Classics of modern science : $b (Copernicus to Pasteur)
History
Classics of modern science : $b (Copernicus to Pasteur)
Science; Science -- History
But points have a property, by which they draw on as well as throw
off the electrical fluid, at greater distances than blunt bodies can.
That is, as the pointed part of an electrified body will discharge the
atmosphere of that body, or communicate it farthest to another body,
so the point of an unelectrified body will draw off the electrical
atmosphere from an electrified body, farther than a blunter part of
the same unelectrified body will do. Thus, a pin held by the head,
and the point presented to an electrified body, will draw off its
atmosphere at a foot distance; where, if the head were presented
instead of the point, no such effect would follow. To understand
this, we may consider, that, if a person standing on the floor would
draw off the electrical atmosphere from an electrified body, an iron
crow and a blunt knitting-needle, held alternately in his hand, and
presented for that purpose, do not draw with different forces in
proportion to their different masses. For the man, and what he holds in
his hand, be it large or small, are connected with the common mass of
unelectrified matter; and the force with which he draws is the same in
both cases, it consisting in the different proportion of electricity
in the electrified body, and that common mass. But the force, with
which the electrified body retains its atmosphere by attracting it, is
proportioned to the surface over which the particles are placed; that
is, four square inches of that surface retain their atmosphere with
four times the force that one square inch retains its atmosphere. And,
as in plucking the hairs from the horse’s tail, a degree of strength
not sufficient to pull away a handful at once, could yet easily strip
it hair by hair, so a blunt body presented cannot draw off a number of
particles at once, but a pointed one, with no greater force, takes them
away easily, particle by particle.
These explanations of the power and operation of points, when they
first occurred to me, and while they first floated in my mind, appeared
perfectly satisfactory; but now I have written them, and considered
them more closely, I must own I have some doubts about them; yet, as I
have at present nothing better to offer in their stead, I do not cross
them out; for, even a bad solution read, and its faults discovered, has
often given rise to a good one, in the mind of an ingenious reader.
Nor is it of much importance to us to know the manner in which nature
executes her laws; it is enough if we know the laws themselves. It is
of real use to know that China left in the air unsupported, will fall
and break; but how it comes to fall, and why it breaks, are matters of
speculation. It is a pleasure indeed to know them, but we can preserve
our China without it.
Public-domain text, read in full here on John Shaqi.
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