April 13th , 1780
Alexander Mitchell, (13 April 1780 – 25 June 1868) was an Irish engineer who from 1802 was blind. He is known as the inventor of the screw-pile lighthouse.
Born in Dublin, his family moved to Belfast while he was a child, and he received his formal education at Belfast Academy – where he excelled in mathematics.
Originally working in brickmaking in Belfast, he invented machines used in that trade, before patenting the screw-pile in 1833, for which he would later gain some fame. The screw-pile was used for the erection of lighthouses and other structures on mudbanks and shifting sands, including bridges and piers. Mitchell’s designs and methods were employed all over the world from Portland breakwater to Bombay bridges. Initially it was used for the construction of lighthouses on Maplin Sands in the Thames Estuary (the first light application, in 1838), at Fleetwood Lancashire (UK) Morecambe Bay (the first Ever Beacon Lit ) completed, in 1839), and at Belfast Lough where his lighthouse was finished in July 1844.
