Experiments and Observations on Electricity Made at Philadelphia in America

By Benjamin Franklin

Page 45

surface than the glass would
naturally draw in; this increases the repelling power on that side, and
overpowering the attraction on the other, drives out part of the fluid that
had been imbibed by that surface, if there be any non-electric ready to
receive it: such there is in all cases where glass is electrified to give a
shock. The surface that has been thus emptied by having its electrical
fluid driven out, resumes again an equal quantity with violence, as soon as
the glass has an opportunity to discharge that over-quantity more than it
could retain by attraction in its other surface, by the additional
repellency of which the vacuum had been occasioned. For experiments
favouring (if I may not say confirming) this hypothesis, I must, to avoid
repetition, beg leave to refer you back to what is said of the electrical
phial in my former papers.

34. Let us now see how it will account for several other
appearances.--Glass, a body extremely elastic (and perhaps its elasticity
may be owing in some degree to the subsisting of so great a quantity of
this repelling fluid in its pores) must, when rubbed, have its rubbed
surface somewhat stretched, or its solid parts drawn a little farther
asunder, so that the vacancies in which the electrical fluid resides,
become larger, affording room for more of that fluid, which is immediately
attracted into it from the cushion or hand rubbing, they being supply'd
from the common stock. But the instant the parts of the glass so open'd and
fill'd have pass'd the friction, they close again, and force the additional
quantity out upon the surface, where it must rest till that part comes
round to the cushion again, unless some non electric (as the prime
conductor) first presents to receive it.[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. As this charg'd part of the globe comes round to the
cushion again, the outer surface delivers its overplus fire into the
cushion, the opposite inner surface receiving at the same time an equal
quantity from the

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 5
--Size of rods for conductors to buildings.
Page 54
In her early years she had been sent to the continent, and entered a convent with the design of becoming a nun; but the climate not agreeing with her constitution, she was obliged to return to England, where, as there were no monasteries, she made a vow to lead a monastic life, in as rigid a manner as circumstances would permit.
Page 63
Before I relate the particulars of my entrance into business, it may be proper to inform you what was at that time the state of my mind as to moral principles, that you may see the degree of influence they had upon the subsequent events of my life.
Page 85
In September, 1752, Franklin entered upon a course of experiments, to determine the state of electricity in the clouds.
Page 130
Hence a bottle cannot be electrised that is foul or moist on the outside, if such moisture continue up to the cork or wire.
Page 137
The operator, who holds the picture by the upper end, where the inside of the frame is not gilt, to prevent its falling, feels nothing of the shock, and may touch the face of the picture without danger, which he pretends is a test of his loyalty.
Page 140
--Experiments may possibly be invented hereafter, to discover this.
Page 164
It is true, there is an experiment that at first sight would be apt to satisfy a slight observer, that the fire, thrown into the bottle by the wire, does really pass through the glass.
Page 168
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.
Page 176
Page 201
Towards the middle of A, bring the excited glass tube, and holding it a short time, at the distance of a few inches, each pair of balls will be observed to separate: withdraw the tube, and the balls of A will come together, and then repel each other again; but those of B will hardly be affected.
Page 215
The spire was split all to pieces by the lightning, and the parts flung in all directions over the square in which the church stood, so that nothing remained above the bell.
Page 229
I think all the phenomena on which it.
Page 253
And this instance agrees with others in showing, that the second and principal intention of the rods is obtainable, viz.
Page 266
There is something in it similar to the old observation, I think mentioned by Aristotle, that the bottom of a boiling pot is not warm; and perhaps it may help to explain that fact;--if indeed it be a fact.
Page 271
On each box, lay a wire six inches long and one-fifth of an inch thick, tapering to a sharp point; but so laid, as that four inches of the _pointed_ end of _one_ wire, and an equal length of the _blunt_ end of the _other_, may project beyond the ends of the boxes; and both at eighteen inches distance from the prime conductor.
Page 287
Germain, May 20, 1752, gives the following Account (printed in the Philosophical Transactions) of the Experiment made at Marly, in.
Page 304
interest of Great Britain with regard to, 39.
Page 310
17, 27, 41, 43, 44.
Page 324
extract from his vulcanus famulans, ii.