72 



THE WORLD'S ADVANCE 



turns, pushing all the garbage that has 

 been placed on the shelf into the can. In 

 order to empty more garbage into the 

 can it is again necessary to place the 

 handle in the right position, and when 

 the lid is lifted the shelf is again found 

 perfectly clean. 



Equipment for Hygienic Ventilation 



The Chicago ventilation commission 

 some years ago came to the conclusion 

 that ventilation with cold outdoor air 

 is impracticable owing to the tendency 

 of very cold air to resist diffusion with 

 the warmer air of the room. The air 

 warmed by the radiators goes to the 

 ceiling, while the cold air falls to the 

 floor. 



A new design of ventilator just placed 

 on the market overcomes the foregoing- 

 mentioned difficulty in two ways : First, 

 by blowing the cold air to the ceiling 

 with sufficient velocity to cause it to creep 

 along the ceiling until it falls away in 

 all parts of the room, and, secondly, 

 when the weather is very cold (below 

 25 degrees Fahr.) by mechanically mix- 

 ing enough warm air to bring the tem- 

 perature of the mixture to a normal cool- 

 ness (about 30 degrees Fahr.). The re- 

 sult is that a uniform temperature exists 

 from floor to ceiling and absolutely no 

 drafts are felt; in fact, it is impossible 

 to feel that cold air is coming into the 

 room. 



The ventilator consists of a motor- 

 driven blower fitted with a combined duct 

 and mixing chamber for bringing outdoor 

 or indoor air to the blower, or a mix- 

 ture of the two sufficient to maintain a 

 comfortable atmosphere in the room. 

 When the slide in the duct is brought for- 

 ward the blower draws only cold outdoor 

 air; while on the other hand, when it is 

 pushed back, the cold air from the room 

 is recirculated. When the slide in the 

 duct is open half way the result is that 

 both outdoor and indoor air are taken 

 into the mixing chamber and passed 

 through the blower. By adjusting the 

 slide any temperature can be had at the 

 nozzle, between the outdoor and indoor 

 temperatures. The cold mixture upon 

 being blown to the ceiling, spreads out., 

 against it, and, after losing its momen- 



tum, gradually sinks through the warm 

 air and is breathed by .the persons in the 

 room. 



The ventilating equipment is operated 

 by current taken from the ordinary sock- 

 et. No special wiring is necessary. It 

 can be installed or removed in a few 

 minutes, and the placing of the window 

 board in the window frame, which serves 

 to hold it in place, causes no damage to 

 the woodwork. 



A Watch for Studying Time 



Modern efficiency methods as applied 

 to factories and shops often make it 

 necessary to study the time required for 

 different operations in the manufacture 

 of certain products. For this work it 

 is absolutely necessary to have a stop 

 watch. However, the conventional stop 

 watch leaves much to be desired for the 

 reason that, while it gives the time 

 elapsed for a certain operation, it is nec- 

 essary to indulge in considerable calcu- 

 lation for determining the output per 

 hour or day. 



A time-study watch of new design has 

 recently been evolved for the purpose of 

 eliminating all computation and making 

 it possible for an observer to read from 

 the dial the quantity desired. The cir- 

 cumference of the dial of the watch is 

 divided into 100 parts, as in the well- 

 known decimal dial, but instead of these 

 divisions being numbered in the ordi- 

 nary manner, they are marked with fig- 

 ures which indicate the number of op- 

 erations per hour, when the time of a 

 single operation is represented by the 

 elapsed time. In the instance of very 

 short operations, ten operations instead 

 of one can be timed and the figure read 

 off the dial is then multiplied by ten. 



The hand of the watch can be started 

 or stopped by pushing a lever at the side. 

 The hand can be returned to zero by 

 giving the crown a push. 



A device for counting persons enter- 

 ing street cars, which operates by means 

 of an electrical mechanism connected to 

 the steps, has recently been patented by 

 two Wisconsin inventors. 



