THE ATMOSPHERE. 
91 
wet sponge 125), and are abruptly intercepted by the Andes of 
Patagonia, whose cold summit compresses them, and with its low- 
dew-point squeezes the water out of them. Captain King found 
the astonishing fall of water here of nearly thirteen feet (one 
hundred and fifty-one inches) in forty-one days ; and Mr. Darwin 
reports that the sea water along this part of the South American 
coast is sometimes quite fresh, from the vast quantity of rain that 
falls. 
142. We ought to expect a corresponding rainy region to be 
found to the north of Oregon ; but there the mountains are not so 
high, the obstruction to the southwest winds is not so abrupt, the 
highlands are farther from the coast, and the air which these 
winds carry in their circulation to that part of the coast, though 
it be as heavily charged with moisture as at Patagonia, has a 
greater extent of country over which to deposit its rain, and con- 
sequently the fall to the square inch will not be as great.* 
143. In like manner, we should be enabled to say in what part 
of the world the most equable climates are to be found. They 
are to be found in the equatorial calms, where the northeast and 
southeast trades meet fresh from the ocean, and keep the temper- 
aiture uniform under a canopy of perpetual clouds. 
144. Amount of Evaporation. — The mean annual fall of rain 
on the entire' surface of the earth is estimated at about five feet. 
145. To evaporate water enough annually from the ocean to 
cover the earth, on the average, five feet deep with rain ; to trans- 
port it from one zone to another ; and to precipitate it in the right 
places, at suitable times, and in the proportions due, is one of the 
offices of the grand atmospherical machine. This water is evap- 
orated principally from the torrid zone. Supposing it all to come 
thence, we shall have, encircling the earth, a belt of ocean three 
thousand miles in breadth, from which this atmosphere evaporates 
a layer of water annually sixteen feet in depth. And to hoist up 
as high as the clouds, and lower down again all the water in a 
lake sixteen feet deep, and three thousand miles broad, and 
* I have since, through the kindness of A. Holbrook, Esq., United States Attorney 
for Oregon, received the Oregon Spectator of February 13, 1851, containing the Rev. 
G. H. Atkinson's Meteorological Journal, kept in Oregon City during the month of 
January, 1851. The quantity of rain and snow for that month is 13.63 inches, or 
about one third the average quantity that falls at Washington during the year. 
