STILL RUNNING THE GAUNTLET ON TIIE RIVER. 491 
28th of January, we obtained north latitude 0° 20' 0". 
By boiling point I ascertained that the declination was 
nearly 120 feet in these twenty-two miles, the altitude 
above sea at the Seventh Cataract being 1511 feet. As 
there are only seven miles really occupied by the Sixth 
and Seventh Cataracts, the intermediate fifteen miles 
being calm flowing water, we may not be far wrong in 
giving the slope of the river at the two falls a declina- 
tion of seventeen feet to the mile. 
The rocky point- of the left bank was formerly con- 
nected with the rocky island of the Wenya by a ridge, 
SEVENTH CATARACT, STANLEY FALLS. 
which appears to have fallen southward, judging from 
the diagonal strata, but since that period the river has 
worn down this obstruction, and the cataract is now 
about three hundred yards south-east of the straits, 
pounding away at the ledge with the whole of its force. 
A glance at the sketch of the Seventh Cataract of the 
Stanley Falls shows a line of tall poles planted below 
the falls, which assist us not only to form some estimate 
of the depth of the water, but also of the industry of 
the Wenya. A space of about 300 yards, in the middle 
of the falls, is unapproachable, but to a distance of 100 
