98 



Messrs. V. H. Veley and J. J. Manley. 



A second example taken from the descending portion, namely, for 

 acids of percentage values from 60*60 to 65*80 per cent., illustrates 

 the same phenomenon. 



Here also the result for the 60'60 per cent, acid belongs to the 

 straight line drawn from the 53'8 origin, and conversely those for 

 the 63'83 and the 65'8 per cent, acids belong to the straight line 

 drawn from the 6 3 -6 per cent, origin, while the remaining two can 

 equally be represented as belonging to either line. 



Secondly, a transition stage, in which the observation points lie 

 upon neither of the straight lines. This is best exemplified by the 

 results obtained at all three temperatures for the alteration at about 

 20 21 per cent, concentration, which was more particularly investi- 

 gated in consequence of the divergence between the observed and 

 calculated results for the acids of about 19-5 per cent, concentration. 



In the three succeeding tables the observed contractions are com- 

 pared with those calculated either forwards or backwards from the 

 two respective origins of co-ordinates. 



