Popular Science Monthly 



105 



previously mentioned they simply cause 

 switches back of each key to pick out the 

 right set of lamps to blazon forth the letter 

 it is desired to show in a given letter-block. 

 Since the letter-blocks are arranged in long 

 lines it is possible 

 to spell out words 

 and phrases, simply 

 by causing the indi- 

 vidual letter-blocks 

 to show the char- 

 acter desired. The 

 principle is made 

 clearer in the illus- 

 trations. 



Changes in the 

 wording of the sign 

 are effected as fast 

 as the operators can 

 work the keyboard 

 — one man devoting 

 his entire attention 

 to a single line on 

 the sign, but to- 

 gether with his fel- 

 lows getting orders 

 from cardboards in 

 the hands of the 

 chief operator. A 

 given message is 

 made to flash on the 

 sign very much as 

 type is set up on a 

 linotype machine. 

 In the linotype case 

 the printer punches 



proper keys to spell out one line, strikes 

 a lever convenient to his right hand, and 

 the matrices pass on into the machine to 

 mold the type while he is busying himself 

 with the next line. In the same way, the 

 operators of the new sign punch proper 

 keys to spell out a given message, strike 

 a lever, and the message flashes on the 

 sign. While people are reading it, the 

 men are setting keys for the next com- 

 munication, which 

 appears the next in- 

 stant. 



The sign was orig- 

 inally patented by 

 W. W. Arnold, of 

 Hamilton, Ohio, but 

 it has been worked 

 out in a commer- 

 cially practicable 

 way by M. E. Laun- 

 branch, an engineer 

 of Chicago. 



A message is made to flash on a sign very 

 much as type is set up on a linotype machine. 

 The operators punch the keys to spell it out 



Compared with Electricity Gas Is 

 Still the Cheaper Medium 



IN spite of the decreased cost of electric 

 service and the increased efficiency of 

 electrically operated 

 devices, the fact re- 

 mains that of the 

 two sources of en- 

 ergy generally avail- 

 able for heating, 

 lighting and cooking, 

 namely, electricity 

 and gas, gas is by far 

 the cheaper medium. 

 At the present time 

 one thousand elec- 

 tric heat units 

 cost fourteen times 

 as much as one 

 thousand gas units. 

 Furthermore, it is 

 impossible to cook 

 as rapidly with elec- 

 tric heating devices 

 as with gas cookers. 

 In the lighting field 

 gas is, under certain 

 conditions, cheaper 

 than electricity, al- 

 though it has not 

 the large variety of 

 applications that 

 electricity has. 



A Telephone Attachment Which Per- 

 forms the Services of a Watch Dog 



RUPERT H. GREENLAW, of New 

 York, has invented a meter attachment 

 which is a mechanical watch-dog for your 

 telephone. It consists of a 

 small case containing a 

 locking and registering 

 mechanism, a clamp which 

 fastens it to the telephone 

 standard, and a rod which 

 engages with the tel- 

 ephone receiver. By 

 removing the receiv- 

 er the rod is forced 

 in and out of the 

 interior of the meter. 

 It is impossible to 

 replace the receiver 

 upon the hook until 

 the call has been 

 registered. 



The attachment which locks the telephone 

 when it is not in use and registers all calls 



