Page:Popular Science Monthly Volume 40.djvu/592

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574

��THE POPULAR SCIENCE MONTHLY.

��as much game as possible, which is to be given to his father-in-law. The latter dresses the meat and invites the whole tribe to a feast. Then he and his family in their turn go hunting, and present the game they have obtained to the young man's fa- ther, who gives a feast to the whole tribe. At this time the girl's father returns all the payments he has received to the young man's father. For a number of days the couple live with the girl's family. When the young man goes to reside with his wife he asks all his friends to support him, and they give him presents of food and clothing. The lat- ter he puts on, one suit on top of the other, goes to his father-in-law, and gives him all the ^ property he carries. The latter dis- tributes this property among the whole tribe according to the contributions every one has made. Then the young couple re- move to the young man's family ; and before leaving her father's house the bride is fitted out with presents in the same way as the young man was when he came to reside with her family. This is a present to the young man's father, who also distributes it among the tribe."

Some Cliaracteristics of Waves. — The

friction of the wind upon the sea-surface, the convulsions of deep-seated earthquakes, and the attraction of the heavenly bodies, give rise to three different kinds of sea- waves. If the wind blows directly parallel to the sea-surface, says a writer in Cham- bers's Journal, the friction may cause an ocean - current without wave - disturbance. As a rule the direction of the wind is in- clined to the sea-surface, and its immediate effect is to produce a depression, which re- lieves itself by means of a wave to leeward and another to windward. This latter ele- vation is opposed by the wind, and gradu- ally dies away, while the leeward wave is correspondingly accelerated. Each undula- tion shelters the water under its lee from the wind, which consequently impinges up- on the sea a little in advance of the newly formed wave ; and thus we get a series of parallel ridges and hollows, provided the wind remain steady in direction and inten- sity. There is no necessary connection be- tween the advance of a wave and the for. ward movement of the water composing it,

��as may be seen by running the fingers along the keys of a piano. An inverted ware travels along, but the keys merely move up and down. Similarly, a wave may often be observed running along the ripe ears of golden grain ■while the stalks are firmly rooted in the soil. The onward progress of a sea-wave is easily perceptible, and by watch- ing some light substance floating on the sur- face the fact is revealed that the water is not moving with the same velocity as the advancing wave. Should the wind direction suddenly change, a new series of waves will be generated, and cross -seas soon confront the mariner. Hence it is that in a cyclone, or revolving storm, where the wind is fre- quently changing, there are high waves roll- ing along from various directions, each as distinct as the ripples in a river, which cross one another without swerving from their course. Waves become short and abrupt in shallow water, and are far more dangerous to shipping than the long, regular billows of the ocean. It is probable that the great- est slope of a wave in open waters does not exceed thirty degrees, and frequently not more than fifteen degrees. Waves raised by the friction of the wind upon the water are relatively superficial. In heavy gales, however, lower depths become troubled, and the undulations more and more imposing. Occasionally an exceptionally large solitary wave is met with, advancing in awe-inspir- ing grandeur, its white crest towering high above all its fellows. Such ocean giants may be due to the fact that the elevations of se- ries of waves having different lengths hap- pen to coincide ; or may be caused by squalls of wind, which are sometimes as terrible in intensity as they are sudden in formation.

The Wagging of the Dog's Tall.— Prof.

Eimer, in his work on Organic Evolution, is not able to explain why the dogs of Constan- tinople erect the tail and carry it upright, while the ancestral wolf and the jackal carry it hanging down. Dr. Joseph L. Han- cock suggests, in the American Naturalist, that the reason may be found in the fact that as the dog becomes domesticated it is prone to use the tail as an organ for express- ing mental states — wagging it when pleased, dropping it between the legs when disap- pointed or frightened. The ancestral wolf

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