390 Barometric Anomalies about the Andes. 
Upon the same principle and for the same reason, I should ex- 
pect to find*in Southern Chile and Western Patagonia a bank of 
atmosphere to windward of the Andes, and a depression to lee- 
ward—the lee side in this place being the eastern, and the wind- 
ward side the western side—of the Andes. Now, Lima is in the 
range of permanent trade winds, and Lieut. Herndon, by assum- 
ing the barometer at the sea level of Callao, to be 30-019, would, 
after leaving that city, make the heights of all places determined 
by him, from 210 to 380 feet too high with regard to the Pacific, 
depending of course, upon the season of the year; for the fluc- 
tuations of the barometer here are periodical as well as diurnal. 
t Para, at the mouth of the Amazon, where we have a low 
barometer not from mountain agency, but from the effect of the 
equatorial belt of calms upon the barometer, Herndon’s heights, 
except under the remarkable banking up of the atmosphere to the 
windward of the Andes, are not far from 230 feet too great'as 
compared with the sea level of the Atlantic at the mouth of the 
Amazon. Assuming the barometer at the level of the sea, for the 
mouth of the Amazon, to-be on the average 30-019, Lieut. Hern- 
don by the boiling point, which agrees well with direct barome- 
tric determination elsewhere, makes the city of Para to be 255 
feet above the level of the sea. , 
ara is about 90 miles from the sea, in an alluvial country ; It 
is about 15 feet above the mean tide-water level, and if we sup- 
pose that the river has thence to the sea a total fall of 10 feet, 
{more than an inch to the mile,) we should make Para 25 feet 
above the sea level. It can scarcely be much more than 25 feet, 
e we know, or rather because we are entitled to assume 
that the Amazon has no very great raf@ of descent near its mouth. 
Assuming, then, that Para is only 25 feet above the level of the 
sea, Herndon’s mean boiling point at Para, reduced to the sea level, 
would be equivalent to a mean barometric pressure of 29°64. BY 
the mean of actual barometric observations taken at Para, he 
makes the barometer at the sea level, supposing Para to be 25 
feet only above it, 29-57, his readings being corrected for temper- 
ature only. 
