Q66 



NATIVE GOLD DUST. 



milar to that of chocolate, which imparts a blue colour to 



the acids in which it is dissolved, and appears to differ from 



the preceding in the oxidation of the molybdena, and in 



containing more sulphuretted hidrogen ^nd less sulphur. 



Thus we have two compounds of this kind; and the latter 



appears capable, uncjer certaiii circumstances, of being coa-» 



verted into the former. 



ant^ sulphn- 4thly. Pure sulphuretted hidrogen gas equally combine^ 



retted hidro- . -^ ' . , » i .• r^* j- 



„e„_ with molybdena, exhibiting pneuomen^i that ludicate a dis- 



oxigeaation, and forms products simiicir to those resulting 

 from their combinations. The passage of this gas through 

 a solution of molybdate of ammonia gives rise to a triple 

 compound, which is soluble in water, decompofable by 

 heat, and rendered by it similar to the native sulphuret of 

 molybdena. 

 one usion. ] j -^^^^ conclude the publication of my experiments on 

 molybdena. I am free to confess, that luey do not exhibit 

 a complete work; but I flatter myfelf, that some conclusions 

 may be drawn from my labours not altogether unimportant 

 to the science of chemistry. Besides it was necessary, that 

 such experiments should be some time made; and I can 

 aver, that I employed all the care and attention possible, so 

 that complete reliance may be placed on their accuracy. 

 Farther experiments will complete what I have begun. 

 Farther expe- These I shall undertake, as soon as I have procured a suf- 

 mised. ficient quantity of molybdena, and my occupations will af- 



ford me leisure. 



III. 



On the native Gold Dvft found in the Hills in the Environs 

 of the Commune of St. Geoj'ge^s, in the Department of 

 the Dcire: by Mr. GiULio, Prefect of the Department 



of the Sesia *. 



Native gold JL T has long been known, that a great number of rivers 

 found in I le^ and brooks carry with them particles of native gold, of 



* Journal des Mine?, No. 116, p. 145, 



larger 



