1894.] 



BEN NEVIS OBSERVATORY.— LOG-BOOK. 



187 



the Richards Barg. in top room of tower rose 0*250 during 

 a squall. 



March 12.— St Elmo's Fire seen at l h . 



March 16. — Box changed at 12 h . Height not altered. 

 Lunar fog box at l h . 



March 17. — Fog coming up from W. in early morning 

 and as it crossed summit on other side of first gorge, it 

 flowed down into the corry close to cliff. 



March 19. — Mouse seen and caught as it was quite 

 tame, but was let off again at l h in lobby. Fog-bows and 

 triple coronae seen at night. 



March 21. — From 3 h to 3 h 30 m observed lunar glories 

 formed on passing fog. Observer on top of tower was 

 often out of the fog. When the fog was between him 

 and moon a very bright triple corona was seen, and when 

 it passed tower a single-ringed glory bounded by a 

 faint red ring was observed. Repeated measurements of 

 the outer edge of red gave 2° 45' as radius, and this was 

 in all the trials made exactly the same as the outer edge 

 of inner red of corona. A bright fogbow was seen at 

 same time, radius 35 o, (extreme outside). The glory was 

 seen against the snow not twenty yards from base of tower. 

 The fog kept passing in great waves, and flowing sheer 

 down the cliff all morning. 



March 22. — Thermometer box shifted after l h . Height 

 not altered. Top cleared after ll h leaving sky cloudless 

 but thick haze all around below. Haze was yellowish 

 white under sun and moon, but dark blue, almost black, on 

 opposite side of observer. Immediately over the haze and 

 directly under the moon the sky was a dark copper colour 

 all night. Bright aurora seen at midnight. 



March 23. — The boundary between the white haze on 

 the side of the moon and the dark blue haze on opposite 

 side was well defined to-day. At 4 h this boundary was 

 measured by stephanome and found to be 59° 30' from a 

 point in the horizon perpendicularly under moon. At 21 h 

 45 m a double moon was seen. The real moon was just 

 clear of the horizon to eastward and the spurious moon 

 a little higher — an exact copy of real moon but much 

 fainter, it partly overlapped the real moon. There was 

 no appearance of cirrus at time. It was probably a 

 mirage. At 22 h 5 m a pillar of light 1° 50' long descended 

 perpendicularly from the moon to where the "mirage" 

 had been seen. The moon at time was behind streaky 

 cir.-s. At same time a mock moon was seen 23° 3' to S. of 

 moon — same height above horizon. 



March 24. — Faint glimmer in nothern sky all last night 

 and in early morning to-day — probably auroral. The cir.-s. 

 that was seen to S.E. from 22 h to midnight last night 

 covered the whole eastern half of sky at 2 h and 3 h , then 

 gradually vanished. It lay in long bands lying N. and S. 

 while some cir.-c. stripes in it lay E. and W. The upper 

 limit of haze rose at l h . The Zodiacal light was seen last 

 night and again to-night. Snow bunting seen at 15 m and 

 a mouse in snowporch at midnight. 



March 25. — Haze higher to-day than last three days. 

 Zodiacal light and faint aurora seen at night. 



March 26. — Thick haze in sky ; very clear overhead all 

 day. Zodiacal light seen at 21 h . 



March 27. — Haze as before. Snow bunting seen at ll h . 



March 28. — Haze as before but rather higher. 



March 30. — Faint aurora seen at 3 h , and bright aurora 

 at 21 h , and all night after that accompanied, with strong 



earth currents in telegraph cable. The currents were in 

 both directions but continued for several minutes in each 

 direction at a time. At 21 h the aurora was all over the 

 sky in the form of bands stretching from W.S.W. to 

 E.N.E. with a very dark belt to S. the centre of which 

 was about 30° above horizon. There were also thinner 

 dark bands to N. 



March 31. — At l 1 ' and 2 h aurora consisting of a crown 

 at zenith and streamers radiating from it in all directions,, 

 but chiefly to W.S.W. and E.N.E. Snow bunting seen 

 at 7 h on summit. 



April 1. — When the summit was clear to-day it was- 

 noticed that the haze, which had been very thick all 

 round since March 22, had disappeared. 



April 8. — For the three days, 6th, 7th, and 8th, fog 

 covered the hills below in broken cumulus-like masses and 

 occasionally blew over Ben Nevis also. The crystals formed 

 out of the fog were quite white, no brown or other colour 

 in them. To-day the temperature was very unsteady, alter- 

 ing as much as 7 in a hour as the fog went on and off. 



April 11. — At 15 h 5 m thermometer box put one stage 

 lower on stand. Instruments and box not changed. 

 Shower of rain and sleet about 19 h 30 m , and earth 

 currents in telegraph cable all afternoon. Lunar halo 

 seen at 23 h . 



April 12. — Lunar halo seen at l h . 



April 15. — Thermometer box shifted at 4 h 20 m . Height 

 above snow not altered. Double lunar corona seen at 

 midnight. 



April 16. — Lunar halo seen at 2 h . 



April 18. — Thermometer box shifted at 15 h 23 m . 

 Height not altered. 



April 19. — Lunar halo seen at 2 h and Solar halo at 

 14 h . 



April 26. — Thermometer box shifted at 20 h 10 m . 

 Height above snow not altered. 



April 28. — Aurora seen at 2 h , a single faint arch, no 

 streamers. Solar halo seen at 16 h . 



April 29. — Mist most of the day, but at 10 h , 19 h and 

 20 h it only just reached the level of Ben Nevis filling the 

 valleys and passing over the summit. 



May 1 . — The fog on summit sank just below the level 

 of hill top in the evening. At 18 h and 19 h fog was 

 passing, but at 20 u it was all below, hiding all the other 

 hills, and the temperature rose nearly 5°. At midnight the 

 fog was passing over summit occasionally again and tem- 

 perature fell 6°. Solar halo seen at 18 h and 19 h on cir.-str. 



May 5. — Thermometer box shifted at 9 h 10 m . 

 Height above snow not altered. Summit clear, but fog on 

 hills below and sky half covered with cirrus and cir.-cum. 

 at 9 h , 10 h and ll h . Solar halo seen at 10 h . 



May 9. — Solar halo seen at 8 h . Thermometer box 

 shifted at 10 h 10 m . Height above snow not altered. 

 Some glories were seen at 19 h . 



May 12. — Thermometer box shifted at 10 h 10 m . 

 Height not altered. 



May 13. — Thermometer box shifted at 4 h 12 m . Height 

 above snow not altered. Earth shadow seen at 4 h . 



May 16. — Thermometer box shifted at 12 h 10 m . 

 Height above snow not altered. At 16 h top cleared, 

 but fog lay over hills at 4000 feet till 19 h , after which 

 it broke into detached masses, and by 22 h was risen up as 

 cumulus. 



