1814.] On the Composition of Sulphuret of Antimony. 95 



and the present 100 metal + 24*42 oxygen; eacli approaching 

 nearer than the preceding to the numbers ol Berzelius. 



Article IV. 



On the Composition of Sulphuret of Antimony. By Thomas 

 Thomson, M.D. F.Pt.S. 



Suu'HL'RET of antimony is a mineral that has been so long and 

 so universally known to all my readers, thar I consider it as cube 

 superfluous to give any description of it. It is mentioned both bv 

 Dioseorides and Pliny as a metallic substance; though neither of 

 them had any idea of its composition. Agricola, in his treatise 

 De Natura Fossilium, gives a particular description of it, and shows 

 how it may be distinguished from other minerals to which it has 

 some resemblance. He knew that the metal called antimony could 

 be extracted from it, for a process had been published lung before 

 by Basil Valentine ; but there is nothing in his writings to lead us 

 to suppose that he was acquainted with the real nature of this 

 mineral. 



The same remark, as far as my observation goes, applies to all the 

 chemical and mineralogical writers who followed Agrieola, during 

 a period of nearly 200 years. The first person who ascertained that 

 crude antimony is a simple compound of metallic antimony and 

 sulphur, I conceive was Mender, who published at Dresden, in 

 173S, a dissertation entitled Analysis Antimonii Physico-chyfi). 

 RationalU, in which be establishes the true composition of the 

 mineral in question by satisfactory experiments. Soon after we 

 (ind this composition recognised by Pott and Margraaf as an esta- 

 blished and well known fact. 



The first person who endeavoured to ascertain the proportion of 

 the constituents of this mineral was Bergman, in his dissertation 

 entitled De Antimonialibus Sulphuratis, first published in 1782. 

 His method was to dissolve sulphuret of antimony in a mixture of 

 three parts muriatic and one part nitric acid. Such a mixture, 

 according to him, dissolves the antimony without touching the 

 sulphur, Towards the end of the process it is necessary to apply 

 heat, in order to free, the sulphur completely from antimony. 

 I conceive it to be possible by this method to dissolve the whole 

 antimony without touching the sulphur; but the chances against 

 complete success are almost infinite, unless we be previously • •- 

 quainted with the proportion of metallic antimony present. That 

 is-, unless we ;ire previously acquainted with the very point to be 

 determined. For if we use too much nitric acid, pari of the sul- 

 phur will he converted into sulphuric a id; audit' we use too little, 

 the muriatic aeid will come into actiot) as a solvent, and a portion 



