Lake Tana & The Blue Nile An Abyssinian Quest - By Major R.E. Cheesman, C.B.E.

Major Cheesman was appointed Consul for North-west Abyssinia in 1925, survey work not being part of his official duties, but rather in his case to have been a hobby. This book describes his expedition to, among other objectives, map the correct course of the Blue Nile and of its tributaries, and to measure water levels along the river in order to plot a longitudinal section of the river, that would illustrate its fall at any particular point.