The ordinary atmospheric influences of our climate, sun, frost, dust, rain, and mud, all exercise a deteriorating influence on the vehicle. The general temperature most congenial to the durability of the carriage is that of the workshop in which it is constructed. In atmospheric air containing a certain amount of moisture, wood possesses a certain standard of bulk. If it be subjected to the influence of an atmosphere containing a greater amount of moisture it increases in bulk, or, as it is popularly termed, it swells; in a drier atmosphere it shrinks and is apt to crack. To resist these evil influences all the wood used in carriages is well covered with paint, the surface of which will resist moisture. If this operation is well and carefully done it is very successful, but woe betide slop-work, though in no trade is there so little room for a scamping workman to flourish. The result of bad painting is that moisture sooner or later finds its way into the wood and spoils the glossy appearance, and if it be placed in a very dry situation the panels will split, just as ships’ decks would leak if not wetted several times a day during the heat of the sun. This might be applied in a modified degree to carriages, more especially to the wheels. If due allowance be made for expansion and contraction, the metal-work of carriages, as springs, suffers very little from heat or cold, but moisture is apt to work a very destructive influence upon it, especially where the paint is worn away by friction. There the rust seizes hold of it and gradually insinuates itself beneath the whole covering of the paint, which strips off in flakes. Beneath the surfaces of the spring-plates also rust is continually working damage, and disfiguring the appearance with dirty brown lines of oxide of iron on the exterior. Brass and plated work also are considerably affected by damp.