204 J. A. POLLOCK. 
length for the open circle, a result slightly different to that 
given above, where the distance between the ends of the 
resonator was much greater than in Kiebitz’s experiment. 
Sarasin and De la Rive’ as the result of their final 
measurements, give the wave length of the vibration con- 
nected with open resonators, made of stout wire 1 cm. in 
diameter, as 600 cms. for an open circle 234 cms. in circum- 
ference, and 400 cms. for one 156 cms. in circumference. 
This makes the wave length 2°56 times the length of the 
circuit. Macdonald, “‘ Hlectric Waves,’’ p. 111, in con- 
sidering the question of stationary waves in open circuits, 
calculates the wave length for any resonator, and finds for 
the fundamental mode of vibration 4,=2°53 1 where I is the 
length of the circuit; a value in wonderful agreement with 
Sarasin and De la Rive’s conclusions. Apparently, accord- 
ing to theory the wave length is independent within wide 
limits of the diameter of the wire of which the resonator 
is made, and the ratio of wave length to length of circuit 
independent of the size of the circle. 
By extrapolation (see Fig. 2) the present experiments 
give for a circle 200 cms. in circumference, the value 2°45 
for the ratio of perimeter of rectangle to length of circuit. 
This is less than the ratio of wave length to circumference 
as given above by Sarasin and De la Rive for a similar 
size circle, and as calculated by Macdonald. In considering 
the difference, it is necessary to remember that extra 
capacity effects at the ends of the resonator may not have 
been altogether negligible in Sarasin and De la Rive’s 
apparatus. On the other hand, the wave length of the’ 
vibration connected with narrow rectangular closed cir- 
cuits, made of wire of finite thickness, may bea little longer 
than their perimeters. Again, the wave length may be 
? Sarasin and De la Rive—Comptes Rendus, cxv., 1280, 1892. 
