on Monday, June + 3, 1889. [Reprinted from the _Liverpool University College + Magazine_.]] + +By Prof. OLIVER LODGE. + + +To persons occupied in other branches of learning, and not directly +engaged in the study of physical science, some rumor must probably +have traveled of the stir and activity manifest at the present time +among the votaries of that department of knowledge. + +It may serve a useful purpose if I try and explain to outsiders what +this stir is mainly about, and why it exists. There is a proximate and +there is an ultimate cause. The proximate cause is certain experiments +exhibiting in a marked and easily recognizable way the already +theoretically predicted connection between electricity and light. The +ultimate cause is that we begin to feel inklings and foretastes of +theories, wider than that of gravitation, more fundamental than any +theories which have yet been advanced; theories which if successfully +worked out will carry the banner of physical science far into the dark +continent of metaphysics, and will illuminate with a clear philosophy +much that is at present only dimly guessed. More explicitly, we begin +to perceive chinks of insight into the natures of electricity, of +ether, of elasticity, and even of matter itself. We begin to have a +kinetic theory of the physical universe. + +We are living, not in a Newtonian, but at the beginning of a perhaps +still greater Thomsonian era. Greater, not because any one man is +probably greater than Newton,[2] but because of the stupendousness of +the problems now waiting to be solved. There are a dozen men of great +magnitude, either now living or but recently deceased, to whom what we +now know toward these generalizations is in some measure due, and the +epoch of complete development may hardly be seen by those now alive. +It is proverbially rash to attempt prediction, but it seems to me that +it may well take a period of fifty years for these great strides to be +fully accomplished. If it does, and if progress goes on at anything +like its present rate, the aspect of physical science bequeathed to +the latter half of the twentieth century will indeed excite +admiration, and when the populace are sufficiently educated to +appreciate it, will form a worthy theme for poetry, for oratorios, and +for great works of art. + + [Footnote 2: Though, indeed, a century hence it may be premature + to offer an opinion on such a point.] + +To attempt to give any idea of the drift of progress in all the +directions which I have hastily mentioned, to attempt to explain the +beginnings of the theories of elasticity and of matter, would take too +long, and might only result in confusion. I will limit myself chiefly +to giving some notion of what we have gained in knowledge concerning +electricity, ether, and light. Even that is far too much. I find I +must confine myself principally to light, and only treat of the others +as incidental to that. + +For now well nigh a century we have had a wave theory of light; and a +wave theory of light is quite certainly true. It is directly +demonstrable that light consists of waves of some kind or other, and +that these waves travel at a certain well-known velocity, seven times +the circumference of the earth per second, taking eight minutes on the +journey from the sun to the earth. This propagation in time of an +undulatory disturbance necessarily involves a medium. If waves setting +out from the sun exist in space eight minutes before striking our +eyes, there must necessarily be in space some medium in which they +exist and which conveys them. Waves we cannot have unless they be +waves in something. + +No ordinary medium is competent to transmit waves at anything like the +speed of light; hence the luminiferous medium must be a special kind +of substance, and it is called the ether. The _luminiferous_ ether it +used to be called, because the conveyance of light was all it was then +known to be capable of; but now that it is known to do a variety of +other things also, the qualifying adjective may be dropped. + +Wave motion in ether, light certainly is; but what does one mean by +the term wave? The popular notion is, I suppose, of something heaving +up and down, or, perhaps, of something breaking on the shore in which +it is possible to bathe. But if you ask a mathematician what he means +by a wave, he will probably reply that the simplest wave is + + y = a sin (p t - n x), + +and he might possibly refuse to give any other answer. + +And in refusing to give any other answer than this, or its equivalent +in ordinary words, he is entirely justified; that is what is meant by +the term wave, and nothing less general would be all-inclusive. + +Translated into ordinary English the phrase signifies "a disturbance +periodic both in space and time." Anything thus doubly periodic is a +wave; and all waves, whether in air as sound waves, or in ether as +light waves, or on the surface of water as ocean waves, are +comprehended in the definition. + +What properties are essential to a medium capable of transmitting wave +motion? Roughly we may say two--_elasticity_ and _inertia_. Elasticity +in some form, or some equivalent of it, in order to be able to store +up energy and effect recoil; inertia, in order to enable the disturbed +substance to overshoot the mark and oscillate beyond its place of +equilibrium to and fro. Any medium possessing these two properties can +transmit waves, and unless a medium possesses these properties in some +form or other, or some equivalent for them, it may be said with +moderate security to be incompetent to transmit waves. But if we make +this latter statement, one must be prepared to extend to the terms +elasticity and inertia their very largest and broadest signification, +so as to include any possible kind of restoring force and any possible +kind of persistence of motion respectively. + +These matters may be illustrated in many ways, but perhaps a simple +loaded lath or spring in a vise will serve well enough. Pull aside one +end, and its elasticity tends to make it recoil; let it go, and its +inertia causes it to overshoot its normal position; both causes +together cause it to swing to and fro till its energy is exhausted. A +regular series of such springs at equal intervals in space, set going +at regular intervals of time one after the other, gives you at once a +wave motion and appearance which the most casual observer must +recognize as such. A series of pendulums will do just as well. Any +wave-transmitting medium must similarly possess some form of +elasticity and of inertia. + +But now proceed to ask what is this ether which in the case of light +is thus vibrating? What corresponds to the elastic displacement and +recoil of the spring or pendulum? What corresponds to the inertia +whereby it overshoots its mark? Do we know these properties in the +ether in any other way? + +The answer, given first by Clerk Maxwell, and now reiterated and +insisted on by experiments performed in every important laboratory in +the world, is: + +The elastic displacement corresponds to electrostatic charge (roughly +speaking, to electricity). + +The inertia corresponds to magnetism. + +This is the basis of the modern electro-magnetic theory of light. Now +let me illustrate electrically how this can be. + +The old and familiar operation of charging a Leyden jar--the storing +up of energy in a strained dielectric, any electrostatic charging +whatever--is quite analogous to the drawing aside of our flexible +spring. It is making use of the elasticity of the ether to produce a +tendency to recoil. Letting go the spring is analogous to permitting a +discharge of the jar--permitting the strained dielectric to recover +itself, the electrostatic disturbance to subside. + +In nearly all the experiments of electrostatics, ethereal elasticity +is manifest. + +Next consider inertia. How would one illustrate the fact that water, +for instance, possesses inertia--the power of persisting in motion +against obstacles--the power of possessing kinetic energy? The most +direct way would be to take a stream of water and try suddenly to stop +it. Open a water tap freely and then suddenly shut it. The impetus or +momentum of the stopped water makes itself manifest by a violent shock +to the pipe, with which everybody must be familiar. The momentum of +water is utilized by engineers in the "water ram." + +A precisely analogous experiment in electricity is what Faraday called +"the extra current." Send a current through a coil of wire round a +piece of iron, or take any other arrangement for developing powerful +magnetism, and then suddenly stop the current by breaking the circuit. +A violent flash occurs if the stoppage is sudden enough, a flash which +means the bursting of the insulating air partition by the accumulated +electro-magnetic momentum. + +Briefly, we may say that nearly all electro-magnetic experiments +illustrate the fact of ethereal inertia. + +Now return to consider what happens when a charged conductor (say a +Leyden jar) is discharged. The recoil of the strained dielectric +causes a current, the inertia of this current causes it to overshoot +the mark, and for an instant the charge of the jar is reversed; the +current now flows backward and charges the jar up as at first; back +again flows the current, and so on, charging and reversing the charge +with rapid oscillations until the energy is all dissipated into heat. +The operation is precisely analogous to the release of a strained +spring or to the plucking of a stretched string. + +But the discharging body thus thrown into strong electrical vibration +is embedded in the all-pervading ether, and we have just seen that the +ether possesses the two properties requisite for the generation and +transmission of waves--viz., elasticity and inertia or density; hence, +just as a tuning fork vibrating in air excites aerial waves or sound, +so a discharging Leyden jar in ether excites ethereal waves or light. + +Ethereal waves can therefore be actually produced by direct electrical +means. I discharge here a jar, and the room is for an instant filled +with light. With light, I say, though you can see nothing. You can see +and hear the spark indeed--but that is a mere secondary disturbance we +can for the present ignore--I do not mean any secondary disturbance. I +mean the true ethereal waves emitted by the electric oscillation going +on in the neighborhood of this recoiling dielectric. You pull aside +the prong of a tuning fork and let it go; vibration follows and sound +is produced. You charge a Leyden jar and let it discharge; vibration +follows and light is excited. + +It is light just as good as any other light. It travels at the same +pace, it is reflected and refracted according to the same laws; every +experiment known to optics can be performed with this ethereal +radiation electrically produced, and yet you cannot see it. Why not? +For no fault of the light; the fault (if there be a fault) is in the +eye. The retina is incompetent to respond to these vibrations--they +are too slow. The vibrations set up when this large jar is discharged +are from a hundred thousand to a million per second, but that is too +slow for the retina. It responds only to vibrations between 4,000 +billions and 7,000 billions per second. The vibrations are too quick +for the ear, which responds only to vibrations between 40 and 40,000 +per second. Between the highest audible and the lowest visible +vibrations there has been hitherto a great gap, which these electric +oscillations go far to fill up. There has been a great gap simply +because we have no intermediate sense organ to detect rates of +vibration between 40,000 and 4,000,000,000,000,000 per second. It was, +therefore, an unexplored territory. Waves have been there all the time +in any quantity, but we have not thought about them nor attended to +them. + +It happens that I have myself succeeded in getting electric +oscillations so slow as to be audible. The lowest I have got at +present are 125 per second, and for some way above this the sparks +emit a musical note; but no one has yet succeeded in directly making +electric oscillations which are visible, though indirectly every one +does it when they light a candle. + +Here, however, is an electric oscillator, which vibrates 300 million +times a second, and emits ethereal waves a yard long. The whole range +of vibrations between musical tones and some thousand million per +second is now filled up. + +These electro-magnetic waves have long been known on the side of +theory, but interest in them has been immensely quickened by the +discovery of a receiver or detector for them. The great though simple +discovery by Hertz of an "electric eye," as Sir W. Thomson calls it, +makes experiments on these waves for the first time easy or even +possible. We have now a sort of artificial sense organ for their +appreciation--an electric arrangement which can virtually "see" these +intermediate rates of vibration. + +The Hertz receiver is the simplest thing in the world--nothing but a +bit of wire or a pair of bits of wire adjusted so that when immersed +in strong electric radiation they give minute sparks across a +microscopic air gap. + +The receiver I have here is adapted for the yard-long waves emitted +from this small oscillator; but for the far longer waves emitted by a +discharging Leyden jar an excellent receiver is a gilt wall paper or +other interrupted metallic surface. The waves falling upon the +metallic surface are reflected, and in the act of reflection excite +electric currents, which cause sparks. Similarly, gigantic solar waves +may produce aurorae; and minute waves from a candle do electrically +disturb the retina. + +The smaller waves are, however, far the most interesting and the most +tractable to ordinary optical experiments. From a small oscillator, +which may be a couple of small cylinders kept sparking into each other +end to end by an induction coil, waves are emitted on which all manner +of optical experiments can be performed. + +They can be reflected by plain sheets of metal, concentrated by +parabolic reflectors, refracted by prisms, concentrated by lenses. I +have at the college a large lens of pitch, weighing over three +hundredweight, for concentrating them to a focus. They can be made to +show the phenomenon of interference, and thus have their wave length +accurately measured. They are stopped by all conductors and +transmitted by all insulators. Metals are opaque, but even imperfect +insulators such as wood or stone are strikingly transparent, and waves +may be received in one room from a source in another, the door between +the two being shut. + +The real nature of metallic opacity and of transparency has long been +clear in Maxwell's theory of light, and these electrically produced +waves only illustrate and bring home the well known facts. The +experiments of Hertz are in fact the apotheosis of that theory. + +Thus, then, in every way Maxwell's 1865 brilliant perception of the +real nature of light is abundantly justified; and for the first time +we have a true theory of light, no longer based upon analogy with +sound, nor upon a hypothetical jelly or elastic solid. + +Light is an electro-magnetic disturbance of the ether. Optics is a +branch of electricity. Outstanding problems in optics are being +rapidly solved now that we have the means of definitely exciting light +with a full perception of what we are doing and of the precise mode of +its vibration. + +It remains to find out how to shorten down the waves--to hurry up the +vibration until the light becomes visible. Nothing is wanted but +quicker modes of vibrations. Smaller oscillators must be used--very +much smaller--oscillators not much bigger than molecules. In all +probability--one may almost say certainly--ordinary light is the +result of electric oscillation in the molecules of hot bodies, or +sometimes of bodies not hot--as in the phenomenon of phosphorescence. + +The direct generation of _visible_ light by electric means, so soon as +we have learnt how to attain the necessary frequency of vibration, +will have most important practical consequences. + +Speaking in this university, it is happily quite unnecessary for me to +bespeak interest in a subject by any reference to possible practical +applications. But any practical application of what I have dealt with +this evening is apparently so far distant as to be free from any +sordid gloss of competition and company promotion, and is interesting +in itself as a matter of pure science. + +For consider our present methods of making artificial light; they are +both wasteful and ineffective. + +We want a certain range of oscillation, between 7,000 and 4,000 +billion vibrations per second; no other is useful to us, because no +other has any effect upon our retina; but we do not know how to +produce vibrations of this rate. We can produce a definite vibration +of one or two hundred or thousand per second; in other words, we can +excite a pure tone of definite pitch; and we can demand any desired +range of such tones continuously by means of bellows and a keyboard. +We can also (though the fact is less well known) excite momentarily +definite ethereal vibrations of some million per second, as I have +explained at length; but we do not at present seem to know how to +maintain this rate quite continuously. To get much faster rates of +vibration than this we have to fall back upon atoms. We know how to +make atoms vibrate; it is done by what we call "heating" the +substance, and if we could deal with individual atoms unhampered by +others, it is possible that we might get a pure and simple mode of +vibration from them. It is possible, but unlikely; for atoms, even +when isolated, have a multitude of modes of vibration special to +themselves, of which only a few are of practical use to us, and we do +not know how to excite some without also the others. However, we do +not at present even deal with individual atoms; we treat them crowded +together in a compact mass, so that their modes of vibration are +really infinite. + +We take a lump of matter, say a carbon filament or a piece of +quicklime, and by raising its temperature we impress upon its atoms +higher and higher modes of vibration, not transmuting the lower into +the higher, but superposing the higher upon the lower, until at length +we get such rates of vibration as our retina is constructed for, and +we are satisfied. But how wasteful and indirect and empirical is the +process. We want a small range of rapid vibrations, and we know no +better than to make the whole series leading up to them. It is as +though, in order to sound some little shrill octave of pipes in an +organ, we are obliged to depress every key and every pedal, and to +blow a young hurricane. + +I have purposely selected as examples the more perfect methods of +obtaining artificial light, wherein the waste radiation is only useless +and not noxious. But the old-fashioned plan was cruder even than this; +it consisted simply in setting something burning; whereby not the fuel +but the air was consumed, whereby also a most powerful radiation was +produced, in the waste waves of which we were content to sit stewing, +for the sake of the minute--almost infinitesimal--fraction of it which +enabled us to see. + +Every one knows now, however, that combustion is not a pleasant or +healthy mode of obtaining light; but every one does not realize that +neither is incandescence a satisfactory and unwasteful method which is +likely to be practiced for more than a few decades, or perhaps a +century. + +Look at the furnaces and boilers of a great steam engine driving a +group of dynamos, and estimate the energy expended; and then look at +the incandescent filaments of the lamps excited by them, and estimate +how much of their radiated energy is of real service to the eye. It +will be as the energy of a pitch pipe to an entire orchestra. + +It is not too much to say that a boy turning a handle could, if his +energy were properly directed, produce quite as much real light as is +produced by all this mass of mechanism and consumption of material. +There might, perhaps, be something contrary to the laws of nature in +thus hoping to get and utilize some specific kind of radiation without +the rest, but Lord Rayleigh has shown in a short communication to the +British Association at York that it is not so, and that, therefore, we +have a right to try to do it. + +We do not yet know how, it is true, but it is one of the things we +have got to learn. + +Any one looking at a common glow-worm must be struck with the fact +that not by ordinary combustion, nor yet on the steam engine and +dynamo principle, is that easy light produced. Very little waste +radiation is there from phosphorescent things in general. Light of the +kind able to affect the retina is directly emitted; and for this, for +even a large supply of this, a modicum of energy suffices. + +Solar radiation consists of waves of all sizes, it is true; but then +solar radiation has innumerable things to do besides making things +visible. The whole of its energy is useful. In artificial lighting +nothing but light is desired; when heat is wanted it is best obtained +separately by combustion. And so soon as we clearly recognize that +light is an electric vibration, so soon shall we begin to beat about +for some mode of exciting and maintaining an electrical vibration of +any required degree of rapidity. When this has been accomplished the +problem of artificial lighting will have been solved. + + * * * * * + + + + +ON PURIFICATION OF AIR BY OZONE--WITH AN ACCOUNT OF A NEW METHOD.[1] + + [Footnote 1: Paper read in Section C, Domestic Health, at the + Hastings Health Congress, on Friday, May 3, 1889.] + +By Dr. B. W. RICHARDSON. + + +During the time when I was engaged in my preliminary medical +studies--for I never admit to this day of being anything less than a +medical student--the substance called ozone became the topic of much +conversation and speculation. I cannot say that ozone was a discovery +of that date, for in the early part of the century Von Marum had +observed that when electrical discharges were made through oxygen in a +glass cylinder inverted over water, the water rose in the cylinder as +if something had either been taken away from the gas, or as if the gas +itself had been condensed, and was therefore occupying a smaller +space. It had also been observed by many electricians that during a +passage of the electric spark through air or oxygen, there was a +peculiar emanation or odor which some compared to fresh sea air, +others to the air after a thunderstorm, when the sky has become very +clear, the firmament blue, and the stars, if visible, extremely +bright. + +But it was not until the time, or about the time, of which I have +spoken, 1846-49, that these discovered but unexplained phenomena +received proper recognition. The distinguished physicist Schonbein +first, if I may so say, isolated the substance which yielded the +phenomena, and gave to it the name, by which it has since generally +been known, of _ozone_, which means, to emit an odor; a name, I have +always thought, not particularly happy, but which has become, +practically, so fully recognized and understood, that it would be +wrong now to disturb it. + +Schonbein made ozone by the action of the electric spark on oxygen. He +collected it, he tested its chemical properties, he announced it to be +oxygen in a modified form, and he traced its action as an active +oxidizer of various substances, and especially of organic substances, +even when they were in a state of decomposition. + +But Schonbein went further than this. He argued that ozone was a +natural part of the atmosphere, and that in places where there was no +decomposition, that is to say, in places away from great towns, ozone +was present. On the high tower of a cathedral in a big city he +discovered ozone; in the city, at the foot of the tower, he found no +ozone at the same time. He argued, therefore, that the ozone above was +used up in purifying the town below, and so suggested quite a new +explanation of the purification of air. + +The subject was very soon taken up by English observers, and I +remember well a lecture upon it by Michael Faraday, in which that +illustrious philosopher, confirming Schonbein, stated that he had +discovered ozone freely on the Brighton Downs, and had found the +evidence of it diminishing as he approached Brighton, until it was +lost altogether in the town itself. + +Such was the beginning of our knowledge of ozone, the precise nature +of which has not yet been completely made out. At the present time it +is held to be oxygen condensed. To use a chemical phrase, the molecule +of oxygen, which in the ordinary state is composed of two atoms, is +condensed, in ozone, as three atoms. By the electric spark discharged +in dry oxygen as much as 15 per cent. may, under proper conditions, be +turned into ozone. Ozone has also been found to be heavier than air. +Professor Zinno says, that compared with an equal volume of air its +density is equal to 1,658, and that it is forty-eight times heavier +than hydrogen. Heat decomposes it; at the temperature of boiling water +it begins to decompose. In water it is much less soluble than oxygen, +and indeed is practically insoluble; when made to bubble through +boiling water, it ceases to be ozone. The oxidizing power of ozone is +very much greater than that of oxygen, and, according to Saret, when +ozone is decomposed, one part of it enters into combination, the other +remains simply as oxygen. + +It is remarkable that some substances, like turpentine and cinnamon, +absorb ozone and combine with it, a simple fact of much greater +importance than has ever been attached to it. I found, for instance, +that cinnamon which by exposure to the air has been made odorless and, +as it is said, "spoiled," can be made to reabsorb ozone and gain a +kind of freshness. It is certain also that some substances which are +supposed to have disinfecting properties owe what virtues they possess +to the presence of ozone. + +On some grand scale ozone is formed in the air, and my former friend +and colleague, the late Dr. Moffatt, of Hawarden, with whom I wrote a +paper on "Meteorology and Disease," read before the Epidemiological +Society in 1852-53, described what he designated ozone periods of the +atmosphere, connecting these with storms. When the atmospheric +pressure is decreasing, when with that there is increasing warmth and +moisture, and when south and southwesterly winds prevail, then ozone +is active; but when the atmospheric pressure is increasing, when the +air is becoming dry and cold, and north and northeasterly winds +prevail, then the presence of ozone is less active. These facts have +also been put in another way, namely, that the maximum period of ozone +occurs when there is greatest evaporation of water from the earth, and +the minimum when there is greatest condensation of water on the earth; +a theory which tallies well with the idea that ozone is most freely +present when electricity is being produced, least present when +electricity is in smallest quantity. Mr. Buchan, reporting on the +observations of the Scottish Meteorological Society, records that +ozone is most abundant from February to June, when the average amount +is 6.0; and least from July to January, when the average is 5.7; the +maximum, 6.2, being reached in May, and the minimum, 5.3, in November. +This same excellent observer states that "ozone is more abundant on +the sea coast than inland; in the west than the east of Great Britain; +in elevated than in low situations; with southwest than with northeast +winds; in the country than in towns; and on the windward than the +leeward side of towns." + +Recently a very singular hypothesis has been broached in regard to the +blue color of the firmament and ozone. It has been observed that when +a tube is filled with ozone, the light transmitted through it is of a +blue color; from which fact it is assumed that the blue color of the +sky is due to the presence of this body in the higher atmospheric +strata. The hypothesis is in entire accord with the suggestion of +Professor Dove, to which Moffatt always paid the greatest respect, +viz., that the source of ozone for the whole of the planet is +equatorial, and that the point of development of ozone is where the +terrestrial atmosphere raised to its highest altitude, at the equator, +expands out north and south in opposite directions toward the two +poles, to return to the equator over the earth as the trade winds. + +It is necessary for all who would understand the applications of ozone +for any purpose, whether for bleaching purposes or pure chemical +purposes, or for medical or sanitary purposes, to understand these +preliminary facts concerning it, facts which bring me to the +particular point to which I wish to refer to-day. + +In my essay describing the model city, Hygeiopolis, it was suggested +that in every town there should be a building like a gas house, in +which ozone should be made and stored, and from which it should be +dispensed to every street or house at pleasure. This suggestion was +made as the final result of observations which had been going on since +I first began to work at the subject in 1852. It occurred to me from +the moment when I first made ozone by Schonbein's method, that the +value of it in a hygienic point of view was incalculable. + +To my then young and enthusiastic mind it seemed that in ozone we had +a means of stopping all putrefaction, of destroying all infectious +substances, and of actually commanding and destroying the causes which +produced the great spreading diseases; and, although increase of years +and greater experience have toned down the enthusiasm, I still believe +that here one of the most useful fields for investigation remains +almost unexplored. + +In my first experiments I subjected decomposing blood to ozone, and +found that the products of decomposition were instantly destroyed, and +that the fluid was rendered odorless and sweet. I discovered that the +red corpuscles of fresh blood decomposed ozone, and that coagulated +blood underwent a degree of solution through its action. I put dead +birds and pieces of animal substances that had undergone extreme +decomposition into atmospheres containing ozone, and observed the +rapidity with which the products of decomposition were neutralized and +rendered harmless. I employed ozone medicinally, by having it inhaled +by persons who were suffering from foetor of the breath, and with +remarkable success, and I began to employ it and have employed it ever +since (that is to say, for thirty-seven years), for purposes of +disinfection and deodorization, in close rooms, closets, and the like. +I should have used it much more largely but for one circumstance, +namely, the almost impracticable difficulty of making it with +sufficient ease and in sufficient quantities to meet the necessities +of sanitary practice. We are often obstructed in this way. We know of +something exceedingly useful, but we cannot utilize it. This was the +case with ozone. I hope now that difficulty is overcome. If it is, we +shall start from this day on a new era in regard to ozone as an +instrument of sanitation. + +As we have seen, ozone was originally made by charging dry oxygen or +common dry air with electricity from sparks or points. Afterward +Faraday showed that it could be made by holding a warm glass rod in +vapor of ether. Again he showed that it could be made by passing air +over bright phosphorus half immersed in water. Then Siemens modified +the electric process by inventing his well known ozone tube, which +consists of a wide glass tube coated with tinfoil on its outside, and +holding within it a smaller glass tube coated with tinfoil on its +surface. When a current of dry air or oxygen was passed in current +between these two tubes, and the electric spark from a Ruhmkorf coil +was discharged by the terminal wires connected with tinfoil surfaces, +ozone was freely produced, and this was no doubt the best method, for +by means of a double-acting hand bellows currents of ozone could be +driven over very freely. One of these tubes with hand bellows +attached, which I have had in use for twenty-four years, is before the +meeting, and answers as well as ever. The practical difficulty lies in +the requirement of a battery, a large coil, and a separate bellows as +well as the tube. + +My dear and most distinguished friend, the late Professor Polli, of +Milan, tried to overcome the difficulties arising from the use of the +coil by making ozone chemically, namely, by the decomposition of +permanganate of potassa with strong sulphuric acid. He placed the +permanganate in glass vessels, moistened it gradually with the acid, +and then allowed the ozone, which is formed, to diffuse into the air. +In this way he endeavored, as I had done, to purify the air of rooms, +especially those vitiated by the breaths of many people. When he +visited me, not very long before his death, he was enthusiastic as to +the success that must attend the utilization of ozone for +purification, and when I expressed a practical doubt, he rallied me by +saying I must not desert my own child. At the theater La Scala, on the +occasion of an unusually full attendance, Polli collected the +condensible part of the exhaled organic matter, by means of a large +glass bell filled with ice and placed over the circular opening in the +roof, which corresponds with the large central light. The deposit on +this bell was liquid and had a mouldy smell; was for some few days +limpid, but then became very thick and had a nauseous odor. When mixed +with a solution of one part glucose to four parts of water, and kept +at a temperature of from 20 deg. to 24 deg. C., this liquid underwent a slow +fermentation, with the formation, on the superficies, of green must; +during the same period of time, and placed under the same conditions, +a similar glucose solution underwent no change whatever. + +By the use of his ozone bottles Polli believed that he had supplied a +means most suitable for directly destroying in the air miasmatic +principles, without otherwise interfering with the respiratory +functions. The ozonized air had neither a powerful nor an offensive +smell, and it might be easily and economically made. The smell of +ozone was scarcely perceptible, and was far less disagreeable than +chlorine, bromine, and iodine, while it was more efficacious than +either of these; if, therefore, its application as a purifier of a +vitiated air succeeded, it would probably supply all the exigences of +defective ventilation in crowded atmospheres. In confined places +vessels might be placed containing mixtures of permanganate of potassa +or soda and acid in proper quantities, and of which the duration of +the action was known; or sulphuric acid could be dropped upon the +permanganate. + +This idea of applying ozone was no doubt very ingenious, and in the +bottles before us on the table, which have been prepared in Hastings +by Mr. Rossiter, we see it in operation. The disadvantages of the plan +are that manipulation with strong sulphuric acid is never an agreeable +or safe process, and that the ozone evolved cannot be on a large scale +without considerable trouble. + +In 1875 Dr. Lender published a process for the production of ozone. In +this process he used equal parts of manganese, permanganate of potash, +and oxalic acid. When this mixture is placed in contact with water, +ozone is quickly generated. For a room of medium size two spoonfuls of +this powder, placed in a dish and occasionally diluted with water, +would be sufficient. As the ozone is developed, it disinfects the +surrounding air without producing cough. + +Lender's process is very useful when ozone is wanted on a limited +scale. We have some of it here prepared by Mr. Rossiter, and it +answers exceedingly well; but it would be impossible to generate +sufficient ozone by this plan for the large application that would be +required should it come into general use. The process deserves to be +remembered, and the physician may find it valuable as a means by which +ozone may be medically applied, to wounds, or by inhalation when there +are foetid exhalations from the mouth or nostrils. + + +A NEW METHOD. + +For the past ten or fifteen years the manufacture of ozone, for the +reasons related above, has remained in abeyance, and it is to a new +mode, which will, I trust, mark another stage of advancement, that I +now wish to direct attention. Some years since, Mr. Wimshurst, a most +able electrician, invented the electrical machine which goes by his +name. The machine, as will be seen from the specimen of it on the +table, looks something like the old electrical machine, but differs in +that there is no friction, and that the plates of glass with their +metal sectors, separated a little distance from each other, revolve, +when the handle of the machine is turned, in opposite directions. The +machine when it is in good working order (and it is very easily kept +in good working order) produces electricity abundantly, and in working +it I observed that ozone was so freely generated, that more than once +the air of my laboratory became charged with ozone to an oppressive +degree. The fact led me to use this machine for the production of +ozone on a large scale, in the following way. + +From the terminals of the machine two wires are carried and are +conducted, by their terminals, to an ozone generator formed somewhat +after the manner of Siemens', but with this difference, that the +discharge is made through a series of fine points within the +cylinders. The machine is placed on a table with the ozone generator +at the back of it, and can be so arranged that with the turning of the +handle which works the machine a blast of air is carried through the +generator. Thus by one action electricity is generated, sparks are +discharged in the ozone generator, air is driven through, and ozone is +delivered over freely. + +If it be wished to use pure oxygen instead of common air, nothing more +is required than to use compressed oxygen and to allow a gentle +current to pass through the ozone generator in place of air. For this +purpose Brin's compressed oxygen is the purest and best; but for +ordinary service atmospheric air is sufficient.[2] + + [Footnote 2: For illustration to-day, Messrs Mayfield, the + electrical engineers of Queen Victoria Street, E. C., have been + good enough to lend me a machine fitted up on the plan named. It + works so effectively that I can make the ozone given off from it + detectable in every part of this large hall.] + +The advantages of this apparatus are as follows: + +1. With care it is always ready for use, and as no battery is required +nor anything more than the turning of a handle, any person can work +it. + +2. It can be readily moved about from one part of a room or ward to +another part. + +3. If required for the sick it can be wheeled near the bedside and, by +a tube, the ozone it emits can be brought into action in any way +desired by the physician. + +I refer in the above to the minor uses of ozone by this method, but I +should add that it admits of application on a much grander scale. It +would now be quite easy in any public institution to have a room in +which a large compound Wimshurst could be worked with a gas engine, +and from which, with the additional apparatus named, ozone could be +distributed at pleasure into any part of the building. On a still +larger scale ozone could be supplied to towns by this method, as +suggested in Hygeiopolis, the model city. + +It will occur, I doubt not, to the learned president of this section, +and to others of our common profession, that care will have to be +taken in the application of ozone that it be used with discretion. +This is true. It has been observed in regard to diseases, that in the +presence of some diseases ozone is absent in the atmosphere, but that +with other diseases ozone is present in abundance. During epidemics of +cholera, ozone is at a minimum. During other epidemics, like +influenza, it has been at a maximum. In our paper Dr. Moffatt and I +classified diseases under both conditions, and the difference must +never be forgotten, since in some diseases we might by the use of +ozone do mischief instead of good. Moreover, as my published +experiments have shown, prolonged inhalation of ozone produces +headache, coryza, soreness of the eyes, soreness of the throat, +general malaise, and all the symptoms of severe influenza cold. +Warm-blooded animals, also, exposed to it in full charge, suffer from +congestion of the lungs, which may prove rapidly fatal. With care, +however, these dangers are easily avoided, the point of practice being +never to charge the air with ozone too abundantly or too long. + +A simple test affords good evidence as to presence of ozone. If into +twenty ounces of water there be put one ounce of starch and forty +grains of potassium iodide, and the whole be boiled together, a starch +will be made which can be used as a test for ozone. If ozone be passed +through this starch the potassium is oxidized, and the iodine, set +free, strikes a blue color with the starch. Or bibulous paper can be +dipped in the starch, dried and cut into slips, and these slips being +placed in the air will indicate when ozone is present. In disinfecting +or purifying the air of a room with ozone, there is no occasion to +stop until the test paper, by change of color, shows that the ozone +has done its work of destroying the organic matter which is the cause +of impurity or danger. For my own part, I have never seen the +slightest risk from the use of ozone in an impure air. The difficulty +has always been to obtain sufficient ozone to remove the impurity, and +it is this difficulty which I hope now to have conquered.--_The +Asclepiad._ + + * * * * * + + + + +HEAT IN MAN. + + +At a recent meeting of the Physiological Society of Berlin, Prof. +Zuntz spoke on heat regulation in man, basing his remarks on +experiments made by Dr. Loewy. The store of heat in the human body at +any one time is very large, equal, in fact, to nearly all the heat +produced by the body during twenty hours, hence the heat given off to +a calorimeter during a given period cannot be taken as a measure of +the heat production. This determination must be based rather upon the +amount of oxygen consumed and of carbonic acid gas given off. The +purpose of the experiments was to ascertain what alteration the +gaseous interchange of the body undergoes by the application of cold, +inasmuch as existing data on this point are largely contradictory. + +The observations were made on a number of men whose respiratory gases +were compared, during complete rest, when they were at one time +clothed, at another time naked, at temperatures from 12 deg. to 15 deg. C., +and in warm and cold baths. Each experiment lasted from half an hour +to an hour, during which period the gases were repeatedly analyzed. As +a result of fifty-five experiments, twenty showed no alteration of +oxygen consumption as the result of cooling, nine gave a lessened +consumption, while the remaining twenty-six showed an increased using +up of oxygen. This diversity of result is explicable on the basis of +observations made by Prof. Zuntz, who was himself experimented upon, +as to his subjective heat sensations during the experiments. He found +that after the first impression due to the application of cold is +overcome, it was quite easy to maintain himself in a perfectly passive +condition; subsequently it required a distinct effort of the will to +refrain from shivering and throwing the muscles into activity, and +finally even this became no longer possible, and involuntary shivering +and muscular contraction supervened, as soon as the body temperature +(_in ano_) had fallen 1/2 deg. to 1 deg. C. During the first stage of cooling, +Zuntz's oxygen consumption showed a uniform diminution; during the +period also in which shivering was repressed by an effort of the will, +cooling led to no increased consumption of oxygen, but as soon as +shivering became involuntary there was at once an increased using up +of oxygen and excretion of carbonic acid. + +This explains the differences in the results of Dr. Loewy's +experiments, and may be taken to show that in man, and presumably in +_large_ animals, heat regulation as directly dependent upon alteration +(fall) in temperature of the surrounding medium does not exist; the +increased heat production is rather the outcome of the movements +resulting from the application of cold to the body. In _small_ +animals, on the other hand, there undoubtedly exists a heat regulation +dependent upon an increased activity of chemical changes in the +tissues set up by the application of cold to the surface of the body, +and in this case the thermotaxic centers in the brain most probably +play some part.--Dr. Herter gave an account of experiments made by Dr. +Popoff on the artificial digestion of various and variously cooked +meats. Lean beef and the flesh of eels and flounders were digested in +artificial gastric juice; the amount of raw flesh thus peptonized was +in all cases greater than that of cooked meat similarly treated. The +flesh was shredded and heated by steam to 100 deg. C. The result was the +same for beef as for fish. When compared with each other, beef was, on +the whole, the most digestible, but the amount of fish flesh which was +peptonized was sufficiently great to do away with the evil repute +which fish still has in Germany as a proteid food. Smoked meat +differed in no essential extent from raw meat as regards its +digestibility. + + * * * * * + + + + +PRESERVATION OF SPIDERS FOR THE CABINET. + + +For several years past, I have devoted a portion of my leisure time to +the arrangement of the collection of Arachnidae of the Natural History +Museum of the University of Gand. This collection, which is partially +a result of my own captures, is quite a large one, for a university +museum, since it comprises more than six hundred European and foreign +specimens. Each group of individuals of the small forms and each +individual of the large forms is contained in a bottle of alcohol +closed with a ground glass stopper, and, whenever possible, the +specimens have been spread out and fixed upon strips of glass. + +The loss of alcohol through evaporation is almost entirely prevented +by paraffining the stoppers and tying a piece of bladder over them. + +Properly labeled, the series has a very satisfactory aspect, and is +easily consulted for study. The reader, however, will readily +understand how much time and patience such work requires, and can +easily imagine how great an amount of space the collection occupies, +it being at least twenty times greater than that that would be taken +up by a collection of an equal number of insects mounted in the +ordinary way on pins and kept in boxes. + +These inconveniences led me to endeavor to find out whether there was +not some way of preserving spiders, properly so called, in a dry +state, and without distortion or notable modification of their colors. + +Experience long ago taught me that pure and simple desiccation, after +a more or less prolonged immersion in alcohol, gives passable results +only with scorpions, galeodes, phrynes, and mygales, and consequently +with arachnides having thick integuments, while it is entirely +unsuccessful with most of the spiders. The abdomen of these shrivels, +the characteristic colors disappear in great part, and the animals +become unrecognizable. + +Something else was therefore necessary, and I thought of carbolated +glycerine. My process, which I have tried only upon the common species +of the country--_Tegenaria domestica_, _Epeira cucurbitina_, _Zilla +inclinata_, etc., having furnished me with preparations that were +generally satisfactory. I think I shall be doing collectors a service +by publishing it in the _Naturaliste_. + +The specimens should first be deprived of moisture, that is to say, +they should be allowed to remain eight or ten days in succession in 50 +per cent. alcohol and in pure commercial alcohol. Absolute alcohol is +not necessary. + +After being taken from the alcohol, and allowed to drain, the +specimens are immersed in a mixture compound of + + Pure glycerine 2 volumes, + Pure carbolic acid in crystals 1 volume. + +In this they ought to remain at least a week, but there will be no +harm if they are left therein indefinitely, so that the collections of +summer may be mounted during winter evenings. + +What follows is a little more delicate, although very easy. After +being removed from the carbolated glycerine, the spiders are placed +upon several folds of white filtering paper, and are changed from time +to time until the greatest part of the liquid has been absorbed. An +insect pin is then passed through the cephalothorax of each individual +and is inserted in the support upon which the final desiccation is to +take place. This support consists of a piece of sheet cork tacked or +glued at the edges to a piece of wood at least one inch in thickness. +Upon the cork are placed four or five folds of filtering paper, so +that the ventral surface of the pinned spider is in contact with this +absorbing surface. For the rest, the legs, palpi, spinnerets, etc., +are spread out by means of fine pins, precisely as would be done in +the case of coleoptera. + +[Illustration: SETTING BOARD FOR SPIDERS. + +A. Absorbent papers. B. Sheet cork. C. Wooden support.] + +The setting board is put for two or three months in a very dry place +under cover from dust. + +The spiders thus treated will scarcely have changed in appearance, the +abdomen of the largest Epeiras will have preserved its form, the hairs +will in nowise have become agglutinated, and a person would never +suspect that glycerine had performed the role. + +The forms with a large abdomen require a special precaution; it is +necessary to pass the mounting pin through a piece of thin cardboard +or of gelatine prolonged behind under the abdomen, because the latter +is heavy, and the pedicel that connects it with the cephalothorax +easily breaks. + +The specimens are mounted in boxes lined with cork, just as insects +are. + +As there is nothing simpler than to have in one's laboratory three +bottles, two of them containing alcohol and the other containing +carbolated glycerine, and as it is easy to make setting boards capable +of holding from twenty to thirty individuals at once, it will be seen +that, with a little practice, the method is scarcely any more +complicated than the one daily employed for coleoptera and orthoptera, +which latter, too, must pass through alcohol, and be pinned, spread +out, and dried. There are but two additional elements, carbolated +glycerine and absorbent paper. I do not estimate the time necessary +for desiccation as being very long, since the zoologist can occupy +himself with other subjects while the specimens are drying. Let us add +that the process renders the preservation indefinite, and that +destructive insects are not to be feared. Some vertebrates, such as +monkeys, that I preserved in the flesh ten years ago, by a nearly +identical method, are still intact.--_F. Plateau, in Le Naturaliste._ + + * * * * * + + + + +DRIED WINE GRAPES. + + +According to a report of the Committee of the Grape Growers' and Wine +Maker's Association of California, the drying of wine grapes on a +large scale was begun during the vintage season of 1887, in which +season about eight carloads in all were made and sold, the bulk of +which came from the vicinity of Fresno; that year, the committee are +informed, the growers netted about three and a half cents per pound. +During the season of 1888 about 112 carloads were dried, packed, and +sold, netting the growers from two and a half to three and a half +cents per pound, depending on the quality of the fruit. The great bulk +of that year's product has entered into consumption, but there yet +remains unsold to consumers, we are informed, about ten carloads, +which, it is expected, will be sold during the next three months. It +has been observed by those handling this product that the largest +sales of dried wine grapes in 1888 and 1889 took place at those points +to which the first lots were shipped in 1887, which would show that as +the product becomes better known it finds a readier market. + +Dried wine grapes are prepared in a similar manner to raisins; that is +they are dried in the sun, but do not require the same care in +handling that are given to raisins. Wooden trays 2 x 3 are sometimes +used, but it is by no means necessary to go to the expense of +procuring trays, as it has been found that a good quality of coarse +brown paper will answer every purpose, and this, with care, may be +made to last two or three seasons. The drying was last season +principally done on the bare ground, but there is much loss by +shelling, as those dried are required to be turned; a pitchfork is +used for that purpose. Brown building paper can be procured of city +paper dealers in large rolls at four and a half cents per pound; +according to the thickness, it will cost from one and three-quarters +to three and a half cents per square yard. A thin, tough, waterproof +paper is also made in rolls at about six cents a square yard. Wine +grapes dry in from ten days to three weeks, according to variety and +weather, and with the exception of Malvoisie, Rose of Peru, and Black +Hamburg, from three and a half to four and a half tons of the green +fruit are required to make one of the dried; these three varieties, +however, being large, meaty, and a firm pulp, do not require more than +from three to three and a half tons of the green fruit to produce one +ton of dried, and are, therefore, the most profitable for drying; they +also command better values in the market. The grapes are sufficiently +dried when, on being rolled between the thumb and finger, no moisture +exudes, and also when the stems are found to be dry and brittle, so +that they can be separated readily from the berries. After the grapes +have reached the proper state of dryness, they are taken in boxes or +sacks to the packing house, where they are stemmed and cleaned, after +which they are packed in white cotton sacks, holding from fifty to +seventy-five pounds each, and when marked are ready for shipment. + +The stemming and cleaning of the dried grapes is done by special +machines designed for that purpose, which leaves the fruit in a +bright, clean condition attractive to purchasers. These machines are +at present built only by James Porteous, Fresno, and are operated +either by hand or power. The cost of a stemmer and cleaner complete is +$80, f. o. b. cars at Fresno. Where several producers can do so, it +would be advisable to club together and get the machine in this way. +Much extra expense could be avoided and one set of machinery would +serve several vineyards, possibly an entire district where time was +not a great object; or some one person in a district could purchase an +outfit and do the work by contract, going from place to place. The +capacity of the stemmer and cleaner is from five to eight tons per +day, when the grapes are in proper condition; and the cost or charge +for stemming, cleaning, sacking, and sewing up the sacks is from four +to five dollars per ton when the producer furnishes the sacks. Good +cotton sacks, holding about seventy-five pounds, cost from eight to +ten cents each, including the necessary twine. Last year dried grapes +were generally sold for cash, f. o. b., but it is probable that other +markets could be secured by selling on consignment. + +As to the advisability of such a course, each producer must himself be +the judge. It is, however, quite certain that until consumers have an +opportunity to try this product, the sales will necessarily be more or +less limited, unless vigorously pushed by merchants and others +interested in extending the markets for California products in the +Eastern cities not yet tried. The varieties most suitable and +profitable for drying, and especially for consumption in the Eastern +markets, are the Malvoisie, Rose of Peru, Black Hamburg, Mission, +Zinfandel, Charbono, Grenache, and in some localities the Carignan, of +the dark varieties, and the Feher Zagos and Golden Chasselas of the +white grapes; there are many other white grapes that are excellent +when dried, but are too valuable for wine-making purposes, or are too +small or deficient in sugar for use as dried grapes. + +The same is true of the dark grapes, some of which ripen so late that +it would be impossible to dry them in the sun, and the use of +artificial heat is, at present prices, too expensive. Therefore, the +varieties mentioned, which generally mature early, are found to be the +most suitable for this purpose. This product is sold by dealers in the +Eastern cities for cooking purposes, and as a substitute for dried +fruits, such as peaches, apples, apricots, etc., in comparison with +which it is usually much cheaper; while for stewing and for puddings +and pies it answers the same purpose. The demand for this product will +probably be gauged by the Eastern fruit crop; that is, the quantity +that can be disposed of will depend upon the quantity of Eastern fruit +in the market, and the prices will be largely dependent upon that of +dried fruit. + + * * * * * + + + + +WALNUT OIL. + +By THOMAS T. P. BRUCE WARREN. + + +This oil, which I obtained from the fully ripened nut of the _Jugluns +regia_, has so many excellent properties, especially for mixing with +artists' colors for fine art work, that I am surprised at the small +amount of information available on this interesting oil. + +Walnut oil is largely used for adulterating olive oil, and to +compensate for its high iodine absorption it is mixed with pure lard +oil olein, which also retards the thickening effect due to oxidation. +The marc left on expression of the oil is said to be largely used in +the manufacture of chocolate. Many people, I am told, prefer walnut +oil to olive oil for cooking purposes. + +The value of this oil for out-door work has been given me by a friend +who used it for painting the verandas and jalousies of his house (near +Como, Italy) some twenty years ago, and which have not required +painting since. In this country, at least, walnut oil is beyond the +reach of the general painter, and I do not know that the pure oil is +to be obtained as a commercial article, even on a small scale. + +It was in examining the properties of this and other oils, used as +adulterants of olive oil, that I was obliged to prepare them so as to +be sure of getting them in a reliable condition as regards purity. The +walnuts were harvested in the autumn of 1887, and kept in a dry airy +room until the following March. The kernels had shrunk up and +contracted a disagreeable acrid taste, so familiar with old olive oil +in which this has been used as an adulterant. Most oxidized oils, +especially cotton seed oil, reveal a similar acrid taste, but walnut +oil has, in addition, an unmistakable increase in viscosity. The nuts +were opened and the kernels thrown into warm water, so as to loosen +the epidermis; they were then rubbed in a coarse towel, so as to +blanch them. The decorticated nuts were wiped dry and rubbed to a +smooth paste in a marble mortar. The paste was first digested in CS2, +then placed in a percolator and exhausted with the same solvent, which +was evaporated off. The yield of oil was small, but probably, if the +nuts had been left to fully ripen on the trees without knocking them +off, the yield might have been greater. It is by no means improbable +that oxidation may have rendered a portion of the oil insoluble. The +decorticated kernels gave a perfectly sweet, inodorous, and almost +colorless oil, which rapidly thickens to an almost colorless, +transparent, and perfectly elastic skin or film, which does not darken +or crack easily by age. These are properties which, for fine art +painting, might be of great value in preserving the tinctorial purity +and freshness of pigments. + +Sulphur chloride gives a perfectly white product with the fresh oil, +but, when oxidized, the product is very dark, almost black. The iodine +absorption of the fresh oil thus obtained is very high, but falls +rapidly by oxidation or blowing. A curious fact has been disclosed +with reference to the oxidation of this and similar oils. If such an +oil be mixed with lard oil, olive oil, or sperm oil, it thickens by +oxidation, but is perfectly soluble. Such a mixture is largely used in +weaving or spinning. Commercial samples of linseed oil, when +cold-drawn, have a much higher iodine absorption, probably due to the +same cause. Oils extracted by CS2 are very much higher than the same +oils, especially if hot-pressed.--_Chem. News._ + + * * * * * + + + + +THE PYRO DEVELOPER WITH METABISULPHITE OF POTASH. + +By Dr. J. M. EDER. + + +Lately I called attention to the metabisulphite of potassium as an +addition to the pyro solution for development, and can give now some +of my experiences with this salt. + +The metabisulphite of potassium, which was introduced into the market +by Dr. Schuchardt, and whose correct analysis is not known yet, is a +white crystal, which in a solid condition, as well as in an aqueous +solution, has a strong smell of sulphurous acid. An aqueous 2 per +cent. solution of this salt dissolves pyrogallic acid to a weak +yellowish color, being distinguished from the more light brown +solution of sulphite of soda and pyro. The solution kept very well for +four weeks in half-filled bottles, and showed a better preservation +than the usual solution of pyro and sulphite of soda. More than 2 per +cent. of the metabisulphite of potassium is without any advantage. If +this solution is mixed with soda, a picture will develop rapidly, but +the same will show a strongly yellow coloration in the gelatine film. +Sulphite of soda has to be added to the soda solution to obtain an +agreeable brownish or black tone in the negatives. + +If the contents of metabisulphite and pyro-soda developer are +increased, it will act very slowly; larger quantities of the +metabisulphite of potassium, therefore, act like a strong retarder. In +small quantities there is no injurious retarding action, but it will +have the effect that the plates obtain very clear shadows in this +developer, and that the picture appears slower, and will strengthen +more slowly. The strongly retarding action of larger quantities of +metabisulphite might be accounted for in that the bisulphite will +give, with the carbonate of soda, monosulphite and soda bicarbonate, +which latter is not a strong enough alkali to develop the bromide of +silver strongly with pyro. An increase of soda compensates this +retarding action of the metabisulphite of potassium. + +Good results were obtained by me with this salt after several tests, +by producing the following solutions: + + A. + + Pyrogallic acid 4 grammes. + Metabisulphite of potassium 11/2 " + Water 100 c. c. + +This solution keeps for weeks in corked bottles. + + B. + + Crystallized soda 10 grammes. + Neutral sulphite of soda 15 " + Water 100 c. c. + +Before using mix-- + + Pyro solution A 20 c. c. + Soda solution B 20 " + Water 20 " + +The developer acts about one and a half times slower than the ordinary +pyro soda developer, approaching to the latter pretty nearly, and +gives to the negatives an agreeable color and softness, with clear +shadows. If the negatives are to be thinner, more water, say 30 to 40 +c. c., is taken. If denser, then the soda is increased, and the water +in the developer is reduced. An alum bath before fixing is to be +recommended. + +An advantage of this development is the great durability of the +pyro-meta sulphite solution. The cost price is about the same as +that of the ordinary pyro developer. At all events, it is worth while +to make further investigation with the metabisulphite of potassium, +the same being also a good preservative for hydroquinone +solutions.--_Photographische Correspondenz; Reported in the Photo. +News._ + + * * * * * + + +A New Catalogue of Valuable Papers + +Contained in SCIENTIFIC AMERICAN SUPPLEMENT during the past ten years, +sent _free of charge_ to any address. MUNN & CO., 361 Broadway, New +York. + + * * * * * + + +THE SCIENTIFIC AMERICAN + +Architects and Builders Edition. + +$2.50 a Year. Single Copies, 25 cts. + +This is a Special Edition of the SCIENTIFIC AMERICAN, issued +monthly--on the first day of the month. 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