PHYSICAL CHAEACTEES OF MIXTUEES AND SOLUTIONS. 
335 
Table II. 
Per cent-., by weight, of 
absolute methylic 
alcohol. 
Specific heat found. 
Specific heat 
calculated. 
Difference. 
10 
98-582 
95-832 
+ 2-750 
20 
95-914 
91-665 
4-249 
30 
92-658 
87-497 
5-161 
40 
89-219 
83-330 
5-889 
50 
84-645 
79-162 
5-483 
60 
80-177 
74-995 
5-182 
70 
75-500 
70-827 
4-673 
80 
69-999 
66-660 
3-339 
90 
64-282 
62-492 
1-790 
100 
58-325 
Section II . — Heat produced by the mixing of Methylic Alcohol and Water. 
The amount of heat produced is estimated as follows : — An annular vessel made of thin 
brass, such as described in the section Specific Heat, and capable of holding about 100 
cub. centims., is immersed in the water of the calorimeter. The vessel has two openings 
provided with short tubes, which reach above the surface of the water when the whole 
body of the vessel is submerged. Through one of these tubes passes tightly a rod con- 
nected with an efficient stirrer moving up and down the annular space ; the other tube 
carries a small glass funnel which can be closed by a stopper. The experiment is con- 
ducted as follows : — One of the two liquids is weighed out in the brass vessel, the other 
is weighed out in a thin glass bulb, the quantity of liquid remaining in the bulb when 
it is emptied, and that which adheres to the sides of the small funnel, which experience 
had shown to be a very constant quantity, being allowed for, so that the exact amount 
of liquid necessary is delivered into the brass vessel. The brass vessel is now fixed in its 
proper position in the calorimeter, which is then filled with water a little below the 
temperature of the room ; and the glass bulb containing the other liquid is also immersed 
in the calorimeter. After the lapse of fifteen minutes, the water in the calorimeter 
having been stirred from time to time, the temperature of the various fluids has become 
equalized. The glass bulb is now taken out without touching it with the hand, and its 
contents are poured rapidly through the funnel into the brass vessel; the funnel is 
closed, and the two fluids in the brass vessel thoroughly mixed by means of the stirrer. 
The temperature of the water in the calorimeter, which is constantly stirred, reaches a 
maximum in from 4 to 5 minutes ; it is observed during 2 or 24 minutes longer, and 
any fall observed is added as a correction to the highest temperature reached. As, 
however, the whole rise is small, this correction usually amounts to very little, and fre- 
quently to nothing. From the data thus obtained the heat produced by mixing the 
liquids in the brass vessel is calculated, the water value of the mixture in the brass 
vessel being of course added to the water value of the calorimeter and contents. 
