Page:Popular Science Monthly Volume 92.djvu/47

 Popular Science Monthly

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��the gunners would have to depend upon the gun's telescopic sights, and there would be no checking up of hits or misses by the spotters in the mast tops.

Thus, the means of communication is the crux in the modern method of pointing and firing a battleship's guns. In our Navy, voice tubes are generally preferred to electrical apparatus. Speaking tubes are just metallic pipes made airtight.

��Why Do You

Laugh When You

Are Tickled?

ALTHOUGH it .is usually done in fun, the habit of tickling is supposed to be a somewhat danger- ous one, according to physicians. The ticklish areas are lo- cated over the least protected parts of the body, where delicate vital or- gans are to be pro- tected. The reason for the ticklishness is that the skin is highly sensitive there and "aware" of intrusion, as a means of protec- tion from possible injury.

This sensitive- ness, or awareness, the physicians say, is a relic of the days when man's pre- historic ancestors had to guard their lives constantly against creeping insects and the hea\-y' penetrating pressure of animals' teeth. That is why, according to this theory, the tickle reflex is elicited prin- cipally by a light running motion over the skin, and by sudden prods.

The reaction, in this age, is a \'iolent discharge of energy in the form of laugh- ter and efforts to be free. But it is easy to imagine the shrieks of terror or pain that might have been the forerunner of the laughter. Humanity takes ages to outgrow its prehistoric impulses.

���The highly compressed gas in the "bomb," on being let out through the "buoy," forces out the combustible oil with it

��The Liquid Fire of the Trenches Is Not as Deadly as It Looks

THE effect of jets of liquid fire on men in the trenches is more terrible to the eye than to the body. But despite this fact, it is still used as a weapon. The bulky, rectangular tanks found in the original outfits have been replaced by the less cumbersome and more efficient "life buoys" and "bombs" of the lat- est flame projec- tors. In operation, the Germans let out the gas under compression, so that it forces a stream of combus- tible oil from the buoys through a connecting line of hose. The oil, which travels fast under the great pressure, passes a lighted wick in the nozzle of the hose. The burning jet is then direct- ed toward the enemy.

But improve their apparatus as they may, the Ger- mans have no con- trol over the ac- tion of the air. By lying flat at the rear of their trenches, the men, being attacked, are in little danger. It is the German soldier who has suffered most from fire. The British, in self- defence, have combated liquid fire with the flaming shell. This, as explained in the October issue of the Popular Science Monthly, does not ignite until it hits the ground. If the guns are pointed so that the shell strikes just in front of the trenches, both flames and debris will shower over the enemy troops. Moreover, the British have found that by firing at the enemy's tanks, these are often exploded, killing their operators in the action.

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