Pelletier on Gold. 123 



of gold. In general, the solution is reduced to the metallio 

 state, and the vegetable substances are attacked by the oxygen 

 .of the oxide, the chlorine, and the muriatic acid. Finally, 

 the author draws the following conclusions from his experi- 

 ments : 



1. Gold ought to be considered as an electric negative metal, 

 i. e,y as a metal forming oxides, which tend rather to act as acids 

 than as bases. 



2. The oxides of gold cannot form true salifiable compounds 

 with the acids. 



3. The per-oxide of gold will unite to the alcalies and other 

 metallic oxides, forming combinations which possess peculiar 

 properties. 



4. Gold in solution in aqua regia is in the state of per-chlo- 

 ride, and the supposed triple salts of gold are only mixtures in 

 which the gold is still in the state of per-chjoride. 



5. Gold unites to iodine, forming a compound of which the 

 proportions are constant and easily determinable. 



6. According to the proportions of the iodide of gold, those 

 of the oxides and chlorides may also be ascertained as given in 

 the Memoire. 



7. The vegetable acids and salts have diflferent actions on tl^ 

 chloride? and oxides of gold. Amongst them may be distin- 

 guished the oxalic acid and the oxalates, because their action 

 IS very peculiar, and supports the opinion of M. Dulong on the 

 oxalic acid. 



Art. XIIL— Gw ^Ae new Hygrometer. J5y J. F. Daniell, 

 Esq., F.R.S., & M.R.I. 



I HAVE now completed twelve months' regular ob^ei;vations 

 with my new hygrometer, and although not entitled to dra^ 

 conclusions which, to be depended upon, can only be the result 

 of many years unremitting labour, I shall endeavour to point 

 out inferences which may fairly be considered as approxima- 

 tions, tp that accuracy whi^ch it is so desirable to attain. The 



