150 Knight and Priestley . — The Respiration of Plants 
A series of experiments was carried out in this manner, the corrected 
curves showing a similar coincidence with the normal curve (Table XI). 
It should be noted here, and the same applies to all temperature cor- 
rections, that such corrections can only be regarded as approximate owing 
to the difficulty of making accurate determinations of temperature. 
The rate of conduction of heat through peas is very slow, and in some 
extreme cases it was observed that after electrification there was a difference 
of temperature between the highest and lowest level of seeds of 6° C. 
This is liable to increase the possible error of temperature readings, which, 
in order to be consistent, were always taken with the thermometer bulb just 
covered with seeds, and readings were taken as often as convenient, viz. at 
intervals of five or ten minutes. 
This inaccuracy probably accounts for the fact that the corrected curve 
mentioned above is not quite smooth, as a normal curve should be. 
Steps were now taken to ascertain if, as the form of the corrected curve 
seemed to suggest, when temperature effects were eliminated, the effect of 
the discharge upon respiration was also eliminated. 
This was first attempted in an indirect manner thus : 
The respiration chamber was immersed in a large water-bath, and 
instead of applying the discharge, the temperature was regulated by means 
of the bath, and was made to vary to the same extent and at the same 
intervals as in No. 98. 
