igi} Mr Kleeman, The Atomic Constants 
TABLE III. 
Values of Ca. 
H=1, C=530, 0=594, F=576, Cl=840, Br=1065, 
Sn=1468, [1=15-49. 
Name of substance Zu Ze, T,,(Exp.) | 7’, (Cal.) | 
| 
Chloro benzene 45-2 | 21-31 | 633 | 620-7 | 
Octane 60:4 | 34-27 | D697 seaesr | 
Ether Ot | 20°43 | AGT ee { 
Carbon dioxide 17-2 | 6-63 | 304-3 | 426-5 | 
Methane 9-3°))- 6°03 Or amelie | 
Hydrogen 2 2 38°5 28°5 
Ethylene 14-6 8:07 | 282 290:7 
Carbon tetrachloride | 38:°9 | 18-45 | 556°1 | 557-2 
Pentane 38-5 | 22°17 |) 470: 34ers 
Heptane 53:1 | 30-23) 539,08 Raaks | 
Di-pheny! methane 73°6 | 34°41 | 768:6 5869-2 
and density of liquid and saturated vapour, can be obtained for | 
any temperature from those of a known substance by means of} 
the law of corresponding states. By comparing these quantities | 
with those found by experiment useful information for the guid-. 
ance of further experiments is obtained. As an example of the 
application of these principles let us calculate the critical and 
other quantities of the substance O,;, which Ladenburg believes is 
produced in a vacuum tube through which an electric charge 
passes, supposing that it exists as a pure substance, that is, not 
as a mixture of substances whose formulae are of the type Op. 
The critical density, temperature, and pressure in atmospheres 
are found’ to be ‘495, 603, and 83°3 respectively. At a tempera- 
ture of 16°C. (room temperature) the substance would have a. 
vapour pressure of 30°7 mm. of mercury, and the temperature of ) 
its boiling point would be 134° C. | 
Useful information may also be obtained by means of the | 
foregoing equations about the purity of a substance, that is, 
whether or no it consists of a mixture of two or more substances, | 
a special case of which is partial polymerization of the molecules. | 
For example, the values of c, and ¢, for an atom of copper, deduced 
by interpolation from the values of ¢, and ¢, for a number of atoms | 
given in Tables I and III are 9°81 and 5:18 respectively. The 
critical temperature of liquid copper should therefore be 190°C. 
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