848 REPORT— 1898. 



Some time ago we made a number of experiments to ascertain whether contact 

 with other gases than air would influence this igniting point, and also whethei- 

 any or what effect would bs produced on gun-cotton when exposed at about 100° 

 to the following gases: — Carbon dioxide, carbon monoxide, hydrogen, sulphur 

 dioxide, nitrous and nitric oxides, chlorine, hydrogen chloride, bromine, ammonia. 



None of these gases was specially puritied, but they were dried very thoroughly. 



The carefully dried gun-cotton, in fine powder, was exposed to a current of the 

 wases in a tube. The tube was provided with a jacket through which steam or 

 alcohol vapour, &c., could be driven, so as to obtain approximately definite 

 temperatures. 



With the exception of ammonia, not one of these gases above named had any 

 effect at temperatures below 100°. 



With ammonia the first indication of an action was the ignition, and sometimes 

 detonation, of the gun-cotton at about the temperature of boiling alcohol. The 

 gun-cotton became yellow or brown just before exploding. 



To ascertain the temperature of firing more nearly, the cotton was placed in a 

 U-tube heated externally by a water bath. Some samples, fine powder, fired at 

 76° (temperature of water bath). Others as high as 80° or 82°. Pulped gun-cotton 

 fired at the lowest temperatures. 



It was noticed that when the current of ammonia was very slight, red fumes 

 and a white cloud formed in the tube just before firing. 



As this indicated a possible oxidation of the ammonia at the expense of the 

 N0„ of the gun-cotton, some experiments were conducted in a similar manner, but 

 at temperatures not exceeding 20°. 



No change was visible until the ammonia had passed over the cotton for some 

 hours, and then only a slight yellow colouration. 



On washing this yellow product with water, a solution was obtained contaimng 

 a considerable quantity of nitrite. 



Fresh gun-cotton of the same make gave but the slightest traces of nitrous 

 acid, even when boiled with water. 



All alkaline solutions, boiled on gun-cotton, give strong reactions for nitrites. 

 The solutions are generally yellow. 



Some gun-cotton was now spread out under a bell glass and ammonia gas 

 steadily introduced. After a few days moisture was observed condensing on the 

 interior surfaces of the bell glass, so the arrangement was simplified and the gun- 

 cotton supported a few inches above some strong ammonia solution under a large 

 bell glass. It was allowed to .stand for some weeks in a cool place. The cotton 

 gradually became quite brown, and at the end of a month partially liquefied into 

 a brown jelly. 



Exposure to light was found to very materially shorten the time necessary to 

 get this brown stage. 



The substance was tested from time to time for nitrites. The amount appeared 

 to increase up to the liquefying stage and then diminish. 



After six weeks' exposure to the damp ammonia atmosphere the mass was 

 placed over sulphuric acid in a desiccator and a good vacuum maintained for 

 three weeks. The mass swelled up and dried to a brown, porous, and friable body, 

 without a sign of the original cellulose structure. Some ammonia was retained, 

 and was not entirely removed by heating for several days in a current of dried air. 



The brown product is almost completely soluble in water and in alkaline solu- 

 tions, but scarcely at all in alcohol or ether and very slightly in acetone. Strong 

 alkalies evolve ammonia. 



Strong sulphuric acid causes an effervescence, and SO., is evolved. Much car- 

 bonisation takes place. 



Nitric acid (cold, strong) dissolves it quietly, and on dilution with water there 

 is no precipitate. 



When heated in a dry state ammonia is first given off. It then explodes ] 

 feebly, producing red fumes and leaving much carbon. 



Acetyl and benzoyl chlorides act upon it very energetically, and a hght yellow 

 resin is left on evaporation. 



