MOUTH GLUE affords a very convenient means of uniting papers, and other small light objects; it is made by dissolving by the aid of heat, pure glue, as parchment glue, or gelatine, with about one quarter or one-third of its weight of coarse brown sugar, in as small a quantity of boiling water as possible; this, when perfectly liquid, should be cast into thin cakes on a flat surface _very_ slightly oiled, and as it cools cut up into pieces of a convenient size. When required for use one end may be moistened by the mouth, and is then ready to be rubbed on any substances it may be wished to join; a piece kept in a desk or workbox is exceedingly convenient. PASTE is usually made by rubbing up flour with cold water and boiling; if a little alum is mixed before boiling it is much improved, being less clammy, working more freely in the brush, and thinner, a less quantity is required, and it is therefore stronger. If required in large quantity, as for papering rooms, it may be made by mixing one quartern of flour, one quarter pound of alum, and a little warm water; when mixed, the requisite quantity of boiling water should be poured on whilst the mixture is being stirred. Paste is only adapted to cementing paper; when used it should be spread on one side of the paper, which should then be folded with the pasted side inwards, and allowed to remain a few minutes before being opened and used; this swells the paper, and permits its being more smoothly and securely attached. Kept for a few days, paste becomes mouldy, and after a short time putrid; this inconvenience may be obviated by the use of— PERMANENT PASTE, made by adding to each half-pint of flour-paste without alum, fifteen grains of corrosive sublimate, previously rubbed to powder in a mortar, the whole is to be well mixed; this, if prevented from drying, by being kept in a covered pot, remains good any length of time, and is therefore convenient; but unfortunately it is extremely poisonous, though its excessively nauseous taste would prevent its being swallowed accidentally; it possesses the great advantage of not being liable to the attacks of insects. LIQUID GLUE.—Several preparations under this name have from time to time found their way into use. The liquid glue of the shops, however, is a totally different preparation, being inodorous, and very much cheaper. It is made by dissolving shell-lac in water, by boiling it along with borax, which possesses the peculiar property of causing the solution of the resinous lac. This preparation is convenient for its cheapness and freedom from smell, but it gives way if exposed to long-continued damp, which that made with naphtha resists.