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

By Benjamin Franklin

Page 110

divers there, who, when under water in their business, need
light, which the curling of the surface interrupts by the refractions
of so many little waves, let a small quantity of oil now and then out
of their mouths, which rising to the surface smooths it, and permits
the light to come down to them. All these informations I at times
revolved in my mind, and wondered to find no mention of them in our
books of experimental philosophy.

At length being at Clapham, where there is, on the common, a large
pond, which I observed one day to be very rough with the wind, I
fetched out a cruet of oil, and dropt a little of it on the water.
I saw it spread itself with surprising swiftness upon the surface;
but the effect of smoothing the waves was not produced; for I had
applied it first on the leeward side of the pond, where the waves
were largest, and the wind drove my oil back upon the shore. I
then went to the windward side where they began to form; and there
the oil, though not more than a tea spoonful, produced an instant
calm over a space several yards square, which spread amazingly,
and extended itself gradually till it reached the lee side, making
all that quarter of the pond, perhaps half an acre, as smooth as a
looking-glass.

After this I contrived to take with me, whenever I went into the
country, a little oil in the upper hollow joint of my bamboo cane,
with which I might repeat the experiment as opportunity should offer,
and I found it constantly to succeed.

In these experiments, one circumstance struck me with particular
surprise. This was the sudden, wide and forcible spreading of a drop
of oil on the face of the water, which I do not know that any body
has hitherto considered. If a drop of oil is put on a highly polished
marble table, or on a looking-glass that lies horizontally, the drop
remains in its place, spreading very little. But when put on water,
it spreads instantly many feet round, becoming so thin as to produce
the prismatic colours, for a considerable space, and beyond them so
much thinner as to be invisible, except in its effect of smoothing
the waves at a much greater distance. It seems as if a mutual
repulsion between its particles took place as soon as it touched the
water, and a repulsion so strong as to act on other bodies swimming
on the surface, as straw, leaves, chips, &c. forcing them to recede
every way

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Text Comparison with Experiments and Observations on Electricity Made at Philadelphia in America

Page 0
_) The PREFACE.
Page 1
_ _But of these, and many other interesting circumstances, the reader will be more satisfactorily informed in the following letters, to which he is therefore referred by_ _The_ EDITOR.
Page 4
Touch the top and bottom together, and the equilibrium will soon be restored, but silently and imperceptibly; the crooked wire forming the communication.
Page 5
Set the electrified phial on one, and then touch the wire; that book will be electrified _minus_; the electrical fire being drawn out of it by the bottom of the bottle.
Page 10
The same if another gentleman and lady, _C_ and _D_, standing also on wax, and joining hands with _A_ and _B_, salute, or shake hands.
Page 12
But if a man holds in his hands two bottles, one fully electrify'd, the other not at all, and brings their hooks together, he has but half a shock, and the bottles will both remain half electrified, the one being half discharged, and the other half charged.
Page 18
When it is well charg'd it begins to move; the bullet nearest to a pillar moves towards the thimble on that pillar, and passing by electrifies it and then pushes itself from it; the succeeding bullet, which communicates with the other surface of the glass, more strongly attracts that thimble on account of its being before electrified by the other bullet; and thus the wheel encreases its motion till it comes to such a height as that the resistance of the air regulates it.
Page 22
10.
Page 26
When a great number of clouds from the sea meet a number of clouds raised from the land, the electrical flashes appear to strike in different parts; and as the clouds are jostled and mixed by the winds, or brought near by the electrical attraction, they continue to give and receive flash after flash, till the electrical fire is equally diffused.
Page 27
_ in the most northern part, and the appearance proceeds southward, tho' the fire really moves northward.
Page 29
If the source of lightning, assigned in this paper, be the true one, there should be little thunder heard at sea far from land.
Page 32
Take away these atmospheres by touching the balls, and leave them in their natural state: then, having fixed a stick of sealing wax to the middle of the vial to hold it by, apply the wire to A, at the same time the coating touches B.
Page 39
Perhaps this may be the reason; when there is not a perfect continuity in the circle, the.
Page 40
From the before mentioned law of electricity, that points, as they are more or less acute, draw on and throw off the electrical fluid with more or less power, and at greater or less distances, and in larger or smaller quantities in the same time, we may see how to account for the situation of the leaf of gold suspended between two plates, the upper one continually electrified, the under one in a person's hand standing on the floor.
Page 41
Thus the difference of distance is always proportioned to the difference of acuteness.
Page 42
But, if the electrical fluid so easily pervades glass, how does the vial become _charged_ (as we term it) when we hold it in our hands? Would not the fire thrown in by the wire pass through to our hands, and so escape into the floor? Would not the bottle in that case be left just as we found it, uncharged, as we know a metal bottle so attempted to be charged would be? Indeed, if there be the least crack, the minutest solution of continuity in the glass, though it remains so tight that nothing else we know of will pass, yet the extremely subtile electrical fluid flies through such a crack with the greatest freedom, and such a bottle we know can never be charged: What then makes the difference between such a bottle and one that is sound, but this, that the fluid can pass through the one, and not through the other?[8] 29.
Page 45
[10] But if the inside of the globe be lined with a non-electric, the additional repellency of the electrical fluid, thus collected by friction on the rubb'd part of the globe's outer surface, drives an equal quantity out of the inner surface into that non-electric lining, which receiving it, and carrying it away from the rubb'd part into the common mass, through the axis of the globe and frame of the machine, the new collected electrical fluid can enter and remain in the outer surface, and none of it (or a very little) will be received by the prime conductor.
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35.
Page 48
Now the globe being turn'd, could draw no fire from the floor through the machine, the communication that way being cut off by the thick glass plate under the cushion: it must then draw it through the chains whose ends were dipt in the oil of turpentine.
Page 52
Containing Remarks, with practical Observations, on Tumours of the Gall Bladder, on the Thigh, and the Trachea Arteria; on the Use of the Trepan; of Wounds in the Brain, Exfoliation of the Cranium, Cases of pregnant Women, faulty Anus in new born Children, Abscesses in the Fundament, Stones encysted in the Bladder, Obstructions to the Ejaculation of the Semen, an inverted Eyelid, extraneous Bodies retained in the Oesophagus, discharged through Abscesses; of Bronchotomy, Gastrotomy, native Hare-lips; of the Caesarean Operation; a new Method of extracting the Stone from the Bladder, on a Cancer of the Breast, an elastic Truss for Hernias, remarkable Hernias of the Stomach, and through the Foramen Ovale.