XXXI INTRODUCTION. 
with the interior of the country through which it descends, by means of mission- 
aries, and slave agents ; so confined indeed is our knowledge of the course of this 
remarkable river, that the only chart of it, which can have any pretension to ac- 
curacy, does not extend above 130 miles, and the correctness of this survey, as 
it is called, is more than questionable. 
There can be little doubt however, that a river, which runs more rapidly, and 
discharges more water, than either the Ganges or the Nile, and which has this 
peculiar quality of being, almost at all seasons of the year, in a flooded state, 
must not only traverse a vast extent of country, but must also be supplied by 
large branches flowing from different, and probably opposite directions ; so that 
some one or more of them must, at all times of the year, pass through a tract 
of country where the rains prevail. ‘To ascertain the sources of these great 
branches then, will be one of the principal objects of the present expedition : 
but in the absence of more correct information, the instructions regarding the 
conduct to be observed, can be grounded only on probable conjecture. 
The unusual phenomenon of the constant flooded state of the Zaire, as men- 
tioned by the old writers, and in part confirmed by more recent observations, 
would seem to warrant the supposition, that one great branch, perhaps the 
main trunk, descends from the tropical region to the northward of the Line; 
and if in your progress it should be found, that the general trending of its 
course is from the north-east, it will strengthen the conjecture’ of that 
branch and the Niger being one and the same river. 
It will be advisable therefore, as long as the main stream of the Zaire shall 
be found to flow from the north-east, or between that point and the north, 
to give the preference to that stream ; and, to endeavour to follow it to its 
source: at the same time, not to be drawn off by every large branch of the 
river, that may fall into the main stream from the northward, but to adhere to 
the main trunk, as long as it shall continue to flow from any point of the com- 
pass, between the north and east. 
It is also probable that a very considerable branch of the Zaire will be found to 
proceed from the east, or south-east; asit has been ascertained, that all the 
rivers of southern Africa, as far as this division of the continent has been tra- 
versed from the Cape of Good Hope, northwards, flow from the elevated lands 
on the eastern coast, across the continent, in a direction from west to north- 
west: and it may perhaps be considered as a corroboration of the existence of 
some easy water conveyance between the eastern and western coasts of south 
Africa, that the language of Mosambique very nearly resembles the language 
spoken on the banks of the Zaire. 
