The Complete Works in Philosophy, Politics and Morals of the late Dr. Benjamin Franklin, Vol. 2 [of 3]

By Benjamin Franklin

Page 122

move out of its way all the air its whole
dimension meets with between the pricked lines CG and DG. Thus both
the fluids give resistance to the motion, each in proportion to the
quantity of matter contained in the dimension to be removed. And
though the air is vastly lighter than the water, and therefore more
easily removed, yet the dimension being much greater its effect is
very considerable.

It is true that in the case stated, the resistance given by the air
between those lines to the motion of the sail is not apparent to the
eye, because the greater force of the wind, which strikes it in the
direction EEE, overpowers its effect, and keeps the sail full in the
curve a, a, a, a, a. But suppose the wind to cease, and the vessel in
a calm to be impelled with the same swiftness by oars, the sail would
then appear filled in the contrary curve b, b, b, b, b, when prudent
men would immediately perceive, that the air resisted its motion,
and would order it to be taken in.

Is there any possible means of diminishing this resistance, while
the same quantity of sail is exposed to the action of the wind, and
therefore the same force obtained from it? I think there is, and
that it may be done by dividing the sail into a number of parts, and
placing those parts in a line one behind the other; thus instead of
one sail extending from C to D, figure 2, if four sails containing
together the same quantity of canvas, were placed as in figure 3,
each having one quarter of the dimensions of the great sail, and
exposing a quarter of its surface to the wind, would give a quarter
of the force; so that the whole force obtained from the wind would be
the same, while the resistance from the air would be nearly reduced
to the space between the pricked lines _a b_ and _c d_, before the
foremost sail.

It may perhaps be doubted whether the resistance from the air would
be so diminished; since possibly each of the following small sails
having also air before it, which must be removed, the resistance on
the whole would be the same.

This is then a matter to be determined by experiment. I will mention
one that I many years since made with success for another purpose;
and I will propose another small one easily made. If that too
succeeds, I should think it worth while to make a larger, though at
some expense, on a river

Last Page Next Page

Text Comparison with Benjamin Franklin Representative selections, with introduction, bibliograpy, and notes

Page 47
" Though clearly not the chief interest of his life, it was one to which he was fundamentally and consistently attached.
Page 61
"[i-271] Carl Becker pointedly observes: "Where Jefferson got his ideas is hardly so much a question as where he could have got away from them.
Page 62
Sir Isaac Newton demonstrated mathematically that the universe was governed by a fagot of immutable, universal, and harmonious physical laws.
Page 109
Page 146
) Priestley, J.
Page 186
We arriv'd safe however at Boston in about a Fortnight.
Page 213
Robert Grace, a young Gentleman of some Fortune, generous, lively and witty, a Lover of Punning and of his Friends.
Page 358
She will reap _equal_ Benefits without equal Risque of the Inconveniencies and Dangers.
Page 362
Hence the Prince that acquires new Territory, if he finds it vacant, or removes the Natives to give his own People Room; the Legislator that makes effectual Laws for promoting of Trade, increasing Employment, improving Land by more or better Tillage, providing more Food by Fisheries; securing Property, &c.
Page 378
Page 428
_Venus_ revolves round the Sun in an Orbit including that of _Mercury_ within it: For she is always seen in the Neighbourhood of the Sun, and never appears in the West when the Sun is in the East, nor contrariwise; nor ever removes above forty-eight Degrees from him.
Page 434
_| | 20 | 24 | [Sextile] [Mars] [Venus] | | 21 |[Pisces] 6 | [Sun] in [Cancer] | | 22 | 18 | _He that best understands_| | 23 |[Aries] 0 | _the_ | | 24 | 12 | [Conjunction] [Moon] [Mars] [Opposition] | | | | [Sun] [Saturn] | | 25 | 25 | .
Page 449
7 | 7 23 | 10 | 14 | | 26 | 0 50 | 8 20 | 11 | 15 | | 27 | 1 45 | 9 18 | 12 | 16 | | 28 | 2 47 | 10 18 | 1 | 17 | | 29 | 4 0 | 11 18 | 2 | 18 | .
Page 498
25 | 4 35 | | 28 | 6 |=INNOCENTS.
Page 503
3 | | 27 | 6 | 8 | 16 | 18 | 13 | 1 | 5 | +----+-------+--------+---------+-------+-------+---------+----------+ [Illustration] +----+----------+----------+----+------+ | D.
Page 533
"--If it was not quite unreasonable, I should desire you to write to me every post, whether you hear from me or not.
Page 672
see our Country nourish, as it will amazingly and rapidly after the War is over.
Page 684
Page 752
TO DAVID HARTLEY Philad^a, Dec^r 4, 1789.
Page 778
He professes himself "a bigotted Admirer of the Antients, and all their Performances" (p.