602 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



As will be seen later, paste plates show no such flat place in their 

 curves. [§11.] 



The values for this Plants cell, discharged at 2 amperes at various 

 temperatures [Table III], are all plotted on the curves of Figure 5. 

 The corresponding voltage curves will be found in Figure 6. 



The characteristic points appear in each curve, and the flat place 

 moves toward a later point in the discharge curve, as might be ex- 



90 

 TIME -MINUTES 



Figure 6. Voltage curves of Plante cell during discharge at various 

 temperatures. 



pected, when the temperature is raised. This means merely that the 

 material of the plate can be better reached and utilized at the higher 

 temperature, and that therefore more of the active material on the ribs 

 enters the reaction, leaving the mass of material at the bottom of the 

 grooves for a later period of the discharge. 



It is by no means easy to be sure that the cell has reached the steady 

 state corresponding to any given temperature, except by maintainmg 

 it at the new temperature for several hours. The lag of resistance be- 

 hind its final value when temperature is quickly changed is very no- 

 ticeable and caused us much trouble. We finally found it best to keep 

 the cell for at least six hours at the new temperature before trying to 

 take a discharge curve. 



It will be noticed that the curve for 25° C. does not fit in very well 



