322 SULPHURET OP LEAD; COPPER, AND ANTIMONY. 



Doubts of the author there professes his doubts of the existence of triple, 

 higherthaa quadruple, and greater combinations ; and his opinion, 

 binary that all combinations are binary. In consequence he endea- 



m ma ions. vours ^ re f er ^ one f ^he latter the nature of the com- 

 pound, that gives rise to endellion ; considering it as formed 

 by the intimate combination of sulphuretof lead, or galena, 

 and that kind of copper ore, which the Germans call 

 fahlertz. I cannot conceive on what reasons the author 

 grounds his opinion, that there can be no triple, quadruple, 

 or greater combination. On the contrary the possibility of 

 these combinations seems to me demonstrated by the simple 

 facts, that I have already brought forward in the second 

 Ultimate par- volume of my mineralogy, p. 390, in order to show, that 

 have a re^ulaT tne mo ^ ecu ^ es °^ bodies, considered as principles of minerals, 

 figure. possess, as well as the integrant molecules which result from 



the combination of these, the property of having a regular 

 figure. The act of combination of these molecules, in 



observations, which had enabled me to make this substance, winch 

 is peculiar to England, more thoroughly known, and to render my 

 account of it more complete. 

 Combinations The second part of my paper was intended to include some re- 

 more than flections on a fact highly interesting both to the mineralogist and 

 m^! y may the chemist, which is the possibility or impossibility of the exist- 

 ence of triple, quadruple, and other combinations in the mineral 

 kingdom. Mr. Smithson, in one part of his paper, sought to 

 establish the principle, that all combinations could only be binary, 

 and adduced endellion in confirmation of his opinion. After 

 having laid down the reasons, that seem to me to preclude all doubt 

 of the possibility of more than binary combinations, it was 

 necessary for me to show the weakness of the argument deduced 

 from endellion ; which could not be made to answer this purpose 

 without giving an arbitrary proportion of the component parts of th« 

 ' two sulphurets, the binary combination, of which produced it, 

 or at least a proportion different from that usually admitted by 

 chemists. I confess, however, that, had I not found occasion to 

 answer the critique included in the same paper, it would not pro- 

 bably have been in the Philosophical Transactions, that I should 

 have pointed out this obvious errour. However, if the committee 

 of the Royal Society had requested me, to suppress this part of my 

 paper, I should not have hesitated a single moment to comply 

 with its wishes, however interestiug I conceived it to be. 



2 forming 



•XKt. 



