Noting the direction of the wind is part of the regular routine of observations at the Observatory on the summit of Ben Nevis. Owing to the frequency of frozen fogs in winter, anemometers are practically useless, but the record is made complete enough for many purposes by the hourly observations; at each hour of the day and night the wind, at the time of making the observation, is noted, and the number of entries of each wind direction in the day, month, or year must very nearly represent the relative frequency of such winds for that time. Table I. is a summary giving the number of times each wind is observed in each month of the year on an average of six years (1884–89) expressed in percentages; thus in January, out of the 744 hours of the month, there are 120 hours or 16·1 per cent, of N. wind. For the year the most frequent wind is N., next come S.W., S.E., and S., all about equal, and the least frequent is E. N. is the point of greatest frequency in all months except May, when S.E. takes its place; in May 1889 there were only 15 hours in the whole month with N., N.W., or N.E. winds, and during three-fourths of that month the air was moving from the S. or S.E. This was, of course, an exceptional month, but in the six years there are only two (1887–88) in which N. was the most frequent wind in May.