(33.) _Felting._--The felting of wool may be defined as a property depending on the curls and serrations of the fibre, by which it is allowed to move only with the root foremost, and by which it is enabled to catch and retain a hold on fibres that are near it, so as to form a web or cloth. Felting is best brought into operation by alternate pressure and relaxation, which may be produced in a variety of ways: the ancient method, and one still pursued by the Tartars, was to tramp on a mass or layer of moist unwrought wool, so as to form a coarse cloth or carpet; while the modern, and more perfect plan is, either, as in hat making, to apply pressure with the hands, or, as in the finishing of cloth, to pass the fabric repeatedly through rollers. The way in which a close fabric is formed, by the juxta-position of a few scattered hairs, gave rise for long, as well it might, to serious disputations among philosophers; and the favourite theories of each, unbased as they were on observation, might till now have agitated the scientific portion of our manufacturers, had not the microscope brought to light much of what is true and valuable in our researches. Moisture appears to be of service during the felting of wool, as it induces it to curl, enabling the fibres to expand, and catch one on another, after they have been bent and compressed, by the force applied to them, and is of itself sufficient to felt a fabric, as we frequently perceive in the instance of stockings, which have been allowed to remain too long in water, when they become short from undergoing contraction, and resemble after such treatment an imperfect cloth. It is for this reason that the hatter, after tumbling over, in all directions, the fur of which the hat is to be made, wets it before applying pressure; and, that the woollen manufacturer, after freeing the web from grease, soaps it before its subjection to the action of the rollers. Without felting, cloth would resemble a net, and would unravel on being cut, from the fibres crossing only in two directions; but the strokes of the mill put an end to this, by laying the fibres in every possible direction, and so twining them one with another, as to render them a coherent mass. (34.) _Different kinds of Wool._--The wool of this country is divided into two great classes--long and short: the former varies in length from three to eight inches, and before being made into stuffs and worsted goods, requires to be deprived of its felting tendencies, by passing it through heated iron combs, which remove the feathery parts, or serrations, and make it resemble silk or cotton.