Popular Science Monthly 



271 



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. 



