the Transmutting Antenna in Wireless Telegraphy.. 127 
small piece (c) of cylindrical hard-rubber rod, in which 
a groove was made down to the axis, along a plane through 
Fig. 1. 
(b) 

the axis, was fastened to the hard-rubber plate (p) by wax, 
and the detector was then hung on the stretched wire at any 
place desired. 
The curves are plotted from the mean of at least three 
sets of readings. 
The published accounts of the exploration of wires about 
which electrical disturbances are produced as in wireless 
telegraphy, are not numerous, and, as far as I can learn, in 
no case has the exploration been at all minute. 
In the present investigation three methods, well-known 
in practice, have been used to excite the oscillations. 
Marconi’s Simple Method. 
This arrangementis illustrated in fig.2. The “ oscillator ” 
in this case consisted of two cylindrical brass rods, AB, CD, 
9°5 mms, in diameter and 12°5 cms. long, ending in spherical 
knobs B, C, 3°8 cms. in diameter. One half of the doublet 
is shown on a larger scale at the left-hand of fig. 2. From 
Fig, 2. 
4 
1 ik 
21} 
| € 0 B 
4/2 ROC 
| E 


as wt oe aaa 
D led off the antenna DE. In some experiments A was 
connected to earth, in others a wire similar to DE was 
attached to A, while in one series this end of the doublet 
was left entirely free, 
