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RE: Bulges



I am almost sorry I brought up the subject of the "tidal bulges". However,
I do have a couple of further comments before we postposne this for another
year. (:-)

The original question was whether Newton appealed to the common CM
explanation for the bulges --- I guess we have concluded thta he did not.

He *did* incorectly predict that the ocean's surface was a prolate spheroid
with it's axis along the Moon/Earth line. Paul Middents gives the
references for this.

Paul also suggests the following:

S. Chandrasekhar in his beautiful commentary "Newton's Principia for the
Common Reader"

for which I thank him very much -- because I have given up trying to
understand the Motte version.

Let me point out two things more:

1) Some here are talking about a deformation of the somewher solid Earth
proper and some are talking about the shape of the gravitational potential.
Some think they are talking about the shape of the oceans.

And I now feel constrained to say that

2) There are no such things as tidal bulges in the oceans. (David Bowman
was waiting for me to say this, weren't you). I have been working to
complete a statement on this for some time, but I still need to get a point
or two cleared up. With great reluctance and only at the urging of a couple
of list members, I offer a sketch of this work at

http://www.sisna.com/users/jmgreen/tides.htm

Please comment privatly, but be merciful when you do. (:-)

TX







Jim Green
JMGreen@sisna.com