56 Causes of Water Spouts. 
veral spouts appeared at their inferior extremities like tubes, through 
which clouds of smoke were seen to rise. 
According as the particles which form the spout are heavier and 
larger, they have a greater breadth, and are formed into a tube ; in 
one experiment a tube of sand was observed, containing in its interior 
a column of impalpable blue glass ; in the case just cited, it is proba- 
ble that the bottom of the spout was composed of drops of water, | 
and that these formed the tube, = which a thinner vapour rose in 
visible clouds. 
In the course of these experiments, in endeavoring to form spouts 
with sand, I remarked a circumstance which appears worthy of ms 
stated. 
When the oolanais of water which rested on the sand, was not very 
high, and when a circular movement was given it, not only at the 
center, but throughout the mass, in turning it quickly with a rod, un- 
til the sand which is at the bottom of the vessel, is drawn in and min- 
gled with the water, it settles, by deposition, at the bottom of the ves- 
sel in a cone as regular as if formed by the 
The ascending current has no longer force enough to raise the 
sand in a spout, though it has enough to collect it at the center. If 
the point of the cone is destroyed with a rod, it may be formed anew 
by gently circulating the water ; the grains of sand are then seen to 
rise from the bottom on all sides of the little conical mountain, and by 
degrees to reestablish the point. May we not explain by a similar 
cause, the formation of those little conical mountains, which are so 
common in Sandy, pa and in many — where oo regular 
the mechanism of the phenomenon is reversed; instead of drawing the water from 
below, the primitive whirl, which commences near the sea, draws the clouds from 
current, which draws them, the spout is less we by we lateral columns of air ; 
the centrifugal force ‘| ter, especially near 
the clouds, where a rep] long th e axis is more easy. Experiment 3d, Fig. 
2, represented this effect very exactly, 
An analogous mechanism is perceived in the currents of smoke which are some- 
times produced by the firing ofa cannon. The circular cylinder which forms ‘ 
revolves with such rapidity, that when it comes in contact with the trees, it visibly 
agitates the foliage ; instead, however, of dispersing immediately, they retain their 
form for 15 or 20 seconds. In this phenomener, Oe  Pepiacneees of the portions of 
the surface, which have a tendency to remove from centre of rotation, cannot ex- 
ist anywhere, the cylinder being circular and continuous ; the current citigt there- 
fore subsist as long as the impulse which it received on leaving the gun continues. 
