The work to be gilded will require several coats of composition: the first, or priming coat, is made of size thinned with water, and a little whiting; with this the work is brushed over, using a thicker mixture when there are defects which need to be stopped. Successive coats are then laid on to the number of seven or eight, and the last, being moistened with water, is worked over and smoothed on the plain parts with Dutch rushes. After this is completed, a coating is laid on, composed of bol ammoniac 1 pound, black lead 2 ounces, ground up on the stone with 2 ounces of olive oil. This is one out of many receipts; all, however, are diluted for use with parchment size warmed up with two-thirds water, and forming what is called water gold-size. Two coats of this should be laid on; the part about to be burnished should then be again rubbed with a soft cloth till quite even, and care taken that each coat be perfectly dry before the subsequent one be laid on. The work is now moistened in successive portions with a camel-hair brush and water, and while moist covered with gold-leaf in precisely the same manner as described in the directions for oil-gilding, great caution being observed in order to avoid wetting the leaf already laid down, as a discoloration would be the result. The work is now left for about four-and-twenty hours, when the parts which are to be burnished may be tried in two or three places. Care should be taken not to let the work get too dry, as in that case it would require more burnishing, and yet not give a good result. This state is known by its polishing slowly, and if it be too wet it will peel off; but should the places where the trials are made all polish quickly and evenly, the work may then be finished; for which purpose agates cut in proper forms and set into handles, are sold at the artists' colour-shops.[121]