"This is very strange, Uncle Philip: the hair is smooth; how can my fingers make it move so?"
"No, that is a mistake, boys, the hair is not smooth. If some kinds of coarse hair are seen through the microscope, each one will seem to be, not one hair, but ten or twelve smaller ones, which are joined at the root, and form a hollow tube, like a straw; and sometimes it will have joints just like some kinds of grass or straw. In some sorts of finer hair you cannot see this even with the microscope; but you can feel it, as you did just now when you moved your fingers. These joints overlap one another, just as if you should take several pieces of straw and stick them into each other. I will show you some pictures of hairs as seen through the microscope, and then these joints will be plain enough."
Hairs of (a) the Bat, (b) the Mole, and (c) the Mouse.
"These are strange-looking hairs, Uncle Philip."
"Yes, they are curious; but now you may see why, when hairs are worked together, they may be made to stick to each other. These rough parts catch into each other, and hook themselves; and the more you press them or move them, the more closely you work them into one solid mass, which you cannot easily pull to pieces. Besides, you must remember that the hairs will work only one way, as you found out just now when your finger ends caught upon the little joints and moved them along. Now, suppose that a very large heap of hairs, or wool, or fur, after it is made ready, should be put upon a table, and covered with a linen cloth, and pressed down in different directions. Each hair would begin to move in the direction of its root, just as it did between your fingers, and so all would be joined together at last into one solid piece."
"We understand you, Uncle Philip."
"Then you understand, boys, the way in which a hat is made. These hairs are all worked together by the hands of the hat-maker, and to make them work more easily (for curled hair, such as wool, does not move easily) the hatter uses hot water, and dips his hat in it while he is working it. After it is done, it is died, and then put upon a wooden block to give it shape, and is ironed smooth."
"And this is the way, then, Uncle Philip, to make hats: it is curious, is it not?"