Thanks for sharing the info on the Philadelphia experiment
LostLos 
I too think that there's a curious connection btw this and 'having to move the island to save it' message Locke got in cabin. Even long before that it was quite clear that some travel in space-time continuum was part of the deal with the island.
Majority of Nicola Tesla's lifetime works have later been credited to Einstein unfortunately. The scientific idea behind P.E. is one of those Tesla was working on since 1930s and thinking it would have drastic consequences, he had withdrawn himself from the project short before his death.