VOYAGE FROM KEW YORK TO RIO DE JANEIRO. 19 
reference to latitude must have been attended by a corre- 
sponding change of climate with reference to altitude. 
Three degrees of temperature correspond to about one 
thousand feet of altitude. If, therefore, it is found that 
the ancient limit of glacier action descends on the Andes, 
for instance, to 7,000 feet above the level of the sea under 
the equator, the present line of perpetual snow being at 
15,000, it is safe to infer that in those days the climate 
was some 24 or thereabouts below its present temperature. 
That is, the temperature of the present snow line then pre- 
vailed at a height of 7,000 feet above the sea level, as the 
present average temperature of Greenland then prevailed in 
latitude 86. I am as confident that we shall find these 
indications at about the limit I have pointed out as if I had 
already seen them. I would even venture to prophesy that 
the first moraines in the valley of the Maranon should be 
found where it bends eastward above Jaen."* 
Although the weather is fine, the motion of the ship 
continues to be so great that those of us who have not what 
are popularly called " sea-legs," have much ado to keep our 
balance. For my own part, I am beginning to feel a personal 
animosity to " the trades." I had imagined them to be soft, 
genial breezes wafting us gently southward ; instead of 
which they blow dead ahead all the time, and give us no 
rest night or day. And yet we are very unreasonable to 
grumble ; for never were greater comforts and conveniences 
* It proved in the sequel unnecessary to seek the glacial phenomena of 
tropical South America in its highest mountains. In Brazil the moraines are 
as distinct and as well preserved in some of the coast ranges on the Atlantic 
side, not more than twelve or fifteen hundred feet high, as in any glaciated 
localities known to geologists in more northern parts of the world. The 
snow line, even in those latitudes, then descended so low that masses of ice 
formed above its level actually forced their way down to the sea-coast. L A. 
