302 



Mr. G. F. Emery. 



[Apr. 



The weakest of these solutions gave the best results, it seemed as 

 the stronger the solution was the more irregular the E.M.F. bee 

 All that can be said is that acetate of copper is very stror 

 thermoelectric-ally positive, and that a very minute quantity in wt 

 has a very great effect on the value of $. 



These experiments appear to show that a great part of the quantit 

 *> is due to the water, and that the presence of a salt in solution 

 increase or diminish the value of according to the nature of 

 salt. The next step was to see how far this effect was an additive 

 and for this various mixtures of the above salts were used. The 

 for water appears to be in the neighbourhood of = 8*6, but it cant 

 be measured directly, as with pure water the results are very 

 regular. The following table gives the value of 3 as observed for 

 mixture, the values for the separate salts of the same strength, 

 the value which would have if water were 8*6 and the differei 

 for the salts were additive. 



of ^ is not quantitatively additive, yet as far as direction is coucer 

 the differences do add, with the exception of the mixture of copj 

 sulphate and acetate, which turned quite milky during the heatii 

 though there was no trace of irregularity in the change of E.I 

 In a case where the components are both negative for the mixt 

 is below either of the 's for the components, while for a mixture 

 a positive salt with a negative one the value of is between those 

 the components. It will be noticed that in all the mixtures the 

 have one common component, so that there cannct be any 

 between the two salts. These results for mixtures of salts seem 

 be of value as supporting the theory that the final 5 in a solut 



