sentences:  Prompted by Charles Wyville Thomson—of the University of Edinburgh and Merchiston Castle School—the Royal Society of London obtained the use of "Challenger" from the Royal Navy and in 1872 modified the ship for scientific tasks, equipping her with separate laboratories for natural history and chemistry.The expedition, led by Captain George Nares, sailed from Portsmouth, England, on 21 December 1872.Other naval officers included Commander John Maclear.