Morasses rest on limestone. Of immense extent 116
Salts from animal and vegetable bodies decompose each other, except marine salt. Salt mines in Poland. Timber does not decay in them. Rock- salt produced by evaporation from sea-water. Fossil shells in salt mines. Salt in hollow pyramids. In cubes. Sea-water contains about one- thirtieth of salt 119
Nitre, native in Bengal and Italy. Nitrous gas combined with vital air produces red clouds, and the two airs occupy less space than one of them before, and give out heat. Oxygene and azote produce nitrous acid 143
Iron from decomposed vegetables. Chalybeat springs. Fern-leaves in nodules of iron. Concentric spheres of iron nodules owing to polarity, like iron-filings arranged by a magnet. Great strata of the earth owing to their polarity 183
Hardness of steel for tools. Gave superiority to the European nations.
Welding of steel. Its magnetism. Uses of gold 192
Artificial magnets improved by Savery and Dr. Knight, perfected by Mr. Michel. How produced. Polarity owing to the earth's rotatory motion. The electric fluid, and the matter of heat, and magnetism gravitate on each other. Magnetism being the lightest is found nearest the axis of the motion. Electricity produces northern lights by its centrifugal motion 193
Acids from vegetable recrements. Flint has its acid from the new world. Its base in part from the old world, and in part from the new. Precious stones 215
Diamond. Its great refraction of light. Its volatibility by heat. If an inflammable body. 228
Fires of the new world from fermentation. Whence sulphur and bitumen by sublimation, the clay, coal, and flint remaining 275
Colours not distinguishable in the enamel-kiln, till a bit of dry wood is introduced 283