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, £S — Section from Teneriffe to Sombrero, 

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

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



