276 Mr Bevan, A Method of following the Course 



the solution. The solution was made in a beaker in the thermo- 

 stat, and was well stirred before being placed in the conductivity 

 vessel to have a well-mixed solution when the observations were 

 made. But in this case also any effect would be to make the initial 

 resistance too great, and therefore the initial conductivity too small, 

 so that as the mixing became more complete the initial rate of 

 increase of conductivity would be too great. These two purely 

 practical causes would then lead to a diminution of the induction 

 effect rather than to its production. 



There remains another consideration. It is well known that 

 with very dilute solutions the molecular conductivity decreases 

 rapidly with increasing dilution. When the action begins the 

 hydrochloric acid is for some time present in very small quantities, 

 and it might be thought that some effect of this kind might give 

 too slow an increase of conductivity initially. To decide this an 

 experiment was performed in which the solution was made with 

 a dilute solution of hydrochloric acid instead of water. In this 

 case the hydrochloric acid was present already in sufficient quantity 

 for any addition to it to produce an additive effect in the con- 

 ductivity. The following table gives the results of this experiment. 



Time in minutes 



Conductivity x 10 6 



5-1 



3973 



6-5 



3972 



12-5 



3978 



15-5 



3981 



17-7 



3984 



19-5 



3989 



21-3 



3992 



23-8 



3997 



27-1 



4004 



30-8 



4013 



32-8 



4020 



41 



4037 



43-5 



4046 



44-8 



4049 



49-2 



4057 



55-2 



4074 



58 



4082 



62 



4090 



64-5 



4098 



68 



4107 



