14* Analyjis of the ArfenlattS 



mull thev evpr be from truths evident to our fcnfes, ana 

 fupported bv palpable experiments! 



To follow Nature through the minutise of her labours, anci 

 behold her reproducing the fame primitive materials in many 

 different fl^iajx.s, has always been deemed a lefs fplendid 

 achievement of fcience, than to difcover one more of thofe 

 iimple fubftance?, bv the union of which flic forms the com- 

 plicated effecls we daily admire. Yet to mc it appears, that 

 in no inftance is {he more truly wonderful than in tlie un- 

 bounded variety wliich flie has fometimes produced from a 

 fmall fund of original refources, and when we can fciirly 

 follow a few primitive fubftances through a feries of com-» 

 binations infinitely multiplied. 



In addition to the two chemifts who, as is mentioned In 

 the preceding paper by the Count de Bournon, appear to 

 have had fome knowledge of the exiftence of a natural arfe- 

 niate of copper, I nnift name M. Vauquelin. Jn a letter to 

 me laft year, he communicated the difcovery of fuch a fub- 

 ftance in France. Of the different varieties which thefe gen- 

 tlemen, McflTrs. Klaproth, Prouft, and Vauquelin, have exa- 

 mined, I (hall have occafion to fpeak in the courfe of thefe 

 experiments : but it was referved for the Count de Bournon 

 to ftate, in the faid paper, with his ufual talent and perfpi- 

 cuitv, the fciL-ntific detail of the external charafters, parti- 

 cularly of the cryffalline forms, by which he had identified 

 their nature. The free aecefs to the extenfive coUcftions of 

 the Right Hon. Charles Greville and of Sir John St. Aubyn, 

 alfo the eafy communication with the native foil of this mi- 

 neral, were the peculiar advantages, which enabled the Count 

 de Bournon and myfolf to purfue the mineralogical and che- 

 mical refearches which are ftatcd in thefe communications to 

 the Society. 



When the Count de Bournon had completed what ap- 

 peared to him to be the mineralogical claffificaiion of thefe 

 copper ores, he gave mc fome fpecimens of each kind, num- 

 bered indifcriminately, for the very purpofe of excluding pre- 

 judice; and it was not till my tafk was ended that we com- 

 pared our obft^rvations. If 1 had been admitted into any 

 previous knowledge of the arrangement diftated to him by 

 the principles of crvftallography, I fliould have been afraid 

 that I had merely thought true what I wiflied to be fo. But 

 I can, moft confcientioullv, indulge in the fatisfaftion which 

 the according refidts of different means to prove the fame 

 propofition naturally excite; and which is juitly due to the 

 truth of the outward marks, however delicate, yet ftill to be 



perceived. 



