Contents. 



Distribution of Temperature in nearly land-locked Basins, 38 — Increase of 

 Temperature from the Surface towards the lower Strata in the Polar 

 Regions, 39 — Distribution of Oceanic Temperature effected through the 

 Agency of Currents, 40 — Formation of Intermediate Strata, 41 — Connection 

 between the Gradients of the Curve and the relative Motion of the different 

 Strata, 42 — Illustrations from the Temperature Soundings of H.M.S. 

 " Challenger," 42-45. 



CHAPTER III. 



CURRENTS OF THE OCEAN. 



The Aqueous and the Aerial Oceans, 46 — Resemblance between the Phenomena 

 in the two Terrestrial Envelopes, 47 — Thermal Circulation, 47 — Disproportion 

 between the Vertical and the Horizontal Extension of the Aqueous and Aerial 

 Envelopes, 48 — Conclusions based upon this Disproportion, 49 — Influence 

 of the several Areas of the Earth's Surface upon Oceanic and Atmospheric 

 Circulation, 50 — Parallelism between Oceanic and Atmospheric Currents, 

 50 — Formation of Belts of Calms and Belts of Currents, 51 — The Critical 

 Latitudes, 52 — Effect of the present Distribution of Land and Water upon 

 Atmospheric and Oceanic Circulation, 52 — -Subdivision of the latter into 

 Distinct Areas of Circulation, 52— Atmospheric and Oceanic Currents 

 revolve round Areas of High Barometric Pressure, 53 — Effect of the 

 Sun's apparent Progress from Tropic to Tropic upon Atmospheric and 

 Oceanic Currents, 53 — Surface and Under-Currents, 54 — Relation between 

 the Colour of Sea-water and the Percentage of Salt held in solution, 54 — 

 Limits of the Specific Gravity of Salt Water according to Temperature and 

 to Percentage of Salt, 55 — Change of a Surface-Current into an Under- 

 Current, or Vertical Circulation of the Oceanic Waters, 56— Diagram of 

 the System of Circulation in an Oceanic Basin, 57. 



CHAPTER IV. 



THE TEMPERATURE SECTIONS SURVEYED BY H.M.S. "CHALLENGER" IN THE 



ATLANTIC. 



Explanation of Diagrams and Tables, 5S — Section from Tenerifife to Sombrero, 

 59 — Contrast between the Eastern and Western Basin of the North Atlantic, 

 6 1 — Observed Rise of the Isotherms with the Sea-bottom, 62 — Section 



