e Amateur - 

 Eloctrician 



T^nd Wii'eless Operator 



Delicate Recorder for Wireless 

 Telegraph Signals 



PROF. TURPAIN, a prominent Parisian 

 scientist, has been engaged for some 

 time past on the subject of recording 

 instruments for wireless waves, and has 

 brought out a very sensitive recorder which 

 is intended for long-distance 

 % wireless working, and which 

 will take down signals so weak 

 that ordinarily they could only 



A sensitive recording device for receiving 

 signals too weak to be heard in a receiver 



be heard in the telephone. The device con- 

 sists of a powerful permanent magnet M 

 of the type used for ocean cable work, with 

 a flat swinging coil A, mounted on the 

 fiber suspension B. On the coil is a light 

 arm C which connects by a thread D to the 

 recording device, so that the slight move- 

 ments of the coil will produce larger move- 

 ments of the pen. The recorder consists 

 of a swinging arm E which is pivoted at F 

 in the usual way. The lower end of the arm 

 carries the pen P. Under the pen, but 

 without touching it, passes the paper band 

 H mounted on the rollers G. The novel 

 part of the invention consists in making the 

 record without having the pen touch the 

 paper, for this would cause too great a 

 friction for the small amount of pull 

 afforded by the swinging coil. The pen 

 contains a volatile liquid, such as ammonia, 

 and the vapors of this substance are made 

 to act on a paper that is moistened with a 

 uitable chemical preparation so that the 



ammonia v^apor will produce a color upon 

 the paper. Certain compounds of phenol 

 can be used for this purpose. When the 

 paper travels along and the pen operates, 

 the signals will be recorded in a wavy line 

 corresponding with Morse dots and dashes. 



A Self-Contained Battery Lamp 

 for Physicians' Use 



THE illustration shows an improvement 

 over the usual kind of batter>' lamps 

 which physicians or surgeons use for ex- 

 amining the eye or the mouth. Generally 

 the battery- is carried in the pocket, but 

 the flexible cords often become tangled. 

 Besides, where a contact device is used for 

 the lamp, the hands should be left free. In 

 the device shown, the entire outfit is carried 

 on the head and is self-contained. A suit- 

 able head-strap holds the battery-case, and 

 the electric lamp is held ver>' conveniently 

 on the under side of the box. The lamp- 

 holder with its lens is mounted so as to 

 swing on a piv- 

 ot, and a rack- 

 pinion operated 

 by a milled head 

 provides a way 

 to throw the 

 beam up or 

 down. A flexi- 

 ble cord leads 

 to a spring con- 

 tact which is 

 carried in the 

 mouth, so that 

 contact can be 

 made by the 

 teeth for light- 

 ing the lamp. 

 This device 

 leaves the operator's hands entirely free 

 and eliminates the bother encountered 

 with the cords of the pocket lamp. 



Battery and light 

 strapped on forehead 



627 



