48 Proceedings of the Royal Physical Society. 
has a mean temperature about 2°°5 F. warmer than the air. 
This river runs east, consequently throughout its course the 
climate is nearly the same.” 
TABLE VIII. 
Temperature of the Amazon (prepared from Lieutenant 
Herndon’s observations). 
Month. Locality. Air at 9 A.M.| Water. | Water Excess. 
¢ ae From the Huallaga to the | iiaz) eee | iS 
851. 8° | “F | 9° 
Sept. 1851 Ucayali, a (eae 80°5 , 0 
— { From the Ucayali to meee | gre | 
Nov. { Tabatinga, 7 ae ae 81% 4°0 
was { Between T tbatinga and | 79-9 | 81°5 | 7 
ereRanel |) ihe Purus, HY cae": ener ng 
> | 
Jan, 1852. Fen: eons to at 78°5 | 82-0 3°5 
From the Rio Negro to moe 
‘eh ‘8 82 2 
Feb. ” the Madeira, ay | 17°8 | 820 4°2 
78°35 | 81°5 3°2 
I now turn to another great tropical river that ought, in a 
similar manner, to reflect the influence of running with the 
latitude, though here it flows west. This is the Congo. Dr 
A. von Danckelman, whilst engaged in making meteorological 
observations at Vivi between the summers of 1882 and 1883, 
took from one to three temperatures of the river each month, 
all of which are considerably higher than the air means for 
their respective months. The results as employed by me are 
here appended; and although the river observations are very 
limited, their possible deviation from the mean of each 
month is small, since the extreme variation of all the water 
temperatures taken in the twelve months was barely eight 
degrees. We perceive, on referring to the chart of the curves, 
that the Congo, in its relation to the air temperature, behaves 
very similarly to the Amazon, and maintains a_ higher 
temperature than the air throughout the year. Both rivers 
illustrate in the same manner the effect of flowing with the 
latitude. 
