Stress and Strain on the Properties of Matter. 99 



velocity of sound in centimetres per second as deduced from the 

 numbers in the first column will be, within 001 per cent., in all 

 three series of trials the same, namely, 280,100. Experiments VI and 

 VII furnish results which are rather more consistent with each other 

 and attended with a slightly less probable error, as judged by the 

 departure of each individual value of the velocity of sound from the 

 mean value, but still the agreement seemed to be very good in the 

 case of the other metals. Thus with annealed iron wire of the same 

 length as the silver wire, and which was tested not only for the 

 fundamental note and the first and second octaves but also for the 

 third octave, the following values of the velocity of sound were 

 deduced : — 



Velocity of sound in 

 centimetres per 

 second. 



Note. 



509,700 



Fundamental. 



510,000 



First octave. 



510,400 



Second octave. 



508,400 



Third octave. 



509,600 mean. 





Again a hard drawn copper wire of the same length gave the 

 following results : — 



Velocity of sound in 

 centimetres per 

 second. 



Note. 



395,600 

 395,400 

 396,400 



Fundamental. 

 First octave. 

 Second octave. 



395,800 mean. 



The velocity of sound for the other wires given in the next table 

 was determined only from observation of the fundamental note and 

 the first octave. All the metals, except tho piano-steel, the annealed 

 iron and the German silver, were obtained from Messrs. Johnson, 

 Matthey and Co., and were stated to be chemically pure. 



