S10 Proceedings of Philosophical Societies, [Oct. 



difficult to obtain this metal in considerable quantities. M. Laugier 

 has satisfied tbeir wishes to a certain extent. Wben platinum is 

 dissolved in nitro-muriatic acid, there remains a black powder, 

 composed of iridium and osmium ; and hitherto it was tins powder 

 only that supplied osmium to chemists. But M. Laugier, having 

 perceived that the acid employed to dissolve platinum, when sepa- 

 rated from it by distillation, emits a strong odour of osmium, sup- 

 posed that it contained this metal: and he found that when this 

 acid is saturated by caustic alkalies, or still better by quick-lime, 

 and the mixture is distilled, a solution is obtained, containing a 

 notable quantity of osmium, which formerly was entirely lost. 



We spoke in 1808 of the successful trials made at Liege to 

 obtain zinc in a malleable state in the large way, and of the advan- 

 tage that might be derived from substituting it for lead as a covering 

 for houses, and for some other purposes. An attempt was made to 

 substitute this metal for tinned copper, and to form of it vessels for 

 preparing food ; but the Ministers of the Interior and of War 

 having consulted the Class on the subject, the sections of chemistry 

 and medicine found that zinc is too soluble in even the weakesc 

 acids, in fat, and even in water, and that the salts which it forms 

 are too acrid, and in certain cases act too violently on the intestines, 

 to allow us to employ the metals for such purposes without incon- 

 venience. M. Sage has made some experiments on the subject, 

 and has found that distilled water kept in vessels of zinc acquires a 

 decided styptic taste, and that the juices of fruits, when boiled in 

 similar vessels, dissolve a portion cf. them, and form a sufficient 

 quantity of salt to render their taste disagreeable. This is a result 

 so much the more to be lamented, ;:s the mines from which the 

 zinc is extracted contain no arsenic, as is the case with some others, 

 and on that account there was no risk of any injury in the present 

 case from that poisonous metal. We have a new proof of this in 

 the analysis of the ore made by Sage, which he read to the Class. 



MM. Vauquelin and Thenard have given an analysis of the 

 mineral water of Provins, from which it follows that it contains in 

 the litre (6T02y cubic inches). 



Carbonate of lime 0*554 



Oxide of iron 07<' 



Magnesia 0-03.") 



Manganese 0*01 7 



Silica 026 



Common salt 0*042 



Carbonic acid 33-§- English cubic inches. 



Besides traces of muriate of lime and of a fatty matter; but it 

 contains no sulphuric acid whatever, though the presence of that 

 acid in it had been suspected. 



M. Thenard has published the first volume of an elementary 

 treatise on chemistry, in which that science, which daily makes so 

 much progress, and to the advancement of which M. Thenard 

 himself has contributed so considerably, is exhibited in its pfe&nt 



