May, Andrew. "The Gravity Engine"
Divergence: c 1830 CE
What if: The laws of physics wre slightly different, to the extent that Faraday's experiments in the connection between elecricity and magnetism failed and he was labeled a crackpot.
Summary: Twenty years later, Faraday instead makes a successful demonstration electro-gravitism.
Published: Posted on-line at The Quantum Muse, July 2000.
Web link: Andrew May's website