74 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



[1888. 



Aug. 25. — A lunar corona was observed at 2 h . Except 

 for some thin mist or fog passing occasionally, the summit 

 was clear of cloud from 7 h till after 18 h . A rainbow was 

 seen at IS 1 '. 



Aug. 30. — An aurora was seen at 23 h . 



Aug. 31. — A lunar corona was seen at 2 h . 



Scj>t. 2. — The summit was enveloped in mist till 18 h , 

 and clear thereafter till midnight, but the sky remained 

 overcast with cum. and cum.-s., and fog covered the lower 

 hills around. 



Sejrf. 3. — At 5 h and 6 h the summit was clear of mist s 

 but enveloped for the rest of the day. After 6 h observa- 

 tion, a glory and fog-bow were seen. The following 

 are the measurements obtained by stephanome : 



Glory — Radius of outer red . . 4° 56' 



Radius of inner red . . 2° 42' 



Order of colours : — Centre, bright yellowish space, 



spectrum blue to red, and spectrum blue to red again. 



Fog- bow — Radius = 35° 4'. 



Sept. 4. — Top cleared after 20 h , and some cirrus types 

 were observed on sky, and mist was seen covering sur- 

 rounding hills. 



Sept. 8. — The summit cleared at 4 h , and remained 

 clear for the rest of the day, but fog lay on the other hills 

 around and occasionally rose to almost the level of 

 summit, and on this fog, during the forenoon, glories were 

 observed. The following measurements of these glories 

 were Rot : — 



Hour. 



Radius of Red Rings. 



Order of Colour from 

 Shadow outwards. 





Outer 



Middle Inner 





9 h 20 m 



6° 27' 



4° 52' 





ll h 40 m 



8° 13' 



6° 18' 3° 40' 





ll h 25 m 



8° 13' 



6° 18' 3° 46' 



Bright, y, b, g,y, r, v, 



Immediately \ 

 after above j 



8° 13' 



4° 56' 



b, g, y, r, b, g, y, r. 



llh 40m 



5° 34' 



/ 2° 56' \ 

 t2°45'j" - 



Bright, y, r, v, b, g 

 y. r, b, g, y, r. 



The last observation was made from the East Point, the 

 others from the North Cliff. At 6 h 41 m a double solar 

 corona was observed, and measured : radius of outer red, 

 2° 51', and of inner, 1° 40'. A coating of dew was 

 observed on the black bulbs at 20 h . A faint grey 

 glimmer at N. horizon at 23 h was probably auroral. 



Sept. 9. — At l h and 2 h a faint aurora was seen low 

 to N. A pink fore glow, with streamers, was' observed a 

 short time before sunrise, 6 h 35 m , and at 6 h 40 m the 

 shadow of Ben Nevis was seen above the horizon. Fog 

 lay on the surrounding hills all day, rising and en- 

 veloping the summit for short intervals at ll h and again 

 at 17 h . After sunset, the after glow, with streamers, was 

 observed. 



Sept. 10.— From 19 h till 23 h the sky was quite cloud- 

 less, but by midnight it was overcast with cirrus stratus. 



Sept. 13. — The mist cleared away after 4 h , and except 

 for a little passing fog at times in forenoon, the summit 

 was clear for the rest of the day. All forenoon there was 



fog in valleys all round, and thick haze in afternoon. 

 An aurora was observed at 22 h , and again at midnight. 

 The fore glow was observed in morning and the after glow 

 and earth shadow were seen in evening. 



Sept. 14. — From 2 h till 7 h mist or fog on hill top ; 

 clear for the rest of the day, and except for a little cirrus 

 near the horizon the sky was cloudless, but thick haze 

 filled the valleys all around. 



Sept. 15. — Sky cloudless till 3 h and cloudy with cir.-c. 

 till 5 h . Thick fog came on at 6 h , and changed to mist and 

 rain at 8 h , which prevailed for the rest of the day. The 

 zodiacal light was visible in E. sky at 3 h , and before sun- 

 rise a red fore glow was observed. 



Sept. 16. — After 4 h summit cleared and remained clear 

 for rest of day. Fog on hills around all day, rising about 

 midday to near level of summit, but sinking again at 

 night. At 6 h 10 m a glory was seen from the top of tower 

 on a mass of low cumulus to W. of summit : radius of 

 inner red, 2° 24', of outer, 10° 7', of extra outer, 5° 14'. 

 A fog-bow was seen at same time, radius 35° 4'. The 

 order of the colours in the glory was : — from shadow out- 

 wards, bright y, r, g, y, r, g, y, r, y, r. At 7 h 10 m an- 

 other glory was seen, in which order of colours was : — 

 shadow, bright y, r, b, g, y, r, b, g, y, r — radius of inner 

 red, 2° 41', and of outer red, 5° 0'. 



Sept. 17. — The zodiacal light was seen at 3 h and 4 h . 



Sept. 18. — At 22 h a lunar corona was observed. 

 At 23 h and midnight fog lay in the valleys all round. 

 At 23 h a lunar glory was seen. The observer's shadow 

 was well defined, and about it there was a bright glow 

 which was bounded by a faintly marked red ring of 

 radius, 2° 29'. The fog on which the glory was formed 

 was pretty thin. At the same time a lunar fog-bow was 

 observed. 



Sept. 19. — Very fine sunrise. Just before the sun 

 rose, long pink streamers were seen diverging from E. 

 horizon, passing overhead, and converging to W., where a 

 rosy belt topped the earth shadow. The shadow of Ben 

 Nevis was well seen in the earth shadow, and afterwards 

 in the rosy belt shortly after sunrise (5 h 56 m ). The 

 valleys were filled with fog all forenoon, over which, after 

 4 h , thick haze crept up from the S. In the after- 

 noon, the fog had disappeared, but the haze continued in 

 valleys. At 23 h and midnight an aurora was seen. 

 It consisted of a single, well-defined, but not very bright, 

 arch spanning the N. sky from W. to N.E., and rising at 

 23 h to 15° alt. atid at midnight to 8°. 



Sept. 20. — Aurora visible all morning till 5 h , single 

 arch, highest to N.W. and bent down a little to N. 

 Upper glow seen at 5 h , deep reddish colour. Earth 

 shadow and shadow of Ben Nevis seen as usual at sunrise. 

 Upper glow seen after sunset at 19 h . Thick haze topped 

 at times by stratus fog all round all day, only the higher 

 hill tops showing above it. 



Sept. 21. — Upper glow seen at 5 h . Sun seen at 6 h 2 m . 

 Thick haze topped *by layer of fog or cloud all round the 

 whole day to about 3000 feet. 



Sept. 22. — Earth shadow and Ben Nevis shadow seen 

 at sunrise (about 6 h ) as usual. Thick haze and fog in 

 valleys, similar to yesterday ; air very dry in forenoon. 



Sept. 23.— Earth shadow and shadow of Ben Nevis 

 seen at sunrise as usual; seen also at sunset. Sun last 

 seen at 18 h 20 m . Fog or cloud layer on hills all round 



