40 



able. Contains numerous grains of felspar, hornblende, and other 

 extraneous minerals. 



Composition. — Peroxide of iron, - 67*25 per cent. 



Protoxide of iron, - 26-50 do. 



Oxide of manganese, - 0-50 do. 



Oxide of titanium, - a trace. 



Silica, - - - 2-10 



Alumina, &c. - - 3-00 



The analyses of these ores being undertaken with a view to 

 ascertain more particularly the quantity of metallic iron, the pro- 

 cess adopted was to dissolve the powdered ore in nitro-muriatic 

 acid, precipitate the iron by potash, to redissolve it in excess of 

 acid, and subsequently precipitate it by ammonia. 



A portion, considered as representing the average composition 

 of the specimen, w^as selected for examination. In each instance 

 the specific gravity has been taken by Nicholson's hydrometer. 



Five or six times the amount which was employed for analysis 

 being finely pulverized, from ten to twelve grains were generally 

 used, this being found the most convenient quantity for accuracy. 



It deserves the attention of those engaged in manufacturing iron 

 from these ores, that very frequently the portion of the vein lying 

 immediately beneath the surface, and the fragments and grains of 

 the ore, which often fill the soil in very considerable abundance, 

 are much softer than the ore in the main body of the vein. The 

 action of atmospheric agents upon it appears to have rendered it 

 more yielding, and it consequently mingles more readily in the fur- 

 nace with the other materials, greatly facilitating the smelting of 

 the mass. The clay and earthy matters, which remain attached 

 to the surface ore, even after it is washed free from the loose soil, 

 account, in part, for its beneficial effects; for, the highly silicious 

 nature of the foreign minerals in the ore, seem to counteract, in 

 part, the fluxing agency of the limestone, and render it less 

 eflicient than when other ores are smelted. Some trials have 

 been made at the Oxford Furnace, which consisted in mixing a 

 loamy clay with the ore, in addition to the limestone, and were 

 decidedly encouraging. The loose surface ore, therefore, merits 

 the attention of the smelter. At Oxford Furnace, the soil con- 



