Page:Popular Science Monthly Volume 88.djvu/299

 Popular Science Monthly

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��Hotel Keys Which Take the Place of Shouting Call Boys

NO longer will hotel clerks have to "page" the corridors, lobbies and bars when a visitor asks for a guest who cannot be found in his room. It will only be necessary to take the key which Mr. Jones has left at the desk, and after a glance say, "^Ir. Jones may be found in the grill room."

The labor-saving device which will make this possible is a novel key tag which has recently been patented by a Chicago inventor. The tag, on which the num- ber of the room is stamped, is oval, and is imprinted with a clock face. By means of a pin in the center of the tag the key may be fastened so that it will act as the clock hand, indicating the approxi- mate time when the user expects to re-

���This key tells where to look for missing guests, when a pin is inserted to indi- cate the place where he can be found

��turn. On the outer edge of the tag are a series of small holes. Near these are stamped the names of the various public rooms of the hotel. Another pin is at- tached to the tag by means of a light cord or chain, and this may be placed in any of the holes, indicating the place where he may be found.

Water That Cannot Be Cut

A FACTORY in Grenoble, France, utilizes the water of a reservoir sit- uated in the mountains at a height of two hundred yards. The water reaches the factory through a vertical tube of the same length, with a diameter con- siderably less than an inch, the jet being used to move a turbine. Experiments

���A stream of water under high pressure will

break the blade of a sword if an attempt

is made to cut it

have showed that the strongest men can- not cut the jet with the best tempered sword; and in some instances the blade has been broken into fragments without deflecting a drop of the water, and with as much violence as a pane of glass may be shattered by a blow from an iron bar. It has been calculated that a jet of water a small fraction of an inch in thickness, moving with sufficient velocity, could not be cut by a rifle bullet.

The engineers of some big water pow- er projects of the Far West are willing to wager that a two hundred pound man, swinging a four-pound ax with all his might, cannot make a "dent"' in the wa- ter as it emerges from the nozzle at the power house. Burying an ax in a stream of water looks like child's play, and the average two hundred pound visitor is likely "to bite." He invariably loses. So great is the velocity of the water emerg- ing from the nozzle in these modern power plants that an ax. no matter how keen its edge, is whirled from the hands of the axman as soon as it touches the water. The water tra\els under a pres- sure exceeding 500 pounds to the square inch in many instances, and no power on earth can turn 'it off at the nozzle, once it gains mometum. It has the same ef- fect on one's fingers as a rough emery wheel, and will shave a plank with the nicety of a razor-edged plane. When, as frequently happens, it is necessary to shut down a power plant operated by one of these streams, the nozzle is de- flected by means of a powerful set of gears.

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