Autograph Letter Signed, to Mr. Wicksteed, agreeing to assist him in erecting Lightning Conductors on his buildings [in London], describing the three possibilities open to him, including “the kind of Conductor applied to the Nelson Pillar in Trafalgar Square”, suggesting that “a flat conductor of Copper Sheet such as I propose for Ships & which would I think answer well”. 4 pp.7 x 4½ inches, fine. Plymouth, 23 June 1844. Uncommon. “I think you will find in my work every information requisite for boxing Conductors to Buildings.” Sir William Snow Harris (1791–1867) was an English physician and electrical researcher, nicknamed Thunder-and-Lightning Harris, and noted for his invention of a successful system of lightning conductors for ships. It took many years of campaigning, research and successful testing before the British Royal Navy changed to Harris’s conductors from their previous less effective system. One of the successful test vessels was HMS Beagle which survived lightning strikes unharmed on her famous voyage with Charles Darwin.