104 Progress of Foreign Science. 



probable, and on the other, the denomination which I have em- 

 ployed expresses clearly ray notions of the nature of the triple 

 prussiates. — Ann. de Chim. et Phys. xxii. 320. 



5. Note on the Purpuric Acid, by M. J. L. Lassaigne. 



M. Vauquelin in repeating the experiments of Dr. Prout and 

 M. Gaspard Brvtgnatelli, on the peculiar acid which is formed, 

 by the mutual action of nitric and uric acids, obtained results 

 different from those announced by these two chemists. He ob- 

 served that two acids were usually produced, viz., a coloured acid, 

 and a white acid of great power. These two acids are essentially 

 different; the first is coloured, and forms an insoluble salt with 

 lead; the second is white, and affords a soluble salt with the 

 oxide of the same metal. Neither of these acids exhibited the 

 properties detailed in the Memoirs of MM. Prout and Brugna- 

 telli ; a circumstance which he ascribes to these chemists not 

 having obtained it in a state of purity. 



Although M. Vauquelin did recognise the formation of two 

 distinct acids in the above process, their real existence appeared 

 to him somewhat doubtful. He thinks there may be truly but 

 one, whose properties might be modified by a colouring matter 

 developed at the same time. He supports this opinion by plau- 

 sible considerations. M. Lassaigne subjected to the action of 

 voltaic electricity a weak solution of coloured purpurate of am- 

 monia in a glass tube, connected by threads of amianthus with 

 another, containing distilled water. He obtained at the end of 

 some hours, a colourless acid at the positive pole, which, when 

 combined with ammonia, produced a colourless salt, exhibiting all 

 the characters of the white salt obtained by M. Vauquelin, and 

 not precipitating the solutions of lead and silver, as happened 

 before the transfer of the pure acid to the positive pole. M. Las- 

 saigne considers this experiment as decisive of the justness of 

 M. Vauquelin's views, and of the impurity of the substance ope- 

 rated upon by Dr. Prout. The name purpuric acid, he accordingly 

 proposes to change into superoxijgenated uric acid. May not this 

 superoxygenation, which destroys the colour, be acquired at the 

 positive voltaic pole ? — Ann. de Chim. et de Phys. xxii. 334. 



6. New mode of forming Cyanic Acid. By F. Wohler of 

 Iliedelberg. 

 The researches of M. Gay Lussac shewed that the proportion 

 of carbon to azote in uric acid, is the same as in cyanogen ; and 

 it is known that during the igneous decomposition of uric acid, 

 some prussic acid is produced. M. Wohler prepared a large 

 quantity of urate of mercury, by mixing a solution of corrosive 

 sublimate, with a hot solution of the sparingly soluble urate of 

 potash, prepared in M. Bracoimot's way. He then exposed the 



