on 
( 663 ) 
in connection with KueENEN'’s!) observations on mixtures of methyl 
chloride and carbon dioxide. 
No determinations exist for the plait point constants of carbon 
dioxide and methyl chloride or for isothermals of mixtures in the case 
that the quantity of one of the substances is very small. To calculate 
@ and /? I shall therefore start from the constants A,,, etc. derived 
by KAMERLINGH ONNES and REINGANUM ?) for these substances from 
KUENEN’S observations. They represented the critical temperature 
and pressure of the mixtures, considered as homogeneous by: 
K: Kz 
Tx = Cy ee, Prk = Cz 
T 
while: 
Ky = Ky (le)? + 2 Kigz (le) + Kog 2, 
be == by, (Aa)? + 2 bijge (1—2) + bag 2°, 
in which, therefore, as x is always supposed to be small, the index 
1 refers to the substance present in quantity, the index 2 to the 
admixture, Then: 
ee 
Kin by; 
eae (5) 
12 12 
gy es 
acy Nd hee 
Ky = 2.176; Ky= 3.314; b,,= 0.000780; bj = 0.000893. 
Then : 
a = 0.378, B — 0.088. 
This gives for 7 = 273.0 + 9.5 = 282.5, at which temperature accor- 
dpm, 
ding to AMAGAT for carbon dioxide: pm = 43.64, a = 1.088, and 
the specific volumes of saturated vapour and liquid are also according 
to AMAGAT: = = 0.0151 and == 0.00230, while I put 
iff 
himself wanted to repeat his experiments with a compound pump (described in Comm. 
N° 39, Proceedings May 1897) so as to avoid this. In the calculation therefore [ have 
used for these volumes AmaGat’s values for carbon dioxide, and for methyl chloride 
the values derived by means of the law of corresponding states from Youne’s data. 
1) KueNeN, Thesis for the Doctorate, Communication N°, 4. Proceedings April 1892. 
2) KAMERLINGH ONNES and REINGANUM, Comm. N° 59, Proceedings September 
1900, p. 295. 
8) Comp. VAN DER Waats, Contin. II, p. 174, 
*) KAMERLINGH ONNES and REINGANUM, l.c. 
44 
Proceedings Royal Acad. Amsterdam. Vol. IV. 
