CONTENTS. 
xix 
mense Body of warm Water drifting South, 268. — Currents about the Equator, 
270. — Under Cukrents : Experiments of Lieutenants Walsh and Lee, 271. — 
Proof of under Currents aftbrded by Deep Sea Soundings, 272. — Currents caused 
by Changes in Specific Gravity of Sea Water, 273.— Constituents of Sea Water 
every where the same ; affords Evidence of a system of Oceanic Circulation, 274. — 
Currents of the Atlantic : The great Equatorial Current : its Fountain-head, 
275.— The Cape St. Roque Current proved to, be not a constant Current, 276. — 
Difficulties of understanding all the Currents of the Sea-shore of the Atlantic can 
not be accounted for without the aid of under Currents, 277. . . , , , Page 124 
CHAPTER VIL 
the open sea in the arctic ocean. 
How Whales struck on the east Side of the Continent have been taken on the west 
Side, ^ 278.— Right Whales can not cross the Equator, 279. — How the Existence 
of a northwest Passage was proved by the Whales, 280. — Other Evidence in Favor 
of it, 281.— An under Current sets into the Arctic Ocean, 282. — Evidences of a 
milder Climate near the Pole, 284. — The Water Sky of Lieutenant De Haven, 285. 
— This open Sea not permanently in one Place, 286 146 
CHAPTER VHL 
the salts of the sea. 
What the Salt in the Sea Water has to do with the Currents in the Ocean, 4 389. — 
Reasons for supposing the Sea to have its system of Circulation, 290. — Arguments 
furnished by Coral Islands, 293. — What would be the Eflect of no system of Cir- 
culation for Sea Water 1 295.— Its Components, 297. — The principal Agents from 
which Dynamical Force in the Sea is derived, 300. — Illustration, 302. — Sea and 
Fresh Water have different Laws of Expansion, 308.— The Gulf Stream could not 
exist in a Sea of fresh Water, 309. — The effect of Evaporation in producing Cur- 
rents, 310. — How the Polar Sea is supplied with Salt, 323. — The Influence of this 
under Current upon open Water in the Frozen Ocean, 326. — Sea Shells : The 
Influence exerted by them upon Currents, 330. — Order among them, 335. — They 
assist in regulating Climates, 336. — How Sea Shells and Salts act as Compensa- 
tions in the Machinery by which Oceanic Circulation is conducted, 339, — Whence 
come the Salts of the Sea 1 344 150 
CHAPTER IX. 
the equatorial cloud-ring. 
Description of the Equatorial Doldrums, § 346. — Oppressive Weather, 348. — The Of- 
fices performed by Clouds in the terrestrial Economy, 349. — The Barometer and 
Thermometer under the Cloud-ring, 350. — Its Offices, 353. — How its Vapors are 
brought by the Trade- Winds, 361. — Breadth of the Cloud- ring, 363. — How it 
would appear if seen from one of the Planets, 364. — Observations at Sea interest- 
ing, 368 171 
