PROPERTIES OF PHOSPHOR-BRONZE WIRES 



2 1 5 



The length of the wire was usually 30 cms. and the initial 

 twist in most cases was 10 degrees per cm. length of the 

 suspension. 



To make clear the method of observation, and the nature of 

 the results, a sample of the data follows : 



SAMPLE OF DATA. 

 (Wire No. 4, d=.145 mm; Load=154 g. ; Approximate period=11.8 sec.) 



The above data were then tabulated in the following form : 



Vib. 



No. 



No. of 

 vibs. 



Ave. time 

 (from above) 



Time betw. 

 Readings 



Period 

 (sees.) 



Amp. Ave. 

 Amp. 



The first column represents the number of vibrations that 

 have been executed since the pendulum was set into vibration. 



It might here be said that the elastic after effect was very 

 marked in this alloy and so the zero point had to be re-deter- 

 mined several times during an experiment. The zero point was 

 known to shift as far as nine degrees in the direction of the 

 initial twist. This, of course, would introduce quite an error 

 in the time readings if the above precautions were not taken. 



