680 



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. 



