Regarding the arrangement of the metals pro» posed by M. Thenard as the most perspicuous and scientific of any I had hitherto seen, I determined to avail myself of the suggestions of that able chemist in consequence of which I found it requisite to new model the whole of the Tenth Chapter; especially as his classification is entirely different from that which I had previously adopted. All the new metals are now admitted; and the nature and properties of each, to gether with those of the whole class, have been so circumstantially described that this part of the work has been unavoidably extended to nearly double its former limits.