Chemical Science. 383 



other products are ammonia, water, carbonate of ammonia, carbonic 

 acid, oxide of carbon, and cyanogen. 



Oxamide occurs in imperfectly crystallized plates, or as a granu- 

 lated powder. When well washed and pulverized, it is a dirty white 

 powder, looking like uric acid, having no taste or odour, and not 

 affecting test papers. Heated carefully in an open tube, it vola- 

 tilizes ; heated in a retort, part sublimes, whilst part is decomposed, 

 yielding cyanogen and a very bulky, light charcoal remains. It is 

 scarcely soluble at common temperatures ; a saturated solution at 

 212 F. deposits confused crystalline flocculi of the unaltered sub- 

 stance. 



As oxamide is an azoted substance, the ratio of the azote and 

 carbon to each other was first ascertained by combustion with oxide 

 of copper in a glass tube. In this mode of analysis, M. Dumas 

 points out the necessity of collecting the whole of the gas evolved, 

 and ascertaining its composition. Portions of the gas often differ 

 from each other ; and if the composition of the whole be deduced 

 from these portions, great errors may occur. In experiments on 

 the oxamide, two volumes of carbonic acid were produced for each 

 one of azote, so that the carbon and the azote are in the same pro- 

 portion as in cyanogen; 100 parts of oxamide gave 26.95 carbon, 

 and 31.67 azote. 



When oxamide was heated with great excess of concentrated 

 sulphuric acid, it yielded a mixture of carbonic acid and of carbonic 

 oxide gases in exactly equal volumes ; no cyanogen was formed ; this 

 is precisely what takes place with oxalic acid. When the sulphuric 

 acid was diluted and saturated with potash, much ammonia was 

 evolved, so that a sulphate of ammonia had been formed. In this 

 way, therefore, oxamide is resolved into ammonia, carbonic oxide, 

 and carbonic acid. 



When oxamide was heated for some time with strong solution of 

 potassa in great excess, much ammonia was disengaged. The 

 potash, afterwards neutralized by nitric acid, was found to contain 

 oxalate of potassa, so that potassa evolves oxalic acid and ammonia 

 from oxamide, and those substances only. 



These results created a suspicion, that oxamide was to oxalate of 

 ammonia what pyrophosphoric acid is to the ordinary phosphoric acid. 

 The substance, therefore, was compared to oxalate of ammonia, sup- 

 posed to be dry, both by theory and experiment. The carbon is to 

 the azote as 2 proportionals to 1 in both compounds; but 100 parts of 

 oxamide contain 26.95 of carbon, and 31.67 of azote, whilst 100 

 parts of dry oxalate of ammonia contain only 2:2.6 of carbon, and 

 26.6 of azote. When 100 parts of oxamide were converted by 

 potash and sulphuric acid into the elements of oxalate of ammonia, 

 they gave products amounting to 120 parts, i. e., 26.95 carbon, 

 31.67 azote, 54.70 oxygen, and 6.3 hydrogen 119. 62. Now, the 

 sulphuric acid and the" potash could neither of them give carbon or 

 nitrogen, but might communicate oxygen and hydrogen from the 

 water present with them: withdrawing 19,62 of these elements in the 



