The above-mentioned phenomena are the result of that same long-hidden property, and which is nothing more than a certain clothing or covering, entirely surrounding the stem of every hair, in the form of very minute scales, so very minute, indeed, that it requires the aid of a very powerful microscope to enable the beholder to discern them, and even then but faintly. These scales, which cover thickly every filament of animal hair, wool, fur, &c., are thin pointed lamina, quite similar to the scales on a fish, and overlapping each other as do the shingles or slates upon a house. This state of the hair being understood, the _modus operandi_ of the above examples may be thus explained: When the hair was held by the point, it was easily cut by the edge of the razor entering under the scales; but when held by the root, the instrument slipped smoothly over them; and the hair that was drawn through the fingers, when held by the point, felt rough and tremulous, from the jagged points of the scales, but smooth when drawn in their own direction. The twirling of the hairs between the finger and thumb, resulting in their travelling motion, was on account of the points of the scales catching on the fingers, in the act of rubbing, similar to the heads of wheat or barley at harvest time which school-boys put into the sleeves of their coats, and which are sure to come out at some other extremity to that at which they were put in, caused by the working of the boy's arm upon the jaggy beard or awn of the barley head. The task of counting the number of these lamina that clothe the body of these hairs, must have been both tedious and difficult, from their very minuteness and profusion. On a single filament of merino wool, as many as 2400 barbed scales, like teeth, projecting from the centre stem, have been counted in the space of one inch. On Saxony wool there were 2700, while other wools were as low as 1860, and none were found to have so few as 1000 to the inch. No vegetable wools whatever, such as cotton, &c., have any such appendage upon their fibres, and, consequently, cotton or cotton goods never shrink in the act of washing, as woollen goods do. Cotton, therefore, never can become a suitable material for felting purposes, every fibre being smooth from end to end in either direction, and in contradistinction to fur, which, though equally smooth as the cotton in one way, rebels triumphantly when irritated in the contrary direction, as already described. Mechanically speaking, cotton is smooth, solid, and triangular, whilst wool is rough, tubular, and cylindrical. The grand cause of that mysterious and curious operation called felting, fulling, shrinking, thickening, and solidifying of a fabric, whether of original loose wool, fur, or other stuff, or of that spun into yarn and woven into cloth, is the presence of these scales.