196 
DE. A. VERNON HARCOURT ON THE VARIATION WITH 
A few experiments made by various authors are appended (II.—XIII.). Most of 
these (II.-IX.) appear to satisfy the conditions for a stable* communication of heat 
energy to chemical energy at the temperatures of the experiments, and confirm the 
law of connexion between chemical change and temperature assumed in the previous 
discussion of Harcotjrt’s observations. The others (X.-XIII.) show a variation in 
the value of m which sometimes increases and at other times decreases with 
temperature. In these cases the values of m are calculated from the formulm of the 
authors, which for this calculation are a suflicient approximation to the true values. 
But the relations thus obtained between m and temperature must be regarded as 
empirical, and hold good only for the range of temperature of each set of observations. 
These variations in the values of m are considered to be side effects of temperature 
which interfere with the main effect of temperatures upon the chemical changes. 
II. ‘ Influence of the Temperature on the Bate of Hydrolysis of Ethyl Acetate by 
Caustic Soda,’ Beicher, quoted by van ’t Hoff, translated by Ewan, 1896, 
p. 130 (4). 
The values of k are calculated from the relation — (T/Tj)™, m being 18’9. 
t. 
h 
Found. 
Calculated. 
Author. 
9-4 
2-307 
2-31 
(2-307) 
14-4 
3-204 
3-22 
3-2 
24 • 22 
6-161 
6-10 
(6-151) 
35-14 
12-096 
12-00 
11-97 
44-94 
21-648 
21-77 
(21-648) 
The values of h enclosed in brackets are assumed by the author to be correct. The 
two remaining values of k are calculated from the relation 
log k = •0074T-1780T-' + 4-53. 
The simpler relation 
log A— 18-9 log (T/Ti)+'364, 
in which the constants are calculated by the method of least squares, gives values of 
k agreeing with those found within the limits of experimental error. 
III. ‘ Influence of the Temperature on the Velocity of the Beaction between 
Potassium Chlorate and Ferrous Sulphate in presence of Sulphuric Acid,’ Hood, 
quoted by van’t Hoff, translated by Ewan, 1896, p. 132 (5). 
The values of k are calculated from the relation kW = (T/Ti)”*', m being 26T8. 
