Relief shown by hachures and spot heights. "Mr. Petherick's Routes, as well as those of his Agents (Mussaad & Awat), are Coloured [red.]" Discharge of Nile, Gazelle, and Sobat rivers (cubic feet per second) in 1863 is shown. Includes table: Heights [of stations] determined from the temperature of the boiling point of water, observed by Mr. Petherick. From: The Journal of the Royal Geographical Society of London. Vol. 35, (1865), pp. 289-300; held in Firestone Library. Call number: G7 .J687 v.35 1865