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

By Benjamin Franklin

Page 79

in your opinion, that the rising of the
tides in rivers is not owing to the immediate influence of the moon
on the rivers. It is rather a subsequent effect of the influence
of the moon on the sea, and does not make its appearance in some
rivers till the moon has long passed by. I have not expressed myself
clearly if you have understood me to mean otherwise. You know I
have mentioned it as a fact, that there are in some rivers several
tides all existing at the same time; that is, two, three, or more,
high-waters, and as many low-waters, in different parts of the same
river, which cannot possibly be all effects of the moon's immediate
action on that river; but they may be subsequent effects of her
action on the sea.

In the enclosed paper you will find my sentiments on several points
relating to the air, and the evaporation of water. It is Mr.
Collinson's copy, who took it from one I sent through his hands to a
correspondent in France some years since; I have, as he desired me,
corrected the mistakes he made in transcribing, and must return it to
him; but if you think it worth while, you may take a copy of it: I
would have saved you any trouble of that kind, but had not time.

Some day in the next or the following week, I purpose to have the
pleasure of seeing you at Wanstead: I shall accompany your good mamma
thither, and stay till the next morning, if it may be done without
incommoding your family too much.--We may then discourse any points
in that paper that do not seem clear to you; and taking a walk to
lord Tilney's ponds, make a few experiments there to explain the
nature of the tides more fully. In the mean time, believe me to be,
with the highest esteem and regard, your sincerely affectionate
friend,

B. FRANKLIN.




TO THE SAME.

_Salt-Water rendered fresh by Distillation.--Method of relieving
Thirst by Sea-Water._


_Craven-street, August 10, 1761._

We are to set out this week for Holland, where we may possibly spend
a month, but purpose to be at home again before the coronation. I
could not go without taking leave of you by a line at least, when I
am so many letters in your debt.

In yours of May 19, which I have before me, you speak of the ease
with which salt water may be made fresh by distillation, supposing it
to be, as I had said, that in evaporation the

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

Page 3
So wonderfully are these two states of Electricity, the _plus_ and _minus_, combined and balanced in this miraculous bottle! situated and related to each other in a manner that I can by no means comprehend! If it were possible that a bottle should in one part contain a quantity of air strongly comprest, and in another part a perfect vacuum, we know the equilibrium would be instantly restored _within_.
Page 4
Place a man on a cake of wax, and present him the wire of the electrified phial to touch, you standing on the floor, and holding it.
Page 7
--When in this state, if you present to the shot the point of a long slender sharp bodkin, at six or eight inches distance, the repellency is instantly destroy'd, and the cork flies to the shot.
Page 8
1.
Page 9
--To _C_, standing on the floor, both appear to be electrised: for he having only the middle quantity of electrical fire, receives a spark upon approaching _B_, who has an over quantity; but gives one to _A_, who has an under quantity.
Page 16
20.
Page 19
'Tis amazing to observe in how small a portion of glass a great electrical force may lie.
Page 23
21.
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 passing along leaf-gilding 'tis visible: for the leaf-gold is full of pores; hold a leaf to the light and it appears like a net; and the fire is seen in its leaping over the vacancies.
Page 30
8.
Page 31
To explain this: take two apples, or two balls of wood or other matter, each having its own natural quantity of the electrical fluid.
Page 33
On these accounts we suppose electrified bodies discharge their atmospheres upon unelectrified bodies more easily and at a greater distance from their angles and points than from their smooth sides.
Page 37
To determine the question, whether the clouds that contain lightning are electrified or not, I would propose an experiment to be try'd where it may be done conveniently.
Page 38
But having no paint at hand, I pasted a narrow strip of paper over it; and when dry, sent the flash through the gilding; by which the paper was torn off from end to end, with such force, that it was broke in several places, and in others brought away part of the grain of the Turky-leather in which it was bound; and convinced me, that had it been painted, the paint would have been stript off in the same manner with that on the wainscot at _Stretham_.
Page 39
The gold was melted and stain'd into the glass as usual.
Page 41
By a little practice in blunting or sharpening the heads or tails of these figures, you may make them take place as desired, nearer, or farther from the electrified plate.
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 51
Page 19.
Page 52
The whole illustrated with Notes and References to the principal Geographers whose different Sentiments are cited and examined.