1912-13.] Application of the Law of Torsional Oscillation. 18$ 
XVIII. — On a Continued Investigation of the Application of the 
Law of Torsional Oscillation to Various Metals and Alloys. 
By James B. Ritchie, B.Sc., Carnegie Research Scholar in Physics,. 
University College, Dundee. Communicated by Professor W. Peddie. 
(MS. received November 18, 1912. Read November 18, 1912.) 
This paper is a continuation of one already submitted to the Society, and 
published in their Proceedings * 
It showed that an equation of the form y n (x -\-a) = b could be applied 
to give close representation of results in the determination of the law of 
decrease of torsional oscillations of wires of different materials. This 
empirical equation, in which y represented the range of oscillation, x the 
number of oscillations since the commencement of observations, and n, a,. 
and b constants for any one experiment, their numerical values depending 
upon the initial conditions of the wire and its subsequent treatment, was 
found to hold over a large range of oscillation for wires of many metals,, 
and the present paper gives an account of further work on the subject. 
Continuation of Former Work.* 
Brass Wire. 
In the paper referred to there is given (p. 430) a diagram showing 
the relationship between the value of the constant n, and the tem- 
perature to which the wire had been initially subjected. After the 
temperature reached 370° C. two values of n were obtained for each 
temperature, the plotted curves ( logy against log (a? + a*)) giving two 
straight lines inclined at a gradually increasing angle, and cutting each 
other at a point corresponding to, roughly, twenty oscillations. It was. 
found on comparing the separate curves for each temperature that the 
crossing point shifted fairly uniformly with increase of temperature, the 
change being directed upwards towards the points representing the smaller 
oscillations. 
The actual results obtained are as follows. It will be noticed that the 
product of the temperature and the value of lo gy at the crossing-point 
remains fairly constant. 
* Proc . Roy . Soc . Edin vol. xxxi. p. 424. 
