Causes of Water Spouts. 49 
being entirely immersed in the liquid. 1 then caused the mill to re- 
volve about twice in a second, and after continuing the motion for a 
minute, the water at the bottom began to whirl round and to rise a 
little in a conical form, and soon after, from the summit of the little 
cone a fine column of water sprung up all of a — until it got 
into the vanes of the mill. (Fig. 1.) 
This little water spout rising through the oil, was about two lines 
in diameter and resembled a tube of flexible glass; the water which 
it brought up into-the mill was driven to the circumference of the 
whirl and descended afterwards in small drops with a narrow screw 
motion to the bottom, but so slowly that it was quite practicable to 
cause all the water to rise and mingle with the oil. 
As the latter liquid easily loses its transparency by its mixture with 
the water and as it was nevertheless necessary to examine the motion 
of the whirl in all its parts, I instituted the following experiment. 
Second Experiment.—l filled with pure water another vessel two 
feet high and nine inches in diameter, and threw into it an ounce of 
copal, coarsely pulverised ; this substance having a specific gravity 
very little superior to that of water, remains a long time suspended, 
and yields to the slightest motion of the fluid which it renders visible. 
I adjusted the mill as in the last ex 
When I commenced the experiment the coarser pieces of copal 
formed a layer at the bottom and the finer remained suspended. At 
the first turn of the mill, those in the direction of the axis ascended 
rapidly into the vanes, and those near the circumference took a spi- 
ral movement which carried them toward the bottom of the vessel. 
This whirling was propagated from layer to layer by means of these 
two motions, and when it had reached the particles at the bottom 
they rose, like the water in the first experiment but in a much thick- 
er column, being from four to six lines in diameter, and ascended 
into the vanes of the mill, thus rendering the whirling spout very dis- 
tinctly obvious. 
To be able to follow a single isolated particle. throughout its 
march, I threw in a few fragments of gum lac, which were easily 
- distinguished by their red color. They were seen ascending rapid- 
ly in the center in the direction of a very elongated helix ; the mill 
threw them to various distances according to. their sizes and drove 
them in narrow Spirals to the bottom, where they were brought again 
to the center to renew the same sport. 
Vor. XXV.—No. 1. 7 
