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XXXI. — An Attempt to Improve the present Methods of Determining the Strength and 

 Direction of the Wind at Sea. By C. P. Smyth, Esq., F.R.S.E., Professor of 

 Astronomy in the University of Edinburgh. (With a Plate.) 



(Read April 3 and 17, 1848. ) 



Last year, my friend Captain Cockburn, R. N., brought to my notice the very 

 lax method which is usually pursued at sea in determining the strength and di- 

 rection of the wind ; and said, that he had for many years been trying to contrive 

 some sort of anemometer that might be useful on board, as well as an easy method 

 of eliminating the effect of the motion of the ship on the true character of the 

 wind, but hitherto without success. I undertook, therefore, to endeavour to sup- 

 ply him with these two desiderata. He thought that they would be useful, in a 

 practical point of view, in seamanship ; and as I considered that they might be of 

 importance in meteorology, I was the more ready to lend my assistance. 



The foundation of meteorology as a science, may be considered to reside in a 

 knowledge of the general motions of the atmosphere ; and these may be far more 

 correctly determined at sea than on any station on land, where local circumstances 

 always produce more or less of an artificial climate, circumscribed, perhaps, to a 

 few miles, or even less, and therefore of no moment to the world at large. 



But although a ship, traversing the uniform surface of the ocean, of nearly 

 unvarying temperature, day and night, and winter and summer, is thus naturally 

 under highly favourable circumstances for advancing the science, still those op- 

 portunities seem never to have been turned to full account. 



The usual mode of entering the wind in the log-book used to be, and may be 

 still in the greater part of the merchant navy, " a hard breeze, or a stiff breeze, or 

 strong breezes, and squally," &c., &c. ; each person judging by his feelings merely, 

 and having a nomenclature of his own for those feelings ; so that there is no way 

 of reducing them all to any one uniform natural standard. 



On account of the flagrant absurdity of this method, in a scientific point of 

 view, Admiral Beaufort, of the Hydrographical Office, proposed and procured 

 the general adoption of, in all Her Majesty's ships, a well-digested table of the 

 names of different strengths of wind, and of the means of judging of them, in the 

 terms of the numbers of which table all entries in the log-book were to be made. 



Admiral Beauforfs Wind-Table. 



0. Calm. 



1. Light air, Or just sufficient to give steerage way. 



„ T • 1. ^ 1 "1 Or that in which a well-conditioned ( ■, ^ o , . 



2. Light breeze, .. . I r. .^, „ ., ^1 1 to 2 knots. 

 „ „ ° , , 1 man-ot-war, with all sail set, ] „ ^ , j 



o. urentle breeze,... > , , i. ,, u ■ ,.u \ " to * do. 



. ,, , ^ , I andcleanrulljwouidgoinsmootn I c ^ e j 



4. Moderate breeze, I ^ o I to o do. 



) water, for . . . \. 



VOL. XVI. PART IV. 6 A 



