CONSTANT FOR ELECT ROLYTES—-HEBB. 411 
each case to break up into three ions, as, according to Prof. 
* MacGregor’s Diagram of Freezing-point depressions, it seems to 
do. 
In the case of MoSO, each gramme-molecule contains two 
eramme-equivalents, hence k=}m; and since each molecule 
breaks up into two ions we get /=1. 
In the case of H,PO,, if each gramme-molecule contains 
three gramme-equivalents, we have =m; also, if each molecule 
breaks up into two ions, as Loomis’s and Jones’s results seem to 
imply, we have l= 31. 
As the constants, 7 and 7, depend so simply on the constants, 
k and 1, the accuracy of their determination will depend on the 
accuracy with which we can determine k and /. Dr. MacGregor 
has shewn that the values of / can be determined with a much 
greater degree of accuracy than can hk. 
Thus if AB or AB’ be the true curve representing the rela- 
tion between 6 and a—the curves for different electrolytes bend 
in different ways—then the equation 6=k (1—a)+la will repre- 
sent the straight line AE, i.e, the tangent to the curve at 
infinite dilution if AC represents unity. 
a tA 
AAA 
Ba 
