Introduction to the Study of Mineralogy. 459 



of Jakes which have disappeared by the same natural process 

 in every country. 



I fear, Mr. Editor, I have trespassed much too far on the 

 limits of your truly estimable record of scientific papers; yet 

 I trust the subject is one of superior interest, by bringing us 

 acquainted with the origin of those beautiful excavations 

 which adorn so much of our landscape, and add so much of 

 pleasurable variety to every excursion. They offer how- 

 ever, still higher claims to our attention from their para- 

 mount usefulness in the provident (economy of Nature, by 

 operating, with such admirable and subservient address, and 

 such a harmonized system of combination, as the universal 

 conduits of all the waters of every country. 



I am, sir, your most obedient humble servant, 



John Carr, 



princes Street, Manchester, 

 June 10, 1809. 



kXXXII. Introduction to the Study of Mineralogy. By 

 M. Hauy. 



[Concluded from p. 401.] 



XSut the authors of systems of mineralogy, without even 

 excepting chemists, have followed a very different course, 

 They have considered each metal as the base of a particular 

 genus ; and in the case in which this metal existed per se f 

 in the state of native metal, it would form the first species 

 of the genus ; and its combinations with different principles 

 would give the other species. Thus, in the genus of copper, 

 we should have successively, as species, native copper, oxide 

 of copper, sulphuret of copper, carbonate of copper, itiut 

 riate of copper, ike. In short, metallic substances have 

 characters so striking, that they have been adopted with one 

 accord, as the fixed points around which all the combina* 

 tions ought to rally of Which they form part. 



Now, uniformity of method would require, that the same 

 rule which had been followed in the arrangement of metallic 

 substances should also preside over that of substances pro- 

 duced by the union of an earth with an acid 5 z. e. lime, for 



example, 



