130 MR J. Y. BUCHANAN ON THE 



It would seem to indicate that in the solutions of any concentration less than 

 w=l/64 the dissolution of a small quantity of salt produces the same increment of 

 displacement. 



Table V. : — RbBr. — In sub-table a the value of cZA — v decreases very rapidly 



from 0*296 at m= 1/4, and changes to a negative value between m= 1/32 and m= 1/64, 



and then oscillates between alternate high negative values and low positive values. In 



sub-table c there is a regular increase in the negative values from m = 1/64 to m = 1/512. 



We have here definite evidence of expansion on dilution. 



Table VI.: — CsBr. — The character of the decline in positive values for c^A-v 

 is the same as that observed in the case of KBr and RbBr, and change of sign occurs 

 between 7n= 1/16 and m= 1/32. After this there is an irregular oscillation between 

 high positive and high negative values in sub-table a. 



In sub-table c the positive values persist to m= 1/32, after which change of sign 

 occurs, and the negative sign remains for all values down to m= 1/512. The negative 

 values reach a maximum at m= 1/128 and then decline. Here again we have definite 

 evidence of expansion. 



Table VII.: — KI. — A rapid decrease in positive values occurs between m=\/A 

 and w = ]/16. Then, with the exception of the small negative values of 0"01 8 and O'OIO 

 at ni = 1/32 and m = 1/512 respectively, there are small positive values for c?A — v. This 

 holds also in sub-table c, only that the positive and negative values for values of m below 

 1/82 are less. 



The final note for KBr applies with greater force in the case of KI. 



Table VIII. : — Rbl. — In sub-table a there is a sudden fall from a high positive 

 value of 0"133 for m=l/4 to a negative value of 0*012 at m=l/8. and then a 

 reversion to positive at 1/16 ; after this, the values are negative, except where 

 m= 1/1024. 



In sub- table c there is a more progressive decrease in positive values from m = 1/4 

 to m = 1/16, and between this and m = 1/32 there is change of sign. The negative values 

 increase gradually to a maximum of 0'035 at 1/256 and then decrease, and we have a 

 positive value of 0*006 at 1/1024. 



The evidence of expansion is conclusive. The character of these values is com- 

 parable with those of CsBr. 



Table IX. : — Csl. — In sub-table a, with the exception of the sudden fall to a negative 

 value of 0*007 at w= 1/16, there is a progressive decrease to m= 1/32, where change of 

 sign occurs between m= 1/32 and m= 1/64, and an increase in magnitude of negative 

 values to a maximum of 0*193 at w = 1/256, and then a slight fall. 



In sub-table c there is a progressive decrease in positive values to m = 1/32 ; then 

 change of sign, and progressive increase in negative values to 0*131 where m= 1/512, 

 a slight decrease occurring at m= 1/1024. 



The character of values for dA — t; in all three sub-tables is the same. This is the 

 most marked instance where expansion occurs. 



