SÜDIU31 OE, POTASSIUM I EDNVAKD DIVEES. 59 



180° without showing signs of fusing. Silver nitrate does not 

 fuse l)elow 217° (Carnelley). The low melting point of the 

 mixture of the two salts and the increased stability of the nitrite 

 are, however, the only facts showing tliat there is some chemical 

 union, for water separates the two salts. 



jSitralo-hyiwniirite non-existent. — Silver hyponitrite (4 pis.) 

 and silver nitrate (5 pts.) in intimate mixture were heated in a 

 bath. No change was distinctly observed till 175° was reached, 

 when fusion and the evolution of red fumes occurred. The 

 liyponitrite had then disappeared and the fusion may be attri- 

 buted to the decomposition of the hyponitrite as usual into 

 nitric oxide among other things and to the interaction of this 

 nitric oxide with some of the nitrate to form the fusible nitrato- 

 nitrite. 



The attempt Avas also made to prepare a compound of the 

 two salts in presence of water, there being some grounds to ex- 

 pect success. Calcium liyponitrite, a nearly insoluble salt, was 

 ground up with excess of a very concentrated solution of silver 

 nitrate and a dense and strongly yellow precipitate obtained, 

 which was washed with Avater till calcium salt had been all 

 removed. The precipitate was still yielding up a little silver 

 nitrate when the washing was stopped. Drained on a tile and 

 dried in a vacuum, it proved to be somewhat sensitive to light 

 and to heat, but as it contained 76.94 per cent, of silver and 

 could have been washed more free from silver nitrate, combina- 

 tion of the two salts stable in water does not exist. Only can 

 it be said that silver liyponitrite requires long washing to separate 

 the last portions of silver nitrate from it. 



Nitrito-hy])onitrite also non-existent. — In a paper, already 

 referred to, I have recorded getting a minute quantity of what 



