216 Miscellaneous Intelligence. 



itself is calcined, it yields green oxide of chrome. — Ann. de VIndus. 

 i. 121. 



30. Chloride of Silver and Sodium. — When pulverized chloride 

 of silver is boiled in a nearly saturated solution of common salt, a 

 compound of the two substances is produced, which crystallizes as 

 the temperature falls. The crystals are not affected by light, and 

 are decomposed by water. The solvent powers of the chloride of 

 sodium over chloride of silver may be usefully employed in analysis. 

 Similar compounds may be obtained by using the chlorides of 

 potassium or calcium. — Wetzlar, Jahrb. der Chemie, 1827. 



31. Nitrate and Sulphate of Ammonia and Silver. — The nitrate 

 of silver and ammonia is easily obtained by adding ammonia to the 

 nitrate of silver. The salt is very soluble, readily crystallizes, and 

 consists of 



Nitric acid . . . 2641 , 



Oxide of silver . . . 55o| ^ ^^^"^ 

 Ammonia . . . 180 2 atoms 



The triple sulphate of ammonia and silver is formed in a similar 

 way. It is very soluble, crystallizable, and consists of 

 Sulphuric acid . . 21601 , 



Oxide of Silver . . 6065] ^ ^^^"^ 



Ammonia . . . 1940 2 atoms 



Ann. des Mines, N. S., iii. 175. 



32. Artificial production of Ultramarine. — A short time since it 

 was announced in the journals that M. Guimet had succeeded in 

 manufacturing ultramarine. The announcement has drawn from 

 M. Gmelin, of Tubinjen, a note, in which he describes a method of 

 making ultramarine, and expresses regret that, from an indiscretion 

 of his own, he should have been anticipated. It appears, however, 

 that his regret is without foundation ; it is the more so, as every 

 body will be ready to admit that he is the true discoverer of the 

 artificial production of ultramarine, i.e., provided it can be made by 

 his process, since he is the first to publish that knowledge to the 

 scientific world in such a manner as truly to constitute a discovery. 

 M. Guimet, like M. Buran with borax, has resigned (as he had a 

 right to do) the honour, which could only be obtained by a partial 

 sacrifice of his pecuniary interests. 



M. Gmelin was led to consider sulphur as the colouring matter of 

 ultramarine, and from an observation by M. Tassaert (Ami. de 

 Chimie, Ixxxix. 88) concluded that it might be made artifici- 

 ally. M- Tassajrt had remarked the formation of a substance like 

 ultramarine in a furnace used in the manufacture of soda. The 

 following is the method by which ultramarine may be infallibly pre- 

 pared. Pulverised quartz is to be fused with four times its weight 



