248 Proceedings of Royal Society of Edinhurgh. [sess. 
Carbonic Acid. 
20° 
C. 
V. 
30° 
40° 
0 
64-4 
•0025 
109 -0025 
155 -0025 
201 -0025 
150 
•00217S 
200 -0022 
225 -00228 
300 -002255 
300 
•002 
384 -002 
470-5 -002 
560 -002 
e 
-2833 
•2936 
•3136 
•3312 
n 
35-6 
22-7 
24-5 
34-6 
Ult. Vol. 
•001792 
•001766 
•001716 
•001672 
Other deductions from Amagat’s data are given, in considerable 
numbers : — from regions of the CO 2 diagram in which II is respec- 
tively + , — , or even zero, the latter belonging of course to the 
conditions under which it behaves as a true gas. Thus, taking the 
data for volumes 
0-01636, 0-013, and 0-01 
we obtain the values of II given in the first line of the table below. 
Here the substance was, throughout, at density less than the critical. 
The second line gives the corresponding results for a range of 
volumes which includes the critical volume : — viz. 
0-00578, 0-00428, 0-00316. 
The application of the formula to this series (where the part of the 
isothermal which is treated contains a point of contrary flexure) is 
obviously a matter rather of curiosity than of science. 
Finally, the third line gives data for volumes all well under the 
critical volume viz. 
0-00316, 0-00250, and 0-002. 
Values of H for CO 2 (in Atmospheres). 
Temp. 30° C. 35° 40° 50° 60° 70° 80° 90° 100° 
(58-5) 34-3 14-2 4'9 2‘4 0'5 - 1-2 - 2-1 
-73-5 -75-5 -77 - 78‘6 - 80-5 - 80- -81-1 -80-3 
[35-6] -38-6 -43 -42 -46-5 -47 -46-5 -46-5 
The single number in ( ) refers to vapour, that in [ ] to liquid ; 
all the others to gas. The results for volumes greater than the 
critical volume are very interesting. 
198° 
- 8 - 
-80-5 
