AND THE PARACYANIC ACID. 39 



gradually falls. If a sufficient quantity of nitric acid have been added to oxidize 

 the whole, or if the solution be added to hot nitric acid slowly, and as the colour 

 disappears, water, as in the former case, throws down a copious yellow precipi- 



4. When a solution of cyanogen in diluted alcohol, after becoming dark co- 

 loured, is acted upon by a current of chlorine gas, among other compounds formed 

 is a portion of a yellow substance having the appearance and properties of that 

 obtained by means of nitric acid. 



5. The yellow matter obtained by these different processes, well washed and 

 dried at 212° F., is without taste or smell, insoluble in water and alcohol, spa- 

 ringly soluble in cold, more largely and with slight decomposition in hot nitric 

 and sulphuric acids, and soluble to a certain extent in caustic alkalies. 



Heated above 212°, it gradually becomes darker in colour ; about 400° F. it 

 begins to blacken and evolve ammonia ; over the lamp, in a close tube, it gives off 

 ammonia, hydrocyanic acid, and water, and a mixture of carbonic and nitrogen 

 gases, in the proportion of two vols, of the former to one of the latter. It, there- 

 fore, contains water, — either hygrometric or in combination, — and oxygen. A re- 

 sidual black matter remains, which is paracyanogen, and which, by further heat- 

 ing, gives cyanogen gas. 



6. Burned with bichromate of potash, it gave a mixture of carbonic acid and 

 nitrogen gases, of which 



76.75 left 26.5 of nitrogen, 100.5 left 33.1 



83.5 — 28.4 — 189—03 



103 — 34.5 

 The ratio of the carbon to the nitrogen is therefore 2:1, as in cyanogen, and 

 since it contains oxygen and combines with bases, I have given it the name of 

 the paracyanic acid. 



Like paracyanogen, it is exceedingly difficult to burn, either with oxide of 

 copper or with bicyanide of mercury, without the formation of binoxide of nitro- 

 gen, but the presence of this gas in the above experiments does not produce any 

 serious error, as the nitrogen in combining with the oxygen undergoes no change 

 of volume, and the caustic potash employed to remove the carbonic acid absorbs 

 very little of the binoxide, until it has been a considerable time in contact with 

 the gaseous mixture. 



7. The small quantities I have yet obtained of this acid, have prevented me 

 from submitting it in the uncombined state to a sufficient number of analyses, to 

 establish its composition beyond dispute. 4.22 grs. dried carefully at 212° Fahr., 

 and burned with Bichromate of Potash, gave 



Carbonic acid, 1.3466=31.91 percent. 



Water 1.13 = 26.777 per cent. 



