"No, boys, not any thing of that bird; but I was thinking last night of the work done by several other kinds of birds, some of them quite as good workmen as our little tailor; and I thought that, perhaps, you might like to hear of them." "We would, Uncle Philip, be very happy to hear of them, if you will have the kindness to tell us about them. But what kind of work is it they do?" "Various kinds, boys. There are some which make what is called _felt_, just as the hat-maker does; and some are weavers, others basket-makers; some build platforms to live on; and I assure you some birds' nests are as curious as any of the things of which I have yet told you." "Pray let us hear of them, Uncle Philip." "Very well, you shall. I will begin with birds that make felt like the hatter. Do you know how a hat is made?" "Not exactly, Uncle Philip; but we know what it is made of." "What is it, boys?" "Of sheep's wool, and the hair of other animals: is it not?" "Yes, commonly of these things; and to understand what I am going to tell you, I think it will be necessary first to say something about the hatter's trade. The business of the man who makes a hat is to mix up wool or hair in such a way that it will stick together and make felt; or something like a piece of thick, strong cloth. To do this, he does not weave the hairs together, for they are of different kinds, and of different lengths, and it would be endless work to weave every one in; besides the cloth or felt would not be thick enough when it was done." "How do they stick together then, Uncle Philip?" "Why, boys, their sticking together is owing to something in the hairs themselves. I will show you. Pull a hair out of your head; now hold it just between the ends of your two fore-fingers, and rub the fingers gently against each other." "Why, Uncle Philip! see, the hair is moving towards my body." "Very true; and if you will turn it with the other end towards you, and rub your fingers as before, you will see it move from your body." "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." [Illustration: Hairs of (_a_) the Bat, (_b_) the Mole, and (_c_) the Mouse.] "These are strange-looking hairs, Uncle Philip."