Having thus noticed the method originally practised, and the chief variation in the method now employed, we shall pass on to the manner of proceeding with the work to be japanned ; the first in order will be the Priming.—The priming is a composition of strong size and whiting. The size should be of a consistency between the common double size and glue, and mixed with as much whiting as will give it a good body, so as to hide the sur face of whatever it is laid upon. But when the work is of a more particular kind, it is better to employ the glover's or the parchment size, instead of the common, and if about a fourth of isinglass be added it will be still better, and if not laid on too thick, will be much less liable to peel or crack. The work should be prepared for this priming by being well cleaned, and brushed over with hot size, diluted with two-thirds of water, provided it be of common strength ; the priming should then be laid on with a brush as evenly as pos sible, and left to dry. If the surface be tolerably even on which the priming is used, two coats of it laid on in this manner will be sufficient; but if on trial with a wet rag or sponge it will not receive a proper water polish on account of any inequalities not sufficiently filled up, one or more coats must be given it. Previous to the last coat being laid on, the work should be smoothed by rubbing it with the Dutch rushes, or fine glass paper. When the last coat is dry, the water polish should be given, by passing over every part of it with a fine rag or sponge moistened, till the whole appear perfectly plain and even ; the priming will then be completed, and the work ready to receive the japan ground, or coloured varnish. But when wood or leather is to be japanned, the latter being first securely stretched on a frame or board, and no priming is used, the best preparation is to lay on two or three coats of coarse varnish, prepared in the following manner: " Take of rectified spirits of wine one pint, and of coarse seed-lac and resin, each two ounces. Dissolve the seed-lac and resin in the spirit, and then strain off the varnish." This varnish, like all others formed of spirits of wine, must be laid on in a warm place, and all dampness should be avoided ; for either cold or moisture chills it, and thus prevents its taking proper hold of the substance oir which it is laid. When the work is so prepared, or by the priming with the composition of size and whiting before described, the proper japan ground must be laid on.
Japan Grounds.—The proper japan grounds are either such as are formed by the varnish and colour, where the whole is to remain of one simple colour, or by the varnish with or without colour, on which some painting or other deco ration is afterwards to be laid. This ground is best formed of shell-lac var nish, and the colour desired; except in the case of white, which requires a peculiar treatment, as we shall presently explain, or when great brightness is required, in which case also other means must be pursued. The following is the composition and manner of preparing the shell-lac varnish :—" Take of the best shell-lac, five ounces ; break it into a very coarse powder, and put it into a bottle that will hold about three pints or two quarts; add to it one quart of rectified spirits of wine, and place the bottle in a gentle heat, where it must continue two or three days, but should be frequently well shaken. The gum
will then be dissolved, and the solution should be filtered through a flannel bag ; and when what will pass through freely is come o0 it should be put into a proper sized bottle, and kept carefully stopped up for use. The bag may also then be pressed with the hand till the remainder of the fluid be forced out; which, if it be tolerably clear, may be employed for coarser purposes, or kept to be added to the next quantity that shall be made," Any pigments whatever may be used with the shell-lac varnish, which will give the tint of the ground desired, and they may be mixed together to form any compound colours ; but, with respect to such as require peculiar methods for producing them of the first degree of brightness, we shall particularise them below. They should all be ground very smooth in spirits of turpentine, and then mixed with the var nish. It should be spread over the work very carefully and even with a camel hair brush. As metals never require the priming of size and whiting, the japan ground may be applied immediately to them, without any other prepa ration than cleaning, except in the instances referred to below.
White Japan Grenaule.—The forming a ground perfectly white, and of the first degree of hardness, has not yet been attained in the art of japanning, as there are no substances which can be dissolved, so as to form a very hard varnish, but what have too much colour not to deprave the whiteness. The nearest approach, however, to a perfect white varnish already known, is made by the following composition :—" Take flake white, or white-lead, washed and ground up with the sixth of its weight of starch, and then dried ; temper it properly for spreading with the mastic varnish prepared in the following manner : take five ounces of mastic in powder, and put it into a propertie with a pound of spirit of turpentine ; let them boil in a gentle beat till the mastic be dissolved, and if there appear to be any foulness, strain off the solution through flannel." Lay these on the body to be japanned, prepared either with or without the priming, in the manner as above directed, and then varnish over it with five or six coats of the following varnish :—" Provide any quantity of the best seed-lac, and pick out of it all the clearest and whitest grains; take of this seed-lac two ounces, and of gum animi three ounces, and dissolve them, being previously reduced to a coarse powder, in about a quart of spirit of wine, and strain off ;L3 clear varnish." The seed-lac will give a slight tinge to this composition; but it cannot be omitted where the varnish is wanted to be hard, though where a softer will answer the end, the proportion may be diminished, and a little crude turpentine added to the gum ammi, to take off the brittle ness. A very good varnish entirely free from brittleness may be formed by dissolving gum animi in old nut or poppy oil, which must be made to boil gently when the gum is put into it. The ground of white may be laid on in this varnish, and then a coat or two of it may be put over the ground, but it must be well diluted with oil of turpentine before it is used. This, however, is a long time in drying, and is more liable to injury than the other, from its tenderness.