1869.] 



On Aqueous Mixtures and Solutions. 



333 



II. " On the Specific Heat and other physical properties of Aqueous 

 Mixtures and Solutions." By A. Dupre, Ph.D., Lecturer on 

 Chemistry at the Westminster Hospital, and P. J. M. Page. 

 Communicated by C. Brooke, F.R.S. Received February 4,1869. 



(Abstract.) 



Part I. 



Mixtures of Ethylic Alcohol and Water, 



Section 1. Specific Heat. 

 For the methods employed in estimating the specific heat of these mix- 

 tures, see a former abstract, Proceedings of the Royal Society,' vol. xvi. 

 p. 336. 



In the present paper the authors give the specific heat of an additional 

 number of mixtures, so as to complete the series for every 10 per cent, 

 from water to absolute alcohol. 



The following Table gives the mean of the results obtained in all experi- 

 ments, details of seventy-four of which are given : — 



Percentage of 



Specific heat 



Specific heat 



Difference. 



alcohol, by weight. 



found. 



calculated. 



5 



IOI"502 











IO 



103-576 



96-043 



+ 7*533 



20 



104*362 



92-086 



12-276 



30 



I02"602 



88-129 



14*473 



40 



96-805 



84-172 



'2-633 



45 



94-192 



82-193 



11-999 



50 



90-633 



80*215 



10-418 



60 



84-332 



76-258 



8-074 



70 



78-445 



72-301 



6-144 



80 



71-690 



68-344 



3*346 



90 



65764 



64-387 



i'377 



100 



60-430 











Section 2. Heat produced by the mixing of Alcohol and Water. 



This was estimated as follows : — The liquid which formed the smallest 

 portion of the mixture was sealed up in a thin glass bulb ; this was then 

 introduced into the calorimeter, the glass bulb was broken, the mixture 

 formed, and the rise in the temperature of the calorimeter observed. 



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

 were thus calculated, and found to be — 



10 per cent, spirit . 



... 26-6850 



50 per cent, spirit . . 



..35-5850 



20 



jj • 



...43-9545 



60 „ „ 



..27-2620 



30 



f> 



. .. 47*9800 



70 „ „ .. 



.. 18-8200 



40 



a 



... 44-8630 



80 „ „ .. 



.. 12-4775 



45 „ 



jj 



. .. 38-8095 



90 „ „ .. 



.. 7'7025 







Section 3. Boiling-points. 





A small flask was taken ; into this 100 cub. centims. of the mixture was 



