136 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



[1889. 



At 8 h and 9 h the temperature was lower than the range of 

 Gla-hier's tables. In calculating the dew-point, etc., it 

 was assumed that the factor for temperatures below 10° is 

 the same as that for 10°. Lunar coronas seen in early 

 morning, and again at night. Earth shadow and shadow 

 of Ben seen at 8 h . Radiating points of cirrus were at 

 14 h , W.N.W. and E.S.E., at 18 h the same, and at 19 h , 

 W. by N. and E. by S. A snow-bunting was seen at the 

 observatory most of the afternoon. 



Feb. 11. — Lunar coronas were seen at l h , and again at 

 night. A few hailstones (soft) falling at 23 h . 



j? e l K 12.— At 10 h , ll h , 12' 1 , and 16 u , it was difficult 

 to say whether it was mist or fog that was on the top. 

 At 10 h the fog crystals forming were slightly icy ; and 

 at ll h there was a dull icy skin on raingauge. The air 

 temperatures at 10 h and ll h were respectively 20° "8 and 

 21°-6. 



Feb. 15.— Thermometer box shifted at ll h 20 m . A 

 lunar halo was seen at 21 h , 22 h , and 23 h . The radiating 

 points of cirrus were N.N.W. and S.S.E., to N.W. and 

 S.E. after 20 h . The air was dry at midnight — humidity 

 38 per cent. 



Feb. 16. — After l h to-day Bar. 1385 was found to have 

 been slightly out of the vertical. It was readjusted 

 before 2 h . The air was dry at l u and 2 1 ', and the top was 

 clear, except at 3 h , till 5 h . A lunar corona was seen at 

 3 h . From 5 U till ll h the snow was drifting heavily ; and 

 the amounts of snow entered on daily sheet are in con- 

 sequence doubtful. 



Feb. 17.— The thermometer box was shifted after 3 h . 

 The low temperature reading at 3 h , is probably due to 

 the dry bulb having been acting as a wet bulb then. 

 The top was clear from 3 h till 6 U , with haze and detached 

 fog on the lower hills. 



Feb. 20. — In the forenoon the cloud cap was mist, 

 and the snow crystals forming were icy. Maximum 

 temperature 27° "7. 



Feb. 21. — The top cleared after 3 h , and remained clear, 

 except for a little passing fog at times in forenoon, for 

 the rest of the day. The thermometer box was shifted at 

 4 h 30™. The air was dry at 16 h , and for the rest of the 

 afternoon. Detached fog on lower hills most of the day. 

 The radiating points of the cirri clouds to-day were N. 

 by W. and S. by E. During the afternoon there was a 

 very thin stratum of str.-cir. below large cum.-cir. It 

 was moving quickly from N. A lunar corona was seen 

 at 5 h . 



Feb. 22. — Sky overcast till 4 h ; mist thereafter. Ice 

 forming on surfaces till 7 h . Box dripping at 8 h . Drizzling 

 rain the rest of the day. 



Feb. 23. — During breaks in the mist at 2 h , the northern 

 sky was seen to be brighter than the rest of the sky — 

 apparently due to aurora. Detached fog on hills around 

 all day. A triple corona was seen at 15 h . The foreglow 

 and earth shadow were seen at 7 h . 



Feb. 24. — Fog on top till 10 h ; clear thereafter till 

 midnight. Detached cum. fog on hills around till 19 h . 

 Cirrus and cirro-cumulus on sky all afternoon : radiating 

 points N.E. and S.W., motion from N.E. At 21 h to-day 

 the humidity was 13. The zodiacal light was visible at 

 20 h and 22 h . 



Feb. 26.— Top clear at l h and 2 1 ', and from 10 h till 

 20 h sky mostly overcast. At 8 h it was noted the fog 



crystals were brown. Thermometer box shifted at 

 14 h 15 m . 



Feb. 27. — Cum.-cir. and cir. on sky ; radiating points 

 at ll h and 12 h were N.N.E. and S.S.W., and at 22 h N.E. 

 and S. W. Part of a solar halo was seen at 1 2 h , and an 

 aurora at 21 1 '. Cum. fog on hills most of the day. 

 Hoar-frost to sea-level at 8 h . 



March 1. — Faint aurora seen at 23 h , and midnight. 

 The thermometer box was shifted after 23 h . Box was 

 put one step higher (the highest) on ladder stand. 



March 2. — An aurora was seen at l h and 2 h . 



March 4. — Top clear for several hours to-day. Thick 

 haze and cum. fog all round below. Radiating points of 

 cirrus at 8 h , S.E. and N.W. To-day and yesterday a 

 snow-bunting was seen about the observatory. 



March 5. — Thick fog on summit all day. Brown fog 

 crystals forming, sooty in taste. 



March 8. — Top clear several times to-day. At these 

 times, in the forenoon, the sky was cloudless, and there 

 was fog all round below ; but in the afternoon there was 

 stratus or str.-cum. above, and passing showers in the 

 distance. Needle-shaped snow-crystals falling at 14 h . 

 The thermometer box was shifted after 7 h . 



March 11. — Summit clear till 15 h ; fog thereafter till 

 22 h , and mist till midnight. Radiating points of cir.-c. at 

 12 h were N. and S. The thermometer box was shifted 

 at 2 h 15 111 



March 

 midnight 



March 



99k 



— ' -> . 



March 15. — Wet drizzling mist on summit till 18 h . 

 Top clear, with thin mist passing at times, till 22 h , but 

 enveloped again at 23 h , and midnight. At 19 h the sky 

 was cloudless, but from 20 h till 22 h it was covered with 

 cirro-cumulus, on which at 21 h , a faintly marked lunar 

 halo was seen. Double and triple lunar fog-bows were 

 seen, and also corona; on passing mist, from 20 h to 22 h . 

 At 20 h the fog-bow appeared as in diagram below. The 

 chief bow was well defined, and much brighter than lunar 

 fog-bows usually are. The greater part of it was white — 

 the only coloured part being a red fringe on outside. 

 Both inside bows were white, and showed no trace of 

 colour. On each side of the chief bow there was a 

 distinct dark space. Outside the outer dark space, and 

 when the chief bow was at its brightest, another bow was 

 seen. It was from 12° to 15° broad, but very faintly 

 marked. Two sets of measurements of the radii of 

 outside and inside of chief bow were obtained, but before 

 the inner bows could be measured, the stephanome 



13. — Lunar coronas were seen at 22 h , and 

 ; an aurora was also seen at midnight. 

 14. — Lunar coronee were seen at l h and 



