956 
DR. J. JOLY ON THE SPECIFIC HEATS 
This is convenient for use of the slide rule. On this chart, vertical lines were 
drawn at the particular densities cutting the isothermals at points which afforded the 
pressures corresponding to the several isothermals. Unfortunately, Amagat’s results 
do not descend to absolute densities below 0'08. For densities below this, I had to 
call in the few estimations of Andrews’. From these, curves were also plotted, but, 
conveniently, of a different character. Andrews, in fact, gives pressures in atmo¬ 
spheres and fractional decrease of volume (he., the fraction Vj/Vg) at the temperatures 
6°‘5, 64°, and 100° (‘Proc. Poy. Soc.,’ 24, p. 458). Plotting these against each other 
we obtain isothermals which may be availed of by calculating the diminution of 
volume of the gas in the sphere at the temperatures of the isothermals as above. This 
is readily done, as the volume of the sphere (Vg) and the volume (V^) of the mass W 
at one atmosphere and at the above temperatures, may be calculated. These known, 
and the quotient of V^/Vg marked uj^on the isothermals, the points so formed may 
be joined by lines crossing the isothermals diagonally, from which pressures, at any 
intermediate temperatures, may be ascertained. The mean pressures and the values 
of Pj and Pg were taken separately from these charts. At the lowest densities, the 
estimation of pressure is not very satisfactory. All the data necessary to amend the 
result at any time, when more connected results are available, are however contained 
in the tables. 
Upon the completion of the foregoing experiments, as the limit of stress to which 
the vessel might be subjected had not been reached, a fresh series was begun 
extending to higher densities. The sphere was tested with 18'7 grammes of the gas 
at 100° for 15 minutes. The sphere, as already mentioned, further increased in 
volume. The experiments then carried out are contained in Table XV. 
Table XV.—Experiments at High Densities. 
No. 
W. 
q. 
h- 
X. 
a. 
b. 
C„. 
P- 
Mean P. 
- 0-0 
- 0-00 
1 
2 
18'7647 
18-7647 
12-38 
12-33 
99-98 
100-09 
536-5 
586 5 
1-0120 
1-0175 
257 
257 
091 1 
091 / 
0-3223 
0-2096 
81-5 
8 
18-7617 
13-39 
100-08 
536-5 
0-9583 
255 
097 
0-3074 
0-2095 
82-0 
. 4 
.5 
16-8398 
16-8898 
12-50 
12-86 
100-17 
100-23 
536-4 
536-8 
0-8347 
0-8213 
257 
257 
0901 
090/ 
0-2917 
0-1882 
76-7 
6 
16-8398 
14-60 
100-18 
536-4 
0-6533 
251 
109 
0-2334 
0-1882 
77-0 
7 
15-7502 
15-57 
100-25 
536-3 
0-6045 
248 
134 
0-2326 
0-1762 
75-0 
8 
15-7502 
12-56 
100-49 
536-2 
0-7285 
258 
118 
0-2717 
0-1763 
74-0 
9 
14-0813 
14-15 
100-53 
536-1 
0-5182 
253 
128 
0-2175 
0-1572 
69-0 
10 
14-0313 
12-14 
100-61 
536-1 
0-5771 
260 
118 
0-2376 
0-1573 
68-5 
11 
12-8617 
15-09 
100-60 
536-1 
0-4416 
251 
097 
0-2025 
0-1443 
65-5 
12 
12-8617 
12-52 
100-64 
536-1 
0-4561 
259 
115 
0 2030 
0-1444 
65-0 
18 
11-7664 
14-44 
100-62 
536-1 
0-4031 
253 
099 
0-1992 
0-1323 
61-5 
14 
11-7661 
12-67 
100-60 
536-1 
0-4119 
260 
099 
0-1994 
0-1322 
6T0 
15 
]6 
10-4660 
10-4660 
12-47 
12-91 
100-53 
100-47 
536-1 
536-2 
0-3624 
0-3594 
260 
260 
0911 
091 / 
0-1948 
0-1178 
56-5 
17 
10-4660 
15-49 
100-44 
536-2 
0-3478 
249 
090 
0-1942 
01177 
57-0 
