338 
DR. A. DUPRE ON THE SPECIFIC HEAT AND OTHER 
alcoholic mixture in column 6, and affords, therefore, a measure of the relative strength 
of the molecular attraction in the various mixtures. 
Column 8 gives the heights calculated on the assumption that they will be propor- 
tional to the weight of the constituents of each mixture. 
Column 9 gives the difference between columns 7 and 8. 
The observed heights given are in each case the mean of two closely concordant 
experiments. The temperature at which the experiments were made was I3°*5 C. 
Table V. 
1. 
Alcohol 
per cent. 
2. | 3. 
Heights observed. 
4. | 5. 
Heights, assuming 
water 100 millims. 
6. 
Mean of 
columns 
4 and 5. 
7. 
Relative 
molecular 
attraction. 
8. 
Height 
calculated. 
9. 
Difference. 
Tube 1. 
Tube 2. 
Tube 1. 
Tube 2. 
0 
74*575 
51*050 
100*000 
100*000 
100*000 
100*000 
10 
51*875 
35*225 
68*645 
69*001 
68*820 
67*818 
93*334 
-25*416 
20 
44*400 
30*075 
58*749 
58*912 
58*830 
57*264 
86*667 
29*403 
30 
39*550 
26*850 
52*332 
52*595 
52*463 
50*381 
80*001 
29*620 
40 
36*975 
25*000 
48*942 
48*971 
48*947 
46*252 
73*335 
27*083 
50 
34*925 
23*925 
46*212 
46*865 
46*538 
43*136 
66*668 
23*532 
60 
34*925 
23*650 
46*212 
46*327 
46*269 
42*170 
60*002 
17*832 
70 
34*050 
23*125 
45*054 
45*298 
45*176 
40*034 
53*336 
13*302 
80 
33*270 
22*500 
44*022 
43*973 
43*997 
37*955 
46*669 
8*714 
90 
32*100 
21*825 
42*474 
42*750 
42*612 
35*671 
40*003 
4*332 
100 
30*650 
20*850 
41*099 
40*842 
40*970 
33*337 
Section Y. — Specific Gravity and Bate of Expansion. 
The mixtures are made by accurately weighing out the required quantities of absolute 
methylic alcohol and water. This is done in two separate flasks, which are afterwards 
joined together, air-tight, by a short india-rubber tube; and the thorough mixture is 
effected by repeatedly pouring the fluids from one flask into the other through the tube. 
In some of the mixtures a considerable rise in temperature takes place ; but as the mixing 
is effected in a closed vessel no loss of alcohol is experienced. The flasks, still kept con- 
nected, are allowed to cool ; the mixture is put into a bottle, which should not be less 
than three quarters filled, and the air is exhausted from the bottle. In this state the 
bottle is allowed to stand over night, by which means the air dissolved in the mixture 
is got rid of without appreciable loss of spirit. 
Table VI. gives the observed specific gravities of the mixtures at the temperatures of 
10° and 20° C., water at 4° C., taken as the unit, together with the calculated specific 
gravities at 10° and the difference between the observed and calculated specific gravities. 
Table VII. gives the expansion of 100 volumes of the mixture when heated from 10° 
to 20° C., calculated from the data of the previous Table. The figures in column 4 are 
calculated on the assumption that the expansion is proportional to the volumes of the 
constituents, the contraction taking place on mixing being allowed for. 
To facilitate this calculation (as also the compressibility), Table VIII. gives in 
