Intelligence mid Miscellaneous Articles. 323 



contains phosphate of lime. To make this experiment, a little more 

 than an atom, or preferably two atoms of pyrophosphate of soda, and 

 one atom of carbonate of lime are employed. In the aqueous solu- 

 tion, the presence of lime may be discovered by oxalic acid. The 

 phosphate of lime does not always separate so well by evaporating 

 the aqueous solution to dryness, or by passing a current of carbonic 

 acid gas into it, as by decomposing it by carbonate of soda and eva- 

 poration. The phosphate of lime eliminated does not contain any 

 carbonate of lime after washing. 



In this case there is evidently formed a double salt of phosphate 

 of soda and phosphate of lime. The latter separates when a portion 

 of the soda is converted in the solution into carbonate of soda.— 

 L'Institut, Decembre 26, 1849. 



ON INSOLUBLE ALKALINE ANDr EARTHY DOUBLE ARSENIATES. 

 BY M. H. HOSE. 



Arsenic acid forms with the alkalies and earths double insoluble 

 salts, analogous to those of phosphoric acid. The earthy arseniates 

 are always much more readily decomposed by heat and by the alka- 

 line carbonates than the phosphates are ; consequently, if an excess 

 of an alkaline carbonate be employed, the result is a complete de- 

 composition. But if merely an atom of earthy arseniate and an atom 

 of alkaline carbonate be heated together, partial decomposition is 

 soon produced without undergoing fusion. If the calcined mass be 

 treated with water, some earthy carbonate mixed with the insoluble 

 compound remains, in which by long treatment with water the 

 alkali is replaced by an equivalent of water, as already stated with 

 respect to the insoluble double phosphates. 



There is therefore but little chance of success in preparing analo- 

 gous insoluble double salts of arsenic, but they certainly exist ; and 

 what proves this is the circumstance, that the calcined mass, although 

 the washing may be long continued, always contains some alkali. — 

 L'Institut, Decembre 26, 1849. 



ON THE DISCOVERY OF PLATINA IN THE ALPS. 

 BY M. GUEYMARD. 



The author is chief engineer and director of mines, and discovered 

 in 1847, platina on the mountain of Chapeau, in the commune of 

 Champoleon, in the valley of the Droc. It occurs in gray copper 

 ore, which besides contains from some cases as much as 12 per 

 cent, of silver, some antimony, lead, zinc, iron, a little arsenic and 

 sulphur ; the gangue is a mixture of dolomites, quartz and barytes. 



In 1847 platina was found in the alluvion of Columbia, of the Ural, 

 Brazil, and of St. Domingo ; in the rocks of diorite of the high 

 mountains of Columbia (Boussingault), and in the serpentines of the 

 Ural (Leplay). The existence of this metal had not been discovered 

 in other places, and never in the Alps. M. Gueymard states, that in 

 1847 he had performed more than a hundred examinations or analyses 



