410 Mr. Porrett on a New Vegeto-Alkali in Qun-Cotton. 



might be taken of the arrangement of its elementary particles 

 whicji would account for the singular fact of its non-acidity, 

 by supposing it a compound of nitrous acid and oxide of 

 lignin, the said new oxide being also supposed to possess al- 

 kaline properties. 



It was before mentioned that the action of a small voltaic 

 battery on gun-cotton gave but very slight indications of its 

 decomposition, but that slight as they were they were rather 

 favourable to the suggestion ; the indifference of this compound 

 to the electrical action of the battery I found was owing to 

 its highly non-conducting nature, but I succeeded rather 

 better by moistening the gun-cotton with acetic acid, and 

 placing it in a thin layer between a plate of silver and one of 

 zinc, completing the circuit with a copper wire and leaving 

 them for forty-eight hours so arranged ; at the end of that 

 time, on dismounting this little voltaic arrangement, the 

 inner surface of the silver plate was found to be encrusted with 

 a small quantity of matter, which when dry looked white like 

 starch, which powerfully restored the blue colour of reddened 

 litmus paper, and which when heated to redness left a black 

 cai'bonaceous residue ; the minute quantity obtained made 

 further experiments with it impossible, but it increased my 

 desire to be able to procure the same substance by chemical 

 means in any quantity that might be wanted. 



After several trials I succeeded by the following process. 



I took 2 ounces by measure of nitric acid of the specific 

 gravity 1*45, to which I added 50 grains of gun-cotton ; the 

 mixture being gradually heated to 100° of Fahrenheit's scale 

 and kept below 180°, became quite transparent and fluid, and 

 all the cotton disappeared, being quietly dissolved without 

 any evolution of gas ; when a portion of the solution in this 

 state was dropped into water a white precipitate was formed, 

 having all the properties, structure excepted, of the original 

 gun-cotton, the liquid was therefore a simple solution in acid, 

 without decomposition ; but on heating the liquid further up 

 to 240°, deep red acid vapours were given off abundantly for 

 a long time, and these collected in a receiver surrounded with 

 ice proved to be hyponitrous acid. The same effect exactly 

 took place when sulphuric acid was used instead of nitric at 

 the same temperature, so that the hyponitrous acid was merely 

 eliminated in both cases, and not formed from the excess of 

 nitric acid used in the former instance ; the cold and very 

 concentrated nitric solution containing a great excess of acid 

 was now brought nearly, but not quite, towards a neutral state 

 by pouring into it a strong solution of subcarbonate of potash, 

 after which a solution of bicarbonate of potash was used 



