I've always been fascinated by Einstein’s theories about the speed of light and have always wondered about something that I've never been able to find the answer to. Any books I read were either too simple and did not address my question or too complex that I didn't understand it. It's time I put this question forward in the hopes that someone will be able to answer it in terms I understand. It’s in regards to Einstein’s deflection of light by the Sun test. From what I understand, using his equations, he calculated how much the sun would bend light before it could be tested. When it could be tested it was found to be correct and when normal geometry (not sure of the correct term) was used that answer was wrong. My question is: What did they use for the speed of light when they tried normal geometry equations? This has been bothering me for awhile. I’ll explain why after I receive an answer. Thanks, Rocco.