126 Mr. C. A. Chant on the Variation of Potential along 
about the wire obtained by them agrees with that deduced by 
Abraham. 
Slaby’s theoretical treatment* of the problem is much 
simpler than Abraham’s, and from his results he was led to 
his method of syntonic telegraphy. He takes the so-called 
“telegraphic equation,” 
02 L 07 hh oe 
ot 192? a C, Ou” 
where 2 is the current strength at any time at a place 2 on 
the antenna, and R,, Ly, C,, are the resistance, self-induction, 
and capacity per unit length of the wire. A solution T is 
R, 
at 20 
2M on” 
Wea Ne COS t sin a1” 
where T=4”/ LC, / is the length of wire, A is a constant, and 
R, L, C relate to the whole length of the wire. The 
frequency is 1/T and »=4/. From this solution it should 
follow that the disturbance varies according to the simple 
harmonic law, and that the free end of the wire is a potential 
loop, the lower end a potential node, 
Il. Hxperrmental Arrangements and Results, 
In the present investigation all the wires explored were of 
bare copper and were stretched horizontally on the tops 
of wooden poles, about 1:5 m. high and 1°6m. from the 
wall of the room in which the experiments were made. This 
room was a large hall on the first flat, about 22 ms, long, 
12 ms. wide, and with a ceiling 13 ms. high. The manner 
of examining the wire at various points in its length was 
precisely similar to that in the former research. The 
induction-coil and interrupter, the magnetometer, and the 
method of taking readings were identical with those used 
earlier and need not be described again here. 
In most of the work the detector was the one used before, 
but during the course of the experiments it was broken, and 
another, similar to it and indistinguishable from it in its 
behaviour, was constructed, 
The manner of applying the detector to the wire was 
slightly different. Before, the detector was laid on the top 
of a carriage moving on ways along the wires, with the 
little wing (w, fig. 1) in a littie pocket by the wire; now, a 
* A. Slaby, Lond. Electrician, vol. xlvi, Jan. 18, 1901; also vol. xlix. 
April 25, 1902, 
+ See Webster, Flectricity and Magnetism, arts. 255, 256, 
