2 2 4 



REV. S. M. JOHNSTON 



Before passing on to discuss these high values, it is desirable to look at plotted curves 

 and consider what information may be obtained from them. For this purpose curves 

 have been drawn for which I have plotted elevation of the boiling point in degrees 

 Centigrade successively against (1) grammes of salt added to a constant amount of 

 water, (2) percentage composition, (3) gramme equivalents per litre. 



From the tables which have been given for concentrated solutions, and the curves 

 for which gramme equivalents have been plotted against elevation of the boiling point 

 in degrees Centigrade given below, it will be seen that the concentration has in 

 several instances been as great as six or seven gramme equivalents per litre. 



ELEVATION OF BOILING POINT IN DEGREES CENTIGRADE 



Fig. 14. 



Considering that so high concentrations have been reached, the straightness of a 

 considerable number of the curves (see page 222) for which grammes of salt added have 

 been plotted against elevation of the boiling point in degrees, is noteworthy. This 

 is particularly so for the curves for cadmium iodide, ammonium sulphate, ammonium 

 iodide, ammonium bromide, and lithium nitrate. The same is true in a smaller degree 

 for the curves for sodium chloride, sodium bromide, and ammonium chloride, and 

 in a still less degree for the curve for lithium chloride. 



The curves given above on pages 222, 223, and 224 illustrate how change in plotting 

 a ff< sets curvature, those on page 222 being much straighter than either those on page 

 223 or page 224. The curves on page '224 indicate that, for concentrated solutions 

 generally, the boiling-point elevation increases more quickly than the number of 

 gramme equivalents per litre, and those on page 223 indicate that the elevation of 



