power of the best article-and show that this quality is obtainable despite of difference of manipulation in the process, and that it is dependent on the definite chemical composition of the compound itself. The fact is one which affords the most encouraging prospects to those interested in developing the qualities of the article. The trials made with this variety of the cotton with small arms have been very numerous and satisfactory. The ratio of superior power to that of powder, is evidently much greater than in the cannon and mortar practice, but as the experiments are not capable of being expressed in figures, I will not dwell on them in more detail. In all the ordnance experiments above narrated there were remarked— 1.-Entire absence of smoke. 2. As far as could be judged very trivial heating of the guns. 3.-Entire absence of dirt or wetting. The report, recoil and time of flight of the shot and shells seemed equal, as closely as could be estimated, to these effects from the charges of powder required for equal ranges. It should further be observed that of this quality of cotton from 6 to 7 ounces on two trials burst an 8 inch 46 lb. shell, but it should be stated that it was with considerable difficulty this quantity of cotton was forced into the shell. 2d and 3d quality of Cotton. The 2d is prepared as above described, by mixing together the whole of the 100 tola weight manufactured from the quantity of acids above specified. No. 3 or worst, is the product of the last 50 tolas of cotton and expressed acid. It was with the 2d quality my first experiments were made; 4 ounces tried at the Eshapore powder works by Major Anderson and myself gave, with a 68 pound shot, a range of 461 yards, thus :— Best quality, 4 oz. 681b. shot, range 839 yards, tried at Dum Dum. Eshapore. H. C.'s powder, best ordnance quality 189 The effect of the mixture or quality No. 2 it will be observed is inferior to the arithmetical mean of the two forces, the range being 461 instead of 544 yards; but this variation may have proceeded from the mixture on trial having been made with cotton of two different days' manufacture. The preceding experiments show that the worst cotton is superior to the best ordnance powder in the proportion of 250 to 189 in the trials under description, and that the 2d quality is superior to powder in the proportion of 2 to 1. But other considerations arise regarding these inferior qualities which we have found to have faults which more than outweigh the value of the superiority of range. The inferior kind of cotton is of yellowish colour, insoluble in ether so hygrometric that it absorbs from 5 to 10 per 100 of moisture from the air in 24 hours. It soils and wets the guns and leaves in them a body of wavering flame and large quantities of half ignited cotton, a source of the most formidable danger to the gunners, and likely to lead to explosion of ammunition in the vicinity. It is rendered useless by being compressed or even tied in a cartridge bag. In several instances while the loose cotton of this quality gave a very respectable range, an equal quantity tied up in a cartridge bag, scarcely expelled the ball from the gun. But the most fatal objection to the use of this inferior sort is, that stored even in hermetically sealed ammunition chests, lined with copper and without the contact of the air, it changes composition, and in less than six weeks becomes totally inert. Thus a box proved at Dum Dum on the 19th January, of which 4 oz. threw a 68b shot 250 yards from an 8 inch mortar, was re-opened on the 27th of February, and the same quantity barely threw a 46 shot a few feet from the mouth of the mortar. The cause of this change is the same as that which affects so many cyanogen compounds, especially the hydrocyanic acid. The cotton under description was most carefully prepared, and every trace of acid left by the process well neutralized and washed out. Still in six weeks it had changed its composition and become entirely useless, and when the chest was opened there was perceptible a strong smell of nitric oxyde gas. This fact is sufficient to show that it is only the very best kind of cotton which can be depended on for any military use. It next remains to be considered whether to this kind also there may not exist such objections as may counterbalance the very great ad vantages which in point of range, cleanliness, lightness and absence of smoke, I have shown it to possess over ordinary service powder. It has been stated that the low temperature at which this cotton explodes would render rapid firing impracticable in consequence of the heating of the guns. Now the true exploding point is 375° Fahrenht. Under this, whatever may be asserted to the contrary, the best cotton cannot be made to explode. Now whether it arise from the greater quickness of the explosion, or the inferior degree of specific heat in the material, the fact is certain that it would take a greater number of rounds of the best cotton than ever could be fired in the sharpest action to bring the temperature of the gun so as to approach the exploding point. In one set of experiments instituted on this question, 80 rounds of cotton were fired from a gun metal cone of exactly the weight of the whole of the cotton used. The interval was but ten seconds between each round. When the last round was fired, a piece of the best cotton was firmly pressed against the sides of the metal cone in every direction without ignition taking place. On repeating the experiment and taking the temperature of the cone it was found to be below that of boiling water! The next objection made is the assumed probability of spontaneous combustion. Now the combustible material in this compound being already combined with all the oxygen it requires, I can see no reasonable cause for the apprehension of the spontaneous heating, which in raw cotton arises from the absorption of the additional oxygen with which its carbon and accidental oily matters have a tendency to unite. This process I have most carefully studied with reference to an attempt made some years since to fire the arsenal in Fort William, on which occasion a Court of Enquiry, of which I was a member, had satisfactory proof before them that spontaneous combustion was not concerned in what took place. The experiments then carried on led to our being enabled to produce this kind of combustion with perfect certainty in masses of tow, cotton, cloth, &c. duly prepared for the purpose. Such experiments I have repeated with the gun cotton, but I have never detected the least trace of heating. The objection nevertheless is one which time alone can dispose of effectually. As to danger in the process of preparation, I do not deny that there is some risk. But this, I know by sufficient experience, is infinitely less than that is attendant on the manufacture of gun powder. In the preparation of gun cotton there are but two periods of riskthe first is while pressing the cake still full of acid. On one occasion this caused an explosion, but of too trivial a nature to be worth description, and moreover the accident is one which cannot cause injury with a press properly constructed. The last stage of drying unquestionably demands every precaution. In my late experiments, a stray spark ignited at once ten pounds of cotton which scorched more or less severely two men who, contrary to orders, were quietly seated in the middle of the mass. Had this happened with the same proportionate quantity (40lbs.) of powder, there can be no doubt what would have been the result to the lives of the men, and to the premises where the accident occurred. I repeat that during the other stages of the manufacture explosive cotton is prepared with the most perfect safety. While it contains as much moisture as can be perceived by the touch, it may be put into a red hot crucible, or penetrated by a red hot poker with absolute impunity. The hiss of steam and a few sparks are the only phenomena observed. I have next to deal with the cost of the best kind of cotton, and here it is that in a military point of view the chief objection arises to its use. The annexed estimate shows in detail that to prepare gun cotton from acids as sold in Calcutta at present, 1 pound of the best kind costs about 10 Rs. But being fourfold the power of powder, this may be considered as 2 Rs 8 as. for the corresponding quantity of cotton. Now this is at least 8 times the price of ordnance powder, range for range. But on the supposition that Government made their own acids, using nitrate of soda, instead of saltpetre, economizing the washings, reconcentrating the sulphuric acid, &c. the cost of the preparation would be reduced so considerably, that allowing as above for superiority of power the cost of cotton would be 2Rs. 9as 6pie per av. pound, being within a fraction of double the price of powder, using quantities of equal power.* But this statement of course must be regarded as one resting * 10 as. 4 pie for range which would be procured from a pound of powder value 5 as. on views which further experience may modify or disprove. It would be presumptuous to advance a positive opinion that the process may not be cheapened and improved. Professor Schoenbein may have a method of greater simplicity and economy than those employed by the numerous experimentalists who have followed in the track of his brilliant discovery. I have already tried many modifications of the acid method but without success. * One plan still remains for experiment which promises better than the rest, and which I shall bring as soon as possible to the test of a conclusive trial. I allude to the employment of nitric acid previously or simultaneously submitted to the influence of a powerful voltaic current, sufficient to decompose the constituent water of the nitric acid, and thus render this more suited to the conversion of the cotton fibre into cyanic acid or cyamelide. I have to add that I have been enabled by the kindness of Mr. Rogers and Mr. Blechynden, to make adequate trials of the Akundoo and Simal fibres-Manilla and other kinds of Hemp-Jute-FlaxPlaintain and Aloe fibre; and that I have given fair trial to every kind of cotton I could procure. I have also examined the explosive compounds made with wood shavings, saw-dust, unsized paper, &c. The general result is that cotton affords the best preparation—and the better the ordinary quality of the cotton, the stronger and more permanent is the explosive it affords. I have also tried (but merely for trial sake) the finely divided charcoal obtained by igniting cotton in close vessels-of this carbon 100 parts of the best Banda cotton yield 17 to 18. As might be inferred from the theory of the process, no explosive compound was generated— no constituent water having been associated with the carbon, no substition of a nitrogen compound could take place. -- An economical mode of manufacture once discovered, which would, bring cotton and powder to equal prices, range for range,—and the use of the new explosive confined strictly to that of the very best kind,— there remains no objection which I have heard of-no fault which I have myself observed, which may not be fairly found with the best kinds of powder also. Meanwhile although the gun cotton be too costly for military use, and further experiments are required on the effects of long * Using for instance Anhydrous nitrous acid, prepared by distilling the dried nitrate of lead—mixtures of dried sulphurous acid and nitric oxyde gases. |