CHAPTER V 



THE ADDITIVE EFFECT ; INFLUENCE OF LOAD, TEMPERATURE, 

 AND INTENSITY OF STIMULUS 



Greater excitatory efficiency of the break-shock — Additive effect of 

 stimulus — Quantitative relation of additive effect — Effect of load — 

 Measurement of work under different loads — Rate of work — Thermal 

 chamber — Effect of temperature — Effect of increasing intensity 

 of stimulus on response. 



In exciting Mimosa by means of induction-currents we 

 may employ either the make- or break-shock. It has already 



been stated that the break-shock 

 is more efficient than the make- 

 shock. That is to say, as we 

 gradually push in the secondary 

 nearer the primary, excitation is 

 effected earlier with the break 

 than with the make. I will now 

 proceed to demonstrate this fact 

 by experiments. 



For obtaining the record I 

 employed a writer which had a 

 vibration-frequency of 20 times 

 per second. The make and break 

 of the primary current was 

 effected by a metronome. In 

 the primary circuit an electrical 

 signal (fig. 19) was also included, 

 which marked at the base of the 

 figure the moments when the 

 current was made and broken. When the current is made, 

 an up-line is described by the writer attached to the 



52 



Fig. 19. — The electric signal. 



