416 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



[1892. 



sky cloudless except for a little thin scud blowing over at 

 times. Thick fog all round and extending to a consider- 

 able height above Ben Nevis. After 14 h fog came on 

 again but cleared occasionally and air was dry at times. 

 A bright meteor was observed at 5 h S" 1 . Glories were 

 seen frequently from 8 h till 13 u , and a number of measure- 

 ments were obtained. At 2 TO the small thermometer box 

 {winter pattern) was put out on ladder stand No. 2 with 

 dry, wet, and mill, thermometers. Duplicate readings were 

 made up till noon, after which readings of thermometers 

 in big box were discontinued. 



Oct. 14. — Strong gusty E. and N.E. winds all day. 

 Summit clear but sky somewhat cloudy till 16 h but 

 cloudless after that and air pretty dry. Very thick banks 

 of cum. -fog over hills all day and passing over summit at 

 midnight. Aurora single arch seen at 22 h and 23 h . 



Oct. 15. — Strong squally N. and N.E. winds all day. 

 Sky cloudless till 3 h but thick fog all round. Fog- 

 blowing over summit the rest of the day, but sky 

 apparently cloudless. Aurora single arch at 2 h . A 

 meteor seen at 4 h . Glories were seen between 10 h 

 and ll h . 



Oct. 16. — Sky cloudless and air dry till 2 h , but thick 

 fog all round below which ross and enveloped summit 

 thereafter, but top clear occasionally during the day. 

 Aurora single arch at l h and 2 h . 



Oct. 18. — Sky cloudless till 8 h but somewhat cloudy 

 after that, and thick fog below all round which rose and 

 enveloped summit after ] 8 k . Air very clear all round in 

 the forenoon, Ireland and the Outer Hebrides being 

 distinctly seen. Aurora seen from l h till 5 h . There were 

 two well defined arches, the lower one extending from W. to 

 N.E., and bright streamers shooting to the zenith and con- 

 tinually shifting, at 3 h , 4 h and 5 h pulsations were very 

 rapid, and bright. Earth-shadow visible at 7 h . A solar 

 halo at 14 h and 15 h . 



Oct. 19. — The 13 h observation was taken 15 minutes 

 late. 



Oct. 20. — Fog or mist till 10 h , summit clear, but sky 

 overcast with thin cirro-stratus and fog all round below, 

 but rising at times and frequently passing over summit 

 in the afternoon. Slight showers of snow and drizzle in 



the forenoon and again after 22 h . A solar halo was seen 

 between 13 h and 16 1 ' as sketched above. The hori- 

 zontal white circle extended almost completely round 

 heavens; at one time being broken from N. — N.N.E. 

 only (measured approximately 13°). The outermost mock 

 .suns were at right angles to real sun. 



Measurements of Distance between Sun and Inner Mock Suns. 









x = Distance between 



Time. 



Left. 



Right. 



Centre of Reds of 

 Two Halos. 



h m 



24 43 



23 58 



23 17 





24 43 



24 43 



23 17 



13 45 



21 48 

 21 54 



21 481 thicker 

 / cloud. 



| 24 43 



13 52 



24 13 



24 13 ) thinner 



24 35 







24 13 \ cloud. 



24 13 



16 h Red of Halo from Sun 22° 49'. 



Oct. 21. — Summit clear at 4 and 5 hours, but sky 

 cloudy and fog all round. Clear again at midnight 

 and sky cloudless, but thin fog blowing over summit. 

 Slight N. breezes till 15 h (Force 1 to 3) after which 

 wind rose rapidly and blew a strong gale (Force 9) till 

 after 21 h , when it fell quite suddenly again. A consider- 

 able amount of drift blowing about during height of 

 gale, including blocks of snow crystals blown off the roof 

 and sides of tower. An arm of Robinson Anemometer 

 was broken and a rain-gauge blown away, but the latter 

 found again at midnight near "Wragge's Hut. 



Oct. 24. — Fog or overcast sky till 16 h . Sky cloud- 

 less after that, and air dry at times in the evening. 

 Thermometer box shifted at 16 h 20 m . Box was raised 

 one stage on stand. 



Oct. 25. — Sky cloudless all day except for some fog 

 passing over summit at 16 h and 17 h . Detached cumulus 

 at horizon all afternoon, and a little cirrus above horizon 

 to W. and N. at 15 h . Air very clear in forenoon, 

 Skye, Outer Hebrides, and Colonsay being distinctly 

 seen. 



Oct. 26. — Sky cloudless till 10 h , but cloudy or over- 

 cast with cirrus, and fog in valleys to N. and passing 

 over summit at times till 16 h ; continuous fog since. 

 Air was exceptionally clear in the early morning, seven 

 lighthouse lights being distinctly seen from N.N.W. 

 to S.S.W. Glories were seen during the forenoon. 



Oct. 28. — Thermometer box was lowered one step 

 after 14 h . 



Nov. 2. — S.E. winds all day. The fog crystals that 

 formed on all exposed objects were dark brown in colour. 



Nov. 4.— Fog till 10 h and after 20 h . Sky cloudy 

 between those hours and fog below and occasionally 

 passing over summit. At ll h the fog below to W. 

 was hard packed str.-fog, while to E. it was of the loose 

 cum. type. 



Nov. 6. — At 22 h a lunar corona and fog-bow were 

 seen. After 20 h observation, the thermometer box was 

 changed. Height above snow not altered. 



Nov. 7. — Cloudless till noon, but mist below, and at 

 times thin mist covered hill top for short intervals. 

 Lunar coronce were seen in early morning, and a solar 

 fog-bow at ll h . At 4 h a very faint aurora was seen. 

 Fog covered summit from 13 h till 18 h , when it cleared, 

 and sky was overcast till midnight when fog came on 

 again. 



