its big end on the ground.
When the air descends with a violence in some places, it may rise with
equal violence in others, and form both kinds of whirlwinds.
The air, in its whirling motion, receding every way from the centre or
axis of the trumpet, leaves there a _vacuum_, which cannot be filled
through the sides, the whirling air, as an arch, preventing; it must
then press in at the open ends.
The greatest pressure inward must be at the lower end, the greatest
weight of the surrounding atmosphere being there. The air, entering,
rises within, and carries up dust, leaves, and even heavier bodies that
happen in its way, as the eddy or whirl passes over land.
If it passes over water, the weight of the surrounding atmosphere forces
up the water into the vacuity, part of which, by degrees, joins with the
whirling air, and, adding weight and receiving accelerated motion,
recedes farther from the centre or axis of the trump as the pressure
lessens; and at last, as the trump widens, is broken into small
particles, and so united with air as to be supported by it, and become
black clouds at the top of the trump.
Thus these eddies may be whirlwinds at land, water-spouts at sea. A body
of water so raised may be suddenly let fall, when the motion, &c., has
not strength to support it, or the whirling arch is broken so as to
admit the air: falling in the sea, it is harmless unless ships happen
under it; and if in the progressive motion of the whirl it has moved
from the sea over the land, and then breaks, sudden, violent, and
mischievous torrents are the consequences.
* * * * *
_To Dr. Perkins._
_Water-spouts and Whirlwinds compared._--Read at the Royal Society,
June 24, 1753.
Philadelphia, Feb. 4, 1753.
I ought to have written to you long since, in answer to yours of October
16, concerning the water-spout; but business partly, and partly a desire
of procuring farther information by inquiry among my seafaring
acquaintance, induced me to postpone writing, from
_ Read at the Royal Society, Nov.Page 65
But, on the contrary, the vessel grows cold, and even water, in which the vessel is sometimes placed for the experiment, freezes into hard ice on the bason.Page 103
These, with two pieces of soft iron, which together equalled one of the magnets, were inclosed in a little box of mahogany wood, the grain of which ran with, and not across, the length of the box: and the box was closed by a little shutter of the same wood, the grain of which ran across the box; and the ends of this shutting piece were bevelled so as to fit and slide in a kind of dovetail groove when the box was to be shut or opened.Page 105
Now what I would beg leave to recommend to you, is, that you would recollect, if you can, the species of mahogany of which you made my box, for you know there is a good deal of difference in woods that go under that name; or if that cannot be, that you would take a number of pieces of the closest and finest grained mahogany that you can meet with, plane them to the thinness of about a line, and the width of about two inches across the grain, and fix each of the pieces in some instrument that you can contrive, which will permit them to contract and dilate, and will show, in sensible degrees, by a moveable hand upon a marked scale, the otherwise less sensible quantities of such contraction and dilatation.Page 124
) A B is a long boom, from which are hoisted seven jibs, a, b, c, d, e, f, g, each a seventh part of the whole dimensions, and as much more as will fill the whole space when set in an angle of forty-five degrees, so that they may lap when going before the wind, and hold more wind when going large.Page 152
_ _March 10, 1773.Page 178
As we are accustomed to see all the animals, with which we are acquainted, eat and drink, it appears to us difficult to conceive, how a toad can be supported in such a dungeon: but if we reflect, that the necessity of nourishment, which animals experience in their ordinary state, proceeds from the continual waste of their substance by perspiration, it will appear less incredible, that some animals in a torpid state, perspiring less because they use no exercise, should have less need of aliment; and that others, which are covered with scales or shells, which stop perspiration, such as land and sea-turtles, serpents, and some species of fish, should be able to.Page 200
Much expence has also been made, to alter and amend new chimneys which had really no fault; in one house particularly that I knew, of a nobleman in Westminster, that expence amounted to no less than three hundred pounds, _after_ his house had been, as he thought, finished and all charges paid.Page 220
I have wished that some of them would study this branch of that science, and give experiments.Page 233
"When this stove is to be used, it must first be carried into the kitchen and placed in the chimney near the fire.Page 237
0 9Â½ Length of the front plate E, where longest, 0 11 The cover D, square, 0 12 Hole in ditto, diameter, 0 3 Sliding plates Y Y, their length, each, 1 0 ----- ----- ----- their breadth, each, 0 4Â½ Drawer G, its length, 1 0 ----- ----- breadth, 0 5Â¾ ----- ----- depth, 0 4 ----- ----- depth of its further end, only, 0 1 Grate H in the vase, its diameter to the extremity of its knobs, 0 5Â¾ Thickness of the bars at top, 0 0Â¼ ----- ----- ----- at bottom, less, 0 .Page 257
You have doubtless heard the sweet tone that is drawn from a drinking glass, by passing a wet finger round its brim.Page 273
Whoever compares a volume of the Gentleman's Magazine, printed between the years 1731 and 1740, with one of those printed in the last ten years, will be convinced of the much greater degree of perspicuity given by black than by the grey.Page 314
They may as well, when they view the tide ebbing towards the sea, fear, that all the water will leave the river.Page 339
And God said, Have I borne with him these hundred and ninety and eight years, and nourished him, and clothed him, notwithstanding his rebellion against me, and couldst not thou, who art thyself a sinner, bear with him one night? 12.Page 349
_ Hitherto there are none.Page 366
_Federal_ constitution, speech on, iii.Page 389
modern, absurdities of, 344, _et seq.