Memoirs of Benjamin Franklin; Written by Himself. [Vol. 2 of 2] With his Most Interesting Essays, Letters, and Miscellaneous Writings; Familiar, Moral, Political, Economical, and Philosophical, Selected with Care from All His Published Productions, and Comprising Whatever Is Most Entertaining and Valuable to the General Reader

By Benjamin Franklin

Page 228

actually do in such cases, that the river loses itself by running
under ground, whereas, in truth, it has run up into the air.

Now, how many rivers that are open to the sea widen much before they
arrive at it, not merely by the additional waters they receive, but by
having their course stopped by the opposing flood-tide; by being turned
back twice in twenty-four hours, and by finding broader beds in the low
flat countries to dilate themselves in; hence the evaporation of the
fresh water is proportionably increased, so that in some rivers it may
equal the springs of supply. In such cases the salt water comes up the
river, and meets the fresh in that part where, if there were a wall or
bank of earth across, from side to side, the river would form a lake,
fuller indeed at sometimes than at others, according to the seasons, but
whose evaporation would, one time with another, be equal to its supply.

When the communication between the two kinds of water is open, this
supposed wall of separation may be conceived as a moveable one, which is
not only pushed some miles higher up the river by every flood-tide from
the sea, and carried down again as far by every tide of ebb, but which
has even this space of vibration removed nearer to the sea in wet
seasons, when the springs and brooks in the upper country are augmented
by the falling rains, so as to swell the river, and farther from the sea
in dry seasons.

Within a few miles above and below this moveable line of separation, the
different waters mix a little, partly by their motion to and fro, and
partly from the greater gravity of the salt water, which inclines it to
run under the fresh, while the fresh water, being lighter, runs over the
salt.

Cast your eye on the map of North America, and observe the Bay of
Chesapeake, in Virginia, mentioned above; you will see, communicating
with it by their mouths, the great rivers Susquehanna, Potomac,
Rappahannoc, York, and James, besides a number of smaller streams, each
as big as the Thames. It has been proposed by philosophical writers,
that to compute how much water any river discharges into the sea in a
given time, we should measure its depth and swiftness at any part above
the tide: as for the Thames, at Kingston or Windsor. But can one
imagine, that if all the water of those vast rivers went to the sea, it
would not first have pushed the salt water out of

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

Page 2
At the same time that the wire and top of the bottle, &c.
Page 4
EXPERIMENT V.
Page 8
had also occurred to us some months before Mr _Watson_'s ingenious _Sequel_ came to hand, and these were some of the new things I intended to have communicated to you.
Page 9
After such strong spark, neither of them discover any electricity.
Page 10
Give him the electrised bottle in his hand.
Page 12
8, 9, 10, 11.
Page 14
Yet when the situation of the electrical fire is thus altered in the glass; when some has been taken from one side, and some added to the other, it will not be at rest or in its natural state, till 'tis restored to its original equality.
Page 15
The latter we found to be true: for that bottle on trial gave the shock, though filled up as it stood with fresh unelectrified water from a tea-pot.
Page 19
--If instead of two bullets you put eight, four communicating with the upper surface, and four with the under surface, placed alternately; which eight, at about six inches distance, compleats the circumference, the force and swiftness will be greatly increased, the wheel making fifty turns in a minute; but then it will not continue moving so long.
Page 20
allowing (for the reasons before given, s 8, 9, 10,) that there is no more electrical fire in a bottle after charging, than before, how great must be the quantity in this small portion of glass! It seems as if it were of its very substance and essence.
Page 21
Every particle of matter electrified is repelled by every other particle equally electrified.
Page 24
27.
Page 27
It is safer to be in the open field for another reason.
Page 29
It was in this view I wrote and sent you my former papers on this subject, desiring, that as I had not the honour of a direct correspondence with that bountiful benefactor to our library, they might be communicated to him through your hands.
Page 31
If a piece of common matter be supposed intirely free from electrical matter, and a single particle of the latter be brought nigh, 'twill be attracted and enter the body, and take place in the center, or where the attraction is every way equal.
Page 36
Set the iron punch on the end upon the floor, in such a place as that the scales may pass over it in making their circle: Then electrify one scale by applying the wire of a charged phial to it.
Page 42
greatest quantity.
Page 44
Now the departing fire leaving a vacuum, as aforesaid, between these pores, which air nor water are fine enough to enter and fill, the electrical fluid (which is every where ready in what we call the non-electrics, and in the non-electric Mixtures that are in the air,) is attracted in: yet does not become fixed with the substance of the glass, but subsists there as water in a porous stone, retained only by the attraction of the fixed parts, itself still loose and a fluid.
Page 45
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.
Page 53
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