224: J. A. POLLOCK. 
The curves show the effect of extra capacity at the ends 
of the resonator in increasing the period of the free vibra- 
tion. The effect of bringing the ends of the resonator closer 
together is to increase the end capacity, and hence the 
period. In separating the ends practically no change is 
made in the period of the free vibration when the distance 
between the ends exceeds 8 cms. Several attempts were 
made to determine 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. 
A CONTRIBUTION To THE STUDY oF THE DIELECTRIC 
CONSTANT oF WATER at LOW THMPERATURES. 
By O. U. VONWILLER, B.Sc, Demonstrator in Physics in the 
University of Sydney. 7 
[Read before the Royal Society of N. S. Wales, December 2, 1903. ] 
THE experiments described in the following paper were 
carried out with the object of investigating the variation 
of the dielectric constant of water with temperature in the 
neighbourhood of 4 C. OC. B. Thwing’ 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 further. Drude,’ Palmer,’ and other 
observers have failed to obtain evidence of this effect. 
1 C. B. Thwing—Phys. Rev., 11., p. 35. 
2 P. Drude—Wied. Ann., trx., p. 17. *% A. de F. Palmer—Phys. Rev. 
VI.; p. 267. 
