Decorative example of Guillaume De L'Isle's double hemisphere map of the World, published in Paris in 1720.
The map is a marvelous depiction of the routes of a number of important explorers, showing the routes of Magellan (1520), Le Maire (1615), St. Louis (1708), Halley (1700), Mendana (1595), St. Antoine, (1710), Tasman (1642), and Quiroz (1605).
This edition predates the addition of the Russian discoveries, first added to this map after 1741. Interesting incomplete New Zealand, mythical hint of the unknown Southern Continent and incomplete coast of Nouvelle Hollande (Australia).
Includes the mythical Juan De Gama's Land, east of Yeso and Japan. De Gama land seems to be a part of the pre-history of the Northeast Coast of America, which would soon be laid to rest by the voyages of Bering, Cook and others in the region. In the early 17th century rumors began to circulate that a Spanish ship, traveling east from the Philippines to Mexico, had been blown off course and discovered a land in the north rich in gold and silver as all unreachable lands were. In later versions, the ship became Portuguese with a captain named Juan de Gama. In some geographer's minds, de Gama's land and Ezo were one and the same. In others, Ezo was a part of the Asian mainland and De Gama's land was a separate land in the North Pacific.
From the 1720s to 1740s, De Gama Land was a source of intellectual debate, not as to its existence, but its exact location, with such important mapmakers and explorers as De L'Isle, de la Croyere and Tchirikow each opining as to its location.
Guillaume De L'Isle (1675-1726) is probably the greatest figure in French cartography. Having learned geography from his father Claude, by the age of eight or nine he could draw maps to demonstrate ancient history. He studied mathematics and astronomy under Cassini, from whom he received a superb grounding in scientific cartography—the hallmark of his work. His first atlas was published in ca. 1700. In 1702 he was elected a member of the Academie Royale des Sciences and in 1718 he became Premier Geographe du Roi.
De L'Isle's work was important as marking a transition from the maps of the Dutch school, which were highly decorative and artistically-orientated, to a more scientific approach. He reduced the importance given to the decorative elements in maps, and emphasized the scientific base on which they were constructed. His maps of the newly explored parts of the world reflect the most up-to-date information available and did not contain fanciful detail in the absence of solid information. It can be fairly said that he was truly the father of the modern school of cartography at the commercial level.
De L’Isle also played a prominent part in the recalculation of latitude and longitude, based on the most recent celestial observations. His major contribution was in collating and incorporating this latitudinal and longitudinal information in his maps, setting a new standard of accuracy, quickly followed by many of his contemporaries. Guillaume De L’Isle’s work was widely copied by other mapmakers of the period, including Chatelain, Covens & Mortier, and Albrizzi.