344 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



[1887. 



three outer rings, but its shadow did not fall on the 

 observer. At 12 u portion of glory seen on clouds to 

 northward, though at the time the shadow of observer fell 

 inside the edge of cliff (see fig. 10). At 14 h faint brown 

 colour under sun. At about 18 h 3 m lunar corona seen, 

 while sky appeared cloudless. At 18 h 6™ stratus began 

 to form to E.S.E., and at 18 h 8 m sky was overcast. 



Jan. 10. — Faint brown colour under sun in afternoon. 

 White dry fog crystals forming at night. No snow fell 

 apparently at night during the height of the gale, as there 

 was comparatively little drift. 



Jan. 11. — Rain-gauge put out at ll u , as there was an 

 icy crust on the snow, due to drizzling sleet and no drift 

 going. The snow falling in afternoon was large, white, 

 and rather hard. 



Jan. 13. — Thermometer box shifted at 22' 1 15 m . Before 

 this the louvres of box were badly choked with fog crystals 

 and drift. 



Jan. 11. — Lunar corona at 7 h ; colours as under — }) 

 white, yellow, red, violet, blue, green, yellow, red. Only 

 seen occasionally ; too fleeting to measure, and size ap- 

 parently varying. At 13 u small needle-shaped crystals of 

 snow falling. At 17 h (after sunset) faint upper glow with 

 long streamers and purple glow to eastward from 15° to 

 70° above horizon. - Bright aurora at 19 h ; no streamers. 

 On the upper side of the arch, a little on each side of the 

 highest part there was a dark patch partly cutting the 

 aurora through, and marked on the sky above ; stars seen 

 through it. At 23 h the moon was just rising, very yellow. 

 At midnight the dry bulb read 24° - 5 and the wet 22° - 3, yet 

 in less than one minute after reading them very thin fog 

 was blowing over the hill, giving a damp feeling to the 

 air, and a double corona was formed on moon, inner very 

 yellow, outer faint blue-green with red ring outside. 

 Level-topped fog on hills to about 4000 feet at night, with 

 haze above it. 



Jan. 15. — Level sheet of fog on all hills round, at 

 about 4000 feet, all the early morning. Lunar corona at 

 times formed by scud passing high up, though the air was 

 very dry. Upper glow above a bright orange-coloured 

 streak at eastern horizon at 8 h . The fog on the hills 

 broke up into detached bits of cumulus type in the fore- 

 noon, but haze formed round the horizon, and there was a 

 brown colour under the sun in afternoon. At 16 h 5 m dry 

 and wet shifted. 



Jan. 16. — Thick dry fog crystals forming all day, 

 slightly brown in colour. 



Jan. 17. — No rain-gauge was out till 16 h , but apparently 

 no snow fell before ll h . 



Jan. 18. — At 20 h the rain-gauge could not be found, as 

 it was buried in a drift. At 22 h , however, the snow had 

 been so much cut away that the gauge was visible. No 

 gauge was out after 20 h till midnight. 



Jan. 20. — Thermometer box louvres choked with hard 

 ice all afternoon. 



Jan. 21.— Thermometer box shifted at 18 h 30 m . 

 Before this the louvres were badly choked with ice. 



Jan. 22. — Ice forming freely on all exposed surfaces 

 again this afternoon. 



Jan, 23. — From 20 h till midnight an aurora was 

 observed ; single arch — no streamers. Louvres of ther- 

 mometer box badly choked with ice all day. 



Jan. 25. — Thermometer box shifted at l h 30 m . 



Jan. 26. — Very heavy hail in early morning. The 



following measurements were got, but not entered in daily 

 sheet, as the gauge evidently contained a large amount of 

 drifted hail:— At 2 h , 1-460; at 3 h , D733; andat4 h , 2-233. 

 No gauge was out after 4 h till 7 U . The squalls in early 

 morning came in very sudden blasts. 



Jan. 28. — A flash of lightning was observed at 6 h 27 m . 

 Strong earth-currents in telegraph wire at 6 h 52 m and at 

 7 h 10 m . 



Jan. 30.- — The snow which fell at 16 h and subsequently 

 to-day was very small, but not hard. Thermometer box 

 shifted at 18 h 12 m . 



Jan. 31. — Readings of rain-gauge very doubtful. At 

 ll h the gauge was found buried up to the rim, and none 

 was put out till 21 h . The strong winds had blown so 

 much of the late snowfall off that to-day the old surface 

 hardened by the rain of last week was showing in several 

 places. The fog crystals forming to-day were white and 

 rather hard. 



Feb. 2. — At 7 h the rain-gauge was found full of drift ; 

 none was put out after that till 17 h , but all the measure- 

 ments got were unsatisfactory. Thermometer box badly 

 choked up with fine drift during most of the day. 



Feb. 3.— Thermometer box shifted at 9 h 30 m . 



Feb. 4. — At 5 h St Elmo's fire seen on lightning con- 

 ductor and crystal vane, also faintly visible at 6 h . At 

 7 h 2 m bright flash of lightning, followed very closely by 

 thunder. At 7 h 7 m earth-currents in telegraph cable, and 

 7 U 25 m another peal of thunder. 



Feb. 5. — At 12 h the snow that was falling consisted of 

 partly flat soft flakes and partly of hard white (haily) snow. 

 The snow this evening was lying in waves from 20 to 50 

 inches long and about 2 inches high from trough to crest. 



Feb. 6. — Lunar fog-bow and corona seen at 2 h . Inside 

 radius of fog-bow, 33° 56'; outside, 40° 20' — measured 

 from shadow of head of observer. At 3 h faint brown 

 colour under moon. Thermometer box shifted at 3 h 20 m . 

 Earth shadow seen to westward at 8 h just before sunrise. 

 Dense haze or fog hiding Mull all day. Brown colour 

 under sun above this haze in afternoon, but no glare 

 round sun. Earth shadow seen again after sunset. 



Feb. 7. — The drizzle from the mist this morning gave a 

 brown colour to the snow, and the fog crystals were also 

 brown. 



Feb. 8. — At 7 h faint pink glow on thin cir.-str. clouds 15° 

 to 20° above eastern horizon. Sun rose just at 8 h . Dark 

 brown colour under sun at 9 h . No afterglow at 17 h , but 

 sky " smudgy." Double lunar corona at 23 h and mid- 

 night. Rather indistinct, apparently formed on cir. clouds. 

 Radius of inner red, 2° 1'; outer red, 4° 40'. No trace of 

 a halo was observed on the cirrus. This afternoon the 

 snow at the first gorge was found to be overhanging the 

 edge of the cliff 172 inches. 



Feb. 9. — At 6 h double lunar corona seen; colours in 

 following order: — ]), white, red, violet, blue, green, red. 

 Radius of inner red, 1° 45'; violet, 2° 19'; blue, 2° 50'; 

 green, 3° 15'; outer red, 4" 0'. Brown colour under sun 

 at 10 h , and again in afternoon. Haze, thickening into fog 

 to W. and S., in valleys and over all lower hills to-day. 



Feb. 10. — At 4 h cum. fog was rising as high as the top 

 of Ben out of corries to north-eastward, though dry and 

 wet read 28-0 and 23 2. At 7 h the fog was rising higher 

 than the Ben to S.E. and at 8 h it covered the Ben, 



Feb. 12. — Double lunar corona at 7 h ; colours in 

 following order : — 



