Professor GmeliiVs Analysis of Helvine. 269 



who was provided only with a small quantity of this mineral, 

 does not seem to be sufficiently exact. I agreed, therefore, 

 with pleasure to the wish of my friend Mr Breithaupt, who 

 kindly provided me with a considerable quantity of this rare 

 mineral, to subject it to a repeated analysis. 



Specific gravity of Helvine. —This was found by a very sen- 

 sible balance to be 3.166, the temperature of the water being 

 +6° It. According to Mr Breithaupt, it is between 3.1 and 8.3. 



Relations before the blow-pipe. — As to these I refer to the 

 inquiry of Professor Berzelius,* with whom I agreed in the 

 results. The sparkling which ensues, according to Dr Vogel, 

 when Helvine is held in the flame, I have likewise distinctly 

 observed. But I endeavoured, in vain, to discover the sul- 

 phur contained in it, by means of the blow-pipe. It appears 

 that the large quantity of oxide of manganese, which, together 

 with sulphate of manganese, forms an ingredient in Helvine, 

 destroys the reactions for sulphur. The slowness, on the 

 other hand, with which the manganese-reaction, by means of 

 soda upon a platinum lamina ensues, might be derived from 

 the sulphur contained in it. 



Analysis. — (1.) Relying upon the assertion,f that acids do 

 not act upon Helvine, and considering that, in the analysis of 

 Dr Vogel, sulphur is not mentioned to be an ingredient, I 

 resolved to decompose the mineral previously reduced to an 

 impalpable powder by trituration with water, \ by means of 

 carbonate of barytes, in order to discover any alkaline sub- 

 stance that might be contained in it. 3-712 grammes of the 

 powder were mixed with six times their weight of carbonate 

 of barytes, and ignited in a platinum crucible. There was 

 obtained a blackish-blue mass hardly cohering, which, in some 

 spots, appeared in a melted state, muriatic acid being poured 

 upon this mass, previously soaked by water, such a quantity 

 of sulphuretted hydrogen was disengaged, that the vessel, con- 

 taining the solution, required to be removed out of the room ; 



• Use of the blow-pipe, &c. 



•f Leonhard's Handb. der Oryklognosict p. 431. 



+ It deserves to be noticed, that water, with which Helvine is tritu- 

 rated, passes quite clear through the filtre, which, in general, never hap- 

 pens with other minerals similarly treated. 



