1889.] 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



141 



overcast with nimbus, and fog on hills around and 

 brushing top of Ben Nevis at times. 



Aug. 30. — Fog with a few short breaks till 18 h , after 

 which it cleared leaving sky cloudless. Some stratus fog 

 lay over the hills round in detached portions till 21 h . 

 Air became dry (humidity SO) as soon as the fog ceased 

 to blow across the hill top. 



Aug. 31. — Fog began to gather on the hills to N. 

 after 3 h , and spread over all the hills round, those to 

 the S.E. being the last to be covered, and after 12 h 

 rose and covered Ben Nevis also. Mist and drizzle in 

 evening. 



Sept. 1. — Fog on the hills round and often on Ben 

 Nevis also till 6 h , after which there were only detached 

 portions in the valleys and on the hills. After 20 b fog- 

 was blowing across Ben Nevis again. Air slightly hazy 

 during the day. In the forenoon there were cirrus clouds 

 in streaks from N.W. to S.E., and the motion was from 

 the N.W. But at 17 h the sky was covered again with 

 cirrus, having no definite arrangement, and moving from 

 the S.E. ; and at 20 h from the S.W. 



Sept. 3. — Fog on hills round and blowing across Ben 

 Nevis till 9 h , after which continuous fog or mist, very 

 thick at times. 



Sept. 5. — Clear sky but fog blowing across the hill top 

 till 3 h , and after 16 h . Air very hazy between these 

 hours, and fog among the hills round in forenoon. 



Sept. 6. — Clear sky all day, but haze and fog over all 

 the hills round, and in forenoon dry fog blowing across 

 Ben Nevis also. 



Sept. 7. — Sky almost cloudless till 16 h , but haze all 

 round. After 16 h fog or mist on Ben Nevis. Fog lay 

 among the hills round till 7 h , but after that cleared off 

 and only gathered about the hill tops after 15 h . The 16 h 

 observation was taken at 16 h 4 m . 



Sept. 11. — At 17 h and 18 h top was clear but sky 

 cloudy, and streaks of stratus fog lying on and among 

 the hills round. 



Sept. 12. — After 4 h the fog sank down, and lay over 

 or among the hills round and continued to lie there till 

 22 h , after which the top of Ben Nevis was also covered. 

 The fog was not a continuous sheet, but lay in patches. 

 Upper clouds moving from the westward all day. 



Sept. 14. — Thin mist on hill top till 14 h , after which 

 it sank, showing sky partly covered with cirrus, but the 

 fog lay over the hills round all day. Air very dry at 

 night, the humidity being 45 at 18 h and at midnight. 



Sept. 15. — Fog on hill tops round all day, and occasion- 

 ally over Ben Nevis also. Air very dry when clear of 

 this fog, humidities of 40 or 50 being got at several 

 hours in the forenoon. A lunar corona was seen at 5\ 

 and a solar glory and part of a fog-bow at 6 h . A glory 

 was also seen at 8 h . No measurements were got. 



Sept. 16. — Fog on hills round and blowing across Ben 

 Nevis, but sky clear above till 9 h , after that fog or mist. 

 A lunar corona was seen at 5 h . 



Sept. 18. — The heavy rain which fell this afternoon 

 and evening was composed of large drops, not small 

 drizzle. In the two hours from 20 h to 22 h , 0-522 inch 

 was registered by the gauge. 



Sept. 21. — Heavy showers of snow fell during the day. 

 Top clearing at times to-day, showing the tops of the 

 lower hills around covered with snow. At 9 h snow 

 ROY. SOC. TRANS. BDIN. — VOL. XLII. 



crystals in form of straight bars £" long were observed 

 to fall. 



Sept. 22. — At 22 h the summit was clear, and an aurora 

 was observed. 



Sept. 23. — Summit clear most of the day. Detached 

 patches of fog were seen on hill tops around in 

 forenoon. Cirrus and cirro-cumulus on sky, radiating 

 points at 3 h were N.W. and S.E. At 22 h and 23 h a 

 faint aurora was observed. 



Sept. 24. — Aurora seen at l h and 2 h , and at the 

 former hour three flashes of sheet lightning were observed 

 to S. The sky was cloudless before the lightning was 

 seen, but each flash revealed three thin streaks of stratus 

 a little above the southern horizon. The streaks were 

 dark against the lightning in back-ground. The summit 

 remained clear, except for a little fog at 5 h , till 16 h , 

 when fog came on and snow fell heavily till 20 h , and 

 drifted very much all night. "Visibility" to westward 

 to-day. 



Sept. 25. — Snow line at about 2500 feet above sea- 

 level to-day. The summit was clear and the sky cloudless 

 till 5 h , fog or cloudy sky thereafter. 



Oct. 1.— Cloudless till 10 h . Fog at ll h and 13 h . 

 Cumulus (10) in afternoon, but almost cloudless again 

 after 18 h . Fog on hills around all forenoon. "Visibility" 

 to W. and N. in afternoon. At 2 h a faint aurora and the 

 zodiacal light were seen. The latter was best seen at 

 2 h 45 m , its southern boundary being well denned. The 

 zodiacal light, the "Milky Way," and the horizon formed 

 the three sides of a triangle, the enclosed sky being 

 markedly darker than its surroundings. A fog-bow and 

 glory were seen at 10 h . Radius of red of glory 2° 0' 36" 

 per stephauome. The earth shadow was seen at sunrise. 



Oct. 2. — Top clear almost all day, but a little fog in 

 valleys in forenoon, and haze in afternoon. 



Oct. 3.— Air dry (humidity 75 to 90) till 20 h except 

 at 17 h . After 20 h fog covered or was passing Ben Nevis. 

 Sky cloudy all day, chiefly with cumulo-cirrus, which 

 was moving from S.W. in forenoon, and from S.E. at 14 h . 

 A little snow fell after 22 h . A solar halo was seen at 

 15 h . Haze all round below to-day. 



Oct. 7. — A gale which commenced at midnight last 

 night, continued till 6 h this morning. It increased in 

 strength till 3 h , when it was force 10-11, and thereafter 

 gradually moderated. Extra readings were taken of the 

 barometer between 2 h and 5 h , the lowest, 24*345 inches, 

 being observed at 3 h 30 m . Rain, sleet, or snow was 

 falling during the gale, and after 9 h , when the wind 

 backed to the north, snow and hail fell pretty constantly 

 for the rest of the day. 



Oct. 8. — Snow or hail falling most of the day. A 

 lunar corona was seen at 19 h . 



Oct. 9. — A moderate gale from S.E. was experienced 

 in forenoon. At 17 h the summit cleared for a little, and 

 fog was seen on all the lower hills. 



Oct. 10. — The summit was clear till after 3 h to-day. 

 Cirro-stratus and cirro-cumulus covered the sky, and at 

 l h , 2 h , and 3 h a lunar halo was observed. 



Oct. 11. — The top was clear to-day from 14 h till mid- 

 night, except for thin fog at 16 h . After 18 h the sky was 

 cloudless. Cumulus was observed on hills around, and 

 stratus fog in the valleys at night. A lunar corona was 

 seen at midnight. 



T 



