PREFACE. Vll stinguished chemist has proposed several judicious im provements in the prevailing mineralogical systems ; and Dr Murray, in his System of Chemistry, gives a view of the natural characters and chemical properties of the different species, adopting the chemical arrangement. Arthur Aikin, Esq. Secretary to the Geological So ciety of London, has published a useful “ Manual of Mineralogy.” And the work now presented to the public attention, professes to have the same claims and inten tions. It is an enlarged and improved edition of my System of Mineralogy, published sevefal years ago. It contains, as far as my knowledge extends, a full state ment of the principal facts known in regard to the Oryc- tognostic Characters and relations of Simple Minerals ; and I believe it will not be found deficient in what re spects the Chemical Characters and Composition. The Geognostic relations, and Geograpical distributions, are given as fully as is consistent with the plan of the trea tise ; and the Economical Uses, and History of the Spe cies, are also considered. The arrangement followed is that of Werner, somewhat modified. I have not at tempted to enter into the minuter details of Crystallo graphy, because these are not consistent with the nature of this work, which is to be considered as a popular view of the Natural History of Simple Minerals. The Plates which accompany the descriptions, are in tended to represent only the more obvious forms of crys tallised minerals, and in general such as are most fre- b 2 quently