Page:Popular Science Monthly Volume 92.djvu/536

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��Popular Science Monthly

��visibly and to drop vertically. The up- permost one is seen gliding like an air- plane itself in spite of its great weight, in spite of its comparatively small surface and in spite of the fact that it has only a belly in place of wings. The moment bombs drop from their tubes (one-third as slowly as they are swept ahead by the plane) they are swung by momentum and air pressure on their tail planes into a nearly horizontal po- sition. In that position their shape encoun- ters practically no resistance from ahead but a great re- sistance in the direction of gravity, not only because in trying to fall they must cleave the air with their big broad sides, but chiefly be- cause in drop- ping they are now opposed by the inertia of the air encoun- tered in falling, and, in addi- tion, the much greater amount of air encoun- tered in mov- ing ahead. As long as momentum continues, falling is greatly retarded, and, with practically no head resistance, it is bound to continue indefinitely. But as soon as actual falling begins, the head dips a little, aided by the tail planes. In this position the fall itself will preserve and increase the horizontal speed, just as in coasting down hill in a sleigh. If the total surface of a correctly designed bomb were not so extremely small in proportion to its weight, it would seemingly never reach the ground. Balloonists sometimes threw empty bottles from their baskets. They mar- velled at the crazy antics performed by

���Slipping a bomb into an airplane. The tail is being inserted smoothly into the discharge tube

��the bottles and the long time they took in reaching the ground. It was the ap- proximation of streamline form that de- layed the bottles.

Bombing is like torpedoing. Bombs have assumed the shape of torpedoes not to prolong their fall, a thing in it- self rather unfavorable, but because the lower winds have practically no influence

over a torpedo. Guided by its tail, the tor- pedo-shaped bomb simply turns its sharp nose against the wind and cleaves it without deflec- tion.

That is why bomb-drop- ping is more accurate than it was at the outbreak of the war. More- over, bombs are dropped on the shotgun or blunderbuss principle. In other words, they are re- leased a half a dozen or more at a time. One at least will find its mark. By releasing bombs in quick succession.

��errors in judging altitude and speed are readily corrected, because the bombs scatter principally along a line parallel with the path of the machine.

y\re You Afraid to Look at Yourself in a Mirror?

Dr. Martiri has recently found that certain patients are afraid of mirrors,

a result of watching the change in appearance as emaciation progresses. When a dyspeptic is cured his horror of looking in a mirror persists. This is called cattotrt)phobia.

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