Popular Science Monthly 



How the Government Seals Unofficial 

 Wireless Stations 



AMATEUR and 

 l commercial sta- 

 tions alike have been 

 ordered closed. The 

 Government cannot af- 

 ford to take any 

 chances of military in- 

 formation leaking 

 through to the enemy. 

 All aerials have been 

 dismantled, and the in- 

 struments stored away. 

 In the very powerful 

 wireless stations, the 

 further precaution has 

 been taken of sealing 

 the apparatus 

 electrically. 



The manner of seal- 

 ing such a station is 

 well illustrated in the 

 accompanying photo- 

 graph of New York 

 city's most powerful 

 commercial plant. The transformer shown 

 in the foreground was used to convert the 

 low-potential alternating current, that is 

 ordinarily used for light and power pur- 

 poses, into a current of millions 

 of volts in pressure, such as 

 would be required for sending 

 wireless signals. 



The Government's agents 

 have simply wrapped a heavy 

 copper wire around the trans- 

 former terminals, and have se- 

 cured the wire ends with sealing 

 wax on which is stamped the 

 great seal of the United States 

 of America. It is impossible to 

 remove this wire without break- 

 ing the seal — and taking the 

 consequences in imprisonment. 



A heavy wire short-circuits the high-po- 

 tential sending transformer. If an at- 

 tempt should be made to operate the 

 station, the transformer would burn up 



lines are spaced by virtue of an evenly 

 notched rack which allows the tablet to 

 be moved away from the elbow rest by 

 the distance of one 

 notch. 



An improvement on 

 this tablet has been 

 developed by Arthur E. 

 Tremaine, of Boston. 

 By using a straight 

 edge and a brass wire 

 placed three-quarters 

 of an inch above it 

 across the paper, the 

 sightless writer is able 

 to keep the size of 

 his letters uniform. 

 Moreover, by eliminat- 

 ing the elbow-pivot 

 principle, each line will 

 be straight and not 

 curved in the arc of a 

 circle. Ink as well as 

 pencil can be used since 

 neither the beveled 

 straight-edge nor the 

 wire quite touches the 

 paper surface. The straight-edge can be 

 lowered line by line down the paper and 

 evenly spaced by means of notches at 

 the side. In this way a 

 perfectly neat appearance 

 is given to the written 



rii^h-tension 



wt reless t ranstor me 



Teaching the Blind How to Write 

 on Straight Lines 



THE December issue of the Popular 

 Science Monthly contained an article 

 on an instrument invented to aid the blind 

 in writing. This was the writing tablet 

 invented by the French scientist Dr. Emile 

 Ja'-al, His tablet consists of a fixed elbow 

 rest in which the writing arm swings across 

 the paper. The line of writing is thus 

 made comparatively straight, while the 



As the blind man writes, his letters are kept 

 uniform in size by the straight-edge below 

 the pencil-point and the wire above it 



