PROPERTIES OF PHOSPHOR-BR(\\ZK WIRES 



217 



Type II is similar to the above mentioned curve in the larger 

 amplitudes but makes a departure from that type at an ampli- 

 tude of about four degrees per cm. length of the wire, and from 

 that time on, the period gradually increases with a decrease in 

 the amplitude. The curve is marked II (figure 29) and will 

 represent state II. 



Type III is seen to be very different from the other two. In 

 this curve the period increases continually from the large to the 

 small amplitudes. "When the wires follow this type of curve 

 they will be said to be in state III. 



From figure 29 which shows three curves of an identical sam- 

 ple of wire under identical experimental conditions, it is at once 

 seen that the variation from a constant period is very marked. 

 The magnitude of the variation is perhaps best shown by going 

 into these particular curves in detail. 



The wire was .100 mm. in diameter (No. 1), and supported 

 a load of 27 grams. Curve II is drawn from the data of June 

 6, 1915. All experiments of that time showed the wire to be in 

 soi\ 



500 



<m 



__ ? 



/It -•> ,., 



'33 nm 



,/Vr ".-. 



./< »■ * .- 

 ./ft "II 



5' >0 



/5 



Fig. 30. 



state II. The wire was then left hanging under its load through 

 the summer months without vibration and in a room of prac- 

 tically constant temperature. On October 6, 1915, or four 

 months later, the experiments were continued and the pendu- 



