relative to the Earth’s Surface. 47 
toward the latter, as the depression there is much the greater. 
Since the density of sea-water does not increase below the tem- 
perature of 28°, the density of the ocean does not increase 
eyond a certain latitude, and hence there is no flow of the water 
at the bottom from the poles toward the equator, arising from 
the maximum density at the pole, as seems to be the case in a 
very slight degree in the atmosphere, but the under current at 
the bottom, arising from the greater pressure about the parallel 
of 30°, must extend entirely to the poles; so that there must be 
a slight tendency of the water to rise at the poles, and flow at the 
surface some distance towards the middle latitudes. As the wa- 
intercepted by continents, as in the northern hemisphere, the 
water receives a slight gyratory motion from left to right. The 
‘westward motion of the waters of the Atlantic in the torrid zone, 
impinging against the continent of America, causes the surface 
of the water of the Caribbean Sea and the Gulf of Mexico to be a 
little above the general level, while the eastward motion of the 
northern part of the Atlantic causes the surface of the water ad- 
jacent to the eastern coast of North America, in that latitude, to 
ea little lower. Hence there is a flow of warm water from the 
Gulf of Mexico along the coast of the United States toward the 
lower level about Newfoundland, which, on account of the pecu- 
liar configuration of the coast about the Gulf of Mexico, and the 
peninsula of Florida, gives rise to the Gulf Stream. ast: 
ward motion also of the northern part of the Atlantic causes the 
surface of the water on the western coast of Europe to be a little 
higher than the 
torrid zone caus 
43. A portion of the equatorial ¢ 
biting Pp eq te 
Brazil 
