ox METEOKOLOGICAL OBSERVATIONS ON liEN NEVIS. Ill 



results are interesting for 1892 and 1893 : Lowest dew-point, — 27'^"8 and 

 -12°-2, highest dew-point 21°-2 and 32°-8 ; lowest elastic force 0-010 inch 

 and 0'024 inch; highest elastic force 0114 inch and 0"122 inch; and 

 lowest relative liumidity 7 and 18, and highest 47 and 47. These results 

 point to a large excess of aqueous vapour in the air at the Ben Nevis 

 Observatory during 1893. 



The rainfall for the year at the top was 16577 inches, being 18'00 

 inches above the mean annual rainfall. At Fort William the amount was 

 83*54 inches, which is 1037 inches above the mean. These amounts are re- 

 spectively 1 2 and 1 4 per cent, above their averages. The maximum monthly 

 rainfall at the Ben Nevis Observatory was 2566 inches, in December, and 

 the minimum 5*48 inches, in May. The minimum monthly fall for 1892 

 was 5"42 inches in March, and these two years show the largest minimum 

 falls of any of the years since the Observatory was opened. Hence, at 

 this high level situation the rainfall was not only considerably above the 

 mean, but it continued to be relatively large through all the months of 

 this year, which will be long remarkable for an unprecedented drought 

 over a large portion of the British Islands. On the other hand, at the 

 Low Level Observatory the amount of the rainfall was short of the average 

 for each of the five months from March to July, the deficiency amounting 

 to 5-12 inches. 



At Fort William the rain fell on 235 days, and at the top on 260 days, 

 being respectively 3 days under and 26 days above their averages. The 

 maximum number of days on which rain fell was 31 days at the top and 

 29 at Fort William in December, and the minimum number 16 days in 

 March and 12 days in June respectively. 



The maximum daily rainfall at the top was 4-29 inches on Novem- 

 ber 28, and at Fort William 3*25 inches on October 24. At the former 

 station instances of one inch a day or upwards occurred during each of 

 the twelve months, whereas at Fort William, during the five months from 

 March to July, the rainfall on none of the days reached an inch. During 

 the year the rainfall amounted to an inch or upwards on 51 days, but at 

 Fort William the number of days was only 12, being a lower proportion 

 at Fort William, as compared with the top, than has previously been 

 recorded. Thus, while during the spring and early summer of 1893 Fort 

 William participated in some degree in the prevailing drought, the rainfall 

 and moisture at the Ben Nevis Observatory were above their average, a 

 result probably occasioned by the stronger ascending currents from the 

 superheated surface of the earth carrying to higher levels than usual the 

 moisture of lower levels. 



Auroras are reported to have been observed on the following dates : — 

 January 5, 9, 10, and 11 ; February 15 ; March 26 and 29 ; April 3, 11, 

 12, 26, and 27 ; May 9 ; August 12 ; September 11 ; October 4 and 17 ; 

 and November 8, 9, 10, 11, 12, 13, and 14. 



St. Elmo's Fire was seen on February 9 ; April 6 and 20 ; August 15 ; 

 October 25 ; and December 8. 



Thunderstorms occurred on April 6 ; May 19 and 21 ; June 8, 12, 

 and 13 ; July 7, 8, 10, and 11 ; August 15 ; September 8 ; and Decem- 

 ber 11. On May 21 the thunderstorm passed below the level of the 

 summit, being very severe, with much lightning and exceptionally heavy 

 rain and hail at Fort William, while on the summit there was no lichtnino: 

 and only a slight shower of rain. On June 13 the thundercloud enveloped 

 the summit for some time, and the lightning, entering the Observatory, 

 damaged the telegraph cable, and greatly interrupted communication 



