z = 3.83171.
If h is the height to which the liquid will rise in a capillary tube
of unit radius, then the diameter of the largest orifice is
____ ___
2a = 3.83171 \/(2h) = 5.4188 \/(h).
Duprez found from his experiments
___
2a = 5.485 \/(h).
[The above theory may be well illustrated by a lecture experiment. A
thin-walled glass tube of internal diameter equal to 14-1/2 mm. is
ground true at the lower end. The upper end is contracted and is fitted
with a rubber tube under the control of a pinch-cock. Water is sucked up
from a vessel of moderate size, the rubber is nipped, and by a quick
motion the tube and vessel are separated, preferably by a downward
movement of the latter. The inverted tube, with its suspended water,
being held in a clamp, a beaker containing a few drops of ether is
brought up from below until the free surface of the water is in contact
with ether vapour. The lowering of tension, which follows the
condensation of the vapour, is then strikingly shown by the sudden
precipitation of the water.]
_Effect of Surface-tension on the Velocity of Waves._--When a series of
waves is propagated on the surface of a liquid, the surface-tension has
the effect of increasing the pressure at the crests of the waves and
diminishing it in the troughs. If the wave-length is [lambda], the
equation of the surface is
y = b sin 2[pi](x/[lambda]).