kT 
representation of the equation of state, given by the observations. 
I will not enlarge on the way in which the differences in the 
combined reduced equations of state will show themselves in the 
variation of the reduced virial co-efficients with the reduced tempe- 
rature. We will only remark here that the number of terms in our 
polynomials must be chosen so that all the isothermals of the dif. 
ferent substances which we consider in our calculations can be 
represented by means of co-efficients, each of which can be taken 
as derived from the observations. 
The more substances are considered the more difficulties arise. 
Therefore besides hydrogen, oxygen and nitrogen we have taken 
only carbon dioxide, and so the range covered does not extend far 
below the critical temperature. 
From the standpoint { have chosen the results obtained are to 
be considered only as the first preliminary data in our method of 
investigation. A similar calculation will I dare say be required for 
any investigation. And even if my further calculations would fall 
short of my expectations the results obtained will be valuable for 
further investigations by others on the equation of state. They will 
represent the observations over which they extend in a concise and 
easily handled form. This is the reason that I no longer delay the 
publication. 
§ 3. For the development in series the following form was chosen: 
B C D E Ee 
Tt 
pu= A+ 
l 
5 8 (1) 
‘where p represents the pressure in atmospheres (45° northern lati- 
tude), v the volume of the molecular weight!) the unit being chosen 
so that v is expressed in the theoretical normal volume *) and the 
value for A at 0°C. is 
Ay EE 
(I) can also be considered as the series 
B C ; 
Ei +2 
1) Verh. Kon. Akad. v. Wet. 1881, p. 5—7. 
2) Comp. Communication No. 47 cont { 2 Vebr. ’99. 
