1886.] Stress and Strain and the Properties of Matter. 343 



III. " The Influence of Stress and Strain on the Physical Pro- 

 perties of Matter. Part I. Elasticity (continued). The 

 Effect of Change of Temperature on the Internal Friction 

 and Torsional Elasticity of Metals." By Herbert 

 Tomlinson, B.A. Communicated by Professor W. Grylls 

 Adams, M.A., F.R.S. Received April 13, 1886. 



(Abstract.) 



The author has recently had the honour of presenting to the 

 Society a memoir relating to the internal friction of metals when 

 vibrating torsionally at temperatures ranging from 0° C. to 25° 0. He 

 now brings forward results which have been obtained in experiments 

 on the effect of change of temperature on the torsional elasticity and 

 internal friction of metals. The apparatus used and the mode of 

 experimenting are fully described in the paper, so that it will be 

 sufficient, perhaps, to state here that the vibration-period and the 

 logarithmic decrement were very carefully determined at four 

 different temperatures between 0° C. and 100° C, and that the 

 formulae given below were worked out by the method of least squares ; 

 these formulae are to be found in Tables I and II. 



A full account of the method adopted for eliminating the effect of 

 the resistance of the air has been given in the previous memoir above 

 alluded to. 



Table I. 



Metal. 



Silver 



Platinum. . 

 Platinum-silver 

 Aluminium. . . . 



Zinc 



Nickel ........ 



Iron 



Copper 



Formula for the torsional elasticity 

 between 0° C. and 100° C. 

 r t and r Q represent the torsional elasti- 

 city at the temperatures of *° C. and 

 0° C. respectively. 



r t = r (1 - • 0003769* - • 0000001690* 2 ) 

 r t = r (l - • 00004456* - -0000002987* 2 ) 



r t = r (l - • 0003555* + ■ 0000005467* 2 ) 



r t =r (l - • 0005713* - ■ O00O00O1O9* 2 ) 



r t = r (l - • 0010800* - ■ 0000049470* 2 ) 



r t = r (l - • 0002267* - -0000003474* 2 ) 



r< =r (l-0 -0002442* -0 -0000002510* 2 ) 



r t = r (1-0 -0002472* -0" 0000004488 * 2 ) 



Percentage de- 

 crease of tor- 

 sional elasticity 

 when the tem- 

 perature is 

 raised from 

 0°C. to 100° C. 



938 

 744 

 008 

 724 

 747 

 614 

 693 



2-921 



Before the experiments, of which the results are recorded in Tables 

 I and II, were made, the previously well annealed wires were subjected 

 to a preliminary treatment extending over periods ranging from six 



