264 Mr. F. Galton on Meteorological Statistics [Apr. 24, 



in a unit of time. The intention of the present memoir is to show how 

 this desideratum may be most readily obtained, and the precise method 

 by which, when it has been obtained, it should be turned to account. It 

 should be added that in the earlier part of it I am obliged to recapitulate 

 views which I have already published in the Transactions of the British 

 Association, 1866 (Transactions of Sections), p. 17. 



Suppose the meteorological statistics of some ocean district to show 

 that, on the average, out of every 100 ships that visited it the weather 

 recorded in the following Table was experienced : — 



Table I. Statistics of weather. 



30 ships find 



the wind N„ with an average force of 3 



25 „ 



>J 55 55 55 2 



15 „ 



55 S'nj „ ,, 1 



10 „ 



5 * W-., ,, ,, ,, 2 



20 „ „ 



calm, „ „ „ 



100 





At first I will suppose no current to exist. I have grouped the winds 

 under the 4 cardinal points for the sake of simplicity in explanation ; 

 but it must be recollected that in practice they would be grouped under 

 at least 8 points, and probably 16. 



Let the sailing qualities of the ship be those specified in Table II., 

 in which the figures have been extracted from an elaborate but, I fear, 

 only approximate schedule of the performances of the standard ship of 

 meteorologists, commonly described as the " Beaufort Ship." I have 



Table II. Sailing qualities of Ship. 





Number of miles made good in one day's 



sail. 



Force of 



Number of points at which the course of the ship lies off the wind, 

 reckoning to the right. 



wind. 



points, or wind 

 right ahead. 



8 points, or wind 

 abeam (same 

 value as 

 24 points). 



16 points, or 

 wind astern. 



24 points, or 

 wind abeam 

 (same value as 

 8 points). 



1 



5 



12 



12 



12 



2 



10 



38 



34 



38 



3 



24 



89 



79 



89 



4 



38 



139 



125 



139 



5 



62 



230 



202 



230 



protracted the data contained in the original schedule, and formed from 

 them the curves represented in the annexed diagram (fig. 1). 



