Page:Popular Science Monthly Volume 90.djvu/128

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112

��Popular Science Monthly

���To the right is shown a tire which is worn out as it should wear out after journeying 10,000 miles; to the left a tire which has been worn away and some of the fabric material broken by skidding

��and the trans- verse forces applied by the act of steer- ing. Above all, it must act as a shock absorber, thereby protecting the en- gine and other parts of the car so that they may perform their work efficient- ly, protect the en- tire structure so that it may ride easily and safely. Despite all the tales that we- hear of tire costs and tire repairs, let it not be forgotten that auto- mobiling as we know it, became possible only be- cause the pneumatic tire was invented.

��What Balance Means in a Tire In order that you may be able to cope adequately and intelligently with the strains and stresses to which a tire is sub- jected and all the obstacles which it must overcome, the manufacturer has made the tire so that it is, what he calls, well balanced. In other words, he wants it to wear out in all parts at the same time — an ideal which he never quite attains. It would obviously be foolish to provide a tread so excellent that much of it would be left after the carcass had failed. It would be equally foolish to provide side walls which would outlast everything else. To balance a tire, experience is necessary. Defect after defect is removed as it appears. Ultimately, a tire is obtained which, if handled properly, will wear out uniformly. Remember that a tire is the most paradoxi- cal construction in the entire field of auto- mobile engineering. It seems ridiculous to use a substance which is so tender as rubber and yet, if we had no air-inflated rubber tire, there would be no modern, luxuriously comfortable automobile. What- ever its defects may be, the rubber tire is an astonishing construction. It must resist the entire air pressure to which it is sub- jected, the weight of the automobile and its load, the thrust of the motor, the reverse strain set up when the brakes are applied, the blows of thousands of pebbles and obstructions against the inner air.

��Will the Beefsteaks of the Future Be a Product of the Sea?

CONSIDERING the rapidly decreasing acerage which commerce and agri- culture allow to pasture lands together with the soaring prices of almost every kind of food, it does not require a very fertile imagination to conceive of a time when meat will be a luxury for the table of crowned heads and uncrowned capitalists, unless the ever-resourceful commoner, seized with a realization that three-fourths of the surface of the earth is water and prac- tically a waste as far as production of varie- ties of diet are concerned, should re-discover that the mammals of the sea are worthy of cultivation as food.

It is estimated that the meat of one sixty- foot whale, for instance, is equal to that of seventy head of cattle and tastes like choicest beefsteak in flavor, when properly prepared.

Other marine mammals which are good for food as well as for commercial purposes are the seal, the walrus, the dugong and the sea cow. The dugong has always been prized for food by Asiatics, Africans and Australians, and the sea cow formerly found in the waters of the Bering Sea, was so noted for the palatableness of its flesh, its size and for its gentle fearlessness of man that it has been almost entirely extermi- nated through man's greed.

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