Item 202 is America Sive India Nova... a turn of the 17th century Mercator map, engraved by Gerard Mercator's grandson Michael. It depicts the Americas as known at the time, the greatest accuracy being around the Caribbean, with North America surprisingly more accurate than the bulging blob that is South America. It includes two of Mercator's four Arctic islands and the mythical Atlantic islands of Frisland and St. Brendan's Island. There is a massive southern continent, along with a huge, but separate New Guinea, which one might otherwise mistake for Australia, unknown at the time. Interesting. £5,200 (US $7,937).

Item 340 combines mapping with science: A Map of the Real Passage of the Moon's Shadow Over England... In 1764, there was an eclipse of the sun visible from much of England. George Witchell had published a map prior to the eclipse, showing its path, timing, and duration. After the eclipse occurred, he discovered some minor miscalculations, so he republished this map with the path and data revised. £2,000 (US $3,053).

Item 228 is a Civil War map of part of America by a party with no horse in the race. It is Major A.C. Cooke's 1864 map from London, Virginia & Maryland At Present Occupied By The Hostile Armies. Cooke covers territory in which many battles were fought in this separately published broadside map for use by British observers of events in America. £520 (US $793).

Jonathan Potter Limited may be reached at info@jpmaps.co.uk or +44 (0)20 7491 3520. The website is found at www.jpmaps.co.uk.