62 EEPOET — 1886. 



abnormally rapid decrease of temperature -witb height as revealed by all 

 the observations is seldom followed by storms of wind. 



For a number of years past the Scottish Meteorological Society has, 

 through the courtesy of the Commissioners of the Northern Lighthouses, 

 been favoured with meteorological observations from all the light- 

 houses, the keepers being regular observers of the Society ; and an 

 important part of their duty as such is to record the hour of beginning 

 and ending of all strong winds, gales, and storms which occur. The 

 observations, made since the establishing of the observatory in December 

 1883, have been plotted on monthly sheets, which show graphically when 

 storms have occurred at the lighthouses ; and on the same sheets have 

 been entered for the respective districts all cases when storm-signals have 

 been hoisted under direction of the Meteorological Office. This investiga- 

 tion is still in progress, but the following results may be provisionally 

 stated. 



Leaving out of view those cases in which the barometer at the 

 observatory was lowered by high winds, as above explained, by far the 

 larger number of the remaining cases, when the calculated sea-level 

 pressure was less than what was actually observed at Fort William, 

 preceded or accompanied storms, and when the difierences were unusually 

 great the storms were severe and widespread. 



Again, neglecting the occasions during 1884 when the wind at the 

 observatory exceeded 30 miles an hour, there remain nine instances which 

 in the west and north of Scotland were not followed by a storm. On 

 eio-ht of these occasions the observations did not indicate the existence 

 of a disturbance in the lower stratum of the atmosphere between Fort 

 William and the observatory. 



The Ben Nevis Observatory may be regarded as contributing, towards 

 the forecasting of the weather of the British Islands, a body of facts differ- 

 ing wholly in kind from what is contributed by any other meteorological 

 observatory or station in the country. To the bearing of these observa- 

 tions on weather the directors propose to direct attention next year ; and 

 thereafter to use the results that may be arrived at in an examination of 

 the observations of the high-level stations of Europe in their relations to 

 the paths pursued by storms over the Continent. 



Mr. Omond, superintendent of the observatory, has compared the 

 results obtained from the registrations of Professor Chrystal's anemometer 

 with the estimations of wind-force made by him and the assistants on 

 scale to 12, and thereby determined the velocity in miles per hour for 

 each figure of the scale 1, 2, 3, &c. The highest figure for which the 

 doable observations were sufficiently numerous, so as to give a good 

 average, was 8, which was found to be equivalent to a rate of 73 miles an 

 hour. This wind-force is of frequent occurrence, and as regards the 

 higher estimations Mr. Omond estimates force 11, which occasionally 

 occurs, as equivalent to a rate of 120 miles an hour. This paper has 

 been published by the Royal Society of Edinburgh. 



Mr. Omond has written another paper on the rainfall of Ben Nevis 

 in 1885 in relation to the winds. The investigation shows that, as regards 

 the rainfall, the winds arranged in their order of greatest frequency are 

 N., S.W., W., S.B., S., N.E., N.W., and E., the N.W. and E. winds being 

 remarkably few in number. As regards the total fall the order of the 

 winds for wetness is W., N.W., S.W., N., S., N.E., S.E., and E. Thus 

 the direction of wind with which most rain came during 188-5 was a little 



