23$ 



SCIENTIFIC NfcWS, 



Chromate of 

 iron in France. 



Emerald In 

 France j 



and neutral 

 phofphate of 



The fuppofed 



roonic acid is the 

 acetous ; 



and the cobaltic 

 acid is arfenic. 



Vie Seven following Articles are Extracts of a Letter of CiT- 

 Vauquelin to Cit. Van Mons *. 



1 . Difcorery of the Chromate of Iron in France. 

 The chromate of iron has been found in abundance in the 

 department of Var : we can now prepare any quantities of 

 this metal, and ftudy its properties in detail more than we 

 have hitherto been able to do. Above all, we can compofe 

 in a direct way the chromate of lead, which is a very intereft- 

 ing object in painting. The chromate of iron may alfo be 

 uied to form a beautiful green on porcelain or artificial ftones. 



2. Difcovery of the Emerald, 

 In a mineralogical tour which Cit. Lelievre, member of the 

 Council of Mines has juft made, he has difcovered a quarry 

 of emeralds, which are fo abundant, that they are ufed in the 

 country to pave the roads. They are found in the environs of 

 Limoges mixed with granite, often without any regular form, 

 and fometimes cryftallized, but their colour and tranfparency 

 are not beautiful. 



3. Difcovery of the Neutral Phofphate of Iron. 

 Cit. Lelievre has likewife difcovered in the fame place a 

 mineral fufficiently interefting, namely, a perfect phofphate of 

 iron, that is to fay, that the iron is intirely faturated by the 

 phofphoric acid, a combination which had not hitherto been 

 found in nature ; it has a red brown colour, is femi^tranfpa- 

 rent, and has a foliated texture. 



4. On the Zoonic Acid. 



Cit. Thenard has juft finiflied an examination of the zoonic 

 acid, in which he appears to have demonftrated that it is no- 

 thing but the acetous acid combined with a peculiar animal 

 matter. 



5. On the Cohaltic Acid. 



Cit. Darracq has read a paper to the Inftitute, in which he 

 fhews that the acid found in zaffre by Cit. Brugnatelli, and 

 which he named the cobaltic acid, is abfolutely nothing but 

 the arfenic acid. 



You fee that by degrees the number of chemical fubfiances 

 diminiflies, which is a great advantage to the fcience. 

 * Journal de Chiraie, par Van Mons. I. 218. 



ACCOUNT 



