xviii CONTENTS. 
CHAPTER IV. 
RED FOGS AND SEA DUST. 
Where found, ^ 157. — Tallies on the Wind, 158. — Where taken up, 160. — Hum- 
boldt's Description, 163. — Information derived from Sea Dust, 165. — Its Bearings 
upon the Theory of Atmospherical Circulation, 167. — Suggests Magnetic Agency, 
170 . .Page 97 
CHAPTER V. 
ON THE PROBABLE RELATION BETWEEN MAGNETISM AND THE CIRCULATION OF THE 
ATMOSPHERE. 
Reasons for supposing that the Air of the Northeast and of the Southeast Trades 
cross at the calm Belts, <5> 174. — What Observations have shown, 184. — -Physical 
. Agencies not left to Chance, 188.— Conjectures, 192.— Reasons for supposing that 
there is a crossing of Trade-wind Air at the Equator, 194. — Why the extra-trop- 
ical Regions of the Northern Hemisphere are likened to the Condenser of a Steam- 
boiler in the South, 199. — Illustration, 200. — A Coincidence, 202. — Proof, 203. — 
Nature affords nothing in contradiction to the supposed System of Circulation, 204. 
Objections answered, 205. — Why the Air brought to the Equator by the Northeast 
Trades will not readily mix with that brought by the Southeast, 207. — Additional 
Evidence, 209. — Rains for the Mississippi River are not supplied from the Atlan- 
tic, 210. — Traced to the South Pacific, 213. — ^Anticipation of Light from the Polar 
Regions, 216. — Received from the Microscope of Ehrenberg, 217, and the Exper- 
iments of Faraday, 219. — More Light, 221. — Why there should be a calm Place 
near each Pole, 222. — Why the Whirlwinds of the North should revolve against 
the Sun, 223. — Why certain Countries should have scanty Rains, 228. — Magnetism 
the Agent that causes the Atmospherical Crossings at the calm Places, 231 . . 104 
CHAPTER VI. 
CURRENTS OF THE SEA. 
Currents of the Sea : Governed by Laws, ^ 232. — The Inhabitants of the Sea the 
Creatures of Climate, 233. — The Currents of the Sea an Index to its Climates, 235. 
— First Principles, 236. — Some Currents run up hill, 237. — Currents of the Red 
Sea, 238. — ^Top of that Sea an inclined Plane, 240. — How an under Current from 
it is generated, 245. — Specific Gravity of Sea Waters, 248. — Why the Red Sea is 
not salting up, 251. — Mediterranean Currents : How we know there is an un- 
der Current from this Sea, 252. — The sunken Wreck which drifted out, 253. — Both 
Currents caused by the Salts of the Sea, 254. — Currents of the Indian Ocean : 
Why immense Volumes of warm Water flow from it, 255. — A Gulf Stream 
along the Coast of China, 256. — Points of Resemblance between it and the Gulf 
Stream of the Atlantic, 257. — A Current into Behring's Strait, 258.— Geographical 
Features unfavorable to large Icebergs in the North Pacific, 260. — Necessity for 
cold to restore the Waste by the warm Currents, and Evaporation, 261. — Argu- 
ments in favor of return Currents, because Sea Water is salt, 262. — Currents of 
THE Pacific : Its Sargasso Sea, 264. — The Drift on the Aleutian Islands, 265.— 
The cold China Current, 266. — Humboldt's Current, 267. — Discovery of an ini- 
