Shell gold is gold powder mixed up and placed in mussel-shells for use. It is removed from the shell by the application of water, like moist colours, and is adapted for small work and fine lines, in which latter case a quill or reed pen will be found useful. When the work is dry, the gold can be brightened with a burnisher. Saucer gold only differs from shell gold in being placed in china saucers instead of shells. Gold paint is a preparation of bronze in imitation of gold, and is usually sold in two bottles, one of powder and the other of liquid; which two ingredients, when mixed together, form the "paint," the use of which I do not recommend, as in course of time it turns black. The same objection unfortunately applies more or less, also, to the preparations of silver, which, however, are still occasionally used in illumination. Silver leaf is made in the same manner as gold leaf, and the remarks made in reference to that are generally applicable to silver leaf. Shell silver is not really silver, but an amalgam of tin and mercury prepared and placed in mussel-shells, and used with water in the same way as gold shells. Shell aluminium is a preparation of aluminium placed in mussel-shells for use, and is warranted to keep its colour without tarnishing. _If_ this be the case, it will form a valuable addition to the list of materials for illumination, as it will be the only white metal known that can be depended upon for not tarnishing. The preparation is at present a comparatively new one, but bids fair to be very serviceable. Water-mat gold size is a preparation for laying down gold leaf, _i.e._, causing it to adhere to a given surface. The mode of using it is as follows:--Take a small brush saturated with water, and thoroughly charge it with the size. With the brush so charged, trace out the required form or pattern, and upon this lay the gold leaf, pressing it lightly down with cotton-wool. When all is dry, gently rub off the superfluous gold with cotton-wool. "Burnish gold size" is a preparation for laying down the gold leaf that is intended afterwards to be burnished (_i.e._, polished with a tooth or agate burnisher). That prepared by Messrs. Winsor & Newton may be used as follows:--Place the bottle in warm water to dissolve its contents, which, however, must not be allowed to get hot, but merely be made liquid. Stir up the preparation with a hogs-hair brush, which then thoroughly charge with the mixture; with it trace out the pattern required to be burnished, then let the work dry. When quite dry, let the surface of the pattern be wetted with clean cold water, and on it (while damp) place the gold leaf. Let all get perfectly dry, and then burnish as required. When a very bright surface is wanted, two coats of the size should be used; the second being put on after the first is dry.