136 DENSITY OB^ SOLUTIONS — MORRISON. 



the calculated values exceed the observed values are given in the 

 fourth column. They will be seen to bear out this statement. 

 It may be well to note that the values of the constant multi- 

 pliers of p in the two formulae given above, that is, the values of 

 the mean rate of change of density with concentration, through- 

 out concentration ranges of from zero to about 2.5 per cent., in 

 the case of these salts, are approximately the same. They are 

 also approximately the same* as the same rates of change in the 

 case of zinc and magnesium sulphates, and not very different 

 from those of iron, cadmium, copper, aluminium and other 

 sulphates. 



* Trans. Roy. Soc. Can., Vol. VH, (1889), See. iii, p. 31. 



