X CONTENTS. 



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

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

 Gravity of Sea Yv'ater, 44S. — Light cast by Plate X, on the open Sea in the 

 Arctic 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 Vapour, 4:54. — Its Influence upon Climates, 455.— The 

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

 457. — Polar Karefa'ction, 45S. — The Middle Ice, 459. — Position of the open Sea, 

 460 Pagel9S 



CHAPTER X. 



THE SALTS OP THE SEA. 



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

 Character of Sea V/ater, 463. — Hypothesis, 464. — Arguments aftbrded by Coral- 

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

 lation required for the Ocean, 467. — Dynamical Agents, 468. — Currents without 

 Wind, 469.— Influence of Salts and Evaporation, 470. — The under Currents 

 owing entirely to the Salts of Sea Water, 471. — A Property peculiar to Seas of 

 saltwater, 472.— Quantity of Salt in the Sea, 473.— Deductions, 474.— Drift of 

 the "Resolute," 475.— De Haven's Drift, 476. — An anti-polynian View, 477. — The 

 Drift explained, 478. — Thickness of a \Yinter's Ice, 479. — Layers of Water of 

 diiferent Temperature in the Arctic Ocean, 480. — The ice-bearing Drift from 

 the Arctic like the ordinary Drift from the Baltic, 481.— Icebergs drifting north, 

 482. — Temperature of the under Current, 483. — It comes to the Surface, 434. — 

 Sea-shells — their Influence upon Currents, 485. — Solid Matter secreted by them 

 48G. — Dynamical Force derived from, 487. — Their physical Relations, 4SS. — Th 

 Regulators of the Sea, 489. — Whence does the Sea derives its Salts ? 490. — Their 

 Antiquity, 491. — Insects of the Sea — their Abundance, 492. — Ditto, calcareous 

 in the Pacific, silicious in the Atlantic, 493. — The Records of the Sea and of 

 Revelation agree, 494. —Cubic Miles of Sea-salt, 495. — The Saltness of VV'ater 

 retards Evaporation, 496. — The Harmonies of the Ocean, 497. — The Micro- 

 scope and the Telescope, 498.— Sea- shells and Animalculaj in a new Liglit, 

 499 Page 226 



CHAPTEE XI. 



THE CLOUD REGIOX, THE EQUATORIAL CLOUD-RING, AND SEA FOG?. 



Clotid Region — highest in the calm Belts, § 501.— Fogless Regions, 502.— The 

 most stormy Latitudes, 503. — Influences of the Gulf Stream and the ice-bearing 

 Currents of the South, 504. — Sea Fogs rare within 20° of the Equator— Red Fogs, 

 505. — Cloudless Regions and Height of Clouds at Sea, 506. — Height and Velo- 

 city of Waves — Plan for determining, 507. — Determining the Height of Clouds 

 at Sea, 508. — Cloud Regions at Sea in the shape of a double-inclined Plane, 509. 

 — Fogs in the Harbour of Callao, 510. — The Cloudy Latitudes, 511. — Why there 

 should be less Atmosphere in the southern than in the northern Hemisphere, 

 512.— Influence of antarctic Icebergs in expelling the Air from austral Regions, 

 513. — The Horse Latitudes — the Doldrums, 514. — A Frigate under the Cloud- 

 ring, 515.— Subjects which at Sea present themselves for Contemplation, 516.— 

 The Barometer under the Cloud-ring, 517.— Its Motions, 518. — Meteorological 

 Processes, 519.— Snow-line mounts up as it crosses the Equatorial calm Belt, 520. 

 — Otfices of the Cloud-ring, 521.— It acts as a Regulator, 522. — The latent Heat 

 liberated in the Processes of Condensation from and under the Cloud-ring, true. 

 Cause of the Trade-winds, 523.— Imagined Appearance of the Cloud-ring to a 

 distant Observer. 524. — Thunder, 525. — Exceeding Interest attached to physical 

 Research at Sea, 526 Page 260 



