180 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



precluded by the occurrence of the Welle, a river found by 

 Dr. Schweinfurth to run from east to west and northwest. 

 This Welle is supposed not to belong to the system of the 

 Nile, on very good grounds, and there is also reason to be- 

 lieve that it can not be the lower course of the Lualaba. 



Another warrant for not admitting the identity of this 

 river with the Nile is found by a comparison of the quantity 

 of water contained in the two rivers. As regards the Lua- 

 laba, Dr. Livingstone found that in the dry season the current 

 was one and a half to two English miles per hour, with a 

 great depth. If we estimate the minimum breadth at 2000 

 yards, the depth eight feet, and the current one and a half 

 miles per hour, we have a volume of 124,000 cubic feet per 

 second for the Lualaba. A calculation of the water found in 

 the White Nile and its tributaries at the same season of the 

 year shows that its volume is scarcely one third as great as 

 that of the Lualaba, from which consideration it is very evi- 

 dent that the latter can not be an affluent of the former. 



On the other hand, the Congo possesses all the magnitude 

 which the Lualaba must acquire after receiving the Quango 

 and other tributaries. The estimated flow of this river is 

 1,800,000 cubic feet per second, its breadth being estimated 

 at 9000 feet, and its depth sixty. It is thus shown to be 

 larger than the Mississippi, which, according to Humphries 

 and Abbot, carries dowm only a mean of 675,000 cubic feet 

 per second. The Congo collects this water from an area of 

 800,000 square miles, the Mississippi from an area of 1,200,000. 



If we take from the Congo the basin of the Lualaba, there 

 would not remain more than 400,000 square miles, which area 

 would be insufficient to maintain the lowest estimated vol- 

 ume of the Congo, especially as the rain-fall in the interior of 

 equatorial Africa in the rainy season does not exceed fifty- 

 eight inches. For this reason Dr. Petermann concludes that, 

 while the Congo is the only river capable of receiving the 

 Lualaba, so it requires this latter river to account for the 

 enormous volume of the former. 115 A, October 26, 1872, 532. 



EXPLORATIONS OF THE NAVY DEPARTMENT IN THE NORTH 



PACIFIC. 



The arrangements for an extended exploration of the Pa- 

 cific Ocean by the Navy Department, already referred to in 



