Lacus Aquae Dulces – Many students of rare maps of the American southeast will notice a large lake or inland sea of this name or something similar roughly located in what is today Georgia or South Carolina. This curious geographic feature, first seen in Le Moyne’s map of Florida drawn in 1565, persisted until the early 18th century. In later maps it was associated with the Apalache Indians and the Apalache (Appellation) Mountain Range where it was consequently renamed Lake Apalache. With a nearly 200 year history, Lacus Aquae Dulces is one of the more interesting and enduring errors in the early mapping of North America.
The curious story of this lake begins with Jacques Le Moyne who was was part of an ill fated French Huguenot effort to colonize the mainland of North America in the mid 16th century. Le Moyne was commissioned to sketch the local inhabitants and map as much of the land as possible. In his short time in the New World, Le Moyne’s important map of Florida is a impressive achievement. Despite a few irregularities and a pronounced longitudinal distortion, it is a remarkably accurate. For our purposes we need to focus on the Lacus Auqae Dulces, which Le Moyne locates in central Florida as the source of the River May or today’s St. John’s River. Le Moyne maps the River May with a rough approximation of accuracy as an inverted V flowing north from Lake George, the true and original Lacus Aquae Dulces, and then in a southwesterly direction into the Atlantic.
Back in Europe most cartographers followed Le Moyne’s model until the 1606 Hondius edition of Mercator’s Atlas in which the lake and the river were transposed far to the north. How and why this happened is something of a mystery, but we can speculate. We know that many maps of this region made in the 16th and 17th century frequently placed latitude lines up to 20 degrees to the north. These errors can be associated with magnetic variation, temperature issues associated with isothermal lines, and navigational errors related to the erroneous confusion of the star Asfick with Polaris. While Le Moynecorrectly located the mouth of the River May at 30 degrees of Latitude, Hondius maps it between 31 and 32 degrees. This led to a misassociation of the River May with the Savannah River. Thus, while the River May dips southward, the Savannah River heads almost directly NW into the Appellation Mountains, forming the modern southern border of South Carolina. Hondius, no doubt taking his cue from navigators who rarely trekked inland, therefore rerouted the May River to flow from the northwest. Without an accurate picture if the interior, Hondius followed Le Moyne’s example and translocated the great freshwater lake to the north. The influence of the Mercator-Hondius firm was so pronounced in Europe that most subsequent cartographers followed their lead. Lactus Aquae Dulces appeared in maps by Jansson, Laet, Janszoon, Blaeu, Allard, Ogilby, Speed, Homann and others well into the 18th century. In the 1670s the German explorer John Lederer, probably the first European to actually enter this region, claims to have actually seen and sampled the water of this mysterious lake, which he called Ashley. While Lederer’s claim is undoubtedly false, as the lake does not exist, it is unclear why he chose to lie. Quite possible Lederer’s motivation was merely to validate an enhance the importance of his own discoveries. Around 1730 surveyors and other frontiersmen exploring the region added to the cartographic corpus and, failing to identify a major lake in this region, influenced its removal from most subsequent maps.
True, David O., “Some Early Maps Relating to Florida”, Imago Mundi, Vol. 11 (1954), pp. 73-84.
Cumming, W. P., “Geographical Misconceptions of the Southeast in the Cartography of the Seventeenth and Eighteenth Centuries”, The Journal of Southern History, Vol. 4, No. 4 (Nov., 1938), pp. 476-492.