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BEN NEVIS OBSERVATORY. — LOG-BOOK. 



75 



at about 3000 feet all day ; dark hazy look to E. above 

 this fog in afternoon. 



Sept. 24. — The fog on hills round rose higher, and by 

 3 h was beginning to pass across the top of Ben Nevis. It 

 never cleared off completely for more than a few minutes 

 at a time all day. Lunar corona seen in morning, and 

 glories shortly before 16 h — all too fleeting to measure. 



Sept. 25. — Thin, wet mist, with moon gleaming till 4 h , 

 when it sank lower and continued to be about the level 

 of the hill top till 13 h . In the afternoon the air was free of 

 fog, but towards evening — after 16 h — it gathered again on 

 and under the hill top. Upper glow seen at 5 h and at 19 h . 

 Earth shadow seen at 6 h . Sun first seen at 6 h 12 m . 

 Solar corona seen at 6 h 20 m . Three sets of colours : 

 radius of inside of middle red, 2° 28'. At 7 h , portion 

 of fog-bow seen on upper surface of fog under Ben Nevis. 

 Radius (roughly) to inside . . 30° 48' 

 Radius (roughly) to outside . . 42° 57' 

 At 7 h fog crystals, 1 inch long, on chimney stays. Another 

 fog-bow seen at 9 h : 



Radius inside .... 32° 14' 

 Radius outside . . . 37° 3' 



Lunar corona seen at night, usually double. 



Sept. 26. — Fog under hill top till 2 h , but passing across 

 and over the top most of the rest of ihe day. Ice 

 crystals forming freely on all exposed surfaces till noon. 

 Eaint single arch aurora seen at 21 h and 22 h . 



Sept. 28. — At 6 h sky covered with cir. -stratus in streaks 

 lying W. by N. to E. by S. (ark form), and coloured with 

 yellow, pink, and purple. All moving from W. by N. 

 Detached fog among hills and rising out of valleys when 

 clear in morning, but thick mist on Ben Nevis all afternoon. 

 To-day, water had to be carried up from the Red Burn, 

 as the stored supply at the Observatory was exhausted. 



Sept. 29. — Ground white with freshly fallen snow at 

 night. 



Oct. 2. — Top cleared shortly after 22 h , leaving cloudless 

 sky and no fog in valleys, except a few isolated patches, 

 but the air continued saturated. Faint aurora seen at 

 midnight. 



Oct. 3. — Hill top clear at times, and no fog below, but 

 sky always covered with cumulus quite close above the 

 hill tops all round. 



Oct. 4. — Rain fell in forenoon and coated everything 

 with ice. 



Oct. 5. — Snow falling and drifting all morning. The 

 tower door had to be used in forenoon. The winter 

 Stevenson screen was used after 17 h . 



Oct. 6. — Top clear several times for a short while ; no 

 fog below ; sun shining in patches on hills round. The 

 23 h observation was not taken till 23 h 5 m . 



Oct. 9. — Top clear, but detached fog on hills all 

 morning. Glory seen at 7 h . The order of colours was : 

 — -shadow, r, g, y, r, b, g, y, r. Solar halo seen at 10 h . 

 From 15 h onwards, thin mist on hill top but stars seen at 

 night through it. 



Oct. 10. — At ll h fog-bow seen occasionally. Cirrus 

 clouds in morning moving from W. rather fast. 



Oct. 11. — Sky cloudless in morning, but fog on hills 

 round. At 5 h and 6 h sky covered with cirrus-stratus lying 

 N.N.E. to S.S.AV. At 8 h the fog had risen higher and at 

 9 h covered Ben Nevis also. Icy fog crystals forming 

 about noon. After 23 h Robinson anemometer started. 



Oct. 12. — Heavy rain all morning. The snow which 

 fell at night was hard and dry. 



• Oct. 15. — Close, heavy, small rain fell during almost 

 the entire day. 



Oct. 16. — At 21 h the moon and stars began to show 

 through the fog, and from 22 h till midnight the sky was 

 clear, but loose, hazy-looking fog covered the hills round, 

 and occasionally blew across Ben Nevis also. 



Oct. 17. — At about 3 h 5 m meteor seen to N. shooting 

 downwards towards the left. Haze and fog on hills round, 

 and sky frequently covered with cumulus and scud till 7 h , 

 but at 8 h cirrus had gathered over the whole sky and con- 

 tinued till hid by the fog, which came over the hill top in 

 the afternoon. At 6 h sunrise colours seen in a clear streak 

 to E., and at 7 h the shadow of Ben Nevis. 



Oct. 18. — Top clear for a great part of the day, but 

 thick haze and fog covering all the hills round. 



Oct. 19. — Fog and haze on hills, and sky overcast, but 

 air dry till 20 h . After this, mist began to pass across Ben 

 Nevis also, and rain began shortly before 21 h . 



Oct. 20. — Sky cleared at 5 h , and remained almost cloud- 

 less all day, but thick fog lay over all the hills round, and 

 from 7 h to 12 h covered Ben Nevis also. During most of 

 the day no hill top except the ridges of the Aonach More 

 and Aonach Beg (4000 feet) showed above the fog ; but at 

 night a few peaks to the S. became visible. Some glories 

 were seen on this fog, but all misty and badly defined. A 

 fog-bow was seen at 13 h . The earth shadow and shadow 

 of Ben Nevis were clearly seen at sunset, and the upper 

 glow at about 17 h 20 m . No glare at sun or unusual 

 colours in sky. Dew lay on all woodwork and on dark 

 coloured stones at night, but not on whitish stones. 



Oct. 21. — Fog on hill tops, as yesterday, all morning ; in 

 the afternoon, however, it turned more into haze towards 

 the S.W., and the shore of Loch Linnhe was visible through 

 it. The upper glow was seen at 6 h 45 m . The sun rose 

 above the fog at 7 h m , and the earth shadow and shadow 

 of Ben Nevis were seen as usual. Glories were seen on 

 the fog at various times during the day, but no fog-bows 

 either solar or lunar. The following measurements were 

 made of a glory seen from E. end of hill at 13 h 25 m . Four 

 sets of colours — innermost a confused blotch :- — 



Radius of second red ... 2° 28' 

 Radius of third red ... 4° 20' 

 Radius of fourth red . . 6° 7' 



Radius of second yellow . . 2° 4' 

 Radius of third yellow . 4° 0' 



The sun set at 17 h 10 m . The earth shadow, Ben Nevis 

 shadow, and after glow seen as usual. 



Oct. 22. — The fog on hills gradually passed more com- 

 pletely into haze, which became very thick towards night. 

 From 8 h onwards the sky was cloudy, mostly small and 

 rather high cum. Between 19 h and 20 h a shower of 

 rain fell, though the humidity at neither hour exceeded 50 

 per cent. The wet bulb reading at 17 h looks "out," but 

 special note was made of it and it is probably correct. 



Oct. 23. — Thick fog and haze on hills round till 4 h , after 

 which mist covered Ben Nevis also for most of the day. 

 Up to 4 h the air was dry, the humidity being under 70 

 per cent., but a little rain fell occasionally. 



Oct. 27. — Very squally S.W. winds for the last few 

 days ; the squalls frequently showed a tendency to veer 

 in direction as they passed, beginning with S. wind and 



