94 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



[1893. 



into mist, accompanied by drizzling rain at noon, and i 

 lasted till 17 h . At 19 h the fog fell just below our level, 

 and almost all the surrounding country was hidden from 

 view by it, the greater part of the sky being covered with 

 cirrus and cirro-cumulus, which gradually sank and 

 completely covered the sky all the rest of the night. 



July 13. — Summit continued clear till 3 U , after which 

 fog came on and continued the rest of the day, but lift- 

 ing a little between 15 h and 19 h . 



July 14. — Mist or fog till 22 h , but summit clear at 

 times between 13 h and 17 h . At 23 h the top was clear, but 

 the sky was overcast by a thin layer of stratus, which 

 gradually disappeared, leaving the sky cloudless at mid- 

 night. At this time (23 h ) a layer of stratus fog was seen to 

 N. and E., with detached patches elsewhere ; these 

 gradually increased in extent, until, at midnight, the Ben 

 was completely surrounded by fog, reaching to about 4000 

 feet. 



July 15. — The sky became cloudy again at l h , whilst 

 fog began to pass, and continued to envelop the summit 

 till 9 h . Although the sky continued overcast or nearly so 

 the rest of the day, the atmosphere was remarkably clear, 

 Barra Head, coast of Ireland, etc., being seen. A thin 

 blue haze, in which patches of fog kept forming and 

 disappearing till 20 h , was observed in valleys all round, 

 and the clouds kept rising and falling, at times tipping 

 hills all round. 



- July 16. — Top clear and sky overcast till 10 h ; patches 

 of fog were observed in the haze, in valleys, in the early 

 morning, and these increased in extent until, at 10 h , the 

 summit was completely surrounded by fog. The Ben was 

 after this enveloped in fog, which changed to a wet mist, 

 accompanied by heavy showers of rain at and after 19 h . 



July 17. — Pretty strong earth currents were observed 

 on the telegraph instrument, causing the needle to click 

 frequently between 18 h and 20 h . 



July 18. — Summit clear shortly after 3 h till after the 

 5 h observation, with cumulus fog on hills all round 

 and haze to northward. The band of cirrus observed at 

 4 h had its radiating points, lying N.W. and S.E., very 

 well marked. Fine sunrise to-day, the clouds on horizon 

 being tinged a brilliant crimson. At 6 h mist was again 

 on summit, and continued all day, but breaking 

 occasionally between 16 h and 17 h . 



July 20. — The door of the Stevenson screen was found 

 partly open at the 13 U observation, having been tampered 

 with by tourists. 



July 23.— Summit clear from 3 h to 18 h , and at 20 h . 

 A band of cirrus was seen at 3 h lying N.W. and S.E., 

 and having a pretty quick motion from N.W. ; this 

 gradually assumed the form of cirro-cumulus, and loose 

 cumulus-scud began to drift over the sky at noon, and at 

 17 h the sky was overcast with cumulo-stratus. Mist on or 

 passing over summit after 18 h , no fog below, but haze in 

 valleys between noon and 17 h , visibility being 3 at this 

 time. 



July 26.— Mist till 16\ after which it gradually 

 cleared, the fog lifting at times, and at 22 h and midnight 

 th- sky was almost cloudless. A lunar corona was seen at 

 22 h . A Ptarmigan was seen on summit this morning. 



July 27. — Summit clear, but sky cloudy all day. 

 Detached fog continued in valleys till noon, after which it 

 disappeared, leaving a slight haze. The roof was covered 



with hoar frost from 3 h to 5 h , and ice was observed on 

 any small pools in the hollows of the rocks. A partial 

 solar halo was seen at 20 h , a lunar halo at 23 h , and a lunar 

 corona at l h and midnight. 



Aug. 5.— Mist till 13 h , after which the summit cleared 

 till 17 h , when fog again came on, but cleared again at 21 h . 

 At this time the sky was overcast by a layer of stratus, 

 which disappeared, leaving sky cloudless after 22 h . Hoar 

 frost was observed on the roof at 23 h and midnight. A 

 beautiful lunar corona was seen through a thin haze at 

 midnight. 



Aug. 6. — Sky cloudless till 4 h (but fog on summit at 

 2 h ). Top clear again, but sky overcast and thick haze in 

 valleys, till 15 h , mist thereafter. Lunar coroua seen at l h . 

 The hoar frost continued on the roof, stones, etc., till after 

 sunrise, the summit being quite white at 4 h as. if with a 

 thin layer of snow. 



Aug. 7. — Mist till 4 h , after which it sank below our 

 level, leaving sky cloudy or overcast till ll h , and again 

 from 21 h till midnight, mist being on the summit during 

 the interval. Some fine glories were seen this morning. 



Aug. 9. — Summit clear (except at 20 h ), but sky very 

 cloudy all day. A thick haze continued in the valleys 

 below all day, reducing the visibility to (1-2) in the 

 afternoon. Temperature high all day ; the 15 h reading of 

 the dry-bulb (62 - 2) is the maximum for the month of 

 August since the opening of the Observatory. Frequent 

 flashes of sheet lightning were seen illuminating the 

 southern and western horizon at 23 h and midnight, the 

 flashes being almost continuous ; no thunder heard. 



Aug. 10. — Summit clear aud air dry till 3 h , mist on or 

 passing the rest of the day. Lightning continued to be 

 seen on horizon till 2 h . A flash of lightning was seen 

 about 18 h 10 m , and telegraph needle clicked from about 

 19 11 till after 21 h . 



Aug. 12. — Mist with drizzle till 15 h , summit clear and 

 sky cloudy witli cirrus and cirro-cumulus thereafter ; when 

 the top cleared, fog was seen covering the surrounding 

 country and reaching to 4000 feet; this gradually broke 

 up, and disappeared after 21 h , leaving haze in the valleys. 

 A solar halo was seen at 17 h , and an aurora at 23 h and 

 midnight ; it consisted of one arch with long streamers, 

 reaching beyond the pole star to A. Oepheus. The shadow 

 of Ben Nevis was seen at 19 h 30 m . 



Aug. 13. — Top clear and sky cloudy all day, except at 

 2 h and 17 h ; haze all day, and patches of fog forming and 

 disappearing during the greater part of the day, in valleys. 

 The aurora continued very bright till after the 2 h observa- 

 tion. A solar halo, exhibiting prismatic colours, was seen 

 at 19 h , and a quadruple glory round the shadow of the 

 tower at 5 h . 



Aug. 14. — Summit clear during the greater part of the 

 day, but mist after 22 h . Air dry all day, except at 23 h 

 and midnight. Sheet lightning was seen to W. and S.E. 

 at l h . 



Aug. 15. — Mist, fog, or overcast sky all day, with very 

 thick haze in the valleys in the afternoon ; air dry from 

 4 h to 21 h (except at 7 h and 8 h ), saturated the rest of the 

 day. A fragmentary rainbow or sun-dog was seen at 17 1 ' 

 and 18 h 30 m . At 20 h , peals of thunder were heard to 

 S.W., and at 20 h 20 m , vivid flashes of both sheet and 

 zigzag lightning were seen to the S. and S.W., some of 

 them only being followed by a peal of thunder. The 



