Hon. Captain Napier on Watcr-Spouts. 97 
voured to ascertain its cause, taking for granted the following 
axioms. 
First, “ That water in a vacuum rises only to the height of 
82 feet,” or, in other words, that a column of water 82 feet 
high, is equal in weight to a column of the atmosphere of the 
same base.” Secondly, “ That a column of mercury 29^ inches 
high m vacuo, is equal to the same.” Thirdly, That heat ra- 
rities the air and causes a vacuum.” Fourthly, That when 
the lower atmosphere is so much rarihed as to become lighter 
than the impending clouds, that these clouds or vapours fall and 
disperse on the surface of the earth in the shape of rain or mois- 
ture.” Fifthly, That when the clouds descend, the mercury 
in the barometer also descends, and that when the vapours rise 
througli the lower atmospheres, becoming again more dense than 
the vapours themselves, that the mercury in the barometer rises 
also.” 
With these data, were next noted the various phenomena, as 
observed to be connected with the water-spout itself. 
\st. Low, heavy, black clouds were seen to the southward at 
noon, the barometer standing at inches, and the thermo- 
meter at 81°, in a constant current of cool air ; the atmosphere, in 
general, becoming hazy, even thick, in some places, close and 
very hot, — the wind variable and attended with occasional drops 
of rain. A whirlwind next taking place, drawing the water up 
with it, apparently in a state like vapour or steam, advancing in 
a southerly direction to the above-mentioned dark impending 
clouds, increasing also in height and bulk, with a quick spiral 
motion, till it came in contact witli the end of a cloud which 
rather drooped to meet it ; then discharging great quantities of 
water, not in a solid bulk, but in short unconnected streams or 
streaks as it were, attended with a rushing or hissing noise. 
9.dly, That after some time, it returned with considerable velo- 
city to the northward, in opposition to the wind prevailing at the 
ship, the water at the base boiling with a white foam, part pro- 
jecting outwards to a certain circumference, and part arising in 
thick dark vapours, which gradually arranged themselves into 
thin streaks, as they gained in ascent towards the clouds, till 
the whole was dispersed by bursting into a heavy shower, ^dly. 
That the clouds descended, or came gradually nearer to the sur- 
VOL. VI. NO. 11 . JANUARY 1822 . G 
