122 Pelletier on Gold. 



decomposes this substance : a temperature of 150° (302° Faht.) 

 being sufficient. 



The alcalies in solution instantly decompose the iodide of 

 gold. With potash an iodate and a hydriodate of that base is 

 obtained, and the gold remains in a pulverulent metallic state. 

 This phaenomenon is easily explained, but, according to M. Pel- 

 letier, if the action of potash on the chloride of gold be com- 

 pared to its action on the iodide, it may be asked, why, in the 

 first case, the gold becomes oxidized, and why is no chlorate 

 of potash formed ? It appears that the difference is occasioned 

 by the stronger affinity possessed by iodine, than by chlo- 

 rine, for oxygen ; and the stronger affinity of potassium for 

 chlorine than for oxygen. This experiment also tends to 

 prove that the alcaline muriates are chlorides, and not mu- 

 riates. 



This iodide gave on analysis : 



Iodine 34 ; 100 



Gold m 194.1076 



M. Gay-Lussac having shewn the quantity of oxygen corre- 

 sponding to a certain quantity of iodine, M. Pelletier has cal- 

 culated, from the preceding results, the composition of the 

 oxides of gold, and has found the prot-oxide to contain 

 Oxygen .... 3.3495 



Gold 100. 



And the per-oxide. Oxygen .... 10.03 



Gold 100. 



These results differ from those of Berzelius, and therefore the 

 number for the atom of gold must differ also. It appears to 

 be 299, oxygen being 10. 



M. Pelletier has from the above data calculated the following 

 proportions in the compounds of gold : 



p 10 Oxygen ,... prot-oxide. 

 30 Oxygen .... per-oxide.. 

 44 Chlorine .... proto-chloride. 

 132 Chlorine.... per-chloride. 

 M. Pelletier concludes his Memoire with an account of the 

 action exerted by organized vegetable substances on the solutioa 



Gold 299. 



