Popular Science Monthly 



849 



Making Your Watch Tell 

 the Whole Truth 



THE average commercial 

 traveler who journeys 

 about the United States has 

 to keep a close watch on his 

 timepiece to see that it is 

 telling the truth. There is 

 an hour's difference in time 

 when you enter and lea\e 

 some cities and it's an im- 

 portant matter that you do 

 not forget to set your watch 

 back or forward an hour, ac- 

 cording to which way you 

 are traveling. If you over- 

 look it, you may miss a 

 train. 



An express official who 

 travels almost all the time and is so busy 

 that he sometimes forgets to change his 

 watch at Detroit, Mich., for instance, or at 

 Dodge City, la., has frequently had an 

 experience of this kind. Sometimes he has 

 arrived an hour ahead of time or, perhaps, 

 an hour after a train has left, giving him 

 time enough for reflection. 



Recently, he conceived the idea of mak- 

 ing his watch tell all four different times — 

 Eastern, Central, Mountain and Pacific. 

 He went to a jeweler and had extra 

 hour hands put on his timepiece — 

 each of a different color, so that he 

 can recognize it at a glance, on the 

 face of his watch. For instance, the 

 ordinary hour-hand, set at Eastern 

 time, is silver; a blue hand, set 

 an hour back, represents central 

 time; a red hand, for moun- 

 tain time, is set tvvo hours 

 back; and a green hour 

 hand, three hours back, 

 represents Pacific time. 



You can do this to your 

 own watch. The jeweler will 

 make a set of hands of these 

 colors and alter your watch for a 

 consideration of a few dollars, 

 so that when you go traveling 

 it will not be necessary to dis- 

 turb the mechanism of your 

 watch by setting the hour- 

 hands back and forth frequent- 

 ly, according to whether you are in De- 

 troit, Chicago, New York, Denver, San 

 Francisco, or other places on the map. 



But such an arrangement would be parti- 

 cularly useful only to the itinerant sales- 

 man or other frequent traveler. 



The tests relate to ice consumption, temperature distribution, 

 and air circulation within the refrigerators. Ekjuipment 

 inside each refrigerator is connected with the galvanometer 



How the War Department Tests Its 

 Household Refrigerators 



ACCORDING to the Bureau of Stand- 

 . ards, the ordinar\- household refrig- 

 erator, even of the best make, is by no 

 means as effective in the saving of ice as 

 might be desired. Before awarding contracts 

 to supply the army with refrigerators, the 

 War Department uses temperature-measur- 

 ing instruments for testing each t\peoffered. 

 Thedimensionsof therefrigeratorsare 

 measured, as well as the tempera- 

 tures inside and outside, the size or 

 area of ice used, the amount melted 

 per day, the amount of air circulating 

 through the food chambers, and, 

 finally, the heat transmission of 

 the refrigerator walls. 



The temperature measure- 

 ments are made by means of 

 thermocouples (instruments 

 for noting differences in 

 temjjerature by electricity), 

 several of which are mount- 

 ed inside each refrigerator 

 and several others at various 

 points outside. By this means 

 all measurements are made 

 with a single galvanometer (an 

 instrument for measuring the 

 intensity of an electrical cur- 

 rent), shown on the tripod stand 

 in the illustration. The lead 

 wires from each of the thermocouples, some 

 thirty in number, are connected succes- 

 sively with the galvanometer by means of 

 the simple switchboard on the table. 



The temperature is measured in the air 

 entrance and the air exit to the ice chamber. 



You can have addi- 

 tional hands made for 

 your watch so' that it 

 will indicate the time of 

 the locality you are in 



