Mar 20– From "Voltaire’s Letters on The English" (1733)

 The Earth spins round, right round.

Mar 20– From Voltaire’s Letters on The English (1733)

Summary: Isaac Newton did a lot of cool math.

Commentary: Another one where the selection breaks kind of weird, and is shorter than it has to be. For the ones like this where pages don't seem to have an clean/obvious break, I wish we could get a line/paragraph number or a fist/last word or something. No overlap at least.

According to your Cartesians, everything is performed by an impulsion, of which we have very little notion; and according to Sir Isaac Newton, it is by an attraction, the cause of which is as much unknown to us.

VO before the first song on the Isaac Newton rock concept album.

  a man who discovers a new tract of land cannot at once know all the properties of the soil. 

A good thing to remember when you try something new.

Gravity, the falling of accelerated bodies on the earth, the revolution of the planets in their orbits, their rotations round their axis, all this is mere motion.  Now motion cannot perhaps be conceived any otherwise than by impulsion; therefore all those bodies must be impelled.  But by what are they impelled?  All space is full, it therefore is filled with a very subtile matter, since this is imperceptible to us; this matter goes from west to east, since all the planets are carried from west to east.  Thus from hypothesis to hypothesis, from one appearance to another, philosophers have imagined a vast whirlpool of subtile matter, in which the planets are carried round the sun: they also have created another particular vortex which floats in the great one, and which turns daily round the planets.  When all this is done, it is pretended that gravity depends on this diurnal motion; for, say these, the velocity of the subtile matter that turns round our little vortex, must be seventeen times more rapid than that of the earth; or, in case its velocity is seventeen times greater than that of the earth, its centrifugal force must be vastly greater, and consequently impel all bodies towards the earth.  This is the cause of gravity, according to the Cartesian system.  But the theorist, before he calculated the centrifugal force and velocity of the subtile matter, should first have been certain that it existed.

It's interesting reading these old science bits. I'm not an expert, but I'm pretty sure about 80% of this is wrong. (They are, we find out in the next sentence. Hurray,  not worthless as science!) He also talks about north, south, east, and west in space, which hurts my brain a little. I think we've more or less standardized on: coreward, rimward, spinward, and trailing in science fiction.

But being retired in 1666, upon account of the Plague

I know a lot of people who did that in 2020.

Now a heavy body falls, in reality, fifteen feet in the first second, and goes in the first minute fifty-four thousand feet, which number is the square of sixty multiplied by fifteen.  Bodies, therefore, gravitate in an inverse ratio of the squares of the distances; consequently, what causes gravity on earth, and keeps the moon in its orbit, is one and the same power; it being demonstrated that the moon gravitates on the earth, which is the centre of its particular motion, it is demonstrated that the earth and the moon gravitate on the sun which is the centre of their annual motion.

How cool would it be to be the person who did the math for this the first time, and found it all worked? Openheimer would've been a better movie if they showed more of the math. Thanks for showing the math, Voltaire.

I mentioned in one of the histories (Tacitus, I think) that I wish we put excerpts of this stuff in modern text books, and it's the same for science. Gravity is not that exciting. Reading a first or second hand account of the "discovery" of gravity is way better.