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SCIENCE 



[Vol. XVIII. No. 458 



SCIENCE 



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PEOFESSOE WILLIAM FEEEEL. 



William Ferrel was bora in Pennsylvania, 1817. In 1856, 

 at the age of thirty-iiine, he began a series of studies in me- 

 teorology, which, in their more finished form, in later years 

 gave a new aspect to this science, and placed him at the time 

 of his death, Sept. 18, 1891, at the front of American meteorol- 

 ogists. His work was always quietly done, never with any 

 attempt at the conversion of the great public, or almost with 

 indifference to the attitude of the scientific pul)!ic regarding 

 his beliefs; but with the patient conviction that he was work- 

 ing in the right direction and tliat his theories would in time 

 receive general acceptance. Towards the close of his life, 

 this happy end was reached, as far as the better informed 

 meteorologists of the world were concerned, and in Europe 

 as well as in this country, Ferrel was regarded as the leader 

 in the methods of mathematical meteorology; not that others 

 who followed in his paths did not exceed him in complete- 

 ness of demonstrations, but that the methods which he intro- 

 duced into the science were essentially the same as those 

 by which his successors carried it further. A comprehensive 

 narrative of his life is given in the American Meteorological 

 Journal for February, 1888, by Alexander McAdie of the 

 Weather Bureau, and a list of his publications in the same 

 journal for October last; I shall tlierefore here only touch on 

 what seems to me highly characteristic of his work, and of 

 the revolution that it produced in scientific meteorology. 



Unscientific meteorology, such as was current before Fer- 

 rel's work reformed it, cannot yet be said to be excluded 

 from popular acceptance. We still find writers who take 

 Maury as their authority, following bis antiquated views, 

 quite unaware that they are thirty years behind the times. 

 I do not wish to detract in the least from the deserved repu- 

 tation gained by Maury for his persevei-ing study of the 

 winds and currents of the ocean; for the great incentive that 

 he gave to shipmasters to become observers and bring home 

 a careful record of their observations. The tabulation of tlje 

 facts thus gathered formed the basis of wind charts for the 

 several oceans, first produced in tliis country, and closely fol- 



lowed by the hydrographers of many foreign nations. It is 

 on this collection of facts that Maury's reputation rests secure; 

 and not on his theories, for they were essentially wrong and 

 are now practically laid aside. Unfortunately for his suc- 

 cess in this department of science, Maury seems not to have 

 been well equipped with knowledge of physics and mathe- 

 matics, and in his ignorance of these subjects lie was led 

 into serious errors as to the motions of the winds. Those 

 errors have been considered by various writers, but by none 

 earlier or more effectively than by Ferrel, who, in 1856, pub- 

 lished an essay in the Nashville Journal of Medicine, an 

 essay prompted by the insufficiency of Maury's theories. It 

 is not necessary to enter here into an exposition of Ferrel's 

 theory; those who wish to study it may find its fullest state- 

 ment in his latest work, a " Popular Treatise on the Winds," 

 published in 1889. Some statement of these theories may be 

 found in Science, ix., 1887, 539; and xv., 1890, 142. But it 

 may be briefly said that the difference between Maury's, 

 theory and Ferrel's is as the difference between darkness and 

 light. 



Maury thought the return current from the poles was 

 in this hemisphere an east-northeast wind: Ferrel showed 

 t'nat it is a west-north- west wind. Maury 'was not alone in 

 thinking that the polar return current flowed in our latitudes 

 from the north-east. Dove, the leading German meteorol- 

 ogist of the middle decades of this century, had the same 

 idea, and, I tbink, at an earlier date than Maury. Accord- 

 ing to Dove, the alternation of north-east and south-west 

 winds that we feel with the passage of our storms centres is 

 simply the contest of the polar and equatorial currents, of 

 which first one and then the other reach the surface of the 

 earth. This view, embodying the idea of the north-east- 

 south-west course of the polar return current, may be said 

 to have held an accepted place iu meteorology at the time 

 when Ferrel prepared his first essay on the subject. But for 

 those who have followed Ferrel's work, the north-east return 

 current has no existence. His reasons for giving this re- 

 turn current a north-west source are simple and ample; and 

 for those who do not share this view, there is a large fact in 

 nature which cannot be explained; namely, the low pressure 

 about the North Pole; a similar arrangement prevailing ia 

 the Southern Hemisphere, where the return current comes 

 from the south west. 



This seems to be a small matter. It is a slight change to 

 make in words, to say that the return polar cur.-ent comes 

 from the north-west, not from the north-east: and truly, if 

 this were all that could be said, it would not be a great affair.. 

 But if the reader will examine the question carefully, and 

 study the development of our knowledge of the winds, he 

 will soon be convinced that the introduction of Ferrel's idea 

 as to the course of the polar return current and the explana- 

 tion of the low pressure that is bound up with it, marks the 

 introduction of rational physical principles into this depart- 

 ment of meteorology. This change came at a time when the 

 physical study of meteorology was a rare thing. Look, for- 

 example, at Schmid's " Meteorologie" of 1860, a voluminous 

 treatise, well representing the condition of the science then; 

 compare with it Spring's ''Lehrbuch" of 1885, in whicli the- 

 science is presented in the manner introcjuced by Ferrel. 

 The difference is that between statistical, inductive methods, 

 and fully expanded logical methods that utilize all means of 

 inquiry. The science has become a new thing by this change; 

 would that meteorologists had as greatly changed and were 

 not still so content to read instruments and count up totals, 

 and means. 



