DEPRESSIONS FOR ELECTROLYTES MACGREGOR. 217 



Arrhenius, 1 Raoult, 2 Loomis, 8 Jones, 4 Abegg, 5 Wilderraann, 6 Ponsot, 7 

 Archibald 8 and Barnes 8 . The methods used by these observers 

 are, for the most part, well known. Archibald and Barnes used 

 modified forms of Loomis's method. Arrhenius's observations, 

 and some of Raoult's, were made before important improvements 

 in freezing-point determinations had been recognised, as neces- 

 sary. 



In cases in which there was but one series of observations 

 available, I have plotted the actual observations in the diagram, 

 though sometimes smoothing the curves a little. In cases in 

 which two or more series were available, I first plotted the vari- 

 ous observations, and then drew mean curves, making them 

 represent all the observations as well as I could, but giving 

 greater weight to recent observations than to those of earlier 

 date, and to long series of consistent observations than to short 

 series, or to series which were more erratic. 



The following table gives the data employed in plotting both 

 the curves given in the diagram, and those not so given, which 

 are referred to below. The table includes the concentration in 

 gramme-equivalents per litre, the ionization coefficient at 0, and 

 the equivalent depression in degrees centigrade per gramme- 

 equivalent in one litre of solution. The interpolated coefficients 

 are indicated by i, and those extrapolated by e, and the observers 

 from, or by the aid of, whose observations they were obtained, 

 by A, B, D, W, representing Archibald, Barnes, D6guisne and 

 Whetham. Non-significant figures are printed in italics. 



1 Ztschr, f. phys. Chemie. 2, 491. 1888. 



2 Ibid., 2, 501. 1888, and 27, 617, 1898. 



3 Phys. Review, 1, 199 and 274, 1893-4 ; 3, 270, 1896, and 4, 273, 1897. 



4 Ztschr. f. phys. Chem., 11, 110 and 529, 1893 ; and 12, 623, 1893. 

 8 Ibid. 20, 207, 1896. 



Ibid. 19, 233, 1896. 



7 Recherches sur la Cong61ation des Solutions Aqueuses : Paris, Gauthier-Villars, 

 1896. 



