Memoirs of Benjamin Franklin; Written by Himself. [Vol. 2 of 2] With his Most Interesting Essays, Letters, and Miscellaneous Writings; Familiar, Moral, Political, Economical, and Philosophical, Selected with Care from All His Published Productions, and Comprising Whatever Is Most Entertaining and Valuable to the General Reader

By Benjamin Franklin

Page 212

and by the swelling and rising
of the water in the beginning vacuum, which is at first a small, low,
broad cone, whose top gradually rises and sharpens, as the force of the
whirl increases. _At its upper end_ it becomes visible by the warm air
brought up to the cooler region, where its moisture begins to be
condensed into thick vapour by the cold, and is seen first at A, the
highest part, which, being now cooled, condenses what rises next at B,
which condenses that at C, and that condenses what is rising at D, the
cold operating by the contact of the vapours faster in a right line
downward than the vapours can climb in a spiral line upward; they climb,
however, and as by continual addition they grow denser, and,
consequently, their centrifugal force greater, and being risen above the
concentrating currents that compose the whirl, fly off, spread, and form
a cloud.

It seems easy to conceive how, by this successive condensation from
above, the spout appears to drop or descend from the cloud, though the
materials of which it is composed are all the while ascending.

The condensation of the moisture contained in so great a quantity of
warm air as may be supposed to rise in a short time in this prodigiously
rapid whirl, is perhaps sufficient to form a great extent of cloud,
though the spout should be over land, as those at Hatfield; and if the
land happens not to be very dusty, perhaps the lower part of the spout
will scarce become visible at all; though the upper, or what is commonly
called the descending part, be very distinctly seen.

The same may happen at sea, in case the whirl is not violent enough to
make a high vacuum, and raise the column, &c. In such case, the upper
part A B C D only will be visible, and the bush, perhaps, below.

But if the whirl be strong, and there be much dust on the land, and the
column W W be raised from the water, then the lower part becomes visible
and sometimes even united to the upper part. For the dust may be carried
up in the spiral whirl till it reach the region where the vapour is
condensed, and rise with that even to the clouds: and the friction of
the whirling air on the sides of the column W W, may detach great
quantities of its water, break it into drops, and carry them up in the
spiral whirl, mixed with the air; the heavier drops may indeed fly

Last Page Next Page

Text Comparison with The Complete Works in Philosophy, Politics and Morals of the late Dr. Benjamin Franklin, Vol. 1 [of 3]

Page 20
Burton, which consisted of small cheap volumes, amounting in all to about forty or fifty.
Page 63
Some volumes.
Page 77
These were all at length united with the Library Company of Philadelphia, which thus received a considerable accession of books and property.
Page 78
The police of Philadelphia had early appointed watchmen, whose duty it was to guard.
Page 122
will no more conduct electricity than sealing-wax.
Page 125
Thomas Hopkinson, since deceased, whose virtue and integrity, in every station of life, public and private, will ever make his memory dear to those who knew him, and knew how to value him.
Page 131
[26] What is said here, and after, of the _top_ and _bottom_ of the bottle, is true of the _inside_ and _outside_ surfaces, and should have been so expressed.
Page 135
We judged then that it must either be lost in decanting, or remain in the first bottle.
Page 136
The excuse for mentioning it here is, that we tried the experiment differently, drew different consequences from it (for Mr.
Page 142
Smeaton was the first who made use of panes of glass for that purpose.
Page 151
(See Philosophical Transactions, Vol.
Page 166
By the word _surface_, in this case, I do not mean mere length and breadth without thickness; but when I speak of the upper or under surface of a piece of glass, the outer or inner surface of the phial, I mean length, breadth, and half the thickness, and beg the favour of being so understood.
Page 207
--Origin of the Author's Idea of drawing.
Page 212
Those who affect to be thought to know every thing, and so undertake to explain every thing, often remain long ignorant of many things that others could and would instruct them in, if they appeared less conceited.
Page 220
But granting that the friction between salt and water would collect the electrical fire, that fire, being so extremely subtle and active, would be immediately communicated, either to those lower parts of the sea from which it was drawn, and so only perform quick revolutions; or be communicated to the adjacent islands or continent, and so be diffused instantaneously through the general mass of the earth.
Page 234
Hence lightning does not melt metal by a cold fusion, as we formerly supposed; but, when it passes through the blade of a sword, if the quantity be not very great, it may heat the point so as to melt it, while the broadest and thickest part may not be sensibly warmer than before.
Page 268
B.
Page 309
128.
Page 313
469.
Page 334
366.