88 



Mr. H. Tomlinson. The Influence of 



These facts have been ascertained for each of the 73 centres ex- 

 amined. It is obviously impossible here to indicate even the general 

 conclusions thus arrived at, owing to the large number of separate 

 observations which cannot be briefly collated. Reference must there- 

 fore be directed to the original paper. 



The expenses of the research were defrayed by a grant from the 

 British Medical Association. 



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

 perties of Matter. Part I. Elasticity — continued. The 

 Velocity of Sound in Metals and a Comparison of their 

 Moduli of Longitudinal and Torsional Elasticities as deter- 

 mined by Statical and Kinetical Methods." By Herbert 

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

 Adams, M.A., F.R.S. Received April 29 —Read June 

 16, 1887. 



[Plate 2.] 



We owe to Wertheim* a series of carefully executed experiments on 

 the longitudinal elasticity of metals both by statical extension and by 

 longitudinal and transverse vibrations. From these researches it 

 would appear that the values of the moduli of longitudinal elasticity 

 as determined for several metals by the first of these three methods 

 are, as might be expected, less than those obtained by the other two. 

 The differences, however, are very much greater than can be accounted 

 for by the heating and cooling effects of contraction and elongation, 

 and the author has already pointed out what he believes to have been 

 in a great measure the cause of these discrepancies. f As a few 

 observations made with two or three different metals had seemed to 

 him to show the possibility of obtaining more concordant results, he 

 was encouraged to extend his investigations to other metals, and 

 moreover to institute a comparison between the values of torsional 

 elasticity which could be obtained by statical and kinetical methods. 

 •It had originally been the author's intention to use the same 

 specimens of the various metals as were employed in his previous 

 experiments on moduli of elasticity and electrical conductivity, J but 

 on applying to Messrs. Johnson, Matthey and Co. to have these 

 specimens fused and redrawn, he was informed that what was desired 

 would be almost if not quite impossible, inasmuch as several of the 

 metals if fused in small quantities would be rendered too brittle for the 



* ' Annales de Chimie,' vol. 12, 1844. 



f < Phil. Trans.,' yoI. 174, 1883 (Part 1), p. 14. 



X Loc. cit. 



