Notes on the Congo River . 
187 
Mwata ya Nvo, and Dr. de Lacarda 1 records it 
as the “ Guarava,” probably a dialectic form of 
Lualava. It is the Luapula of the “ Geographer of 
N’yassi,” who, with his usual felicity and boldness 
of conjecture (p. 38), bends it eastward, and dis¬ 
charges^ into his mythical Central Sea. 
Dr. Behm greatly under-estimates the Congo 
when he assigns to it only 1,800,000 cubic feet per 
second. He makes the great artery begin to rise 
in November instead of September and decrease 
in April, without noticing the March-June freshets, 
reported by all the natives to measure about one- 
third of the autumnal floods. His elements are 
taken from Tuckey, who found off the “ Diamond 
Rock” a velocity of 3*50 knots an hour, and from 
Vidal’s Chart, showing 9,000 English feet or 1*50 
nautical miles in a Thalweg fifty fathoms deep. 
Thus he assumes only two nautical miles for the 
current, or sixty inches per second, which must be 
considerably increased, and an average depth of 
ten fathoms, which again is too little. For 1,800,000 
cubic feet of water per second, which Tuckey 
made 2,000,000, we may safely read 2,500,000. 
Dr. Livingstone himself was haunted by the 
idea that he was exploring the Upper Congo, not 
the Nile. From a Portuguese subordinate he 
“ learned that the Luapula went to Angola.” He 
1 “ The Lands of the Cazembe/’ p. 47. 
