maker finds it give a pearance to his paper. letter-press printer and

beautiful white apThe engraver and calico printer use

burnt alum to remove any grease from their plates, cushions, and blocks, which would prevent the ink or colour from sticking to them. The surgeon uses it in medicine, to corrode fungous or proud-flesh, and occasionally to stop the bleeding of small vessels. The tallow-chandler is glad of it, it gives his candles firmness, and a glossy appearance. The farmer finds it useful, when properly mixed with cream, in separating the butter. It may also be applied to another very important purpose that of purifying and sweetening water, which has become unpleasant to the smell, and hurtful to drink. Paper soaked in alum-water does not easily take fire, it is therefore useful for preserving gunpowder. Paper so prepared is also used in whitening silver and silvering brass. These are some of the many uses of alum; will you try to remember them?

COAL-MINES.

DID it ever occur to you, while enjoying the warmth of a cheerful blazing fire on a cold winter's day, to think of the hardships and dangers which attend the poor miners in procuring the fuel which affords you so much comfort. I think it will interest you to hear a little about the working of a coal-mine. Coal is believed to be entirely a mass of vegetable matter which has accumulated in certain situations, and has afterwards been covered over and pressed into a hard consistence under other strata, generally consisting at first of mud or sand, and hardened in time into limestone or sandstone. Coal is discovered in various parts of the world in large basin-shaped deposits, called coal-fields: but nowhere is this precious substance found in so great abundance as in Great Britain. Precious we may well call it, since it has tended to raise our country to its present

importance as a manufacturing nation. As a mere article for sale, more value has been raised from our coal-pits than from the goldmines of Peru, but it is impossible to calculate the increase of that value in the various uses to which coal is applied in our manufactories. There is scarcely a thing which we can name, to the perfecting of which coal is not in some way or other applied, from the huge ship's anchor to the pin that fastens a lady's dress. Coal-mines are reached by means of circular shafts: one shaft, called the descending or down shaft, supplies the mine with good air; the other, called the ascending or up-shaft, carries off the bad air: and this is effected by keeping a large furnace constantly burning at the foot of the ascending shaft, the heat from which, by thinning or rarifying the air, causes a constant draught and rush of foul air up one shaft, and a stream of fresh air down the other: the circulation of the pure air, so necessary to life through the narrow lanes and windings of the coal-mine, has further to be secured by means of trap-doors, or valves, placed in