"In the refinery this coarse oil separates into avariety of different substances. There is first of all the clear liquid commonly called paraffin oil, for burning in lamps.
"That which is obtained from petroleum or rock- oil is called kerosene.
"Then, besides this, there is a beautiful, fine, white substance like wax, which is known as solid paraffin, and is largely used in making candles.
"Lastly, that which is left forms a rough coarser kind of oil, which is used for oiling machinery.""Teacher explained to us how the paraffin oil burns in a lamp," said Willie. "The porous wick absorbs the oil, and the heat of the flame makes it evaporate. It is not the oil itself that burns, but the gas or vapor from it, just as the ordinary coal-gas burns in our gas-burners.
"Teacher showed us that the oil itself will notburn. He thrust a burning match into some of it ina saucer. The oil did not take fire. It actually put outthe match.
"He told us that it is only when paraffin is allowed to get heated that there is any danger. When it is heated it gives off this gas, and the gas is very explosive when mixed with air.
