182 Memoranda on Explosive Cotton. [Feb. 



acid is recovered with little diminution either of strength or quan- 

 tity. 



The washings in the several tuhs being neutralized with carbonate of 

 soda, yield on boiling down, a large quantity of mixed sulphate and 

 nitrate of soda, which may be used for the economical manufacture of 

 nitric acid, so as materially to diminish the cost of the process. 



Reserving an account of the cost of manufacture, I proceed now to show 

 the properties and effects of each of the three varieties of the cotton 

 above described. 



Best Quality, No. 1. 



Snow white, explodes without leaving the least residuum or dampness 

 — does not fire powder if ignited over it. Flashed on the hand causes 

 no pain ; is almost entirely soluble in sulphuric ether. One pound weight 

 avoirdupois can easily and safely be compressed into the space of 128 

 cubic inches* without diminishing its explosive power for ordnance or 

 small arms. 



Exposed to the air in a large room, protected from dust this quality 

 of cotton (dried by solar heat for two days) fluctuates in weight accord- 

 ing to the hygrometric state of the atmosphere — the maximum increase 

 having been 1 .34 per 100, as shown in the annexed Table of obser- 

 vations continued during 26 days. 



At this maximum of absorption no diminution of projectile pow- 

 er was experienced in trials made with an eprouvette mandril gun, the 

 invention of Colonel Forbes, especially suited to these experiments. f 

 But when the quantity of moisture designedly added exceeded three 

 per 100, the explosive power fell rapidly, but was regained altogether 

 by redrying the cotton. 



With this quality of cotton trials were made at Dum Dum on the 

 19th and 25th of January, and 24th of February, with the results shown 

 in the accompanying Table. 



* The bulk of 4 pounds of ordnance gunpowder. 



f Of which I hope to be permitted to give a more minute account in a future 

 number of the journal. 



