Dielectric Constant of Water at Low Temperatures. 655 
period of the free vibration when the distance between the 
ends exceeds 8 ems. Several attempts were made to deter- 
mine the period of the free vibration of the resonator with 
bare ends close enough for a spark to pass between them, 
but they were unsuccessful, 
The Physical Laboratory, 
The University of Sydney, 
December 8th, 1902. ’ 


LXXII. A Contribution to the Study of the Dielectric Constant 
of Water at Low YLemperatures. By O. U. VoNwILier, 
B.Se., Demonstrator in Physics in the University of Sydney, 
N.S.W# 
_ experiments described in the foilowing paper were 
carried out with the object of inv estigating the varia- 
tion of the dielectric constant of water with temperature in 
the neighbourhood of 4° C. 
C. B. Thwing (Phys. Rev. ii. p. 35) carried out some 
experiments which apparently showed the existence of a 
critical point at 4° C., the dielectric constant rising to a 
maximum value at that point and then decreasing as the 
temperature rose. On the other hand, Drude (Wied. Ann. 
lix. 1896) and other experimenters have not observed such 
an effect. 
The author’s experiments were carried out with electrical 
oscillations having a frequency of about 25 millions per sec., 
produced in a Lecher wire-system by the oscillatory discharge 
of a condenser. 
The arrangement of the apparatus is shown in fig. 1. A 



Fig. 1. 
is a condenser consisting of two andi circular brass Rey 
30 centimetres in diameter, connected to the ends of the 
secondary of an induction-coil. Fs 
This condenser is discharged by means of a spark between 
two aluminium knobs immersed in kerosene, and joined to 
* Communicated by the Author. Read before the Royal Society of 
New South Wales, at 
