the-Transmittiug Antenna in Wireless Telegraphy. 139 
III. Conelusions. 
The following conclusions seem to follow from my 
experiments : 
1. In the neg Marconi method and the method of 
direct excitation, when the antenna is joined to earth, the 
effect is similar to using a wire the same as the antenna to 
balance it ; that is, considered from an optical point of view, 
the earth acts as a plane mirror. 
2. In these conditions the chief oscillation is the funda- 
mental of the antenna, with wave-length four times its 
length. The condenser circuit in the method of direct 
excitation impresses its wave-length on the antenna, but its 
oscillations are not nearly so intense as those proper to the 
antenna itself. Thus the manner of oscillation is essentially 
the same in the two methods, but the latter is more regular 
and powerful than the former. 
3. In the inductive method of excitation, on the other 
hand, the prominent feature of the oscillations is that one 
due to the condenser circuit. With antenne of different 
lengths there is little change in this oscillation, the curve 
indicating it being decided and definite; but only one- 
quarter of its wave- length is shown. This may be due to the 
great losses from radiation by the wire. The fundamental 
proper to the antenna is also present, but it is not nearly so 
intense as in either of the other two systems. 
4. The effective length of the antenna for proper resonance, 
ao is one quarter wave-length, not a higher multiple. 
. When inductance is inserted between the condenser 
peat and the earth the fundamental oscillation is not so 
regular or intense, other oscillations (overtones) being 
superposed. 
6. For the production of oscillations by the direct method 
a small capacity cannot satisfactorily balance the antenna ; 
in the inductive method, however, a capacity acts like an 
earth-connexion or a similar wire. 
IV. Continuation of Former Investigation. 
In the previous experiments with Hertzian plate oscillators 
of various sizes and with wires ranging in length from 
300 to 860 cms., there was usually one “ chief”? minimum 
of potential-variation between 100 and 200 cms. from the 
free end, and always a marked one about 10 or 15 ems. from 
the other end of the wire. It was hoped that by employing 
longer wires the phenomena of standing waves would be 
much better exhibited, and that several ‘ chief?’ minima 
