THE TRUE EXPLANATION.
We shall here confine ourselves to the consideration of the heat and light produced by chemical action. It will be remembered that by this term (chemical action) is meant the process of uniting two or more different elements to form a compound different from either. We usually consider air essential to combustion, but this is not necessarily the fact. Gold foil or powdered antimony, dropped into a jar of chlorine, spontaneously ignites. Even in the interior of the earth, heat must be produced by the uniting of any elements that have an affinity for each other.
BORACIC ACID IMPARTS A GREEN COLOR TO THE FLAME OF ALCOHOL.[6]
The most common agent of combustion is oxygen. Of this interesting gas some description has been given in a preceding article. It is the fruitful source of almost all of our artificial heat.
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