_Cobalt_ is a whitish-grey, brittle metal, nearly resembling fine hardened steel; is difficult of fusion, but obedient to the magnet. According to Bergman, its specific gravity is about 7.700; though Tassaret makes it 8.538. Formerly all our cobalt came from Saxony. The cobalt ores of Hesse produce a nett profit of £14,000 a year, as stated in Born’s Travels; though once they were used for no other purpose than to repair the roads. But now cobalt is found abundantly in the Mendip hills in Somersetshire, and in a mine near Penzance in Cornwall. Zaffre is now made from the cobalt ores found in these hills. Had it not been for the rapid promulgation of chemical science in these kingdoms, this important metal might have lain in the bowels of the earth undiscovered for ages yet to come. Formerly miners not only threw cobalt aside as useless, but they considered it so troublesome when they found it among other ores, that, as stated in Beckmann’s History of Inventions, a prayer was used in the German church, that God would preserve miners from _cobalt_ and from _spirits_. It is now very valuable to the manufacturers of porcelain. _Manganese_ is of a dark grey color, brilliant, very brittle, of considerable hardness, and difficult fusibility. Its specific gravity has been estimated by Bergman at 6.850, and by Hielm 7.00. It is never found native. It was first procured in its pure metallic form by Kaim and Gahn between 1770 and 1775. It abounds in America, and in various parts of the continent. The manganese which is used in England, is obtained in a state of black oxide from Somersetshire and Devon. It is found either in the state of an oxide or a salt. But the discovery of mines of it in this country is a new acquisition, owing to the spirit of chemical research. Dr. William Dyce, of Aberdeen, has lately communicated to the Society for the Promotion of Arts, &c, the discovery of a mine of great extent, and very fine quality, in the vicinity of that town: for which the gold medal of the Society was sent him. Professor Beattie, of the same place, has also discovered manganese in his neighborhood, on the river Don, of good quality. Scheele discovered this metal in the ashes of burnt vegetables. Proust has lately announced the discovery of a native sulphuret of manganese. That from the Bristol and the Mendip hills generally contains lead. _Tungsten_ is a heavy metal, but its properties are not much known. It is procured from a mineral found in Sweden, and from an ore called _wolfram_, found in Cornwall, Germany, &c. It has been used in France for making vegetable lakes; but is not used here. Though it has been recommended as a proper basis for colors, it shows in some instances a strange fugacious disposition. Its specific gravity is 17.60.