The pipes which are used for carrying off heated air, and which are placed above gas-burners, are too often allowed to pass between the ceiling and the floor above without any regard to the obvious danger incurred. The various close stoves which were introduced to public notice at the time when the price of coal was suddenly doubled, although no doubt economical, are not so safe as the old form of kitchen range, which many a careful housewife has likened to a cavern. The whole of the air which rises through the flue of a closed stove actually passes through the fire, and thus attains a very exalted temperature. In the old stoves, on the other hand, the hot air is always largely diluted with that which is attracted to the chimney from all quarters. It is evident therefore that the chances of fire in the flue of the former are much greater than in that of the latter. Theatres may be said to combine within their walls all the risks which we have as yet alluded to, for they represent factories where work of a most diversified kind is carried on, and where both open and closed fires are in constant use. At pantomime time especially, the number of persons employed in the various workshops of a large theatre is to the uninitiated quite marvellous. Carpenters and 'property-men' (those clever workmen who can make everything from a bunch of carrots to a parish pump) represent a constant source of danger from fire, in that they deal with inflammable material, and require the aid of heat for their size and glue. It is obviously important in a little kingdom where all is make-believe--where the most solid masonry is wood and canvas, where the greenest trees are dry as tinder, where even limpid streams are flimsy muslin, nay, where the moon itself is but a piece of oiled calico--that there should be no mistake about the reality of the precautions against accidental fire. In most theatres, rules are in force of the most stringent character, extending even to such details as clearing so many times a day the accumulated shavings from the carpenters' shops. If such a sensible law were enforced in other places besides theatres, it would be a preventive measure of very great value. Shavings are perhaps the most dangerously inflammable things to be found about a building. A block of wood is a difficult thing to set on fire; but when reduced to the form of shavings, a mere spark will turn it into a roaring fire. The same thing may be said in a minor degree of a lump of iron, which when reduced to filings can be burnt in the flame of a common candle. It is often this difference of bulk which will decide whether a material is practically inflammable or not. Paper affords another example of the same principle; tied tightly in bundles it may smoulder, while in loose sheets its inflammability is evident.