274 Mr Bevan, A Method of following the Course 



The following table contains the results of two such experi- 

 ments. In the first column is the time from the beginning, in the 

 second the observed resistance, and in the third the conductivity. 



T hours 



R 



Conductivity 

 xlO 6 



T 



minutes 



R 



Change of 



Conductivity 



xlO 6 



•036 



247 ; 2 



4046 



9 



200-2 



4996 



■067 



247-0 



4049 



10 



200-0 



5000 



•129 



246-0 



4065 



13 



199-5 



5012 



•177 



245-5 



4074 



16 



199-4 



5014 



•253 



243-7 



4103 



18-3 



199-0 



5025 



•396 



238-0 



4202 



22 



198-4 



5044 



•484 



2350 



4255 



23-5 



198-1 



5048 



•580 



232-6 



4299 



26 



197-6 



5060 



•650 



230-5 



4339 



27-25 



194-7 



5067 



•790 



2265 



4419 



39 



192-0 



5208 









42 



191-0 



523.6 









45 



191-0 



5236 









46 



190-2 



5258 









49-5 



189-5 



5276 









50-5 



189-0 



5291 









53 



188-0 



5319 



These results are plotted in figures 2 and 3. It is obvious 

 from these curves that we have not, in the initial stages of the 

 observations, the increase in conductivity to be expected if the 

 action at once begins as a monomolecular one. We have to con- 

 sider what effects we should expect at the beginning of the action 

 which might be due to the conditions not being the steady ones 

 attained a short time after the action has commenced. Firstly, 

 the temperature of the solution would probably be rather below 

 the steady temperature as the solution has to be made, and in 

 transferring it to the conductivity vessel its temperature would 

 fall slightly. This was avoided as far as was possible by perform- 

 ing all operations in the thermostat. But any effect due to this 

 cause would be in the opposite direction. For if initially the 

 temperature were too low the conductivity would be less than the 

 proper amount, and as the solution attained the steady thermo- 

 stat temperature the conductivity would shew a faster rate of 

 increase than if the temperature all through were constant. 

 Secondly, we might have an effect due to incomplete mixing of 



