Page:Popular Science Monthly Volume 88.djvu/38

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IDEWALK shelters for trolley patrons are to be built at the junctions of the principal trolley lines in the city of Cincinati, Ohio. One of these structures has already been erected at a point where ninety per cent, of the trolley cars of the city pass.

The innovation has received such general approval that the experiment is to be extended. Smaller sheds are to be built at several other points where trolley patrons congregate to board the cars.

The shelters are of metal of the umbrella or mushroom type, the characteristic of which is that the supports are in the middle of the shelter where the least number are required, so that little or no obstruction to the stream of pedestrians is offered.

HOMAS A. EDISON has recently been granted a patent on a phonograph diaphragm which will record only faint sounds, excluding those of any great intensity. Cork or a similar material is used. Faint sounds cause the diaphragm to vibrate only slightly; greater vibrations, caused by loud sounds, are restricted by a small cylinder and plunger working on the principle of a solenoid.

N artificial rain storm has been devised by Charles N. Swanson, superintendent of car shops of the Atchison, Topeka and Santa Fe Railroad, as a means of testing the roofs of new cars and repaired cars before they have been put into service to make sure they are rain proof. The apparatus consists of a spraying device which throws a very large quantity of water controlled from a little house at the side of the tracks. The cars to be tested are hauled under the spray twice. The cars are then entered by the inspectors and all evidences of leakage are chalked for the guidance of the repair men. When the cars have been through the repair shops they are again subjected to the rainstorm test before they are put into service. The volume of water is so great that it is possible to locate leaks in the side sheathing or ends of the cars.