224 



ON* A DIAGRAM OF FREEZING-POINT 



The curves of the diagram are so labelled with the initial 

 letters of observers' names, (Ab for Abegg), as to show both the 

 depression observations, on which they are bsed, and the ioni- 

 ization coefficients used in plotting them. Thus the inscription 

 KC1 (J W), means that Jones' depressions and Whetham's 

 coefficients were used ; H 2 S0 2 (J L B B), that the curve is a mean 

 curve based, mainly at least, on depression observations by Jones, 

 Loomis, and Barnes, and plotted with Barnes' coefficients. The 

 limits of concentration for the curves, are indicated also, in 

 gramme-equivalents per litre. 



Some of the curves are entered on an inset, drawn on four 

 times the scale of the main diagram. 



In interpreting the curves, we must not only bear in mind 

 what has been said above about the probable accuracy of the 

 ionization coefficients, but must in addition note the tendency 

 exhibited by the curves of the various observers, as dilution 

 increases, to run off at great dilution in directions characteristic 

 of the observers, to the left or right relatively to the course pur- 

 sued by them at moderate dilution. Thus Abegg's curves (see 

 Nad, KC1, K 2 S0 4 ), and Jones's (see NaCl, KC1, NH 4 C1, HC1) 

 run off to the right. So do Arrhenius's in a marked manner. 

 Raoult's tendency is also to the right, (see NaCl ; his K 2 SO 4 , not 

 plotted, shows it also ; his most dilute KC1 observation, he him- 

 self clearly regards as accidentally out.) On the other hand, 

 Loomis's curves (see HC1, KN0 3) NH 4 C1, BaCl 2 ) go to the left. 



