710 



MR R. T. OMOND ON 



a rough oval, owing to the westerly component being weaker in proportion to the N.-S. 

 one from 6 h to 12 h than it is from 13 h to 17 h and from l h to 5 h . This oval form of the 

 curve formed by joining the points of origin of the wind at each hour is characteristic 

 of the winds at other places, when reduced by taking account of both velocity and 

 direction, and the diagram shows that it appears in the Ben Nevis summer winds 

 reduced for direction alone, independent of velocity. # There is, therefore, sufficient 

 variation in the air movement from hour to hour to distinctly alter the direction of the 

 wind in summer on the summit of Ben Nevis, and to alter it in a regular manner with 

 progressive change from hour to hour. 



Fio. 6.— The Summer Winds of Ren Nevis. 



The wind observations of the first two summers that the Ben Nevis Observatory 

 was in operation, 1884 and 1885, were discussed, and the results communicated to the 

 Royal Society of Edinburgh in 1 886.1' In this discussion account was taken of the 

 velocity of the wind as estimated hourly by the observers, as well as of the direction ; 

 but only those days on which the wind-force never exceeded 3, equivalent to about 20 

 miles per hour, were used. In the two summers there were altogether seventy-four 

 such days, and their winds were reduced to north-south and east-west components and 



* Compare "St, Helena Wind Records," Annual L'rjiorf. of the Meteorological Committee, London, for the Year 

 ended 31«< March 1908, p. 20. 



t Proc. Roy, Soc. Eilin., vol. xiii. p. 839, "The Diurnal Variation in the Direction of the Summer Winds on Ben 

 Nevis," by B. T. Omond. 



