102 RESPONSE IN THE LIVING AND NON-LIVING 



allowed to cool down to its original temperature. The 

 six following pairs of responses were then taken. 

 That this beneficial effect of annealing was not due 

 to any accidental circumstance will be seen from the 

 fact that both wires have their sensitiveness equally 

 enhanced. 



(4) In addition to this mode of annealing, both 

 wires may be short-circuited and vibrated for a time. 

 Lastly (5) slight stretching in situ will also sometimes 

 be found beneficial. For this purpose I have a screw 

 arrangement. 



By one or all of these methods, with a little practice, 

 it is always possible to bring the wires to a normal con- 

 dition. The responses subsequently obtained become 

 extraordinarily consistent. There is therefore no reason 

 why perfect results should not be arrived at. 



Effect of single stimulus. The accompanying figure 

 (fig. 59) gives a series, each of which is the response- 

 curve for a single stimulus of uni- 

 form intensity, the amplitude of 

 vibration being kept constant. The 

 perfect regularity of responses will 

 be noticed in this figure. The wire 

 after a long period of rest may be in 

 FIG. 59. UNIFORM BE- an abnormal condition, but after a 



SPONSES IN TlN 



short period of stimulation the re- 

 sponses become extremely regular, as may be noticed 

 in this figure. Tin is, usually speaking, almost inde- 

 fatigable, and I have often obtained several hundreds 

 of successive responses showing practically no fatigue. 

 In the figure it will be noticed that the rising portion 



