(591 ) 
From the formula given for v >», it follows that for very great 
volumes pv = 525,5, from which & = 1,140, in good harmony with 
the value 1,138 found by applying Avoarapo’s law as holding 
for the limit !). 
In order to know whether my formulae give also a sufficient 
approximation for very high pressures, I have calculated the critical 
isothermal from AMAGAT’s system of isothermals for carbon dioxide. 
As critical temperature I found 31°,4 C., hence pe = 73,6 atm.; 
for v, I took the value 0.00424 (the normal volume being chosen 
as unit), computed from the critical density 0.464. The following 
table shows that if x = 4 and 6 = 0,00045, my formulae well represent 
the observations up to pressures of about 800 atm. The third column 
gives the pressures I have computed from the volumes observed, and 
the fourth column gives the volumes computed from the pressure 
observed. 
EAB hoe di 
p v p (caleul.) v (calcul) 
1000 0,001752 1055 0,001764 
950 1767 989 1776 
900 1782 927 1789 
850 INES 864 1803 
800 1815 808 1817 
750 1832 752 1835 
700 1847 . 709 1850 
650 1864 659 1868 
600 1887 603 1888 
550 1909 552 1910 
500 1934 504 1936 
450 1965 448,5 1964 
400 1998 397,3 1996 
350 - 2037 346,7 2034 
300 2087 294,3 2081 
275 2115 268,5 2108 
250 2148 242,9 2139 
225 2182 220,8 2175 
200 2220 198,6 2217 
1) Using the theoretical normal density for hydrogen 
0,00008955 > 1.00059 — 0,00008961 
and the molecular weight of C, H,,= 71.82 (Comp. Comm. from the Leiden laboratory 
N®. 47 page 12.) 
45 
Proceedings Royal Acad. Amsterdam. Vol. IL. 
