Experimental Researches on Vegetable Assimilation and RespirationIIIOn the Effect of Temperature on Carbon-Dioxide Assimilation . o insulate it, and toprevent contact with the water. This rubber tube was then tied to a thermometer,so that the thermo-electric junction was just against the bulb. This stood in avessel of water which could be brought to any desired temperature. Very thick copper wire was employed for making the connections with the galvano-meter, since the latter had to be placed in the next room to avoid disturbancesdue to the working of the water-motor supplying the light. It wa
Experimental Researches on Vegetable Assimilation and RespirationIIIOn the Effect of Temperature on Carbon-Dioxide Assimilation . o insulate it, and toprevent contact with the water. This rubber tube was then tied to a thermometer,so that the thermo-electric junction was just against the bulb. This stood in avessel of water which could be brought to any desired temperature. Very thick copper wire was employed for making the connections with the galvano-meter, since the latter had to be placed in the next room to avoid disturbancesdue to the working of the water-motor supplying the light. It was found mostexpedient to connect these wires to those from the thermo-elements by means ofmercury cups. These were all fixed on the edge of the bath to insure equality oftemperature, lest any slight difference in purity between the thin and the thickcopper wires might cause them to act as secondary thermo-elements. The constantanwire from the thermo-element in the leaf was connected with that from the controlthermo-element by another mercury cup. The temperature was not read directly by means of the galvanometer, but a zero. i*-* Section through leaf and chamber and oneof the two U-tubes. 78 MISS C. MATTHAEI ON EXPERIMENTAL RESEARCHES ON method was employed, , the temperature of the water round the control elementwas adjusted until there was no deflection. The temperature of the control ther-mometer then indicated the real temperature of the leaf. This method worked verysatisfactorily, and it was easy to determine the temperature to within half a degree,an accuracy quite sufficient for the purpose. (c) Final Experiments. In Section III. experimental evidence was given showing that from —6° C. to+11° C,if sufficient light be provided, the assimilation increases with the temperature. Inthe present section it has been possible to prove, by determining the internaltemperature of the leaf, that this relation is maintained to within a few degrees ofthe death-point of th
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