Page:Popular Science Monthly Volume 24.djvu/293

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crushing of low intensity and pitch, not metallic or crackling. It occurs when the sand is pressed by ordinary walking, increases with sudden pressure of the foot upon the sand, and is perceptible upon mere stirring by the hand, or even plunging one finger and removing it suddenly. It can be intensified by dragging wood on the beach. Somewhat similar phenomena have been observed in sands at various other places. The authors explain the phenomena upon the hypothesis that the sand, instead of being, as ordinarily, composed of rounded particles, is made up of grains with flat and angular surfaces. In the present instance, the plane surface of feldspar is apparent in many of the grains. Probably a certain proportion of quartz and feldspar grains is adapted to give the sound, while less or more of either component would fail of the result. It is concluded that the sound is produced either by the intermixture of grains having cleavage-planes, or of grains with minute cavities.


Use and Abuse of Check-Reins.—Bearing-reins, or check-reins, in the harness of horses, are useful and advantageous in their places and when rightly adjusted, but the instances in which they simply torture the animals that have to endure them are more conspicuous. In crowded streets, with high-mettled horses that run freely up to their bits, a well-fitted bearing-rein gives the driver a more thorough control of the animal that is valuable in avoiding collisions. A bolting horse, says the "Pall Mall Gazette," endeavors to get his head well down, so as to extend his neck, and thereby obtain a stronger purchase against the restraint of the reins; and if he is restrained by a bearing-rein, so that he can not lower his head below the level to which he would require to carry it for ordinary equilibrium in draught, his powers of bolting are greatly circumscribed, and if he is not excessively borne up he is not conscious that the rein is restraining him, and his powers of draught are not cramped. The fashion of coachmen is, however, to pull the bearing-rein up so tight that the horse's neck is cramped, and the animal is thrown into an unnatural and painful position, and is deprived of much of his power to draw the load that is intrusted to him. His feeling must be much the same as that of a man would be whose head was pulled back so that he would have to stand for hours looking up at the sky without being able to turn his eyes away, and had while in such a position to draw a baby-carriage. The fact that the adjustment of the rein is painful can be recognized from the unnatural attitude of the horse's neck, and from his fretfully tossing his head every few minutes to relieve himself, and shake off the foam from his jaws. "This tossing of the head and flecking of flanks, brisket, and harness with foam, seem to the coachman and to the upracticed observer to be picturesque, and characteristic of high courage; to the experienced eye they betray that the animal is not only inconvenienced but is also pained by his position." Besides this annoyance, the animal thus tightly checked, being unable to throw the head reasonably forward when feeling his collar, can not utilize his natural powers of draught, and, in default of them, has to draw from the lateral purchase of his limbs instead of from his height, and thereby unduly to tire his muscles and joints and strain them; and, if he stumbles, the danger of his falling is increased. The instinct of a horse in stumbling is to let his head drop to a certain point where it helps to restore equilibrium. A rein adjusted to catch the head at that point would be helpful, but the common tight reins prevent its dropping at all, and thereby augment the insecurity of the horse.


Cultivation of the Date-Palm.—Dates are cultivated profitably in two oases of the Algerian Sahara. At the oasis of Rir, where the conditions are most favorable, an unfailing supply of water is obtained by artesian wells from a depth of about two hundred feet. The use of these wells has been known to the natives from time immemorial, but has been facilitated, and the number of them has consequently increased since the introduction of improved systems of boring by the French. Sixty-four of the wells had been bored by the French in 1878, furnishing an average of more than 1,500 quarts of water each a minute. They vary among themselves greatly in capacity, one of them