Chart of the Entrances to the River Thames. William Heather (18th cent.). Engraved map. London, c. 1791. 25 1/4 x 32 3/4 inches sheet. Numerous soundings and depictions of the well-knows sandbanks near the Thames mouth including “Kentish Knock”, “Goodwin Sands”, and the “Margate Sands.” The Tower of London is noted.