544- M M. Svanberg and Struve on the Atomic Weight 



V. 0-3432 grm. sulphuret gave - 3064 molybdicacid. 

 If we deduct the quantities of gangue found in the native 

 sulphurets of molybdenum, 100 parts of native sulphuret 

 yield, according to — 



I. . . . 89-84-1 

 II. . . . 89-912 



III. . . . 89-9*3 



IV. . . . 89-744. 

 V. . . . 89-277 



and these results prove beyond a doubt the identity of the na- 

 tive sulphuret, and the artificial sulphuret of molybdenum. If 

 we calculate the per-centage composition of the sulphuret of 

 molybdenum according to theory, it consists of — 



a. Calc. b. Calc. 



1 at. Molybdenum 588-966 59*464 575-829 59-009 



2 at. Sulphur . . 401-500 40-536 400000 40991 



990-466 100000 975-829 100-000 



The analyses give, after deducting the gangue, for the 

 native sulphuret the following results:— 



It is evident that the gangue in the sulphuret of molyb- 

 denum is a mere mechanical impurity, from its quantity vary- 

 ing in the mineral. If in calculating the analyses we take the 

 gangue into consideration, we find — 



I. II. 



Gangue. . . 2-876 0-800 



Molybdenum . 57*368 58-627 

 Sulphur . . 39-756 40'573 



These analyses differ from those made by Buchholz, Brandes, 

 and Seybert ; but these chemists never determined accurately 

 the amount of gangue in the native sulphuret, and, moreover, 

 the atomic weight employed by them was less certain. 



Having shown the identity of the native and artificial sul- 

 phuret of molybdenum, we will now return to the first ex- 

 periments of roasting the artificial sulphuret, where we found 

 that 100 parts sulphuret (MoS 2 ) furnished 89*7523 parts 

 molylxlic acid. This result is founded solely upon experi- 



