180 Memoranda on Explosive Cotton. [Feb. 



sive cotton, to be of sufficient importance to warrant more extensive 

 trials, I reported them officially to Government, and was immediately 

 directed to prepare a sufficiently large quantity of this cotton for a 

 series of ordnance trials at Dum-Dum. With the valuable assistance of 

 Mr. Frewen of the Mint Assay office, I have accordingly had manufac- 

 tured over 100 pounds of the explosive cotton, and the experience thus 

 gained regarding its preparation and properties enables me to state such 

 facts as may enable others to form a more correct estimate of the degree 

 of practical value of this preparation, for Military proposes, than can be 

 obtained from experiments on the manufacture and properties of a few 

 ounces of the explosive. 



Preparation. 



In the experiments carried on at the mint, 100 tola weight (3 and 

 ^th troy pounds) of cotton was operated on at a time, the cotton having 

 been previously cleaned and loosened out by the native bowstring 

 apparatus. 



The acid mixture consists of equal measures (in all 336 fluid ounces) of 

 sulphuric acid, Sp. gr. 1843, and nitric acid, Sp.gr. 1460. The sulphuric 

 acid weighs 840 tolas=to 2 libs av. and the nitric acid weighs tolas 651 

 =to 17 av. ibs. fractions omitted. The mixture when cool is placed in a 

 large shallow porcelain basin, so situated as to permit the fumes to be 

 carried off by a current of air. The cotton is introduced with iron tongs in 

 small portions at a time, pressed under the surface of the acid for about 

 two minutes and moved to the opposite side of the pan. This is conti- 

 nued till 50 tola weight is introduced. When the last portion has been 

 immersed for about three minutes, the cotton should be lifted out, by 

 the tongs, quickly transferred to a screw-press of iron or stone and the 

 excess of acid pressed out. This is continued till the 50 tola weight is 

 pressed. The cake is then rapidly removed to a large vessel of com- 

 mon water, torn asunder by hand, washed and squeezed and thrown 

 into a second vessel of water ; again washed and squeezed, and the 

 masses thrown into a vessel containing a solution of 1 pound of carbo- 

 nate of soda in 20 gallons of water. Well washed here the mass is 

 placed in a large screw-press — the pressed cake again washed with water. 

 It is now fit for drying, which is best done by sol#r heat on a dry terrace 

 over tarpaulin or sheets of iron, taking the utmost caution to avoid the 

 possibility of explosion by accidental sparks. 



