540 Notices of Books. [O&tober, 
hydrogen, but as the precipitate was accompanied by much zinc 
it was re-dissolved in hydrochloric acid, and again thrown down 
in the same manner. It was next dissolved in sulphuric acid, 
the slightest excess being carefully avoided, and a third time 
precipitated as sulphide. This time the separation was found to 
be perfect. The cadmium sulphide was then re-dissolved, precipi- 
tated, and finally weighed as oxide. The cyanide method was 
also used for the separation of zinc and cadmium, and the 
mean results obtained all agreed within 0-05 per cent. 
The mineral productions of the State appear extensive and 
varied. Iron occurs in the forms of bog-ore, limonite, goethite, 
red hematite, spathic ores, ankerite, specular iron, and sulphurets, 
The latter is generally diffused, ‘‘ occurring in most of the coals, 
shales, and slates, and scarcely any limestone is free from it.” 
Gold is found, though not to any great extent, in the drift sands 
of North Missouri. Silver is found only associated with lead. 
Blende abounds at Granby and Joplin and in other parts of the 
South-west; it is also found in the coal ‘“‘ pockets” of Central 
Missouri, in the lead mines of the same district, in the St. Louis 
limestone, and in the coal-measure limestone. ‘“ Iron-stone 
concretions often inclose a nucleus of zinc-blende. Fragments 
of plant-remains often have minute cracks filled with blende, and 
it occurs in the interior of fossil shells.” Silicate and carbonate 
of zinc occur at Granby and Joplin, and zinc-bloom, though rarely 
in the central and southern parts of the State. Greenockite 
(cadmium sulphide) is associated with blende in the South-west. 
Copper is not specially mined at any part of the State, though 
it exists in small quantities widely diffused, as malachite and as 
copper pyrites. Nickel and cobalt occur as sulphides and arse- 
nides, distributed through the galena, especially at Mine La 
Motte. At the Bluff Diggings the ore was found to contain— 
Copper ° . : : 3 : 1°00 
Nickel : : : : : 18°10 
Cobalt : 4 . : 5 13°90 
Lead : : ; : 17°45 per cent. 
These ores are not washed, but alternate layers of the ore and 
of charcoal are placed on a heap and roasted. When thus freed 
from sulphur they are smelted in a blast-furnace, which yields a 
matte of nickel and cobalt, some little copper, and traces of 
lead. Its sale price on the spot is 75 cents per pound. 
Millerite (nickel sulphide) is found in the St. Louis limestone 
in beautiful hair-like crystals, occupying drusy cavities and rest- 
ing on calcite or on fluor-spar. Lead occurs in profusion as 
galena and carbonate. Pyromorphite (lead-phosphate) is more 
rare. Wolfram is found in Madison County, and manganese 
and manganiferous iron in Iron County. 
Sulphate of baryta, locally known as ‘tiff,’ is found in the 
lead mines of Cole, Miller, and Morgan, and is used, as in Europe, 
