Re: The mystery behind the Einstein-Besso 54 pages manuscript, hiidden for 40 years.

On the advice of Newcomb (through Lorentz and Freundlich) and, in
particular, from Schwarzschild, Einstein got rid of every planet that he
and Besso considered an influence. Also stop treating the Sun as a
liquid rotating sphere.
Going to the fundamentals of Newtonian celestial mechanics, a point-like
Sun was used with the sole presence of Mercury (Newcomb). This was the
original approach of Gerber, in his 1898 paper, who provided the final
formula that Einstein plagiarized, using a mixed math between Newton and
a hack of basic Grossman formula for space void of matter and energy. No
covariance was needed in this fraud.