420 Dr. G. Bakker on the 
§ 2. The curves, which present the relations between the hydro- 
static pressure p L in the direction of the normal to the 
surface of the capillary layer and the reciprocal value 
v = -of the density in the considered point. 
If denotes the thermic pressure * in a point of the 
capillary layer, we may consider the hydrostatic pressure in 
every direction as the difference between 6 and the cohesion. 
In the direction normal to the surface of the capillary layer, 
we have therefore : 
and (see above) 
1 4a 4a W )' 
Hence 
* = *-&+ Skidkh 
Differentiating in the direction of the normal h, we find 
thus : 
dpi_ d6_Y dV X 2 dV d 2 V 
dh dh 2a dh 2a dh dli 2 
Further: d6=-pdV 
and 
X ' -772 ~ * ~^ a P =z ~Ti^i" ^ see aDove ' equation (10)}. 
Hence 
a> 1== \'/dV\> l_J_(dV\* 2 
dh a \dh ) ' R ~ 4tt/ \dh J ' R' * * ^ ll) ' 
Now we have found above for the departure from the law 
of Pascal . 
Equation (15) gives therefore : 
dp 1 _ 2(2h-p> 2 ) nf x 
dh ~ R [ V 
We have thus the following theorem : 
The gradient of the hydrostatic pressure pj in the direction 
of the normal to the surface in a point of a capillary layer, 
which has the form of a spherical shell, is the product of the 
departure from the law of Pascal and the curvature. 
* The thermic pressure is the power of repulsion in the theory of 
Young. 
