1824.] Chemical Composition of Red Silver Ore. 35 



else than antimony. The sublimate, therefore, consisted of 

 sulphuret of antimony. Its weight (determined by weighing the 

 glass fragments before and after the digestion in the acids) was 

 0-0065 gramme. It consisted of course of 0-0047 antimony and 

 0-0018 sulphur. When we subtract this 0-0065 from the 0-011 

 (the total weight), there remain 0-0045, which consisted of a 

 brown-coloured earthy matter, but too small in quantity to be 

 submitted to any tests to determine its nature. 



The sulphuret of copper which had precipitated in the differ- 

 ent phials was collected on a filter, and well washed with water. 

 It was then dissolved in aqua regia, which, after long digestion, 

 left a light-yellow powder, consisting of sulphur. It weighed, 

 when well dried, 0- 1 06 gramme, and burnt easily, leaving a black- 

 greyish residual matter, weighing scarcely a milligramme. The 

 solution in aqua regia was precipitated warm by muriate of 

 barytes. The sulphate of barytes obtained weighed 1-04 gramme, 

 equivalent to 0*143 gramme sulphur. Thus the whole quantity 

 of sulphur amounted to 0-248 gramme. The matter deposited 

 on the chloride of calcium might also contain a little sulphur, 

 left on it by the warm sulphuretted hydrogen gas ; but it is 

 impossible to determine its amount with accuracy. 



The preceding analysis of red silver ore gives us the following 

 constituents : 



Silver 0-8866 or 58-949 



Antimony 0-3436 22-846 



Sulphur.. 0-2498 16-609 



Earthy matter 0-0045 0289 



Loss . 0-0195 1-307 



1-5040 100-000 



If we examine this mineral in a theoretic point of view, we 

 find that 58-949 silver combine with 8-76 sulphur; and that 

 22-846 of antimony unite with 8-549 sulphur. We see further 

 that the sulphuret of silver is a compound of 1 atom silver and 



2 atoms sulphur ; while the sulphuret of antimony consists ol 



3 atoms sulphur and 1 atom antimony. The chemical^ formula 

 for red silver ore, therefore, must be, 3 Ag S- + 2 Sb S', which 

 gives us its constituents as follows : 



Silver M9H 



Antimony *2*4 / 



Sulphur I 7 ' 55 



99-00 

 Appendix. 



To explain the composition of red silver ore to the English 

 readers, it will be merely necessary to substitute the atomic 



i»2 



