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f PREFACE. That even thi* peculiarity, which we find in a very- few cryftallized minerals may be difcoveredin others fpecificaUy different, is proved from the cafe of dia mond, fpinelle, &c ,# It appears from this that the integral mollecule cannot in any inftance be confidered as the type of the fpecies, therefore, the oryctognoftic fyftem of Ilauy, which is built on this fuppofition, muft fall to the ground f. The various attempts that have been made to de^. fcribe and to dii'criminate the mineral fpecies by a * The inftances of the inconfiftencies that occur in the em ployment of the integral mollecule are numerous, but of thefe I fhall only mention one. Zeolite is one of the moft natural and heft afcevtained fpecies in the fyftem, and its fubfpecies are con nected together by agreements in oryCtognoftic and gcognoftic characters. Hauy having, however, found fmall differences in t e integral mollecules of thefe fubfpecies, has divided it into our pecies. Spinelle and diamond are acknowledged by Hauy to have fimilar integral mollecules, yet he confiders them as dif- tinCt fpecies, and diftinguilhes them from one another by hard- nefs and other external charafters. Thus in one inftance we find the integral mollecule affumcd as of fuperior charaCteriftic im portance to all the other external and geognoftic characters com- med , but in the other it yields even to a few of the other ex ternal characters. t Independent of the objections ftated above, there is ftill ano- er, and probably a more forcible one to be oppofed to the fyf- tcm ° Hau y > it is that the greater number of minerals arc not cryftallized, confequently, according to the definition of Hauy, ve no difcoverable integral mollecule, therefore are not fpecies. Hauy indeed fufpeCts that they are not fpecies! ! ! few
