The fallen tree in the forest is slowly consumed by it, not less surely than the flaming wood and coal in our stoves. The human body is a furnace. In the minute corpuscles[7] of the blood, carbon is uniting with oxygen as certainly as are the particles of carbon in the flame of our lamps.
Oxygen is the scavenger that partially cleans our gutters. It is a bird of prey that devours the offal in our fields and woods. It is nothing less than the gnawing tooth of old Father Time himself, which crumbles cities and destroys all things.
Combustion, as we now know it, consists simply in the union of some combustible material with oxygen. The generic term for all this action is “oxidation.” For convenience, special names are given to particular modes. When metallic oxidation occurs we call the product “rusting.” When oxygen unites with vegetable matter we call it decaying or rotting; when with animal substances we term it rotting or putrefaction. When flame is produced, the word combustion or burning is used. The amount of heat generated is, in all cases, proportioned to the amount of chemical action. Great ingenuity and skill have been shown in the discovery and utilization of materials best calculated to combine readily with oxygen. To these, as a class, has been applied the term
HYDRO-CARBONS.
All substances composed essentially of the elements, hydrogen and carbon, would come under this designation. These would include coal, wood, petroleum, the fats, resins, wax and many others, with some of the gases, among which may be named light and heavy carburetted hydrogen, CH₄ and C₂H₄ respectively.
PHOSPHORUS BURNING IN OXYGEN.[8]
In the days of our grandfathers tallow candles were almost universally employed for lighting houses, and wood for warming them. It would not be impossible to find even now, in our own country, homes illuminated (?) by a rag burning in a saucer of fat. Some of us are not too young to remember the bundle of candle-rods—nice, straight sticks used in dipping candles—snugly put away for that purpose, alas! sometimes summoned forth to assist in enforcing family discipline!
GREEN FIRE COLORED BY A SALT OF BARIUM.[9]