TRANSITION TO CLASSIFICATORY SCIENCE. 007 



pally, to their facility of combination with oxygen. Thus, the First 

 Section is the Metals of the Earths ; the Second, the Metals of the 

 Alkalies ; the Third, the Easily Oxidable Metals, as Iron ; the Fourth, 

 Metals Less Oxidable, as Copper and Lead ; the Fifth Section contains 

 only Mercury and Osmium ; and the Sixth, what were at an earlier 

 period termed the Noble Metals, Gold, Silver, Platinum, and others. 



How such principles are to be applied, so as to produce a definite 

 and consistent arrangement, will be explained in speaking of the philo- 

 sophy of the Classificatory Sciences ; but there are one or two pecu- 

 liarities in the classes of bodies thus recognized by modern chemistry, 

 which it may be useful to notice. 



1. The distinction of Metallic and Non-metallic is still employed, as 

 of fundamental importance. The discovery of new metals is so much 

 connected with the inquiries concerning chemical elements, that we 

 may notice the general progress of such discoveries. Gold, Silver, 

 //OH, Copper, Quicksilver, Lead, Tin, were known from the earliest 

 antiquity. In the beginning of the sixteenth century, mine-directors, 

 like George Agricola, had advanced so far in practical metallurgy, that 

 they had discovered the means of extracting three additional metals, 

 Zinc, Bismuth, Antimony. After this, there was no new metal disco- 

 vered for a century, and then such discoveries were made by the theo- 

 retical chemists, a race of men who had not existed before Beccher and 

 Stahl. Thus Arsenic and Cobalt were made known by Brandt, in the 

 middle of the eighteenth century, and we have a long list of similar 

 discoveries belonging to the same period ; Nickel, Manganese, and 

 Tungsten, which were detected by Cronstedt, Gahn, and Scheele, |and 

 Delhuyart, respectively ; metals of a very different kind, Tellurium 

 and Molybdenum, which were brought to light by Mliller, Scheele, 

 Bergman, and Hielm ; Platinum, which was known as early as 1741, 

 but with the ore of which, in 1802 and 1803, the English chemists, 

 .Wollaston and Tennant, found that no less than four other new metals 

 (Palladium, Rhodium, Indium and Osmium) were associated. Finally, 

 (omitting some other new metals,) we have another period of disco- 

 very, opened in 180*7, by Davy's discovery of Potassium, and includ- 

 ing the resolution of all, or almost all, the alkalies and earths into 

 metallic bases. 



[2nd Ed.] [The next few years made some, at least some conjec- 

 tural, additions to the list of simple substances, detected by a more 

 minute scrutiny of known substances. Thorium was discovered bv 

 Berzelius in 1828; and Vanadium by Professor Sefstrom in 1830, A 



