70 EEPORT— 1892. 



being 312 bours in excess of tbe number of bours registered at tbe top. 

 It may be pointed out tbat tbe number of bours of possible sunsbine is, 

 particularly in winter, considerably greater at tbe top tban at Fort 

 William, Tvbicb is enclosed by bills. 



Tbe rainfall for tbe year was 178 02 incbes ; in 1890 tbe amount was 

 IDS'S-i incbes. Tbese are by considerable amounts the beaviest annual 

 rainfalls yet observed. At Fort William tbe amount was 78'81 incbes, 

 or nearly lOO'OO incbes less tban on tbe top of tbe mountain. Hence 

 while tbe rainfall at Fort William was tbe average, tbat of Ben Nevis 

 was 24 per cent, above tbe average. Tbe rainfall of September was 

 phenomenal, amounting at tbe Observatory to 43'55 incbes ; tbe amount 

 for the same month at Fort William being 13'02 inches. One inch of 

 rain or upwards fell on each of 16 days of the month, and on the 1st 

 4'9o incbes were recorded, and 3'37 inches on the 2Dd. It is remarkable 

 that during tbe extraordinarily heavy rains near the east coast on tbe 

 20th and 21st, the rainfall at the top of Ben Nevis was light ; and on tbe 

 other hand, while practically no rain fell in the east on the 17tb, 18tb, 

 and 19tb, the rainfall on tbe Ben amounted to 405 incbes. At several 

 of the stations of the Scottish ]\Ieteorological Society tbe rainfall over 

 this part of Scotland was fully double tbe average of the month ; but at 

 the Observatory it was three times tbe average. 



The number of days un which tbe rainfall was nil, or less tban the 

 hundredth of an inch, was 106, there being only one fair day in August, 

 but the unusually large number of 19 fair days is reported in April, and 

 18 in June. At Fort William there were 138 fair days during 1891, and 

 in April, May, and June 21, 18, and 19 are respectively recorded. 

 Again, while at Fort William at least an inch of rain fell on 18 days 

 during the year, there were 68 such days at the top of tbe Ben ; and 

 while at Fort William there was an entire absence of such wet days in 

 April, May, June, and July, only in April at the top was no such wet 

 day recorded. 



At Fort William the mean atmospheric pressure was 29'857 incbes, 

 or 0"030 inch above the mean pressure. The monthly extremes were, 

 the maximum 30'303 incbes in February, and the minimum 29601 incbes 

 in October, these being 0-328 inch above and 0'219 below tbe means 

 respectively. 



On tbe suggestion of Mr. J. T. Buchanan, who has recently been 

 examining some phases of the bygrometry of Ben Nevis in connection 

 with the cloud and fog observations, it bas been agreed to institute a 

 systematic series of observations, having for their object a carefal record 

 of tbe height above sea-level of the lower surface of clouds tbat from 

 time to time cover the side of the mountain facing Fort Wilham. The 

 importance of this new series of observations will be I'ecognised when the 

 large portion of the year the Observatory is enveloped with a completely 

 saturated atmosphere is taken into considei'ation. 



Mr. R. C. Mossman has investigated the remarkable squall which 

 occurred in tbe British Islands on the morning of February 1, 1892. 

 Tbe more important of tbe results are the rapid rate, about forty miles an 

 hour, with which it swept over the country from N.W. to S.E., tbe sud- 

 den fall and equally rapid rise of pressure being at many places fully six - 

 hundredths of an inch, the sudden great fall of temperature fully ten 

 degi-ees at many places, and tbe sudden change of wind. Tbese features 

 are well marked in the Ben Nevis observations, which show well, among 



