344 BELL SYSTEM TECHNICAL JOURNAL 



using apparatus in which the speech spectrum was divided into thirteen 

 bands of frequencies. The same apparatus has been used in a series of 

 measurements on musical instruments, which are reported in this paper. 

 As with the speech measurements, the data are statistical in nature, 

 and are taken with a view to their engineering applications. These 

 applications are concerned, chiefly, with the transmission and reproduc- 

 tion of music, and the data should show the power and frequency re- 

 quirements for systems which are called upon to perform these func- 

 tions without distortion. In carrying out this purpose it has been 

 thought well to measure both individual instruments, and instruments 

 playing together in orchestras; to make measurements on actual musi- 

 cal selections, rather than on single notes; and to take the measure- 

 ments in such a way as to obtain an average or integrated picture of the 

 selection, as well as the distribution of amplitudes in magnitude and 

 frequency, the extreme values being particularly important. 



Noise Measurements.'^ John C. Steinberg. That noises have a 

 detrimental effect upon human health and happiness has been proved 

 and now efforts are under way to control or eliminate objectionable 

 sounds. Some of the problems involved are outlined and a newly 

 developed "noise meter" is described. 



Fatigue Studies of Telephone Cable Sheath Alloys}^ J. R. Townsend 

 and C. H. Greenall. This paper is a continuation of a previous pa- 

 per presented before the Society by one of the authors in 1927 and 

 further discusses results of fatigue studies of lead sheath for telephone 

 cables. The results of the investigation of the fatigue characteristics 

 of lead cable sheath alloys, using the rotating-beam type fatigue 

 machine, are reported. Data are also given for static fatigue. 



The failure of lead cable sheath alloys as reported in the previous 

 paper is by intergranular fracture and in the case of the lead-antimony 

 alloys repeated stress appears to reduce the solubility of antimony in 

 lead. The type of fracture observed for the rotating beam speci- 

 mens is similar to that of the repeated flexure specimens described in 

 the previous paper. The type of failure on the static fatigue test is a 

 breaking down of the bond between the crystals. 



The fatigue properties of the 0.04-per cent calcium-lead alloy de- 

 scribed in this paper are by intergranular fracture, but there is no loss 

 of solid solubility of the calcium in the lead. Great improvement in 



^ Elec.Engg.,ydi\., 1931. 



^^ Proc. Amer. Soc.for Testing Materials, \'ol. 30, Part II, 193U. 



