BETWEEN THE FREEZING AND BOILING-POINTS. 
253 
Temperature Coefficient of the Radiation Loss. 
It is not possible to obtain a very accurate measure of the temperature coefficient 
of the radiation correction from the present experiments. At the same time we may, 
from the different series covering different ranges of temperature, form some idea. 
During a series of experiments the radiation loss remained exceedingly steady, except 
that repeatedly after the calorimeter had returned from a high point the heat-loss 
was found to have been increased, but tended to return to its old value with lapse of 
time. On account of the slowness of the change, this occurred without producing any 
serious effect on the measure of the specific heat of the water. These changes were 
attributed to the effect of the small trace of occluded gases and vapour left in the 
glass vacuum-jacket. It is interesting in the case of Calorimeter C to trace the 
gradual alteration in the heat-loss, from series to series, during the time of the 
experiments. 
All of the experiments made at a mean temperature of about 30° are given in the 
following table :— 
Date. 
Temperature. 
h observed. 
h corrected to 
30° C. 
Remarks. 
February 20. . 
29-09 
- -04944 
■05008 
22. . 
29-11 
•04937 
■05000 
March 2 . . . 
29-21 
•04965 
■05021 
June 8 . . . 
31-40 
■05334 
■05235 
After trial experiment at 40°. 
„ 9 . . . 
32-17 
•05282 
•05138 
„ 20 .' . . 
32-81 
•05429 
•05230 
„ an experiment at 60°. 
„ 22 . . . 
30-54 
•05364 
•05326 
September 4. . 
29-47 
•05352 
•05389 
,, experiments at 60° and 70°. 
„ 6. . 
31-22 
•05518 
•05432 
November 27 . 
29-43 
•05316 
•05356 
„ experiments at 0°. 
January 1 . . 
29-13 
•05299 
•05361 
February-24. . 
32-26 
•05791 
•05631 
,, an experiment at 86°. 
The values of the heat-loss per degree rise from the experiments on October 14 and 
October 18, with rises of temperature of 8° and 5° respectively, when the flat heating- 
wire was used, are :— 
October 14 . 2877 '05826 '05913 
„ 18. 28'52 '05870 '05975 
These values show a decided increase in the heat-loss, but was due, no doubt, to 
the wire being in direct contact with the glass flow-tube of the calorimeter. 
In regard to the temperature coefficient of the radiation loss, this may be calculated 
from the observations in any of the different series. Series II. is the most suitable, 
extending at different temperatures between 22° and 60°, over the middle of the 
