210 J. A. POLLOCK. 
2498 Bi ae f 
EA 
Fig. 2. 
Closed circuits.—In the case of other than circular 
circuits no attempt was made to make the shape truly 
elliptical, and they must be considered merely as ovals 
approximating to the elliptical form. The perimeter and 
the ratio of the major and minor axes given in the table 
sufficiently indicate their shape. The ratio given is the 
length of the axis parallel to the direction of propagation 
of the waves along the circuit to the length of the axis 
perpendicular to this direction. 
