the method of working up hair or wool into a species of cloth, independent of either spinning or weaving. Felting in Britain is not much practised, excepting in the manufacturing of hats; and as the generality even of those who are employed in making them, are unacquainted with the principles on which they act, a few observations on the method of felting, may, to such, be both useful and agreeable.

If wool, the hair of a rabbit, hare, beaver, or human hair, be examined with a microscope of the greatest magnifying power, the surface of each hair appears perfectly smooth, or if any inequalities are observed, they do not appear so much to arise from an irregular surface, as from some peculiar difference in the colour and transparency of the substances examined; for if their image be viewed by a solar microscope, it terminates in even lines, without the smallest vestige of any roughness. Yet nothing is more evident than that the surfaces of hairs are not perfectly smooth, but either composed of lamellae covering each other, from the root to the point, resembling the scales of fishes; or what some have deemed more more probable, of zones placed over each other, similar to the structure of horns; and to this texture hair, wool, &c. owe their disposition for what is denominated felting.

Let a person take hold of a hair by the root with one hand, and draw it between two fingers of the other, from the root towards the point, he will scarcely perceive any friction, or hear any sound; but should he hold the hair by the point, and draw it between his fingers from the point towards the root, he will feel a sensible opposition or resistance which could not be felt before. A sort of tremulous motion is likewise produced, which can be distinguished by the ear. From this simple experiment it is obvious that the texture of the surface of a hair is not the same from the point to the root, as it is from the root to the point. If a hair is taken hold of by the fore-finger and thumb, and rubbed in a longitudinal direction, a progressive motion is the result, which is invariably towards the root. This is wholly independent of the texture or nature of the skin of the fingers; for if the hair be turned, and the point of it placed where the root formerly was, the movement becomes contrary, or, in other words, it is still directed towards the root.

It is found a very difficult task to unite a knot made in the middle of a hair, on account of its extreme thinness; but if the hair is placed in the bend of the hand, the knot being in a line with the little finger, and if the hair is grasped by closing the hand, and the fist struck several times against the knee, the knot is thereby opened, because the apertures of one end of the hair are in a contrary direction to those of the other, by which means each end of it recedes a little. By the introduction of a pin into the eye thus formed at the knot, it is easily united. Although these observations have a direct reference to long hair; yet they are equally applicable to wool, furs, and almost every species of animal hair. The surface of all these consist of hard lamellae, placed upon each other like tiles, in the direction from the root to the point.

By attending to these remarks, it is easy to see why the contact of woollen stuffs is rough to the skin. The apertures on the surface of the fibres of wool produce a disagreeable sensation, by fixing themselves in the skin, which can only be endured by being accustomed to feel it frequently. The injury done to wounds by the application of wool, is not the result of any chemical property, but is entirely occasioned by the apertures of its surface.

A hatter separates the hairs from each other, by striking the wool with the string of his bow, causing them to spring up in the air, which fall on the table in every possible direction, forming a layer of a particular thickness, which is covered by the workmen with a cloth, pressing it with his hands, and moving the hairs backwards and forwards in different directions. In this manner the hairs are brought against each other, and their points of contact considerably multiplied, and the agitation gives each hair a progressive motion towards the root, in consequence of which the hairs become twisted together. As the mass becomes compact, the pressure ought to be increased, in order to keep up the progressive motion and twisting of the hairs, which is then performed with greater difficulty.

The hair designed for the manufacturing of hats is always cut off with a sharp instrument, and not pulled out by the roots, because the bulb of the hair which would come out with it in the latter case, would render the end which was fixed in the skin very obtuse, and nearly destroy its disposition to unite with the adjacent hairs. But in addition to the tendency of hairs to move progressively towards the root, they should not be straight like needles, for in this case they could not produce any compactness in the stuff. The fibres of wool having naturally a crooked form, that substance is well adapted to the operation of felting. The hair of beavers, rabbits, hares, &c. being straight, it cannot be employed in felting by itself, till it has been subjected to a previous preparation, viz. rubbing and combing on the skin, the brush being dipped in a solution of mercury in nitric acid. This substance, by acting only on one side of the hairs, gives them the disposition to felting which is natural to wool.

When it is not intended that the hairs shall enter into the body of the mass, but serve only as an external coating, which is sometimes given to the outer surface of hats, the operation with the nitric acid need not be performed. They must be uniformly spread upon the surface to which the coating is to be applied, and being covered with a cloth, it is pressed with the hands, and agitated for some time. They receive a particular direction afterwards by means of a brush, and are enabled to keep it by having a hot iron passed over them. Woollen cloth is thickened by fulling, on the same principles that wool and hair become capable of felting.

FELT-Spar, FELD-Spar, or FEL Spar, a mineral substance. See MINERALOGY Index.