WINDS OF BEN NEVIS. 505 



hill stations, rises to a maximum in the very early morning, and falls to its minimum 

 in the afternoon, the reverse of what occurs at sea-level. But the direction of the wind 

 shows no appreciable changes, even in fine summer weather, when the power of the sun 

 is greatest, and such changes might be looked for, except that there is a very slight 

 excess of W. at night and of E. in the forenoon ; and that from 1 to 9 a.m. N. is in 

 excess, from 10 a.m. to 6 p.m. S., and for the rest of the day both these directions are 

 rather below the mean of the whole day. 



This result is substantially the same as that arrived at by a more elaborate examina- 

 tion of the summer winds of Ben Nevis for two years, communicated to this Society in 

 1886 (see Proc. Roy. Soc. Edin., vol. xiii. p. 839). We see no reason to alter the 

 explanation of this very slight diurnal variation given in that paper, viz., that it is 

 entirely due to radiation on the N. and S. sides of the hill, and is not connected 

 with any general system of land and sea breezes. It is rather remarkable that on Ben 

 Nevis there should be practically no diurnal variation in the direction of the wind, 

 situated as it is near the Western Sea, and with the elevated plateau of the Moor of 

 Rannoch, and the great mass of the highest hills of Scotland to the E. of it. At any 

 sea-level station in the neighbourhood, doubtless a diurnal change of marked character 

 would have appeared in a similar set of observations. 





EOY. SOC. TKANS. EDIN. — VOL. XLII. 3 T 



