Lighthouses have guided mariners safely home for centuries, with the first lighthouse reportedly constructed in ancient Egypt (although it was later destroyed). Although GPS is now in everything from ...

SIR WILLIAM THOMSON writes a long letter on this subject to the Times of Tuesday, the letter being the result of a most interesting experimental cruise of ten days on board Her Majesty's ship ...

OWING to the optical properties of the lens employed in revolving lights, a formidable element of difficulty comes in the way of effecting a sharp cut-off on a particular bearing; for the direction of ...