270 



ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1910. 



The form of apparatus I have employed for this purpose is seen 

 diagramatically in the next lantern slide (fig. 7). EE is the 

 magnet which is actuated by the relay R. It then attracts an arma- 

 ture MN, which moves toward the magnet poles and brings a resili- 

 ent hammer H, fitted with a platinum contact p, against the coherer. 

 The coherer AB is also fitted with a collar F and contact pin, so that 

 in the act of striking the coherer the hammer closes a local circuit, 

 and so causes a black mark to appear on the chemical paper. Suc- 

 cessive distinct marks can be obtained in 0.017 second in this way, 

 which is considerably more rapid, I believe, than a decoherer was 

 given credit for. 



There is not sufficient time to show an actual transmission by wire- 

 less, and I should like to make it clear that only sketches of the 

 simplest character are at present being transmitted ; but, as you will 

 see from the result thrown on the screen — a simple portrait of His 



Y 



0- 



K 



f M{^/m ^ ^/i m7\ 



*• i^M'wr 



wzsm- 



M 



N 



Fig. 7. 



Majesty the King — the images are recognizable, and merely require 

 slightly more detail to make them quite comparable with the early 

 results in line obtained by Prof. Korn's telautograph. 



Another result shows a plan transmitted by wireless; here an 

 island is seen represented, and a lighthouse — or it might be a fort — 

 and by means of letters the positions of sections of an army on the 

 island are supposed to be designated, while the shaded portion might 

 mean that the " enemy " is in that part of the island. Such plans as 

 these could be drawn direct in shellac ink on a slip of metallic foil, 

 placed upon a portable machine coupled to a portable military wire- 

 less set, and communicated from one section of an arm}'^ to another. 

 The small portable machines I have already shown are used for the 

 wireless transmissions, and they possess the advantage that "tap- 

 ping" of the communications would be quite impossible. It is for 

 this reason that I think the method would be of such value for mili- 

 tary and naval purposes; even supposing that anyone wishing to 



