SULPHURET O? LEAD, COPPER, AND ANTIMONY. 226 



But is it certain, that the integrant molecule of endellion Endellion more 

 is simply the result of ,a triple combination of the integrant P robab| y a 

 molecules of the three sulphurets of lead, copper, and a ternary com- 

 antimony ? and is it not more natural to consider it as the bination * 

 result of a quadruple combination of the molecules of 

 sulphur, lead, copper, and antimony? I confess, I am 

 much inclined to consider endellion in the latter point of 

 view, particularly when I observe, that the sulphur, wh : ch 

 from the proportion in which it exists in the three sul- 

 phurets should amount to 20-03, forms only 17 hundredths 

 of this substance. 



referring endellion to the binary combination of Composition of 



ga! a and fahlertz, the paper above quoted gives the fol- endel,lon ».** 

 , . given by Mr. 



lowing proportions. Smithsoa. 



/' , f -i sulphur 



U galena (| ^ 



EndcllionJ r^sulphuret of antimony {^P^ 



U fahlertz j , sulphuret of copper j Isul^hur 



From these proportions it would follow, that the suU 

 phuret of lead contains 83 j of lead, and 16| of sulphur: 

 that of antimony 83| of antimony, and 16f of sulphur: 

 and that of copper 66| of copper, and 33j> of sulphur. 



The proportion in which the sulphur is said to combine Those of th« 

 with the lead in galena, or the sulphuret of this metal, »» antimon*^ 

 the same as is given by Mr. Kirwan. As to the two sul- copper differ 

 phurets of antimony and copper, the proportions between "? othe * 

 the sulphur and the metal result probably from the author's 

 own observations, which it is much to be regretted that he 

 has not given. 



According to Proust and Bergman, the only two authors, Proportions in 

 as far as I know, that have established the proportions of sulphuret of 

 sulphur and antimony in the sulphuret of this metal, the 

 sulphur is to the antimony in the proportion of 26 to 74; 

 and this is the proportion hitherto followed by all writers. 



They have in like manner followed the proportion affixed Proportions in 

 by Klaproth to the sulphur and metal in the sulphuret f su, P hu,ctof 

 copper, which is that of 18-5 to 78*5 : and with respect to 

 this sulphuret I will add, that, about the tin* when I laid 



before 



