Page:Popular Science Monthly Volume 92.djvu/594

 578 Popular Science Monthly

Spotting the Submarine From the Using a Maxim Silencer as an Observation Balloon

��THE man who, in his youth was adept at climbing ropes, performing on the trapeze and in indulging in other acro- batic feats

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��finds limitless field for the use of his skill in this war. Here we have a French ob- servation-bal- loonist sliding down a rope from his basket to a steamer that has been towing him around. A hard day's work has just been com- pleted. He has been look- ing for sub- marines in English wa- ters, directing the work of destroyers, and otherwise acting as a lookout. It is climb around in rigging ad- justing ap- paratus, slide down ropes, strain eyes out over wide stretches of water, and operate delicate wireless apparatus all day long. The responsibility and strain are great, and it needs a man in tip-top condition and with a natural p.ptitude to do the job.

Both armies and navies of practically all the countries at war use observation balloons in great number. They are in- dispensable for finding out what opposing forces are doing. The side temporarily without balloons is blind. The observer's job is one of the least spectacular and most important in the whole of the service, and requires men fit in every way.

����Observer slides down after looking all day from a kite balloon for submarines and other hostile craft

��Automobile Muffler

F, said one western manufacturer, the Maxim silencer will deaden the sound of a gun explosion, why would it

not deaden the noise cf the automo- bile engine's exhaust ? Convinced of the sound- ness of this ar- gument, the manufacturer has just placed on the market the Maxim muffler shown in the accom- panying illus- ^.ation. ^\ hile cylindrical in shape like other mufflers, the new type has no baffle plates or per- forated disks through which the gas must be forced, so that the muf- fler is eventu- ally torn apart through the direct imping-

����New silencer for automobile engines on principle of Maxim silencer for guns

��ing pressure of the gases, to the accompa- niment of rattles, which are the automo- bilist's bane. Instead, it has two end plates with a series of non-concentric tubes between. As shown, each tube has an overlapping opening into the one of the next larger diameter through which the gas may expand gradually on its way from one end of the muffler to the other. As everyone is aware, it is the sudden expansion of the hot gases under pressure, to the atmospheric pressure which pro- duces the noise. The object of a silencer is to allow them to expand so gradually that when they reach the outside aperture they are at atmos- pheric pressure.

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