Page:Popular Science Monthly Volume 90.djvu/432

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��Popular Science Monthly

��the strength of the emanation in the sup- phed air at its proper value. For this pur- pose he uses an electric instrument which he reads through sighting apertures. The instrument is operat- ed by the electrically charged emanation, so that the degree of the activity is indicated by the amount the in- strument is affected. The instrument shown in the illustra- tions — an electromet- er, it is sometimes called — can measure the activity in the air to a high degree of accuracy.

Curing rheumatic ailments by the water of the now famous European springs is a treatment which has come down through

many ages. Unknown to the travelers, the success of this treatment was principally due to the action of the radium salts which were dissolved in the springs. When this fact was discovered, the idea immediately suggested itself of using ordinary liquids in which the emanations could be dissolved. The liquids could be charged at stations distributed all over the world, and the treatment made available to almost every- body. This is now actually being done and small iron tanks containing the active liquids can be ordered by mail in Europe.

���teries to a service station for recharging. But a new gas rectifier has been placed on the market which will recharge even as few as three batteries inexpensively. It consists princi- pally of a small bulb filled with nitrogen gas and contain- ing electrodes of tungsten and of graphite. This bulb screws into a socket on a panel of the ap- paratus like the bulb of an ordinary elec- tric light. The com- plete apparatus is connected with the alternating supply main, two leads on the other side of it are connected with the batteries, and a switch turns it on.

��The patient, charged to a high voltage, breathes in the electrically charged air

��A Remarkable Rectifier for Charging Batteries on Alternating Current

EVERYBODY knows that used storage batteries can be recharged only on direct current. The automobile owner whose individual garage is supplied with

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��A Burglar-Alarm for Foiling the Automobile Thief

A PROFESSIONAL automobile thief can break through locks and guards and get almost any automobile started. But one thing he wouldn't count on would be a burglar-alarm clanging with him as he dashes down the street. Such an alarm for announcing his profession to the policemen that he would pass has been invented by William Con- noly, of New York city. An electric circuit-closer is mount- ed directly under the driver's seat and the least pres- sure on it will close a circuit running to a large bell. All the parts are locked in places that cannot be easily reached, and the thief will be greeted with the clanging alarm' as soon as he takes his seat.

Pressure on the seat closes an alarm circuit underneath so that a bell clangs loudly as the thief vainly tries to get away undetected

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