A sketch by chronometer & compass, of St. John's River, by Bar. Bulow, July 22, 23, 24th, 1847 in his progress down the River in a Bongay, about 50 feet long by about 9 feet broad, drawing with a freight of 5 tons and 13 persons, 4 feet water.

Map depicting the St. John, or San Juan, river in Nicaragua. Shows the river running between Lake Nicaragua and the Caribbean Sea. Relief shown by hachures. Shows vegetation around the river. Below title is an "Explanation" with notes on the river, including river conditions and travel. Below this is the scale and related note. Notes around the map list banks, widths, currents, depths, and obstructions for each part of the river. Inset at lower left corner depicts a broader view of San Juan River, Lake Nicaragua, Lake Managua, and surrounding area. Partially coloured. At lower left corner, below inset: "Drawn in Lithography by L. J. Hebert: and Printed at the Lithographic Establishment, Quarter Master Generals Office Horse Guards January 1848." Hand written on verso is: "Sketch of the River St. John de Nicaragua. For Viscount Palmerston."