PHYSICAL CHARACTERS OE MIXTURES AND SOLUTIONS. 
345 
Table X. 
Temperature, in 
degrees Centigrade. 
Specific gravity. 
Difference. 
Found. 
Calculated. 
• 
30 per cent, spirit. 
0 
96540 
93268 
+ 3272 
]0 
95998 
92907 
3091 
20 
95403 
92490 
2913 
30 
94751 
91988 
2763 
70 
91669 
89389 
2280 
20 per cent, spirit. 
0 
97566 
95407 
+ 2159 
10 
97263 
95142 
2121 
20 
96877 
94805 
2072 
30 
96413 
94386 
2027 
70 
93863 
92024 
1839 
1 0 per cent, spirit. 
0 
98493 
97643 
+ 850 
10 
98409 
97508 
901 
20 
98191 
97259 
936 
30 
97892 
96914 
978 
70 
95815 
94815 
1000 
The specific gravity of the 30 per cent, spirit thus really approaches more and more 
to its calculated value ; in the case of the 20 per cent, spirit this approach, though 
still perceptible, is, however, considerably less, both absolutely and proportionally. 
Finally, with the 10 per cent, spirit, the phenomenon is actually reversed, the observed 
specific gravity gradually receding from the specific gravity as calculated ; and so far from 
any dissociation being indicated, the opposite rather seems to take place. 
It may be well here to recall to mind that 5 grins, of a 30 per cent, spirit, when heated 
from 0° to 70° C., require about 25 units of heat in excess of what would be necessary to 
raise the constituents separately through the same interval. This excess amounts to 
about 21 units with the 20 per cent, spirit, and to about 13 units in the case of the 
10 per cent, spirit. No apparent connexion, therefore, seems to exist between the rate 
of expansion and the high specific heat. 
Methylic Alcohol and Water. 
The great volatility of methylic alcohol presents considerable difficulties to the accurate 
estimation of the various properties of these mixtures, more particularly as regards the 
specific heat and the heat evolved on mixing. In addition to this, the elevation of the 
specific heat of the various mixtures above the calculated value is but small, and therefore 
even slight errors will have a much greater influence on any calculations based on the 
difference between the values as found and as calculated. 
