Men in civilized lands do not put the skins of other animals upon their own bodies, but they do what is precisely the same thing in effect. They borrow silk from the worm, or cotton from the grass, or flax from the linen-plant, or wool from the sheep, and by their constructive skill, they spin and weave these substances into cloths, which are much more convenient than raw skins for the fabrication of garments, and which can be made as warm, when this is required. In every case, however, this artificial clothing acts in the same way as natural fur. It is warm, because it prevents the heat, which is produced in the slow furnace within the body from escaping quickly from the little chambers of the living laboratory. Clothing does not really warm the body, it merely keeps it warm; prevents it from being cooled as it would be if this covering were not placed between its surface and the outer air. Warm bodies constantly grow colder, when situated in spaces which are more chill than themselves, provided always that there be no furnaces, quick or slow, within them, for generating new supplies of heat. They do so, because they give the excess of heat which they contain to the neighboring space, in the attempt to make it as warm as themselves. Warm bodies are always very generous, and disinclined to keep what substances near to them are less freely supplied with. If a metallic pint pot, filled with boiling water, be placed on the ground in air which has only the warmth of a March English day—some fifty degrees of the heat scale,—the water gets colder minute by minute until it remains no warmer than the air and ground which are around it. The rapidity with which warm bodies are cooled depends upon how much colder than themselves the space around them is. If one pint pot of boiling water be placed in out-of-door air that is cold as freezing water, and another be placed at the same time in a room where the air has the warmth of a mild summer day, the former will be deprived of all its excess of heat much sooner than the latter. Warm bodies lose their excess of heat in two ways. They shoot it off into surrounding space. This is what learned men call “raying” or “radiating” it away. The sun, you know, shoots or rays its heat off to the earth, and so does the fire to your body when you stand before it. But warm bodies also communicate their heat to substances which touch them, provided those substances be colder than themselves. Place your hand upon a cold metal knob, and you will feel that your hand grows colder as it gives portions of its heat to the knob. This is what learned men call “conveying” heat. [To be concluded.] A TOUR ROUND THE WORLD. By MRS. MARY LOW DICKINSON. [Continued.]