THE NATURAL PERIOD OF LINEAR CONDUCTORS 405 



ductor "Lecher" systems, and since further there are practical 

 advantages in reducing the total length of these systems to a single or 

 half a single nodal length (X/2 and X/4 "Lecher" frames), the problem 

 of the natural period of a rectilinear conductor can be broadened to 

 include a study of the shortest favorable shape of a linear conductor 

 for use as a wave length standard. It is the purpose of this paper to 

 give the results of some experimental work relating to both these 

 questions. At the same time an examination of the operation of an 



Fig. 1 



extended Lecher system as a basic wave measuring apparatus was a 

 necessary preliminary. 



It was a matter of only a small amount of experimentation to 

 demonstrate that the practical Lecher system for wave length measure- 

 ment would necessarily consist of a pair of heavy uniformly spaced 

 copper wires devoid of insulator spacers and at least a couple of wave 

 lengths long. While the attenuation of Lecher systems made of 

 ordinary wire is not great, as attenuations go, the accuracy with which 

 the nodal points can be located, in the manner later described, depends 

 markedly on the degree in which space resonance currents build up, 

 and it is quite necessary to supply sufficient copper. The wire used 

 here was No. 8 B. & S. gauge (3.26 mm. diam.) soft drawn copper 

 and by "ironing" it with a slotted wood piece it was made as smooth 

 as was necessary. It was stretched between two poles out of doors 

 and kept tight with a turnbuckle. The spacing was fixed at 5.15 cms. 

 by a metal bridge at one end and a micarta bridge at the other. The 



