604 
DR. A. DUPRE AND F. J. M. PAGE ON THE SPECIFIC HEAT AND OTHER 
Table VII. 
Per cent, by weight 
of absolute alcohol. 
Specific heat, found. 
Specific heat, 
calculated. 
Difference. 
5 
101-502 
10 
103-576 
96-043 
+ 7-533 
20 
104-362 
92-086 
12-276 
30 
102-602 
88-129 
14-473 
40 
96-805 
84-172 
12-633 
45 
94-192 
82-193 
11-999 
50 
90-633 
80-215 
10-418 
60 
84-332 
76-258 
8-074 
70 
78-445 
72-301 
6-144 
80 
71-690 
68-344 
3-346 
90 
65-764 
64-387 
1-377 
100 
60-430 
Section II . — Heat produced by the mixing of Alcohol and Water. 
The amount of heat produced by mixing alcohol and water in various proportions 
was estimated as follows : — 
The liquid which formed the smallest portion of any given mixture was enclosed in 
a very thin glass bulb with a long narrow stem, the bulb and contents being carefully 
weighed. 
The necessary quantity of the other liquid was then weighed out in a small calori- 
meter, made of very thin polished brass ; into this calorimeter, supported as usual on 
stretched silk cords, surrounded by a cylinder of tin plate, and with a delicate thermo- 
meter immersed in the liquid, the glass bulb with its contents was introduced, and 
allowed to remain for ten minutes, the bulb itself being used to stir the liquid. At 
the end of that time the temperature of the calorimeter was observed ; the glass bulb 
was then raised partly above the surface of the liquid in the calorimeter, broken by a 
smart tap with a file, and, by means of the portion of the broken bulb remaining attached 
to the stem, the contents of the calorimeter were thoroughly mixed. 
In less than a minute the thermometer in the calorimeter reached a maximum, and 
at once began to fall ; this fall was observed for thirty seconds, and added to the rise of 
temperature observed. 
From the data thus obtained, the specific heat of the mixture formed being known, 
the number of units of heat evolved by 5 grms. of the mixture was calculated. 
