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

By Benjamin Franklin

Page 232

consuming
all its smoke._[60] _By Dr. B._ FRANKLIN.


Towards the end of the last century an ingenious French philosopher,
whose name I am sorry I cannot recollect, exhibited an experiment
to show, that very offensive things might be burnt in the middle of
a chamber, such as woollen rags, feathers, &c. without creating the
least smoke or smell. The machine in which it was made, if I remember
right, was of this form, (Plate X. Figure 1.) made of plate iron.
Some clear burning charcoals were put into the opening of the short
tube A, and supported there by the grate B. The air, as soon as the
tubes grew warm, would ascend in the longer leg C and go out at D,
consequently air must enter at A descending to B. In this course it
must be heated by the burning coals through which it passed, and
rise more forcibly in the longer tube, in proportion to its degree
of heat or rarefaction, and length of that tube. For such a machine
is a kind of inverted syphon; and as the greater weight of water in
the longer leg of a common syphon in descending is accompanied by an
ascent of the same fluid in the shorter; so, in this inverted syphon,
the greater quantity of levity of air in the longer leg, in rising
is accompanied by the descent of air in the shorter. The things to
be burned being laid on the hot coals at A, the smoke must descend
through those coals, be converted into flame, which, after destroying
the offensive smell, came out at the end of the longer tube as mere
heated air.

Whoever would repeat this experiment with success must take care that
the part A, B, of the short tube, be quite full of burning coals,
so that no part of the smoke may descend and pass by them without
going through them, and being converted into flame; and that the
longer tube be so heated as that the current of ascending hot air
is established in it before the things to be burnt are laid on the
coals; otherwise there will be a disappointment.

It does not appear either in the Memoirs of the Academy of Sciences,
or Philosophical Transactions of the English Royal Society, that any
improvement was ever made of this ingenious experiment, by applying
it to useful purposes. But there is a German book, entitled _Vulcanus
Famulans_, by Joh. George Leutmann, P. D. printed at Wirtemberg in
1723, which describes, among a great variety of other stoves for
warming rooms, one, which seems

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

Page 11
Every three particles, mutually and equally repelling each other, must form an equilateral triangle.
Page 18
I make no doubt of direct and inverted whirl-winds; your description of them, and the reason of the thing, are sufficient.
Page 22
I imagine spouts, in cold seasons, as Gordon's in the Downs, prove the descent.
Page 71
In either case it may be supposed that large hollows or valleys among hills, might be left filled with sea-water,.
Page 88
_ SIR, I return you Mr.
Page 90
It has long been a supposition of mine, that the iron.
Page 115
That gentleman, who is ever ready to promote what may be of public utility, though his own ingenious inventions have not always met with the countenance they merited, was so obliging as to invite me to Portsmouth, where an opportunity would probably offer, in the course of a few days, of making the experiment on some of the shores about Spithead, in which he kindly proposed to accompany me, and to give assistance with such boats as might be necessary.
Page 133
Perhaps this labour of raising water might be spared, and the whole force of a man applied to the moving of a boat by the use of air instead of water; suppose the boat constructed in this form, figure 14.
Page 142
When you intend a long voyage, you may do well to keep your intention as much as possible a secret, or at least the time of your departure; otherwise you will be continually interrupted in your preparations by the visits of friends and acquaintance, who will not only rob you of the time you want, but put things out of your mind, so that when you come to sea, you have the mortification to recollect points of business that ought to have been done, accounts you intended to settle, and conveniencies you had proposed to bring with you, &c.
Page 180
1.
Page 185
One cannot conveniently make any other use of the fire but that of warming the room.
Page 236
5 and 6, each, 0 8¼ Breadth of the passage between No.
Page 237
0 9½ 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 4½ Drawer G, its length, 1 0 ----- ----- breadth, 0 5¾ ----- ----- 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 5¾ Thickness of the bars at top, 0 0¼ ----- ----- ----- at bottom, less, 0 .
Page 239
_ Let the first fire be made after eight in the evening or before eight in the morning, for at those times and between those hours all night, there is usually a draft up a chimney, though it has long been without fire; but between those hours in the day there is often, in a cold chimney, a draft downwards, when, if you attempt to kindle a fire, the smoke will come into the room.
Page 270
Such, for instance, as the advertisement of a country house to be sold, which had been many years _improved_ as a tavern; and in the character of a deceased country gentleman, that he had been, for more than thirty years, _improved_ as a justice of the peace.
Page 310
This account is transmitted to the emperor, whose ministers can thence foresee a scarcity, likely to happen in any province, and from what province it can best be supplied in good time.
Page 329
F.
Page 332
--In order to be better understood I would premise two things: first, that voluntary seamen may be had for the service, if they were sufficiently paid.
Page 342
--But the non-appointment of bishops for America seems to arise from another quarter.
Page 361
_Day-light_, proposal to use it instead of candle-light, iii.