the grain of the wood is raised by the atmosphere, a coat of filler is put on every part in the same manner as the body, wiping it well with rags, being careful to coat the bottom of bars and tread of wheels, for this material is a bar to all dampness, and will thus render the work more durable. This preliminary coat is not properly the priming, for it is put on to prevent the grain of the wood from absorbing oil and dirt from the smith's hands, and to prevent the rims or felloes from swelling with the water used in putting on the tires. When the ironing is completed, every part of the wood is sandpapered and filed down until nothing but clean wood and iron are seen, and every trace of filler is removed from the surface—for the preliminary coat has fulfilled its mission.
The preparation of the gears at this stage is the main operation, for if they are well done, but little labor remains to be accomplished. The priming is now in order, and going over every part with the filler in the same manner as at first, this is soon ready for standing aside to dry. The wood pores are sealed up, the surface of the wood has a thin film covering it as also the ironwork, and a more tenacious coating is not easily found. The time employed so far upon the gears has been trifling, compared to the old-fashioned method of filling up with white lead and oil.
White Lead Priming. White lead, the base or foundation, should be pure, but dealers have many means of adulterating it with sulphate of baryta, or barytes, gypsum, or plaster of paris and carbonate of lime, or common chalk, all of which are detrimental. Linseed oil, the purest raw oil, should be used, but this is often adulterated with fish oil or cotton-seed oil. The next requisite is pure black, in order to form a gray or lead color. With these ingredients the priming is formed. The white lead is beat up with the raw oil until of paint-like consistency, then a little of the black is added to form a clean lead color. Some add driers, such as brown japan or japan gold size, but many
