GENERAL OBSERVATIONS. 339 



where the water is deepest. The current however in the 

 mid-stream must have been greater than it is generally 

 staled ; as it is admitted by the surveyor, that, with every 

 desire to complete the survey of the river in all its parts, 

 he found it impossible, even with the aid of Massey's 

 machine, to get the soundings in the mid-channel, 

 though the river was, at that time, in its lowest state. 

 Maxwell's chart was found to be incorrect in many re- 

 spects, especially as to distances, which are generally 

 too great. With regard to the flat islands formed by 

 alluvial earth, and overgrown with the mangrove and the 

 papyrus, constant changes are taking place, some gra- 

 dually forming and encreasing in size, while others are 

 wholly or partially swept by the current into the ocean. 



The mistaken notion, Avhich seems to have originated 

 with the Portuguese, that the tide could make no impres- 

 sion on the current of the Zaire, is but partially true ; 

 this mistake is now corrected by frequent observations of 

 the tide forcing the reflux of the stream very perceptibly 

 as high up as the commencement of the narrows at Son- 

 die, where the rise and fall amounted from twelve to sixteen 

 inches ; but though it caused the water to be dammed up, 

 and a counter-current on one or both sides, yet, strictly 

 speaking, the current in the middle of the river was never 

 overcome by the tide. 



The distance at which the narrows commence is about 140 

 English miles from the mouth of the river at Point Padron, 

 and they continue as far as Inga, or forty miles nearly ; the 

 width of the river being generally not more than from 



