marries or dies. He is an obscure man. He may grumble sometimes to his wife, but he does not frequent the grocery, and he does not talk politics at the tavern. So he is forgotten. Yet who is there whom the statesman, economist, and social philosopher, ought to think of before this man? If any student of social science comes to appreciate the case of the Forgotten Man, he will become an unflinching advocate of strict scientific thinking in sociology, and a hard-hearted skeptic as regards any scheme of social amelioration. He will always want to know, Who and where is the Forgotten Man in this case, who will have to pay for it all?
"Certainly there is no harder thing to do than to employ capital charitably. It would be extreme folly to say that nothing of that sort ought to be done, but I fully believe that to-day the next most pernicious thing to vice is charity in its broad and popular sense."
By M. R. RADAU.
IN a former article we endeavored to elucidate some of the principles which have been developed from the later researches and experiments on the relations of our clothing with the atmosphere (see "Popular Science Monthly," October, 1883). The house, also, may be regarded as a kind of clothing, as a large and ample garment, designed to regulate our relations with the surrounding medium, and to deliver us from its tyranny, but not to isolate us. It ought not to deprive us of air, though that point is too often forgotten. Fortunately, no voluntary prison is so tightly calked up that air from out-of-doors does not find entrance without our perceiving it. The fact that water will readily penetrate a wall or ceiling is known to all, for they can see the spots it makes; but the air that passes through walls is not seen, and so we imagine that it does not penetrate them. This is a mistake. Walls would not prevent us from being in communication with the outside air, even if no cracks were left around the doors and windows. If water can find a way through them, what is to hinder a subtile gas from doing the same? The porosity of walls is very far from being an evil; and we shall shortly see that it is necessary to prevent houses being damp.
A very simple experiment by Dr. Pettenkofer illustrates the permeability of building materials. He took a cylinder of dry mortar twelve millimetres (4·7 inches) long and one third as thick, and waxed all of it except the ends, in which he fastened two glass funnels, one of which was extended by an India-rubber tube, while the other terminated in a very fine orifice. Blowing through the India-rubber