9 5 Fyench National Jnjlilufe. 



vhich he has given the name o^ fnhvhjat'wq viercrn'v. It js 

 atteniietl, however, with this dirference, thrit it is not pro- 

 duced under circumftnnces fimiiar to thofe under which gold 

 and filver fufceptibfe of detonation arc obtuined. It is form- 

 ed bv the cbulHtinn of nitrate of mercury with alcohol, and 

 depofits itfelf in a powder, the colour of which varies from 

 white to a gray more or Icfs dark. It was ncceirary to find 

 in the aualyfis of this lubftance an explanation of its pro- 

 liuSion, and that of its refemblance to fulminating gold and 

 lilvcr; and alfo of its differences from them. Mr. Howard 

 concluded from his experiments, that it was compofed of 

 oxalic acid, oxide of niercury, and ethereal nitrous gas. 



^. Eerthollet has fliown by his, that it contains no oxalic 

 acid; but that it contains anmionia ; that it forms in this 

 rcfpeA a combination analogous to fulminating gold and 

 lilver; and that, confeciuently, its eflefts ought to be ex- 

 plained in the fame manner as thofe of thtfe compounds. 

 Fulminating mercury differs from thefe two detonating me- 

 tallic fubltances, by a portion of altered alcohol, which en- 

 ters into the combination, and which, when dccompofed, 

 produces carbonic acid. Fulminating mercury then is a 

 triple combination, while fulminating gold and (ilvcr are only 

 binary combinations of the oxides of ihcfe metals with am-. 

 uionia. 



C. Vaiiquclin read a memoir on the analyfis he made 

 of a copper ore difcovered in Derbvfhire, fpecimens of 

 which had been tranfmitted to the Council of Mines by 

 Count do Beurnon. Vauquelin flates, that this ore is com- 

 pofed of 6a parts oxide of copper, 24 parts of arfenic acid, 

 8 parts arfcniate of iron, and 8 parts water of cryftallizalion. 



Vauquelin having been requefied alfo by the Council of 

 Mines to examine a mineral fent to it by M. Karflein of 

 Berlin, under the name of arfeniated copper, afcertained that 

 this mineral is formed of 60 parts oxide of iron, 2:; parts ar- 

 fenic acid, and 18 parts water of cryftallifation; but that it 

 contains not ah atom of copper. Neither copper nor iron 

 had been before found united to the arfenic acid ; and this 

 is the reafon why the mincralogifts had made no mention 

 in their works of the arfcniate of iron or arfcniate of copper. 

 The labours of C. Vauqr.clin have therefore enriched with 

 two diftinft fpecies the catalogue of mineral fubftances al- 

 ready known *. 



C. Vauquelin read alfo a memoir on a mineral found in 

 the environs of Limoges, which C. Aliuau, direftor of the 

 porcelain nianufadlory in that city, had tranfmitted to him 



• j.'.ii is i rrtiftukt. See rhilofcpliical Tianf. 1801, part i. — Edit. 

 • imder 



