Freezing-point Depressions for Electrolytes. 517 



part with Jones's and Loomis's as well. But in the upper 

 part Jones's curve goes off markedly to the right, and 

 Looinis's markedly to the left. Wildermann's is slightly to 

 the left at the lower end, and diverges somewhat leftwards in 

 the upper part. Ponsot's runs nearly parallel to it somewhat 

 to the left, and diverges to the left at higher dilutions. The 

 JLB-B curve is thus trustworthy in form, but being plotted 

 with Barnes's coefficients it is possibly too low. The actual 

 curve would thus appear to cross the 2-3 (1"85) line not far 

 from its starting-point, bend towards the 4-6 (1*85) line, and 

 run down below that line, finally bending slightly towards it 

 again. Its course is therefore what it would be if it started 

 as a 2-3 curve for k=l'85 or thereabout, changed its curva- 

 ture at a somewhat early stage, and tended to be transformed 

 slowly into either a double-molecule curve or a 2-2 curve, or 

 perhaps both at once. The diagram would therefore indicate 

 that at extreme dilution H 2 S0 4 exists in solution in single 

 molecules dissociating into three ions ; that at an early stage 

 and in a somewhat marked manner, either doubling of 

 molecules sets in, or partial dissociation into two ions or 

 perhaps both ; that the change increases slowly and steadily as 

 dilution diminishes, and that at a concentration of about 0"6, 

 if the coefficients at this concentration are to be trusted, the 

 change is increasing in rate ; also that the depression-constant 

 may quite readily be about 1'85. 



The K 2 S0 4 (LJA-A) curve is based on series of observa- 

 tions which in the main are in good agreement. It very 

 nearly coincides with the Loomis and Archibald curves, and 

 Ponsot's (not shown) runs down slightly to the left. In its 

 lower part it coincides with the Jones curve, but in its upper 

 part Jones's curve (separately represented for great dilutions) 

 runs off to the right. Abegg's curve for higher dilutions 

 runs much more markedly to the right, though it is farther 

 to the left at its lower end. Arrhenius's (not shown) is con- 

 siderably to the right and diverges widely rightwards. The 

 Na 2 S0 4 (LA-A) curve is also almost coincident with both 

 the Loomis and the Archibald curves. Both Raoult's and 

 Arrhenius's (neither shown) are considerably to the right and 

 diverge slowly rightwards. Such of these curves as are 

 entered on the diagram, being plotted with Archibald's 

 coefficients, are probably too high or too low, as the case may 

 be. Those for great dilutions are too discordant to admit of 

 discussion. The mean curves for both salts have the same 

 general form. They run down, as drawn, a little below the 

 21-3 (1*85) line. Their upper ends are so directed as to 

 suggest their running out at the 2-3 (1*85) intersection or 



