On the Physical Geology of the United States, &c. 9 
westward in the southwardly flow in the northern hemisphere, is 
due to the same cause, viz. inertia, and the difference of linear 
velocity of points on the earth’s surface, as the particles of matter 
of the currents reach successively different latitudes. 
This may be illustrated by considering that a particle of matter 
at the equator moves with a linear velocity of about twenty five 
thousand miles in twenty four hours ; and supposing this particle 
‘ 
(5.) Another from the southward sets into the Indian Ocean near the coast of 
New Holland. 
Very numerous currents depending on prevailing or periodical winds, like the 
monsoons, exercise much influence in particular parts of the oceans upon the cur- 
rents mentioned. 
The following references may aid those who wish to trace the state of present 
knowledge on the currents of the ocean and atmosphere. 
De La Becie’s Geological Manual, American edition, pp. 90—101. Purdy’s 
Atlantic Memoir. Kotzebue’s Voyages. Lyell’s Principles of Geology, Vol. 1. 
Lartigue, Description de la Cote du Pérou. Franklin’s observations, Am. Phil. 
Transactions, Vol. 1, p. 314. Blagden on heat of Gulf Stream, Phil. Trans. 
Royal Society, 1781, p. 334. Rennel on heat of Gulf Stream, Phil. Trans. Royal 
Society, 1793, Vol. txxxu1. Wollaston on heat of Gulf Stream, Phil. Trans. 
Royal Society, 1824. Poronall’s Hydraulic and Nautical Observations, quarto, 
London, 1787. Uumboldt’s Political Essay on New Spain, Vol. 1, p.53. Hum- 
boldt's Voyage to the Tropics, Vol. 11. Young’s Nat. Phil. Espy on Storms. 
Daniel’s Meteorological Essays. Redfield, American Journal of Science, Vols. 
xxv and xtv. Maury, (Lt.) American Journal of Science, Vol. xtvi1; Southern 
Literary Messenger, and Army and Navy Chronicle. Edinburgh Encyclopedia, 
Am, edition, Vol. x, pp. 158—159. Ed. Encyc., “‘ Navigation,” Vol. xiv, pp. 
209—213. Ed. Encyc., “‘ Phys. Geography,” Vol. xv, p. 579. Ed. Encyc., “ Hy- 
drography of polar regions,’ Vol. xv1, p. 6. 
The modes of observation by which the set and flow of currents have been de- 
termined, are deflective, and liable to error; it is desirable therefore, that accurate 
observations should be multiplied in every ocean, in every latitude and longitude, 
with a view to elicit truth. A knowledge of the set and flow of ocean currents, 
local as well as general, and the laws that govern them, is readily perceived to be 
of the highest importance to the interests of navigation, and to the whole world. 
Such knowledge can only be obtained by amassing a multitude of facts, systemati- 
zing them, grouping them, and finally generalizing from them. Individual effort 
cannot accomplish this. ‘The aid, the influence, and the power of governments 
are necessary to cause the scattered rays of light to be brought to a focus. If an 
office be established under the direction of the Secretary of the Navy, where me- 
teorological registers accurately kept on board all our national ships; records of 
the set and flow of currents observed on the same ships; the temperature of the 
waters of the ocean at the surface and at considerable depths, (also made daily 
when practicable,) and similar records from our merchant marine could be re- 
corded, and occasionally published—and similar offices under the English, French, 
and other maritime governments, results may be obtained in a few years of great 
importance In navigation, and aid in deducing satisfactorily, the laws that regulate 
the currents of the atmosphere and of the ocean. 
Vol. xxix, No. 1.—April-June, 1845, 2 
