Page:Popular Science Monthly Volume 90.djvu/696

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��Popular Science Monthly

���How the German Aviators Land Safely at Night with their Aeroplanes

BECAUSE of the great danger in making a landing at night the aeroplane is preeminently for use only by day. On the warring fronts in Europe there are some- times flocks of aeroplanes in the air at the same time. But when the sun goes down the aeroplane goes down with it, usually, to stay in safer regions for the night.

But for all the danger connected with night flying there are many aviators intrepid enough to ven- ture forth in the dark. In fact, the problem of making a safe landing at night has been solved by the Germans in an ingenious manner.

In the center of the landing field a large, white light is placed, sunk in a pit in the ground and covered over with a sheet of thick glass to bear the weight of the aeroplane should it pass over it. Sunk in the ground at a distance of about two hundred and fifty feet from this white light are four red lights corresponding to the car- dinal points of the com- pass. Mounted on a mast or tower at some con- venient point is a wind vane. Subterranean cables lead from it to each of the red lights.

At night the central light glows con- stantly, while the red light in the direction of the wind that happens to be blowing also shows, telling the aeroplane pilot of the wind conditions where he is about to land and enabling him to make his own calculations of the field, using the two lights as a working base from which to draw his diagram.

The lights are altered every now and then to prevent enemy airmen from using them as guides.

��An aviator making a landing at night, with the white and red lights on the field below to guide him

���How the wind vane is con- nected with the red lights by means of vmderground wires

��When the Cows Go on Strike, Try Artificial Milk

ALMOST any natural product can be imitated. In the matter of food imita- tions, the original article is first carefully analyzed and its constituent elements noted. These elements are usually ob- tained from vegetables and minerals for the substitution. In fact, the science of substitution is becoming a great factor in

modern industry. In England an artificial milk is being manufac- tured which is claimed to be both wholesome and inexpensive, so that now the market is not whoUydependent upon the product of the cows. The artificial milk is made from pea- nuts, soya beans, sugar, water and mineral salts. About four hun- dred grains of potassium phos- phate or an equivalent of sodium phos- phate is dissolved in two hundred pints of water at 176 degrees Fahrenheit. Enough sugar is added to give four and five tenths per cent to the finished product. Forty pounds of meal prepared from the nuts and beans is stirred in. The solution is boiled in a steam-jacketed pan;

��then it is subjected to the operation of a vacuum pan, and lastly it is treated with a culture of lactic bacteria until the required acidity is obtained. After it is pasteurized and cooled a small per- centage of citric acid is added.

The milk thus produced may be con- densed and sold in cans, or dried and pow- dered, or sold as a liquid in bottles. The addition of nut fats will give a certain pro- portion of cream. By using sufificient lactic bacteria the product may be cultured to give a table cream or a soured mass for making cheese. A milk made from soya beans has long been in use among the Chinese.

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