1898-99.] Sulphuric Acid and Sulphates in Solution. 
511 
Third- Series. 
khso 4 
X . 
Percentage Free Acid. 
Observed. 
Calculated. 
Observed. 
Calculated. 
0-2 
•0748 
•0727 
62-6 
63-6 
015 
•0489 
•0484 
67‘4 
67*7 
o-i 
•0282 
•0271 
71-8 
72-9 
0-05 
•0088 
•0097 
82-4 
80-6 
0-025 
*0025 
•0030 
90-0 
88-0 
The general agreement between the two sets of numbers in each 
series is best seen in the curves of the accompanying diagrams. 
In these the ordinates are the percentages of free acid, while the 
abscissae are the concentrations of sulphuric acid, potassium sul- 
phate, and potassium hydrogen sulphate respectively, in the first, 
second, and third series. The continuous line in each diagram is 
the curve given b'y the observed results, and the dotted line is the 
curve obtained by plotting the results calculated by the mathe- 
matical expression. 
