Hon. Captain Napier on Wdier-Spouis. 'Oil 
Setting aside^ then, the theory of suction, and the idea that 
the water-spout could rise in a hotly to the clouds, by the pres- 
sure of the circumambient atmosphere alone, we shall have the 
following probabilities to bring us to a more rational conclusion. 
1^^, That many opposite currents of wind, all pointing to- 
wards a certain centre, and coming in contact with each other 
with unequal forces, cause a rotatory motion or current of them- 
selves round a central space, which, not partaking of an equal 
or its former pressure, naturally becomes rarified by the existing 
heat, to such an extent, that it speedily acquires a state in a 
great degree approximating to that of a vacuum. This 
continued rotatory motion of the air, forms that which is usually 
denominated a 'whirlwind ; and the pressure of the external at- 
mosphere at the base, forcing the water to a reasonable height 
up the rarified space within, it is then carried upwards by the 
mechanical action of the wind, in light and unconnected streaks. 
The space at the bottom nov/ becoming void, is regularly reple- 
nished by the pressure from without, till the whole spout is in 
due time thus perfectly completed. ' 
The water having now arrived at the ref^ion of the clouds, it 
is naturally attracted, diffused and connected v/ith and among 
them, increasing in density and extent, till the lower atmosphere 
becoming now lighter than the clouds above, these enorm.ous 
masses gradually settling downwards, distend, burst and dissipate 
in rain. 
That the mercury in the barometer did not fall with the rain, 
but, on the contrary, became considerably more convex, was vi- 
sible from observation, and may be accounted for in the follow- 
ing manner ; That during the whole operation of the water- 
spout, which continued not more than SO minutes, the com- 
mencement was too sudden, and the duration too short, to cause 
any change indicative of what actually took place ; and that this 
convexity only prognosticated what woidd have taken place, had 
there been no water-spout at all, and what actually did happen 
afterwards, viz. a very clear atmosphere and hot sultry weather. 
Although this phenomenon was rather terrific in appearance, 
yet I am not inclined to think it would have been attended with 
any serious calamity to the ship, had even the whole quantity 
fallen on board, allowing the loftier sails to have been taken in, 
G 2 
