Association of American Geologists and Naturalists. 139 
cite a single example which he thought might be deemed sufficient. 
Humboldt in his travels in South America took note of the temperature 
at eighteen inches from a surface heated by the sun, and also at the level 
of six feet. Instead of finding a difference of temperature such as 
was due to the elevation or natural state of equilibrium, it was four 
hundred and fifty times greater, being 7° F’. in four feet and a half of 
elevation, which could not have been the case did heated air necessarily 
rise immediately from the surface. We know, too, that in our Ameri- 
can summers we have often a stratum of warm air on the surface, 
brought froma great distance by geographical transfer, so that the ther- 
mometer stands between 80° and 90° F’., which continues even through 
the night, and day after day, at only some nine thousand feet beneath the 
snow line. Now if air heated above its ordinary temperature must im- 
mediately rise, how could this occur? And in so dense a fluid as wa- 
ter, confined under the enormous pressure of the ocean depths, how 
greatly lessened would be the chance of any speedy displacement of the 
heated stratum from the bottom of the deep sea ? 
Heated waters if spread in the bottom of a quiet sea could not per- 
meate or rise through the incumbent colder waters, unless in a state of 
ebullition, or by the slow process of atomic displacement between the 
several planes of equal and differential temperatures, or by that insen- 
sible geographical transfer which probably occurs even at the lowest 
depths. Nor can the overlying colder waters permeate the stratum 
that lies beneath. Moreover, we know from the observations of voya- 
gers, that in deep soundings made in some parts of the ocean, a warmer 
stratum has sometimes been found deeply imbedded beneath colder wa- 
ters. This fact, which he had deemed conclusive, is of more certain 
value than any of our dynamical speculations.* 
* Mr. Redfield annexes the following observations, made by Scoresby, and by 
the expedition commanded by Capt. Buchan in 1818, which showed an increase 
of temperature at increased depths, in certain portions of the arctic seas. It 
should be noted that the law of expansion in water, as its temperature descends 
below 40° Fahrenheit, does not apply to sea-water. 
Tape I.—Scoresby’s Observations. 
Temperature at BELOW THE SURFACE. : 
surface. Temperature. Fathoms deep. Latitude. 
gail 31° i Pe TON Sa TION. 
31 33.3 37 79 
31 34.5 47 79 
31 36 100 79 
3 36 400 79 
31 37 730 79 
29.7 36.3 120 8 
