of the Fishery Board for Scotland. 



357 



la Scotland, at North Unst, Shetland, Fair Isle, Wick, Buchan Ness, 

 Girdle Ness, Bell Rock, St Abbs ; in England, at Shields, Spurn Head, 

 and Yarmouth ; on the Continent, at Helder, Cuxhaven, the Scaw, and 

 Skudesnaes. The information for the English and Continental stations 

 was obtained from the Daily Weather Reports published by the Meteoro- 

 logical Office ; that for the Scottish stations from the daily records in 

 the possession of the Scottish Meteorological Society, which were kindly 

 lent to me by Dr Alexander Buchan, the secretary, who has also given 

 me the benefit of his great experience on this part of the subject. In 

 the English and Continental returns the observations taken at 8 a.m., 

 and in the Scottish returns the record of the prevailing wind during 

 the previous twenty-four hours were selected. As might have been 

 anticipated, the latter records were much more satisfactory than the 

 former, which gave the direction and force of the wind only at one point 

 in the twenty-four hours. A better result would doubtless have been 

 obtained by combining the 8 p.m. observations, but the labour was too 

 great. The tabulated observations in both cases were of direct use in 

 tracing the action of the wind over a short period ; but it was necessary 

 for my purpose to obtain a resultant showing the direction and force of 

 the wind for each month, and this resultant I have termed the effective 

 wind. The method by which this was accomplished was as follows : — 

 The observations at North Unst, Shetland, Buchan Ness, the Bell Rock 

 Lighthouse, Shields, Yarmouth, Helder and the Skaw were selected. 

 Gentle breezes were omitted from consideration, but fresh breezes, strong 

 breezes and gales were included, their force being indicated according to 

 the Beaufort scale ; and such winds in each month at each station were 

 represented according to their direction by a line whose length corres- 

 ponded to the force of the wind, J of an inch being taken as = 1. By 

 combining the lines into a polygon of forces, the resultant or effective 

 wind for the month at the stations was obtained ; and by combining the 

 twelve monthly resultants in the same way the resultant or effective wind 

 for the whole year was determined. 



The results are given in the following Table, and shown in the poly- 

 gons on pi. XI. Comparison can therefore be made between the effec- 

 tive winds in each month and the course of the drift-bottles as detailed 

 in the Tables . 



It will be noticed that although the direction of the effective wind 

 in the same month at a particular station usually varied considerably in 

 the two years, the resultant direction for the whole year is practically 

 the same at the Scotch stations in 1895 and 1896. At these stations 

 the results are founded, as has been said, on the prevailing direction 

 for each twenty-four hours, and not merely on a single daily observa- 

 tion, as with the English and Continental results. For example, the 

 effective wind at North Unst blew from W.S.W. \ S. in 1895, and 

 from W.S.W. in 1896 ; at Buchan Ness it blew from W. by S. \ S. 

 in 1895, and from S.W. by W. in 1896 ; at the Bell Rock it blew from 

 W. by N. \ W. in 1895, and from W. by N. in 1896. These 

 stations are considerably distant from one another, at points from the 

 extreme north to the southern part of the east coast of Scotland ; and 

 by combining the resultants in the two years I find the mean direc- 

 tion of the effective wind to have been W. by S. \ W. in 1895 and 

 W. by S. \ W. — practically the same — in 1896. In the four months 

 of 1894 during which the experiments were carried on — September to 

 December — the resultant for the period was : — Unst, W.N.W. \ W., 

 Buchan Ness, W.S.W., Bell Rock, W. by N., and the mean for the 

 three stations was W. \ S. It is therefore clear that over the whole 



