The other defects belong to the inherent nature of the varnish as at present manufactured, and admitting the secondary cause to be atmospheric influence, it is necessary to inquire why it is that varnish should be subject to such influence. According to the usual way of making varnishes, we know that various metallic salts and chemical compounds are used to increase their drying properties. All these will contain a certain definite amount of water, termed “water of crystallization.” If deprived of this water they lose their crystalline form, but they acquire a tendency of again assuming it by attracting to themselves a proportionate amount of water when it is brought within their power. Now the heat employed in making varnishes is sufficient to expel this water; but the presence of the salts is sooner or later detected, for when the varnish is applied to the work these salts absorb moisture from the atmosphere, and by becoming partially crystallized cause what is known as “blooming,” “spotting,” and “pin-holing.” The tendency to bloom will always remain, even after the varnish has hardened. But if any of these effects take place in the varnishing room, while the varnish is drying, it will be fatal to the appearance of the carriage. To insure as near perfection as possible we want a substitute for these objectionable driers, which will not be subject to atmospheric influence. CHAPTER XII. ORNAMENTAL PAINTING. MONOGRAMS. At the present time nearly all possessors of carriages have their private marks painted on some part of the panels. These take the form of monograms, initial letters, crests, and heraldic bearings or coats of arms. The monogram is the commonest. For crests and coats of arms a duty is levied, from which monograms are free. A few examples are subjoined. They can be multiplied to any extent; and designing monograms and initial letters would be excellent practice for the apprentice. [Illustration: Fig. 33.—V. A. C.] Fig. 33.—Lay in C with dark blue, light blue, and chrome yellow, No. 2; lighted with A to be in Tuscan red, lighted with vermilion and orange; V with olive green, lighted with a bright tint of olive green and white. Separate the letters with a wash of asphaltum. [Illustration: Fig. 34.—I. N. C.] Fig. 34.—Paint C a tan colour shaded with burnt sienna, shaded with asphaltum to form the darkest shades. Put in the high lights with white toned with burnt sienna. Colour I with dark and light shades of purple, lighted with pale orange; N to be lake colour lighted with vermilion. The above may be varied by painting the upper half of the letters with the colours named, and the lower portions in dark tints of the same colour. When this is done, care must be taken to blend the two shades, otherwise it will look as if the letters are cut in two. [Illustration: Fig. 35.—O. T. S.]