All combustion is on the same principle, previous de-electrisation the commencement, and, by the same cause continued, the centrifugal pressure, which is on the increase from being derived from the general pressure. Flame, or the electric spark, de-electrises the gases, oxygen and hydrogen, before their conversion to water takes place; compression effects the same. The inflammable air in mines becomes exploded from the de-electrising consequence of flame, when inadvertently exposed; and at times the de-electrisation is effected by the atmosphere, as in spontaneous combustion. The mine explosion, promoted by the atmosphere, is a case of spontaneous detonation, if not combustion, which, from sad experience taught, should be anticipated by the application of a rocket fired by a train. The foul air should be got rid of timely, not left to accumulate, and the weather dictates when. "The Davy" may be said to insulate the flame of the lamp from the electric matter of the air within the mine. The flame, when exposed, de-electrises the foul air, and in fluent medium of space causes the explosion. WATER. Water is the most compound of fluids, although when pure it promotes little or no sensation, which is owing to the certain proportion of its elements to each other. It seems to have, as constituents, a portion of each of the general elements; of which, when any are in excess or deficiency, the fluid differs from common pure water, but still is an aqueous fluid. All aqueous fluids which differ from pure water, do so from elementary disproportion in their constitution. Ancient philosophers considered water the parent of all things, because it contributes matter of substance and increase, they said, to all kinds of bodies, and because there is nothing elementary belonging to bodies which is not obtainable, by one means or other, from water or its productions. It contributes increase to the whole of the vegetable kingdom, and through vegetable matter to the increase of animal flesh. From the vegetable world are obtainable, by means of art, earths, metals, salts, acids, alkalies, even flame; the primitives of which are of the same kind as the initials of water; also of the atmosphere, which is convertible to water, but is not water, by reason of not only elementary disproportion, but the enormous excess of medium of space in which its elements are involved.