xxii CONTENTS. 



388.— Views of Admiral Smytli and Sir C. Lyell, 389.— Currents of the Indian 

 Ocean, 390. — The Black Stream of the Pacific contrasted with the Gulf Stream 

 of the Atlantic, 391.— The Lagulhas Current and the Storms of the Cape, 392.— 

 The Currents and Drift of the Indian Ocean, 393.— The ice-bearing Currents 

 from the antarctic Eegions, 39'4. — Tlie Currents of the Pacific — Drift-wood, 395. 

 — The Black Current of the Pacific, like the Gulf. Stream, salter tlian the adja- 

 cent Waters, 39G.— The Current of Okotsk, 397.— Humboldt's Current, 398.— 

 The "desolate" Region, 399. — Polynesian Drift, 400. — Equatorial Currents, 401. 

 — The Influence of Kains and Evaporation upon Currents, 402. — Under Currents 

 — Parker's deep-sea Sounding, 403. — The Compressibility of Water — Effect of, in 

 the oceanic Circulation, 404. — Assisted by its Salts, 405. — The Origin of Cur- 

 rents, 406.— Currents of the Atlantic, 407.— The St. Roque Current, 408.— The 

 Greenland Current, 409 Page 175 



CHAPTER IX. 



THE SPECIFIC GRAVITY OF THE SEA, AND THE OPEN WATER IN THE ARCTIC OCEAN. 



Interesting physical Inquiries, § 420. — Voyages of Discovery to the North Pole, 421. 

 — Tlie first Suggestions of an open Sea in the Arctic Ocean, 422. — Harpoons — 

 Habits of the Whales, 423. — The under Current into the Arctic Ocean — its Influ- 

 ences, 424. — Indications of a milder Climate, 425. — How the littoral Waters, by 

 being diluted from the Rivers and the Rains, serve as a Mantle for the Salter and 

 warmer Sea Water below, 42G. — An under Current of warm but salt and heavy 

 Water, 427. — De Haven's water Sky, 428. — Dr. Kane, 429. — Under Currents 

 change Temperature slowly, 430. — Solid Matter annually drifted out of the polar 

 Basin, 431. — Volume of Water kept in Motion by the arctic Flow and Reflow, 

 432. — The Hydrometer at Sea, 433. — Specific Gravity of average Sea Water, 434. 

 — An Anomaly, 435. — Influence of the Trade-winds upon the specific Gravity of 

 Sea Water, 436. — Compensating Influences, 437. — Nicely adjusted, 438. — A 

 thermal Tide, 439. — The isothermal Floor of the Ocean, 440. — Thermal Dilata- 

 tion of the Water, 441. — Experiments on the freezing Point, 442. — Sea Water at 

 summer more expansible than Sea Water at winter Temperature, 443. — Data for 

 Plate X., 444. — A thermal Tide: it ebbs and flows once a Year, 445. — Sea Wa- 

 ter of the southern cooler and heavier. Parallel for Parallel, than Sea Water of 

 the northern Hemisphere, 446. — Testimony of the Hydrometer in favor of the 

 Air Crossings at the calm Belts, 447. — Amount of Salt in, and mean specific 

 Gravity of Sea Water, 448. — Light cast by Plate X. on the open Sea in the Arc- 

 tic Ocean, 449. — The heaviest Water, 450. — Chapman's Experiments, 451. — 

 The Hydrometer indicates the rainy Latitudes at Sea. 452. — Astronomical View, 

 453. — The latent Heat of Vapor, 454. — Its Influence upon Climates, 455. — The 

 Results of the marine Hydrometer, 456. — Barometric Indications of an open Sea, 

 457. — Polar Rarefaction, 458. — The middle Ice, 459. — Position of the open Sea, 

 460 203 



CHAPTER X. 



THE SALTS OF THE SEA. 



The Brine of the Ocean, § 461.— Were the Sea of fresh Water— 462.— Uniform 

 Character of Sea Water, 463. — Hypothesis, 464. — Arguments afforded by Coral- 

 lines in favor of, 465. — Ditto by the Red Sea, 466. — A general System of Circu- 

 lation rcf^uired for the Ocean, 467. — Dynamical Agents, 468. — Currents without 



