340 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



[1886. 



June 17. — At 22 h a dark purple belt was observed to 

 southward, rising from horizon to eastward, to 15° above 

 horizon to south-south-eastward, and sinking again to 

 horizon to south-westward. At same time ordinary sunset 

 colours were observed at north-western horizon. At 23 h 

 and at midnight the cirri clouds to northward shone with 

 a bright silvery light (not auroral) ; the brightest parts 

 were about 15° above the horizon. 



June IS. — From21 h till midnight the roof of Observatory 

 was quite wet with water blown by wind from face of 

 precipice to northwards. 



June 19. — Haze at horizon and over hills to-day till 22 h , 

 when it cleared away. 



June 20. — At 20 h fog, which was observed during the 

 afternoon to westward and north-westward, reached the 

 Ben and began to drive over summit. At the same hour 

 part of a solar halo, a fog-bow, and " glories " were 

 observed. Part of a solar halo was also observed at 15 h ; 

 no measurements were obtained. 



June 23. — At h 10 m the thermometer box was lowered 

 one step on ladder-stand. 



June 28. — The 3 h observation was not taken till 3 h 

 ll m . No corrections applied to readings. 



June 29. — At 12 h the greater part of the clouds was 

 evidently below the level of the top of Ben Nevis. In the 

 afternoon, though there was fog on the hill top, the air 

 was distinctly dry. To-day new rain-gauges, screw plug 

 pattern, but higher in the rim than the last set, arrived at 

 the Observatory. 



June 30.— At 23 h 5 m dry and wet bulbs shifted. 



July 1. — At 10 h the lower clouds were distinctly of 

 cir.-str. type. They formed to W.S.W". of Ben Nevis, and 

 passed quickly overhead at a height of about 200 feet. 

 There seemed to be a strong down current to eastwards of 

 the Ben which sucked them down and made them vanish. 



July 2. — At 15 h 8 m thermometer box shifted one stage 

 down on ladder-stand. 



July 3. — At 15 h and 16 h , though the dry read higher 

 than the wet, there was a large drop of water hanging from it. 



July 4. — Dense cum.-fog over all the hills round at 

 night, rising to over 4000 feet. 



July 5.— At 22 h 20 m dry and wet bulbs put out in 

 large thermometer box. 



July 19. — The 20 h observation was not taken till 20 h 

 5 m . No correction applied to readings. 



Aug. 3. — Very thin fog hanging round hill top, cover- 

 ing at times in early part of night. After 23 h top was 

 almost continuously enveloped, but fog was so thin that 

 sky could be quite well seen. 



Aug. 14. — At 13 h solar halo observed; no colours 

 visible. Measurement per stephanome of radius = 23° 30', 

 23° 3', and 22° 36'. 



Aug. 18. — In early morning sky almost completely 

 covered with very high cumulus, which became slowly 

 denser ; a thin haze lying over the hills. At 3 h the eastern 

 sky was of a deep orange colour, there being a clear band 

 of about 10° between the horizon and the edge of the 

 cloud. At 4 h conditions were much the same, except that 

 the clouds were tinged here and there with red. About 

 4 h 15 m white fog began to form on the hills. Sometimes 

 dark strata were formed in the valleys, which thickened 

 and became fog, and in some places detached masses of 

 mist rose up in cumulus form, and after reaching a certain 

 height folded in and became umbrella-shaped, with long 



filaments hanging down. Meanwhile the clouds above 

 seemed to close in and descend, and at 5 h they formed a 

 thick pallium. The clear band to eastwards persisted 

 after the sun had risen and gone above the edge of the 

 pallium, after which it assumed a green colour. 



Aug. 19. — At 3 b faint fog-bow observed, too large to 

 measure. At 5 b 50 m two arcs of a bow were seen, centre 

 apparently due west, on fog bank lying over west end of 

 hill. The outer edges of these arcs were tinged with red. 

 At 13 11 solar halo observed, radius 24° 14'. 



Aug. 20. — -At 2 h the surrounding hills were entirely 

 covered with fog, which rose to a height of about 15° on 

 all sides, leaving the top of the Ben in the bottom of a 

 sort of cup. The upper edge of the fog was almost quite 

 level all round, and sharply defined. A faint lunar corona 

 was observed, and appearance of stars indicated presence 

 of a good deal of vapour. No clouds were observed except 

 small quantity of cirrus. 



Aug. 27. — At 20 h 50 m heavy hail shower commenced, 

 changing to rain at 21 h . Rain continued, but air being 

 very dry almost no record was given by gauges ; stones, 

 thermometer boxes, &c. remained quite dry till after 22 b . 



Sept. 13.— Dense soft- looking fog in valleys to W. and 

 N. in early morning. 



Sept. 14. — At 22 h lunar fog-bow, white; and misty 

 corona. Both formed on scud. 



Sept. 15. — Fog in patches on hills in morning, and 

 before sunrise dense fog over Loch Arkaig. Level sheet 

 of fog covering eastern hills in the evening, and haze in 

 the valleys round Ben Nevis. 



Sept. 16.— Very thick haze in the valleys rising to 

 rather above the level of Ben Nevis, all day, and blowing 

 across the hill top as thin fog at night. 



Sept. 17. — Haze similar to yesterday, but with patches 

 of cumulus fog in it. 



Sept. 18. — Dense haze and fog in valleys to about 4000 

 feet in early morning. 



Sept. 19. — At 4 h there was dense foggy-looking haze 

 all round and below the Ben, but no corona or uuusnal 

 colours at moon. 



Sept. 21. — To-day the thermometer box and the black 

 bulb were encrusted with snow and ice, the latter so much 

 so as to render it impossible to set it at night. At 21 h an 

 aurora was observed having two arcs, from the lower of 

 which short streamers were seen ascending. At 21 h 5 m a 

 brilliant meteor was seen to south-westward at 45° altitude, 

 moving slowly towards S.E. It was so bright as to light 

 up the upper room of the tower, and lasted for about 6 

 seconds. It made no audible noise. Its length was 

 approximately from 12 to 15 yards. Before fading the 

 head was yellow, the tail being of different colours, having 

 a great amount of blue. 



Sept. 22. — At 15 h 20 m the thermometers (dry and wet) 

 were taken in, being too much encrusted with snow and 

 ice for readings to be satisfactory, and fresh dry bulb and 

 wet bulb were put out. 



Sept. 27. — At 5 U St Elmo's fire observed on lightning 

 conductor. Thunder heard at 15 h 33 m . Thunder and 

 lightning at 19 u 40 m . Several flashes of lightning 

 between 20 h and 21 h . Thunder, lightning, and earth 

 currents about 23 h . 



Sept. 28. — Lightning seen (one flash) at 3 h 3 m ; 

 thunder heard at 5 h 27 m . 



Oct. 5. — Though no rain appeared to fall, the mist con- 



