A. M. Mayer — Researches in Acoustics. 83 



The more carbon a steel contains the less is the fall of its 

 modulus of elasticity on elevating the temperature of the steel. 

 Thus, the modulus of the steel with 1*286 per cent of carbon 

 is 2*24: per cent less at 100° than at 0°, while the steel con- 

 taining 0*15 per cent of carbon has a modulus at 100° which 

 is 3*09 per cent lower than its modulus at 0°. 



So far as experiments on a single steel containing nickel 

 permits of any general deductions, it appears that the presence 

 of nickel in a low carbon steel lowers its modulus of elasticity. 

 Thus, steels Nos. 3 and 4 having respectively '47 and *51 per 

 cent of carbon have a modulus of 2131 X 10 6 , while steel 

 !No. 5, containing *27 per cent of carbon and 3 per cent of 

 nickel, has a modulus of 2080 X 10 6 , which is 2*12 per cent, 

 lower than that of steels Nos. 3 and 4. 



The presence of nickel in a steel may, in a diminished 

 degree, have the effect of carbon in lessening the lowering of 

 the modulus when the temperature of the steel is increased. 

 Thus, the percentage of the lowering of the modulus, by 

 heating from 0° to 100°, of steel No. 5 containing 0*27 of 

 carbon and 3 per cent of nickel, is the same as that of steel 

 No. 3 with 0*47 per cent of carbon. 



If a bar of any one of the substances experimented on is 

 struck with the same energy of blow, by letting fall on the 

 centre of the bar a rather hard rubber ball from a fixed height, 

 the sound emitted by the bar diminishes in intensity and in 

 duration as the temperature of the bar is raised. Thus: 



Brass at 0° 



vibrates during 



75 sees.; 



at 100° 



it vibrates 



during 



45 sees. 



Bell-Metal 



a 



55 " 



a 



" 





15 " 



Aluminum " 



(( 



40 " 



(I 



u 





12 " 



J. & C. Cast Steel " 



" 



80 " 



(< 



CI 





5 " 



Bessemer Steel " 



(C 



45 " 



a 



a 





1-5" 



St. Gobain Glass " 



.1 



6 " 



11 



a 





3-5" 



Zinc at 0° vibrated during 5 sees.; at 20° only during 1*5 

 sees. At 62° it vibrated for so short a time that it only gave 

 three beats with forks of 1090 and 1082 v. s. At 80° it was 

 not possible to determine the pitch of the bar, and at 100° the 

 bar when struck gave the sound of a thud. The bar of 

 silver acted in a similar manner to the bar of zinc — it was 

 even less sonorous than zinc — thus flatly denying the "silvery 

 tones " attributed to it. 



These phenomena do not depend on the fall of modulus but 

 on changes in the structure of the metal on heating, which 

 cause the blow to heat the bar and not to make it vibrate. 



Bell-metal was found to be an alloy peculiarly well suited 

 for bells, as the intensity and duration of its vibrations were 

 the same at 50° as at 0° ; all other substances showing a 

 marked diminution of intensity and duration of sound at 50°. 



