"The Sooloo Archipelago, Laid Down Chiefly from Observations in 1761, 1762, 1763, & 1764", Dalrymple, Alexander
Period: 1771 (dated)
Color: Black & White
24 x 18.5 inches
61 x 47 cm
A large chart of the Sulu Archipelago, located northeast of Borneo, with two smaller inset charts of Sooloo Road and Toolyan Bay. The map features soundings in fathoms, with an interesting pronunciation guide at right, and a key to important lettered points at left. Alexander Dalrymple was a Scottish hydrographer who explored the Philippines in the employ of the East India Company.
The depiction of the land surface features have been a challenge for map makers ever since the earliest maps. The restriction imposed by copper engraving limited the drawings essentially to line work in one color. Areas of slope were generally depicted with hachures with the level areas left blank. Hachures were drawn with the rule that the greater the slope and ruggedness, the denser and darker were the hachures. This map is a fine example of one of the methods employed during the late 18th century to more clearly depict topographical features; these features are etched, rather than engraved. The imprint at bottom credits D. Lerpeniere with the etching and B. Henry with the engraved portions of the chart.
A good impression on a sheet with wide original margins. There are a pair of tiny wormholes in the lower part of the map and the centerfold is lightly toned. A faint damp stain just enters the upper right corner.