1872.] 



of Mixtures of Methylic Alcohol and Water. 



337 



wheel in the inner cylindrical space to serve as stirrer. The steam-oven is 

 heated by the vapour of methylic alcohol. 



The mean results are given in the following Table : — 



Table I. 



Percentage 

 of methylic 

 alcohol, by- 

 weight. 



Specific heat 

 found. 



Specific heat 

 calculated. 



Diilerence. 



10 



98-582 



95-832 



+2-750 



20 



95-914 



91-665 



4-249 



30 



92658 



87-497 



5-161 



40 



89-219 



83-330 



5-889 



50 



84-645 



79-162 



5-483 



60 



80177 



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 2. Heat produced by mixing Methylic Alcohol and Water. 



This is estimated by mixing the alcohol and water, in the required pro- 

 portion, in an annular vessel similar to the one used for the estimation of 

 the specific heat, and observing the elevation of temperature produced in 

 the water of a calorimeter in which the annular vessel is immersed. The 

 units of heat evolved in the formation of 5 grms. of each mixture were thus 

 calculated and found to be : — 



Table II. 



10 per cent. 



spirit . . 



.. 20*930 



60 



per cent, spirit . . 



.. 41-493 



20 



»> • • 



.. 37*276 



70 



)> )> • • 



.. 34-456 



30 



>y • • 



.. 44-744 



80 



a >» 



.. 22-448 



40 



)> • • 



.. 45-384 



90 





13-164 



50 





.. 44-429 









The temperature at which the mixing took place ranged between 16° 

 and 20° C. 



Section 3. Boiling-points. 



The mixtures were boiled in a flask connected with a condenser, by 

 which the vapours are condensed and made to run back into the flask ; the 

 composition of the mixture is thus kept as uniform as possible. 



The cold liquid running back is prevented from disturbing the boiling 

 by having to pass down a tube placed inside the flask, in which it becomes 

 heated nearly to boiling before it flows into the boiling mixture. The 

 following Table gives the results, the barometer standing at 757*4 millims. 

 The numbers in column 3 are calculated on the assumption that the 



