SPONTANEOUS COMBUSTION.
There is undoubted evidence that hay and cotton, when damp, will occasionally take fire without any external source of ignition. Cotton impregnated with oil, when collected in large quantities, is especially liable to take fire spontaneously. Numerous cases are recorded where an accumulation of cotton waste, used in wiping oily machinery, lamps, et cetera, has more than once caused fires and led to unfounded charges of incendiarism. Whether or not such organic substances as damp grain or seeds ever undergo spontaneous combustion is a question that has never been satisfactorily proven, although three French scientists—Chevallier, Ollivier, and Devergie—are authority for the supposition that the burning of a barn investigated by them was caused by the spontaneous combustion of damp oats stored in it. There have been many instances of the spontaneous ignition of coal containing iron pyrites when moistened with water. This is particularly noticeable in coal mined in Yorkshire[{50}] and some varieties found in South Wales. Phosphorus in a dry state is probably the most quickly ignited substance known. It has been seen to take fire, when touched, in a room in which the temperature was under seventy degrees Fahrenheit. Doctor Taylor, a writer on the principles and practice of medical jurisprudence, is authority for the statement that ordinary phosphorus (blue head) matches have taken fire spontaneously, as a result of exposure to the sun’s rays for the purpose of drying.