424 Dr. G. Bakker on the 
If therefore the gradient -77 of the reciprocal value of the 
density p(v= - J has the same sign for every point of the 
capillary layer*, the curve, which presents jd x as a function of 
v, has a form as the curve ABO in fig. 2, where HGPK pre- 
sents the theoretical isotherm. 
§ 3. The curves, which represent the relations between the hydro- 
static pressure p 2 in a direction normal to the radius and 
the reciprocal value v— - of the density in the considered 
point of the capillary layer. 
The radius of the capillary layer, which has the form of 
a spherical shell, gives the direction of the lines of force. 
The hydrostatic pressure p 2 is therefore in a direction normal 
to the lines of force. If 6 denotes the thermic pressure and 
S 2 the cohesion in the designed direction, we have 
p 2 = @ — $2' 
Now the cohesion 8 2 in a direction normal to the lines of 
force is given by the formula : 
_ 1 f/WJMt 
Hence V 2 1 /dV 
X* 1 /dVV 
P2 = e ~ s^fj? " 877/ v/T ) 
In the direction of the lines of force the cohesion S x is 
given by 
Therefore : 
Sl ~~^iv/r) "^1 • 
-0- _Z!_ _L/^IV 
Pi SirfX 2 + $Trf\dh ) ' 
Further we have : a = 2irfX 2 . (See above p. 417.) 
Hence 
^ 2 =*-£- • • • • • (Uft 
* In the Ann. der Phys. xvii. p. 478 (1905) I have demonstrated the 
great probabilitv of this supposition. 
t Phil. Mag."Dec. 1906, p. 560. 
\ The hydrostatic pressures p l and p 2 may be also considered respec- 
tively as the maximum and minimum value of the pressures in the 
considered point. 
