7 2 D O C . 7 2 P O R E S I Z E O F F I LT E R S
The method described here becomes inconvenient when substantially finer fil-
ters are involved. If, e.g,
one would have to use 72 atmospheres overpressure for the measurement. By us-
ing, instead of ether liquid, carbon dioxide, which at normal temperatures has a
capillarity constant just of order of magnitude 1, one would probably be able to ex-
tend the method indicated here to filters of the utmost fineness.
(102 == −6 r0