290 The Age of this Earth. [May, 
round the world. The causes are soft foundations and growin 
superstructures, pressures, sinkings below water, sedimental gath- 
erings, gradual risings, and the repetition of the same actions till 
a solid foundation is secured. When foundations are undermined 
by subterranean water action, submergences of surface areas oc- 
cur suddenly, and the rising again is uncertain. 
Second: “ Violent changes of climate have succeeded one an- 
other.” Opinions vary as to the cause of this in the arctic 
regions. Some follow Mr. Croll in his see-saw theory, or the 
oscillation of the poles. If it takes place, changes of climate 
must ensue; but a very material point seems to have been for- 
gotten, —if the oscillation is cosmical the water would go down 
with the land, there would be no submergence. There would 
be ten thousand years of ice and ten thousand years of warmer 
climate. These changes would be general, but the fossils of 
warmer regions do not prove a general growth, neither do the 
warm-region drifts of the present prove a general action through 
the arctic regions. In the late arctic expedition it was colder 
on one shore of Smith Sound than on the other; and Captain Sir 
George Nares gave this experience of the Arctic and Atlantic 
Oceans to the Royal Geographical Society. 
In the Atlantic Ocean there is “an enormous reservoir of 
heat.” This warm water is forced “ gradually towards the north- 
ward and eastward, modifying the climate of all parts lying in its 
course. There is also a warm current ever running to the north- 
ward through Behring’s Straits.” These warm supplies run at 
present through certain channels, while in other channels “an 
icy cold current” runs to the southward. The polar basin has 
a “warm stream of water constantly pouring into it between 
Spitzbergen and Norway, and a cold icy one as constantly run- 
ning out between Spitzbergen and Greenland, also . . . between 
Greenland and America; . . . so great is the difference of cli- 
mate caused by these powerful distributors of heat and cold that 
the temperature of the sea . . . twenty-two hundred miles from 
the equator is precisely the same as that nearly double the dis- 
tance from the equator.” ` | 
_ As we have these cosmical actions, guided by fixed cosmical 
laws, perpetually circulating the heat and the cold, — not always 
in the same channels, but distributing both according to the 
- direction of either current, — we find a certain cause for the “ v10- 
lent changes of climate” alluded to, instead of the more than 
uncertain oscillation with the doubtful results of Mr. Croll. We 
