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XIX. On the Specific Heat and other Physical Characters of Mixtures of Etliylic 
Alcohol and Water. By A. Dupre, Ph.D ., Lecturer on Chemistry at Westminster 
Hospital , and F. J. M. Page, B.Sc. Communicated by Charles Brooke, F.R.S. 
Received February 4, — Read March 11, 1869. 
Section I. — Specific Heat. 
The authors, having recently had occasion to estimate carefully the specific heat of 
mixtures of alcohol and water, came in the course of these experiments to the unex- 
pected result that the specific heat of such mixtures, up to an alcoholic strength of 
about 36 per cent., is sensibly higher than the specific heat of water itself. These expe- 
riments, to the best of their knowledge, furnish the first example of a liquid having a 
higher specific heat than water, which has always been considered to possess the highest 
specific heat of any substance solid or liquid. They therefore beg leave to lay their 
results before the Royal Society. 
Two methods were employed for the estimation of the specific heat. The first method, 
and the one chiefly used, consisted in heating a metallic weight to a certain tempera- 
ture, and then plunging it into the liquid whose specific heat was to be estimated ; the 
rise in temperature thus produced in different liquids will, after the necessary corrections, 
be inversely proportional to the specific heat of these liquids. 
Two weights were employed, one of brass, the other copper gilt, both 
well polished. They were made in the shape of stout rings — the internal 
diameter of the brass weight being 38 ‘5 millims., its external diameter 
49 millims., its height 39-5 millims., its weight 246-49 grms. ; the 
internal diameter of the copper ring was 39 millims., its external 
diameter 61 millims., its height 39-5 millims., and its weight 614-49 
grms. In the inner cylindrical space of each was inserted a small 
fan- wheel, resembling in its construction the wheel of a smoke-jack, 
so that, when the heated weight is caused to rotate rapidly in a liquid, 
a current is thus drawn through the ring, producing, first, a very com- 
plete mixture of the liquid, and, secondly, a more rapid cooling of the 
weight. 
The weights were heated in an apparatus exactly similar to that employed by Re- 
gnault in his researches on the specific heat of solids — steam, or the vapour of boiling 
alcohol being employed for heating them. 
The liquid whose specific heat is to be estimated is carefully measured in a narrow- 
necked flask, and poured into a calorimeter of very thin polished brass, supported on 
4 k 2 
Fig. 1. 
Annular weight 
and fan-wheel, 
half of the 
former being 
cut away to 
show the fan- 
wheel. 
