Page:Popular Science Monthly Volume 1.djvu/51

Rh though not more than it had given. The wheel, if questioned as to the cause of its inability, must reply as others have done, that it has shut up part of the labor in investments which it cannot realize. The reason, as commonly stated, is, that friction has destroyed part of the labor. The labor is not, however, destroyed. Science has shown that heat and labor are connected; labor may be turned into heat, and heat into labor. The labor absorbed by friction, is but turned into heat. If, however, we try to extract labor from the heat thus diffused through the different parts of the water wheel, and make it available, we find ourselves quite at a loss. The heat gradually diffuses itself through surrounding bodies, and, so far as we are concerned, the labor is wasted, though it still exist, like Cleopatra's pearl dissolved in the cup of vinegar.

If no labor is lost, so neither is any created. The labor we exert is but the expenditure of labor stored up in our frames, just as the labor invested in the wound up spring keeps the clock going. Whence, then, does all this labor originally come? We see the waste—how is compensation made? The answer is simple and easy to give. All the labor done under the sun is really done by it. The light and heat which the sun supplies are turned into labor by the organizations which exist upon the earth. These organizations may be roughly divided into two classes—the collectors and the expenders of the sun's labor. The first merely collect the sun's labor, so as to make it available for the other class; while, just as the steam engine is the medium by which the steam gives motion, so this second class is the medium by which the sun's heat is turned into actual labor.

Still, the sun does not work only through organized labor: his mere mechanical influence is very great. With the moon—the only second post he deigns to fill—he produces the tides by his attraction on the sea. But for the friction of the earth and sea, the tides, once set in motion, would rise and fall without any further effort; but the work done in overcoming the friction is, though due to the sun and moon, not extracted from them, but by them from the earth. For it would take a vast effort to cause the earth to cease rotating. All this effort is, as it were, stored up in the revolving earth. As the tidal waters, then, rub along the bed of the sea, or the waters on which they rest and the adjacent coasts, this friction tends to make the earth move faster or slower, according: to the direction in which the tidal flow is. The general effect is, however, that the friction of the tides makes the earth revolve more slowly; in other words, that part of the energy of rotation of the earth, so to speak, is consumed in rubbing against the tidal waters. All the work, therefore, that the tides do in undermining our cliffs, and washing away our beaches, is extracted by the sun and moon from the work stored up in the rotation of the earth. The diminution of rotation, indeed, is so small as scarcely to be perceived by the most refined observation, but the reality of it is now