PAGE 213 .. 213 213 PAGE Paper-Makers and the Chemical Lubricants. Union...... 205 Notes on the Vulcanization and Decay of India-Rubber A New Oil-Burning Device Report on Manure Material ...... 213 ... 214 ...... 214 Fixing Tannin. .... 207 Permanent Chemical Exhibition 208 Commercial Fertilizers International Exhibition of Mining and Metallurgy Ozonin 208 209 ... 209 White Lead and its Inventors...... 210 Our Book Shelf Correspondence Trade Notes... The Liverpool Colour Market...... 214 Notices. . 214 215 215 215 215 216 217 20 Readers will oblige by making their remittances for subscriptions by Postal or Post Office Order, crossed. We shall esteem it a favour if any of our readers, in making inquiries of, or opening accounts with advertisers in this paper, will kindly mention the Chemical Trade Journal as the source of their information. Advertisements intended for insertion in the current week's issue, should reach the office by Wednesday morning at the latest. Communications for the Editor, if intended for insertion in the current week's issue, should reach the office not later than Tuesday Morning. Articles, reports, and correspondence on all matters of interest to the Chemical and allied industries, home and foreign, are solicited. Correspondents should condense their matter as much as possible, write on one side only of the paper, and in all cases give their names and addresses, not necessarily for publication. Sketches should be sent on separate sheets. We cannot undertake to return rejected manuscripts or drawings, unless accompanied by a stamped directed envelope. Readers are invited to forward items of intelligence, or cuttings from local newspapers, of interest to the trades concerned. As it is one of the special features of the Chemical Trade Journal to give the earliest information respecting new processes, improvements, inventions, etc., bearing upon the Chemical and allied industries, or which may be of interest to our readers, the Editor invites particulars of such when in working order-from the originators; and if the subject is deemed of sufficient importance, an expert will visit and report upon the same in the columns of the Journal. There is no fee required for visits of this kind. THE HE success of the Chemical Union having now become well-nigh assured, and the paper-maker, assisted by the daily press, having done his level best to thwart the combination, a calm succeeds the storm, which all parties may utilise with profit in dispassionately considering the present position, as compared with the status quo ante. Some week or two ago, it was gravely announced that many of the leading paper-makers were about to start a manufacturing concern to make their own caustic soda and bleaching powder. The capital was modestly fixed at a million sterling, but it was not stated how much of this would be found by the enterprising paper-makers, and how much would be placed in the confiding arms of the British public. The opponents to the formation of a Chemical Union, and notably the daily newspapers, seem to have had no idea of how they were giving the lie direct to their own utterences by issuing the foregoing statements. The daily press has been endeavouring to persuade the public that the existing alkali plant is obsolete and well-nigh worn out. Now as a matter of fact, the only process by which caustic soda can be economically manufactured at the present time is the Leblanc process, so that if the leading paper-makers erect a works to make caustic soda, it must be by the Leblanc process, so much vilified and abused during the past few weeks. Of course it goes without saying, that paper-makers will, during the continuance of the Union, have to pay more for their chemicals than they have been in the habit of doing. When bleach was selling at four guineas per ton, the alkalimaker was bearing the loss, while the paper-maker reaped the profit; the alkali-maker now thinks it is high time to stop selling his goods below cost price, and we agree with him entirely. It would be much more to the credit of the papertrade, if greater efforts were made towards economy, by using their utmost endeavours to keep their soda liquors out of our rivers and streams, and we venture to assert that the proprietors of paper mills would get a much better return for their money by recovering the soda from their waste lyes, than by spending it in a co-operative chemical works. One hundred and fifty thousand tons of bleach per annum is about the maximum quantity that can be sold by English houses; there is sufficient plant in existence to make this as a minimum production. If paper-makers manufacture their own chemicals, there will be nothing left for the alkali-maker, but to use his pyrites burners and leaden towers for the manufacture of paper stock, or paper itself, by means of the sulphite process, and so hasten the day of cheaper paper, which, no doubt, will put the daily press once more in an Elysian mood. NOTES ON THE VULCANIZATION AND DECAY OF INDIA RUBBER. [BY WILLIAM THOMSON, F.R.S. E., F.C.S. (Read before section B of the British Association at Leeds.) UN NDER ordinary conditions india-rubber for vulcanizing is usually mixed with sulphur and heated to a high temperature, when chemical combination takes place between the sulphur and the rubber producing a much more valuable compound for ordinary purposes than unvulcanized rubber; the former remaining soft at very low temperatures and firm at high temperatures, whilst the latter becomes hard and quite plastic respectively at those temperatures. In making cloth for waterproof garments, another method is employed for vulcanizing the rubber, viz., by wetting its surface with a mixture of somewhere about five to ten parts of chloride of sulphur dissolved in 100 parts of bisulphide of carbon, and then heating the fabric gently to evaporate away the excess of these substances; the rubber covered cloth cannot be heated to a high temperature like the rubber alone, because the heat would be liable to injure the cotton, silk, or wool of the fabric, or destroy or injure the colours. The bisulphide of carbon softens and penetrates the fine layer of rubber, carrying with it the chloride of sulphur dissolved in it, and it is generally supposed that the chloride of sulphur breaks up, the sulphur combining with the rubber producing vulcanization, and the chlorine combining with the hydrogen producing hydrochloric acid which is liberated. This reaction is clearly not the correct one, and it is probable that the reverse is more in accordance with the facts, viz., that the chlorine of the sulphur chloride combines with the rubber producing vulcanization, leaving the sulphur in the free state, or only partially in combination with the rubber, because in rubber vulcanized by the cold process I have found free sulphur to be present. From a piece of rubber covered cloth I separated the rubber, and submitted it to analysis, by mixing it thoroughly in small pieces with pure sodium carbonate and igniting, then dissolving the whole in water and adding to it peroxide of hydrogen previously treated with excess of barium chloride (to separate sulphuric acid or sulphates). The peroxide ensures the conversion of the lower oxides of sulphur into sulphuric acid, whilst the excess of barium chlorides precipitates the sulphuric acid in the solution which is then weighed as barium sulphate. Another portion of the made up solution was neutralized, and the chlorine present titrated. The rubber previous to ignition, as above described, had been well boiled in water and dried to separate any hydrochloric acid which might be present, but only a faint trace of chlorine compound could be thus separated from the rubber. The total sulphur present in the rubber amounted to 2'60, and the total chlorine to 6'31 per cent. The yellow coloured sulphur protochloride is best adapted for vulcanizing, because it does not act too strongly upon the rubber, whilst the dark coloured chloride of sulphur, containing as it does a large quantity of the higher chlorides of sulphur, is liable to render the rubber quite hard by vulcanizing it too much. The theory generally adopted to explain this is, that these higher chlorides break up easily, liberating their sulphur which thus combines in greater quantity with the rubber; but my experiments and analyses prove that it is chiefly the chlorine and not the sulphur of the chloride of sulphur which produces the vulcanization. A rubber substitute, much used at present, is produced by acting on vegetable oils, such as rape, linseed, etc., with a mixture of chloride of sulphur and bisulphide of carbon; the oil becomes converted into a solid substance resembling india-rubber to some extent, but being much more brittle. This body is now used in large quantity for mixing with india-rubber for the purpose of cheapening its production. On analysis of some samples of this material I have invariably found tnat it contained a much greater proportion of chlorine than of sulphur, and this process therefore is a vulcanization by chlorine rather than by sulphur. Recently I analysed three samples of rubber substitute, the one termed "special another "spongy india-rubber substitute, the third being similar to the first in appearance. The first contained of sulphur 34 and of chlorine 76 per cent.; the second contained of sulphur 456 and of chlorine 8:22, and the third 2'67 of sulphur and 7'90 of chlorine per cent. These rubber substitutes contain considerable quantities of oily matters soluble in ether which I have also found to be chlorine and sulphur compounds of the oils. The first yielded 2010 per cent., the second 14'3 and the third 115 per cent. of these thick oily matters soluble in ether. This oily substance from the first sample contained 26 per cent. of sulphur and 6'1 per cent. of chlorine, whilst that from the second contained 2'97 and 6.87 per cent of sulphur and chlorine respectively. Some rubber manufacturers regard this oily matter as injurious to the rubber, and reject any substitute which contains any considerable proportion of it. I have found, however, by experiment that this oily compound instead of acting injuriously on india-rubber, actually acts as a preservative of it; some rubber threads were smeared with this oily extract, some with ordinary (unvulcanized) rape oil and some left untreated; these were put into an incubator at 150° Fahrenheit for a few days when it was found that the oil treated rubber was quite soft and rotten, whilst the other two had remained sound, after a few days more, the original rubber threads had become quite rotten, whilst the threads smeared with the oily part of the vulcanized oil remained quite sound. The first and second samples of rubber substitute were examined for soluble chlorides or hydrochloric acid, by boiling in water, the first gave o'18 per cent of chlorine soluble in water, and the second o'05 per cent. It has been known for some time that copper salts exert a most injurious influence on india-rubber, copper salts are sometimes used in dyeing cloth, which are afterwards employed for water proofing with india-rubber, and it seems quite astonishing what a small quantity of copper is required to harden and destroy the rubber, and the destructive effect of copper is further enhanced if the cloth contains oily matters in which the copper has dissolved. As an example, here is a piece of cloth, alleged to have damaged the thin coating of india-rubber on it: I found it to contain copper, and with a view of demonstrating this point, I took one piece in its original condition, to the end of this I pasted a similar piece of the cloth from which the oily and greasy matters had been removed by ether, and to the end of this again, I pasted another piece of the same cloth, from which I had removed both oily and greasy matters and copper; these three pieces joined end to end into one, were then coated in the usual way with india-rubber, and then hung in an incubator at 150° Fah. In the course of a few days, the rubber on the original cloth had become soft, and it then hardened and became rotten and useless; the second piece from which the greasy matters had been removed, then became quite hard and rotten, whilst the part from which both greasy matters and copper had been removed has remained in a perfectly elastic and good condition. Professor Dewar observed accidentally, that metallic copper when heated to the temperature of boiling water in contact with the rubber exerted a destructive effect upon it. With a view of finding whether this was due to the copper per se, or to its power of conducting heat more rapidly to the rubber, I laid a sheet of rubber on a plate of glass, and on it placed four clean discs, one of copper, one of platinum, one of zinc, and one of silver. After a few days in an incubator at 150o Fah., the rubber under the copper had become quite hard, that under the platinum had become slightly affected and hardened at different parts, whilst the rubber under the silver and under the zinc remained quite sound and elastic. This would infer that the pure metallic copper had exerted a great oxidising effect on the rubber, the platinum had exerted a slight effect, whilst the zinc and silver respectively had had no injurious influence on it. A still more curious result was this, that the rubber thus hardened by the copper contained no appreciable trace of copper, the copper therefore presumably sets up the oxidising action in the rubber without itself permeating it. I have pleasure in acknowledging the assistance rendered to me in this investigation of my assistant, Mr. Frederick Lewis. A. A NEW OIL-BURNING DEVICE. ROCHESTER, N. Y., mechanic, John Burns by name, has perfected an invention which promises to be of great value wherever oil is used for fuel purposes, inasmuch as it dissipates all risk of accident from explosion or fire. Mr. Burns' idea is simplicity itself. Where oil fuel is used under boilers, or in fact anywhere else, he proposes to prevent the generation of inflammable gases, or the risk of the flame communicating with the supply by forcing the oil through a pipe containing water, the lightness of the oil, of course, bringing it to the top. His plan as given is to fill a pipe with water. At the end where the burner is located is a valve and behind it and above the water pipe, a feed pipe which contains oil, but is directly attached to the water pipe. At the other end of the pipe is the receptacle holding the oil. The oil meets the water a few feet from the receptacle holding the former. Then the valve or the burner which regulates the supply of oil is opened. The oil at the valve starts drop by drop; while at the other end it goes drop by drop through the pipe containing the water. Fire cannot force the oil or flame back through the water pipe, and therefore an explosion of the great body of oil in the feed tank cannot result, the oil tank can be placed as far away from a building as desired, or may be buried underground. It is not necessary to have more than a pint of oil actually on the premises to run a large boiler, and this will be forced drop by drop through the water pipe. A successful trial of the invention has been made, and a company with 500,000 dols. capital incorporated under the laws of the state of Vermont to introduce it.American Manufacturer. ARTIFICIAL SILK. R. VIVIER'S new method of making silk out of cotton on wood MR cellulose, which, it is thought, bids fair to rival the already well known process of M. Chardonnet, is described at length in the columns of La Revue Industrielle. The material is obtained by heating trinitro cellulose, obtained by alkalisation and nitrification of cotton, with a mixture of acetic acid and gelatine, or other equivalent re-agents. This material is transformed into pure filaments, which are a little less tenacious than natural silk, but quite as lustrous, and cost, according to the inventor, about sixty-eight cents per kilogramme, or about thirty-two cents per pound of yarn. The first part of the process consists in the economical and rapid manufacture of pyroligneous acid, from which is then easily extracted the crystallisable acetic acid necessary for the elaboration of the filaments. The succeeding processes are three in number:-(i) The preparation of the tri-nitrocellulose; (2) its treatment by acetic acid; (3) its treatment by the reagents which convert it into silk, or, to be more exact, into a silky material, which must then be transformed into silk again. Taking these processes in their order we have : (1) THE PREPARATION OF THE TRI-NITRO-Cellulose. This comprises two operations, alkalisation and nitrification. The alkalisation of the cotton is effected by treating it with an ammoniacal solution of caustic soda. For this purpose, four kilogrammes of caustic soda are dissolved in twenty litres of water, and to this solution, after it has cooled, are added ten litres of commercial ammonia at twentytwo degrees Be. One kilogramme of cotton is steeped in this solution of ammoniacal soda for three days and three nights, and stirred once a day. The cotton is then pressed and washed in water up to complete neutrality. It is next carded, after drying, in order to open the fibres so as to prepare it for nitrification. Nitrification is effected in an apparatus with a capacity of about 120 litres. This apparatus is charged with about twenty kilogrammes of saltpetre, dryed at 45°, on which are poured, at two or three times, thirty kilogrammes of pure sulphuric acid at 66° Be., the mass being stirred until the ingredients are thoroughly mixed. It should then have a temperature of 85°. Into this liquid, at this temperature, tufts of cotton are introduced in small quantities. The apparatus is closed and made to revolve, with a double revolution, round its horizontal axis, and round its vertical axis, for five or six minutes. Then it is stopped, the lid is lifted, and the material dropped into a tub of water. After washing and drying in an oven, the nitrated cotton is ready to be used for the preparation of silk. (2) THE TREATMENT BY ACETIC ACID. Three solutions are prepared:-(a) A solution of gutta-percha in sulphide of carbon; (b) a solution of isinglass in glacial acetic acid; (c) a solution of tri-nitrated cotton in acetic acid. These solutions are mixed cold, so as to obtain a final solution in which the pyroxiline or tri-nitrated cotton forms seventy per cent., the isinglass twenty per cent., and the gutta-percha ten per cent. To this is added a very small quantity of glycerine or castor oil, and the whole is blended together in a mixing apparatus. After this mixing process, the material is twice filtered, first roughly, and then more delicately. (3) ITS TREATMENT BY RE-AGENTS, WHICH CONVERT IT There has been obtained, by the preceding methods, a semi-fluid viscous substance, which is made into a filament, under water, by driving it through a small orifice. The thread thus produced, passes, with the aid of appropriate machinery, through the following described six chemical baths: (a) A bath of soda to remove the excess of acetic acid. (b) An albuminous bath (of three per 1,000), to make the fibre supple. (c) A bath of bi-chloride of mercury (twenty-five per 100), to coagulate the fibres. The coagulation is accelerated by pas sing the material, afterwards, through an atmosphere of car bonic acid. (d) A ten per cent. solution of ammonia. (e) A bath of sulphate of alumina, which impregnates the fibres with a deposit of alumina. These last two baths are intended to lessen the combustibility. (f) A second bath of albumen (three per 1,000) to render the fibre supple. The proportions can be varied to a certain extent, or even replaced by equivalents, according to the particular results which it is desired to obtain. The filament which remains, after this series of chemical processes, is now wound upon a drum, before which a carriage is made to travel by means of a worm. This carriage is provided with burnishers, which polish the thread, and with guides, which ensure its regular arrangement on the drum. When the drum and its fibre have been dried in a stove, the latter is carried to the winding machine. The bobbins of fibre thus obtained are next carried to the twisting machine, where the yarn is formed by twisting together a number of filaments sufficient to constitute a thread. The filaments on the bobbins, which are reeled as they turn round their common axis, are twisted into one single thread, before reaching the drawer, which takes the thread to the reel. The shafts are hollow, so that if desired, a liquid jet can be projected on the thread as it is forming. In connection with the above a short account of the way in which another distinguished inventor, M. Frémy, proposes to meet the very grave difficulty connected with the use of all silk of this kind, namely, its tendency to blaze up like gun-cotton, owing to the presence of the nitric compound, combined with the cellulose, is also interesting. This nitric compound is eliminated by M. Frémy in the following manner :-The vegetable silk is treate I cold with a dilute solution of the sulphohydrate of ammonia. The nitric element in the tissue is thus rendered soluble in water, and is entirely absorbed by the sulphurous compound. The fibrous cellulose principle remains in the insoluble state, and can be purified simply by washing in cold water. This action of the sulpho hydrate of ammonia on vegetable silk is so rapid that it is complete in a few hours, and so thorough that the resultant fibre does not burn more quickly than threads of cotton. The denitrated silk preserves all its original properties. It is tenacious, it is as glossy as the purest silk in the market, and it is not more inflammable than cotton yarn. FIXING TANNIN. THE HE use of tartar emetic for fixing tannic acid in mordanting cotton which is to be dyed with the basic aniline colouring matters is so universal, that dyers often forget that there are other metallic salts, such as the acetates of tin, zinc, alumina, and iron, the chlorides of tin, and oxalate of antimony, which are equally serviceable. There is a little difference in the tint of the tannined cotton after it has been fixed in these various salts; with tartar emetic, oxalate of antimony, and other antimony preparations, the fibre has a light chamois colour, with zinc salts a brownish yellow, with acetate of alumina a faint grey, with tin white or very faintly yellow, and with iron various shades of blue grey. Tannin itself does not properly fix these colours on the fibre, and when it is used alone there is a loss of colouring matter, as some of the tannin is dissolved off the fibre when in the dye-bath, and this throws down some of the colouring matter as a precipitate. Further, the colour fixed on the fibre is neither so bright nor so fast to washing and soaping as when the tannin is properly fixed on the fibre by a fixing agent before dyeing. As a rule, the cotton, after passing through the tannin bath, is simply wrung and then entered into the fixing bath; which is not the best although it is the quickest system to pursue. The cotton should be dried before, and then the tannin is fixed on the fibre before any of it has had time to become washed off, whereas when it is passed direct into the fixing bath some of the tannin comes off the fibre, and entering into the fixing bath forms, with the fixing agent, an insoluble precipitate, and thus a dirty, cloudy bath results, which is not desirable, especially as some of this precipitate may get on to the fibre in a very loose form, and lead to giving coloured fabrics that rub badly. When the tannin cotton is dried first, a cleaner fixing bath is obtained, which can be used longer and its contents more completely absorbed. It must be borne in mind that the various mordanting and dyeing baths are not completely exhausted of their valuable contents; if these baths be kept as simple in composition as possible and every care be taken to prevent undue soiling, they can be retained in use by keeping their strength up by additions of small quantities of concentrated liquor as may be required. In this way dyeing can be done in a much more economical manner than is always possible with the methods at present in vogue. Of the mordants named above, acetate of zinc gives the cleanest baths, then follow oxalate of antimony, tartar emetic, tin chloride, alumina, and iron. Iron mordants, owing to their giving dark shades, are not useful in dyeing with the basic aniline colours, as they have too great an influence on the shade of the dyed fabrics, blues being made darker, reds turned into maroons, and so on. In some cases this property may be rendered very useful, as in dyeing a maroon with magenta, a chocolate with Bismarck brown, a mode with auramine, etc. Dyers do not avail themselves of this as much as they might. For violet, saffranine, and methylene blue, tin chloride forms the best fixing agent, and gives the brightest shades. Next follow tartar emetic and oxalate of antimony. Zinc acetate produces yellower shades with these colouring matters than the other fixing agents, and it has a similar yellow effect on malachite green; for this colouring matter antimony oxalate or tartar emetic forms the best fixing agent. For auramine acetate of zinc will be found to give good results. PERMANENT CHEMICAL EXHIBITION. THE HE proprietors wish to remind subscribers and their friends generally that there is no charge for admission to the Exhibition. Visitors are requested to leave their cards, and will confer a favour by making any suggestions that may occur to them in the direction of promoting the usefulness of the Institution. Joseph Aird, Greatbridge.-Iron tubes and coils of all kinds. Ashmore, Benson, Pease and Co., Stockton-on-Tees.-Sulphate of Ammonia Stills, Green's Patent Scrubber, Gasometers, and Gas Plant generally. Blackman Ventilating Co., London. Ventilating Machinery. Geo. G. Blackwell, Liverpool. Fans, Air Propellers, Manganese Ores, Bauxite, French Chalk. Importers of minerals of every description. Brunner, Mond and Co., Northwich. Bicarbonate of Soda, Soda Ash, Soda Crystals, Muriate of Ammonia, Sulphate of Buckley Brick and Tile Co., Buckley.-Slabs, Blocks, Tiles, W. F. Clay, Edinburgh.-Scientific Literature-English, French, R. & J. Dempster, Manchester.-Photographs of Gas Plants, Doulton and Co., Lambeth.-Specimens of Chemical Stoneware, Stills, Condensers, Receivers, Boiling-pots, Store jars, &c. E. Fahrig, Plaistow, Essex. - Ozonised products. OzoneBleached Esparto-pulp, Ozonised Oil, Ozone-Ammoniated Lime, &c. Galloways, Limited, Manchester. Photographs illustrating Boiler factory, and an installation of 1,500-h. p. John A. Gilbert and Co., Ltd., London. -Automatic Stills, and Patent Mixing Machinery for Dry Paints, Powders, &c. Grimshaw Bros., Limited. Clayton.-Zinc Compounds. Sizing Materials, India-rubber Chemicals. Jewsbury and Brown, Manchester. Samples of Aerated Waters. Joseph Kershaw and Co, Hollinwood.-Soaps, Greases, and Varnishes of various kinds to suit all requirements. C. R. Lindsey and Co., Clayton.-Lead Salts, (Acetate, Nitrate, etc.) Sulphate of Copper, etc. Chas. Lowe and Co., Reddish.-Mural Tablet. Makers of Carbolic Crystals, Cresylic and Picric Acids, Sheep Dip, Disinfectants, &c. Manchester Aniline Co, Manchester. - Aniline Colours. Samples of Dyed Goods and Miscellaneous Chemicals, both organic and inorganic. Meldrum Bros., Manchester. Steam Ejectors, Exhausters, Silent Boiling Jets, Air Compressors, and Acid Lifters. E. D. Milnes and Brother, Bury.-Dyewoods and Dyewood Extracts. Also samples of dyed fabrics. Musgrave and Co., Belfast.-Slow Combustion Stoves. Makers of all kinds of heating appliances. Newcastle Chemical Works Company, Limited, Newcastleon-Tyne.-Caustic Soda (ground and solid), Soda Ash, Recovered Sulphur, etc. Robinson, Cooks, and Company, St. Helens. -Drawings, illustrating their Gas Compressors and Vacuum Pumps, fitted with Pilkington and Forrest's patent Valves. J. Royle, Manchester.-Steam Reducing Valves. A. Smith, Clayton.- India-rubber Chemicals, Rubber Substitute, Bisulphide of Carbon, Solvent Naphtha, Liquid Ammonia, and Disinfecting Fluids. Worthington Pumping Engine Company, London.- Pumping Machinery. Speciality, their "Duplex" Pump. Joseph Wright and Company, Tipton.-Berryman Feed-water Heater. Makers also of Multiple Effect Stills and WaterSoftening Apparatus. COMMERCIAL FERTILIZERS. REPORT OF KENTUCKY AGRICULTURAL EXPERIMENT STATION. PHOSPHORIC acid.-Next in importance to nitrogen as a plant food comes phosphoric acid. This acid usually combines in the soil with lime magnesia, and iron. In these forms it is insoluble in water, so that practically there is no loss by drainage. The source of loss is that carried off by the crops. The loss can be supplied only by the use of fertilizers. Phosphate of lime is the general source of phos phoric acid in fertilizers. There are many sources from which the phosphoric acid is obtained for commercial fertilizers such as: 1. Bone meal. 2. Bone ash. 3. Bone black. 4. Superphosphate of lime, or acid phosphate. 5. Phosphate rock. 6. Thomas slag and guano. 1. Bone meal.-Bone meal is valuable not only for the phosphoric acid which it contains, but also for its nitrogen. Bones are composed of two distinct substances which interpenetrate one another. There is, as it were, a skeleton of earthy matter, which is called phosphate of lime or bone phosphate, and a flesh of organic matter, which is called ossein. Ossein is a highly nitrogenized substance. The fineness to which bones are ground is an important consideration as to their value. The finer the meal, so much more readily will it putrify and dissolve in the soil, and so much sooner will the crops be fed. There is some difficulty in grinding fresh raw bones. To obviate this difficulty they are generally steamed, or carried through some process whereby the fat is extracted. Steamed or dessicated bones, if not very strongly steamed, are better for fertilizers than raw bones. This is contrary to the general belief, but raw bones contain the fat, which is not only useless to the plant, but adds weight and clogs the meal, and hinders decomposition of the bone in the soil. Of course the steaming process must not be carried on to such an extent as to extract the nitrogenous portion of the bone. It is true that some of the nitrogen is lost, nevertheless the meal from steamed bone has proved itself to be better than from ordinary raw bone. Bone ash is sometimes used as a fertilizer. It is generally used to make other forms of phosphates, such as superphosphates. 2. Bone black. The spent black from sugar refineries is sold to manufacturers of fertilizers. When bones are heated in iron cylinders. into which air is not allowed to enter, gas, water, oily matters, and other products are driven off, while bone charcoal is left in the cylinders. This product is used to take the colour out of raw sugars. After a time it becomes worthless for this purpose, when it is sold for fertilizing purposes, as all the lime phosphate still remains. The decomposition of bone black in the soil goes on slowly, and therefore it is not generally applied as such, but after treatment with sulphuric acid. 3. South Carolina and Florida Rock, Apatite, etc.-These mineral sources of phosphates are with great difficulty decomposed in the soil, and so slowly that in general it does not pay to put these ground rocks on the soil before putting them through a process which will make the most of the phosphoric acid readily available to the plant. This leads us to the consideration of: 4. Superphosphates. In order to make these various phosphates more rapid in their action, they are treated with sulphuric acid, commonly called oil of vitriol. This treatment converts the insoluble phosphate into a soluble phosphate of lime called superphosphate of lime, sulphate of lime or gypsum being formed at the same time. When bone, bone ash, bone black, or mineral phosphates are treated with sulphuric acid in sufficient quantity, the superphosphate formed contains the phosphoric acid in a form soluble in water. After standing, or when superphosphate is applied to the soil, the phosphoric acid is in the reverted form, as it has gone back to a form insoluble in water. This reverting of the phosphoric acid does not materially change its value as a fertilizer, for experiments have shown that plants can take up the phosphoric acid in this state as readily as in the soluble form. When the sulphuric acid is added in sufficient quantities to dissolve all the phosphates, some of the phosphoric acid remains in the insoluble form. This insoluble phosphoric acid is not as available to the plant, and it is much cheaper in the markets. In making an analysis of a fertilizer, therefore, we separate the phosphoric acid into three divisions of soluble, reverted and insoluble phosphoric acid, giving to each its value. The "soluble" and "reverted" forms of phosphoric acid are both readily assimilated by plants, and hence are sometimes included under the common name of "available phosphoric acid." The "available phosphoric acid" in an analysis is equal to the sum of the "soluble' and reverted" phosphoric acid. Potassium.- Potassium ranks next to phosphorous as a valuable food for plants. Plants consume this element in comparatively large quantities, and some soils are unable to supply the demand; especially is this the case with light sandy soils. I'rimarily the plants obtain potash from the decomposition of minerals or rocks containing potash. Thus felspar contains from 10 to 16 per cent. of potash. It is potash combined with silica and alumina. As such it is insoluble and not available to the plant. In the decomposition of this rock clay is formed and a soluble potash salt, which then becomes available. This decomposition goes on gradually, and thus, in most clay soils available potash salts are being continually liberated for the use of the plant. Stirring the soil accelerates this decomposition, and the presence of lime or gypsum increases decomposition. In such soils, therefore, the application of lime has another use besides that of plant food. Plants. vary largely as to the amount of potash they require. For example, an acre of wheat yielding 20 bushels requires about 28 pounds of potash; while an average crop of potatoes requires 100 pounds of potash per acre, and an acre of tobacco yielding 3,8co pounds of leaves and stalks assimilates over 200 pounds of potash. It is evident, therefore, that the continual cropping of soils with potatoes or tobacco will in time exhaust the potash supply. Light and sandy soils require this element from the start. The sources of potash, as generally found in fertilizers, are : Sulphate of potash. I. 2. Muriate of potash. 3. Kainit and sylvanite. 6. Cotton seed hull ashes. More rarely the nitrate of soda. The sulphate and muriate of potash, and kainit and sylvanite are imported from Germany, where they are mined in great abundance. DIFFERENT FORMS OF FERTILIZERS. Usually commercial fertilizers contain two or all of the essential ingredients, viz., nitrogen, phosphoric acid, and potash, but sometimes only one. Plain superphosphates contain only phosphoric acid. Ammoniated superphosphates contain nitrogen and phosphoric acid. Bone contains and is valuable for its nitrogen and phosphoric acid. Potash salts, of course, are valuable for their potash only. A complete fertilizer is one containing nitrogen, phosphoric acid, and potash. INTERNATIONAL EXHIBITION OF MINING AND METALLURGY. (FROM OUR LONDON CORRESPONDENT.) WI HEN the Mining Exhibition was opened at the Crystal Palace a few weeks ago, the non-technical press as in duty bound despatched its ordinary reporters to "do" the exposition in the regular way, and we, most of us, remember the chatty superficial columns that resulted from their efforts. We are loth to find fault with their wellmeant endeavours; general journalistic work is their métier, and is usually executed on the whole fairly creditably. At the same time it was an open secret that considerable difficulty had been encountered in bringing all the exhibitors to the scratch, and that arrangements were in many cases far from complete, and in consequence no adequate report, balanced in all its parts, was practicable even by the omnicient writer for a London daily. To one watching the progress of affairs it is fairly manifest that a point has by this time been reached when a serious attempt may be made to give a comprehensive account of the great show now being held at Sydenham, without running the risk of self-stultification. As is usual with exhibitions of a really useful and important character held at the vitreous fiasco, which was once fondly supposed to be destined to educate and refine the irrepressible cockney, one notices a lamentable absence of visitors in the least degree more interested in what is truly an excellent collection than they would be in so many heterogeneous and purposeless objects in glass cases, and a high state of polish jumbled together to catch their eye as beads do that of a savage. A closer survey, though confirming this impression, leads to the belief that an unobstrusive minority is there with a definite purpose, going quietly to work in search of the information it needs, which the exhibition is well calculated to supply. It is to be hoped that the business directly and indirectly resulting will recoup those who have had the enterprise to exhibit. The portion of the exhibition which perhaps attracts as mixed a band of spectators as any is that contained in the building devoted to machinery in motion, comprising as it does those directly interested in the plant displayed, children old and young who "want to see wheels go wound," and ladies not lacking the quality characteristic of their sex, which leads them to climb perilous ladders and brave dust and dirt in a manner as creditable to them as it is inexplicable by any male process of reasoning. Messrs. Davey, Paxman, & Co., of Colchester, provide the requisite power, having put down two locomotive boilers driving a horizontal engine (Class C, cylinder 20 ̊5 by 32 in.), and supplying steam to other parts of the exhibition. They also show a 5 ft. Huntington Mill, being licencees for the manufacture of this now well-known apparatus; besides this they have also a couple of 8-h.p. portable engines, one single the other compound. Though hardly to be reckoned as machinery in motion there is an interesting exhibit by W. Firth, of Leeds, of his patent steel props for supporting the roofs of mines and collieries, the whole being shown in a full sized model close to the entrance. To those who scorn chlorination and all its works, the exhibit of Messrs. T. B. Jordan and Son will appeal, disclaiming as it does the aid of "calcination, electricity," and that bugbear of the engineer, "chemicals.' It consists essentially of a stone crusher, a pulveriser, and an amalgamator, and for free milling ores would be doubtless efficient. The tools shown by the Britannia Co., Colchester, and the exhibit of Messrs. Stott & Co., the gas engineers, though interesting, do not bear sufficiently directly on mining industries to merit detailed description. Of more importance are the exhibits of Hull, Robinson and Co., of Sheffield, who show a stone crusher of the Blake type, and a pulveriser with a capacity equal to that of a five-head stamp battery. The old-fashioned and well tried battery of stamps really seems at last in danger of being superseded. There is a distinct tendency to replace it by rotatory grinding arrangements, and its relegation to the museum is possibly only a question of time. Nevertheless it has done, and is doing, good work, and before banishment data whereon a comparison of its performances with those of more modern devices may be based, are very desirable. The same firm shows one of Sach's patent rock drills. These very necessary tools are naturally quite a feature of the exhibition; their name is legion and their din deafening, several being shown in action on such sturdy materials as granite. For some occult reason, the show-case of the Delta Metal Co. has been relegated to the shed designated the "Machinery Hall," and a good exhibit of this alloy, which is rapidly growing in favour among engineers, is in danger of being overlooked; ingots, forgings, castings, and finished goods are all worth notice, though the addition of a few fractured test pieces would be an improvement, as the tendency of all such compositions is to segregate, and specimens of excellent exterior sometimes show a startling lack of homogeneity when broken. Among the many other exhibits of which lack of space forbids more than mention, are the model of a revolving stamper shown by Messrs. Harvey and Co., which may be destined to resuscitate in a new form the older kind of pulveriser; and the very ingenious fire-extinguishing buckets, which can be drawn ready filled one after another from their tank, and which are lavishly distributed throughout the galvanised iron shed with praiseworthy forethought for its safety. alone. (To be continued. ) OZONIN. OZONIN is a new bleaching agent just patented in this country by Dr. Ludwig Schreiner, of Stuttgart, and seems to possess wonderful properties. The Doctor takes 22 parts of hydrate of potash and dissolves them in 1261⁄2 parts of water, boils, and adds 125 parts of rosin; when this is dissolved, 150 parts of oil of turpentine are added, and after stirring this is dissolved; then 1261⁄2 parts of peroxide of hydrogen are added; the product is ozonin. If the peroxide is replaced by water, a solution possessing bleaching or oxidising properties is produced. Ozonin, according to the patentee, possesses greater oxidising powers than either turpentine alone or peroxide of hydrogen Thus he says that if a solution of indigo oxide (whatever that may be) and caustic soda with sulphuric acid be taken, 5 drops of ozonin will destroy the colour in half an hour, while peroxide of hydrogen takes 10 drops and requires 48 hours, and the rosin-soap-turpentine solution takes 5 drops and 12 hours. Evidently ozonin has 24 times the strength of the latter mixture, and 192 times that of the peroxide of hydrogen. We are somewhat sceptical as to this, and if time permits shall test the point. A solution of I grm. of ozonin in 1,000 grms. of water is said to powerfully bleach textile materials; it is claimed to have disinfecting and antiseptic properties. The same patentee says that a bleaching agent can be made by agitating together 1 part of turpentine with 1,000 parts of water, making the materials to be bleached in this emulsion, exposing them to the air, and repeating these operations as often as necessary. TEST FOR LEAD IN BLOCK TIN.-An optico-chemical method by which the presence of lead as an alloy of block tin may be speedily ascertained without injury to the siphon or other article constructed thereof, has been discovered by a German chemist. Ten milligrams of the suspected metal is scraped off, dissolved in nitric acid, and the solution made strongly alkaline with caustic potash. If this solution turns dark brown on the addition of sulphuretted hydrogen water, it contains lead. By making it exactly as above, diluting and comparing it with an accurately titrated solution of pure lead, it is said that I per cent. of the alloy can be detected with certainty, after a little practice. |