!36 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



[1886. 



surfaces all afternoon. Thermometer box shifted at 23 h 

 20 m . 



/.; /,. 1 0.— Thermometer box shifted at 10 h 1 5 m . Double 

 solar fog-bow seen at ll h to northward. Traces of red on 

 outside of outer ring, and on inside of inner. Radius of 

 outer bow, 42° 4' ; inner, 33° 0'. Moon gleaming at 

 night, but no corona observed. 



Feb. 12.— At 12 h rain-gauge found full of drift. At 18 h 

 rain-gauge undercut, and leaning over to one side. 



Feb. 13.— Thermometer box shifted at 21 h 20 m . 



Feb. 14. — At ll h glory and fog-bow (see fig. 7). Outer 

 radius of fog-bow, 45° 12'; inner, 40° 0'; radius of red 

 of glory, 1° 6'. Fog-bow tinged with red outside. Out- 

 side of glory red also. Seen on fog in northern valley. 



Feb. 15. — At 9 h solar halo, with portion of reverse halo 

 on upper side of it. Large halo red inside, and blue 

 outside ; portion above red next sun and blue inside 

 curvature. This upper arc overlapped on the main circle, 

 bringing their reds together. The following measurements 

 from centre of sun to the point where the two reds over- 

 lapped were made: — Radius, 21° 42'; 21° 49'; 22° 0' ; 

 22° 0' ; 22° ; 22° 0'. The upper arc was very distinct, 

 but the blue in it was fainter than in the main halo. 

 Double solar corona at ll h . Radius of outer red, 4° 53' ; 

 inner red, 2° 55'. -Brown colour round and under sun all 

 day. At 18 h pinkish haze in air below the upper clouds 

 and above the fog in the surrounding hills. From 19 h to 23 h 

 lunar halo on cirrus, and for most of the time misty corona, 

 also on cirrus. At 19 h the following measurements were 

 made. 



Corona. 



Halo. 



Outside radius, 4° 20' 



Radius, 



24° 28' 



4° 28' 



)> 



23° 17' 





>> 



22° 24' 





!> 



22° 36'. 





J) 

 )) 



23° 30' 



23° 44' 



At 20 1 ' the measurements got were: — Radius of corona, 

 2° 59'; halo, 21° 13'. The corona was a mere bluish 

 space with a red rim. No fog in valleys all day, but haze 

 at horizon, especially to southward, and detached cumulus 

 on hills. 



Feb. 16. — At 2 b misty corona on cirro-cumulus; colours 

 Faint blue as i Q mar gi n - Radius of red, 1° 43'. 



Red Brown colour under moon at 4 h 10 m . 



Yellow Similar colour at 5 h . At 7 h watery glare 



in eastward sky, and purple colour to west- 

 ward about 15° to 30° above horizon. Brown colour round 

 sun all day, strongest on lower side. Dense haze in valleys 

 to southward from S.E. to W. all afternoon. Earth shadow 

 under rosy glow to eastward after sunset at 17 h 30 m . Sun 

 shone red through the haze as it sank into it. Upper 

 glow began at 17 h 40 m and lasted till 18 h . Faint blue 

 colour round moon at night. Long thin auroral arch at 23 h 

 and midnight. Height by stephanome 6£°. 



Feb, 17. — At 3 h blue corona round moon. Brown 

 colour under sun very faint today. Misty corona on 

 cumulus at night. No measurements made. 



Feb. 18. — White fog crystals forming all day. 



Feb. 20. — Fog crystals brown in morning. 



Feb. 21. — Fog crystals brown in morning, but white and 

 more icy in texture at night. 



Feb. 25. — Lunar corona at 5 1 ', colours in following order 



out from moon : — White, yellow, red, violet, green, yellow, 

 red. Pale reddish, or brown glare round sun all day, get- 

 ting stronger near the horizon. Faint light to westward 

 observed at 8 h ; probably zodiacal light. Horizon hazy all 

 day, especially to S.W. and W. Detached cumulus above 

 haze to S. and W. in afternoon. 



Feb. 26. — Solar corona observed at 12 h . Double rings 

 varying in size. Radius of outer red, 8° 22' ; inner red, 

 4° 34'; 4° 23'; 3° 38'. Similar corona at 13 h ; the outer 

 ring was only seen occasionally, and was too faint and 

 fleeting to measure accurately, but was about 5° 30'. 

 Six measurements of the inner red gave as radius, 3° 3' ; 

 2° 47'; 3° 25'; 3° 10'; 3° 2'; 2° 24'. Fog crystals white 

 this morning. 



Feb. 27.- — Top clearing of fog at times in afternoon. 

 Fog crystals white, and very loose in texture and dry. 



Feb. 28. — Fog crystals to-day pure white. 



Mar. 4. — White glare in western sky at 18 h and 19 h . 

 Zodiacal light seen at 20 h ; nothing seen in spectroscope. 

 Thermometer box shifted at 18 h 15 m . 



Mar. 5. — At 8 b fog-bow, corona (3, 4, and 5 rings), and 

 glory (2 and 3 rings), on passing fog, — all too fleeting to 

 measure. Thermometer shifted at 20 h 5 m . Aurora seen 

 at 22 h . To-day Wm. Stewart started to come up to the 

 Observatory, but had to turn back, having lost his way 

 in the dense fog before he got to Buchan's well. Mr 

 Omond, Mr Rankin, and Mr Miller went down in search 

 of him in afternoon. In consequence of this the 15 b 

 observation was not taken till 15 h 3 m ; no corrections were 

 applied to the various readings. 



Mar. 6. — Double solar corona at 12 h . Faint aurora 

 with a few streamers at night. 



Mar. 7. — At 7 h thin pallium over sky to horizon, hills 

 just clear under it. In the valleys to eastward there was 

 an under glow of the same colour, and exactly similar to 

 the upper glow seen before sunrise and after sunset. In 

 this glow between Schehallion and Ben Nevis streamers 

 were visible, which gradually receded and faded away as 

 the sun rose higher. At 7 h 13 U1 the sun broke through 

 the clouds, and at 7 h 16 m a white beam was seen stretch- 

 ing vertically downwards from sun to the edge of Ben 

 Nevis. It passed through a thin stratus cloud. Corona 

 observed at same time. The pallium broke up into 

 detached masses like cumulus, but descending and settling 

 over the hills round. At 7 h 24 m the beam was again 

 seen. 



Double solar corona observed at 10 b — 



Radius of inner 



red, 



3° 46'. 



>) 





3° 37'. 



!> 





3° 30'. 



)> 





4° 1'. 



» 





3° 42'. 



>> 

 >> 





3° 42'. 

 2° 50'. 



Outer red, 



7° 30'. 

 5° 34'. 

 6° 29'. 

 6° 35'. 



The last measurement of the inner red, and the second 

 measurement of the outer, were taken about the same 

 time. 



Halo observed at ll h . The following measurements 

 were made : — 



22° 30'. 



22° 0'. 



Extreme inside of halo, . . 21° 13'. 



Extreme outside „ . . 25° 44'. 



