Wool in its natural state is not used for carriage purposes. In the form of “flocks,” which are the short combings and fibres produced in the process of manufacturing it, it is very largely used for stuffing. In its manufactured state wool is used in great quantities, as cloth, lace, fringe, carpeting, &c. The iron used is that known as wrought iron. To judge of its quality break a piece over the anvil; if it breaks off brittle it is of no use for the purposes it is required for. If it is good wrought iron the fracture will present a bluish, fibrous, silky texture, without any crystalline portions. Inferior iron will either appear bright and glistening (when it partakes of the properties of cast iron) or dull and greyish in tone at the fracture. It may also be tested by bringing it to a red heat and bending it, when any flaws, &c., will at once become apparent. Cast iron is also used in the shape of axle-boxes. Great quantities of wrought iron are used in the construction of modern carriages. One of the best qualities is that known as the “King and Queen,” so called from its brand. This iron is manufactured from pieces of old iron, called scrap iron, which are placed in furnaces and welded under a heavy tilt-hammer, after which it is passed between rollers and converted into bars. Steel also enters largely into carriage construction in the shape of springs, &c. Axles are made of Bessemer steel, and are found to wear very well. Steel consists of iron in which is combined a large proportion of carbon; the more carbon the higher the elasticity of the steel. If steel is over-heated, it gives up a portion of its carbon and approaches once again its original form of iron. CHAPTER IV. POINTS TO BE CONSIDERED BEFORE COMMENCING THE CONSTRUCTION OF A CARRIAGE.—COMPONENT PARTS OF THE BODY.—SMITH’S WORK.—GLUE. As previously remarked the vehicle is divided into two parts—the carriage and the body. After the drawing or draught is carefully worked out to full-size on the black-board in the shop, with all the curves and sweeps developed, and shown in elevation and plan, patterns or templates are made from the draught, and from these the construction of the body proceeds. In commencing the construction of a vehicle there are several things to be borne in mind; such as the purpose to which the vehicle is to be applied, the size of horses to draw it, and other considerations arising from these two. It is popularly believed that the shorter the carriage the lighter it will run; in ascending an incline this may be true, but on ordinary level ground a long carriage and short one must be alike in friction, provided the total amount of weight and other circumstances be equally balanced.