1891.] 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



321 



also. Aurora seen at 3 1 ', and at 19 h to midnight — mostly 

 very faint and low near horizon. 



Oct. 29. — Summit clear except at 20 h and 21 h . Some 

 cirrus on sky, and in forenoon some fog in the valleys, 

 which dispersed by mid-day, giving place to thick haze. 

 Air very dry till noon, getting damper in afternoon and 

 saturated or nearly so at and after 20 h . Faint aurora 

 seen at l h , 2 h , and 3 h . 



Oct. 30. — Summit clear almost all day. Thick haze 

 and broken fog below most of the day. Glory seen at 

 7 h 40 m . 



Oct. 31. — Summit clear till 21 h , thin mist coming on 

 thereafter. Cirrus on sky from 10 h onwards — cloudless 

 previously. Thick haze below all day. Decided rise in 

 temperature when the mist came on. 



Nov. 1. — Thin mist or overcast till noon. Cloudless 

 and air dry thereafter. Broken fog below all day, but 

 the haze observed yesterday below was all gone to-day. 

 Bright glory and fog-bow seen at ll h 15 m . 



Nov. 2. — Cloudless all day and fog below — upper 

 surface ranging from 3000 to 4000 feet above sea level. 

 Air very dry all afternoon. The zodiacal light was seen 

 at 5 h and an aurora faintly at 21 h . 



Nov. 3. — Cloudless and very fine and warm all day. 

 The aurora was seen at l h and 2 h very faintly, and 

 at 22 h , 23 h and midnight faintly also, but showing- 

 short streamers at 21 h . Continuous fog over all 

 the country all day, only the tops of the higher 

 hills showing through. Glories were seen on this 

 fog in the forenoon. The zodiacal light was seen at 

 3 h . 



Nov. 4. — The layer of fog below gradually rose during 

 the early morning at 8 U , and during the rest of the day 

 the summit was enveloped in it, except at 21 h and 

 22 h when it cleared for a little. From 3 h till 7 h the 

 temperature was falling quickly and the humidity 

 rising. At l h , 3 h , 4 h , and 22^ a faint aurora was seen 

 low to N. The zodiacal light was seen at 5 h . 



Nov. 14.— Fog all day, except at 8 h , 9 h , and 20 h . At 

 20 h the sky was almost covered with cirro-stratus on 

 which a lunar halo was seen, and detached pieces of 

 hard cir.-s. were observed near the horizon all around, 

 also cum. -fog on the lower hills. 



Nov. 15. — Fog crystals forming in early morning. 

 The fog to-day was mostly thin, being the top of a fog- 

 layer, which could be seen at times all round the Ben. 

 Owing to the fog the beginning of the lunar eclipse 

 was not well observed. 



Nov. 16. — The summit cleared at 2 h , showing a 

 cloudless sky above. The lower hills were also clear 

 but there was some haze in the valleys. A little scud 

 passed the top occasionally. Fog came on again at 6 h 

 and enveloped the top for- the rest of the day. The 

 end of the lunar eclipse was well observed. The moon 

 was clear of the shadow at 2 h 33 m . The thermometer 

 box was shifted at 3 h 25 m . 



Nov. 17. — At midnight the summit cleared, except for 

 a little fog passing at times. Some detached fog lay 

 below to S.E., N. and E., and the sky was nearly 

 covered with cir.-s. stripes which radiated from E.S.E. 

 and W.N.W. 



Nov. 18. — Sky overcast with cir.-s. till 5 h on which 

 a lunar halo was seen at 2 h , 3 h , and 4 h , fog or mist 

 ROY. SOC. TRANS. EDIN. — VOL. XLII. 



during the rest of the day. This cir.-s. was becoming 

 denser each hour and gradually falling to a lower level. 

 The thermometer box was shifted at l h 20 m . A reading- 

 taken at l h 33 m gave Dry 28-7, Wet 25-8. 



Nov. 20. — St Elmo's Fire was seen at 8 h . Wind 

 very variable — N.E. till 6 h and chiefly N. thereafter. 



Nov. 21. — Top cleared at 5 h and continued clear till 

 9' 1 when fog came on again. When the top was clear 

 there was fog all round below. The thermometer box 

 was shifted at 5 h 10 m . Height above snow not altered. 

 Nov. 22.— Summit clear from 6 h till 21 h . A little 

 cirrus on sky in forenoon, and cum.-s. (8 to 10) in 

 afternoon. The atmosphere was exceedingly clear during 

 the time the summit was free of fog. A shower of 

 drizzling snow fell at 3 h . The snow consisted of tiny 

 ueedle-shaped crystals. Detached fog below in some of 

 the valleys most of the day. 



Nov. 24. — Summit clear and sky cloudless from 4 h 

 till 15 h , but fog lay in the valleys. 



Nov. 26.— Thermometer box shifted at 19 h 20 m . Put 

 one stage higher on stand. Aurora seen from 19 h to 

 midnight. Rather faint and low down. 



Nov. 27. — Sky clear all morning ; detached fog in 

 valleys, which after noon rose and covered Ben Nevis 

 also. 



Dec. 2.— Thermometer box shifted at 8 h 15" 1 . Height 

 above snow not altered. 



Dec. 3. — During the time the temperature was above 

 32° to-day the stormy wind drove the loose icy surface 

 in drift, rendering the raingauges useless. 



Dec. 4. — The temperature fell early this morning, but 

 it continued mist, not fog, and hard ice formed on every- 

 thing. Thermometer box shifted at 10 h 10 m , the hinges 

 being damaged. 



Dec. 7. — Thermometer box shifted at 3 h 25 m . Height 

 not altered. Thin fog till 6 h . Sky overcast with cir.-s. 

 and cir.-c. but air very clear till 17 h ; cloudless after 

 that. Patches of cum.-fog above hill tops round in 

 afternoon, and fog on hills to N. and E. after sunset. 

 Solar halo seen at 13 h and double lunar corona at 18 h . 

 Aurora all night after 18 h , brightest at 21 h , when there 

 were streamers reaching to 60" altitude. Sky very green 

 to N.W. at 14 h and 15 h . Sunset colours bright. 



Dec. 8. — At 1 l h 30 m a solar halo and two mock suns 

 were seen. No measurements taken. 



Dec. 9.— Rain and hail were falling at 20 h and 21 h , 

 but no gauge was out owing to the heavy drift. At 

 midnight St Elmo's Fire seen, most distinctly marked 

 on beard and hat of observer. 



Dec. 10.— Thermometer box shifted at 13 u 20'". 

 Height above snow not altered. Very heavy squalls 

 just before the rapid rise of the barometer at night. 

 Dec. 12— Solar halo seen at 10 h 20 m and at ll h . 

 Dec. 14. — After 16 h top clear except for passing thin 

 fog, but fog lying on hills round, and sky partly clouded. 

 Lunar corona seen at 20 h and 21 h . Thermometer box 

 shifted at I7 h 15 m . Height above snow not altered. 



Dec. 15. — Sky clear, but fog and scud blowing over 

 till 8 h . Lunar corona on this scud. Heavy rain, sleet, 

 and hail after 20 h . 



Dec. 16.— Snow and hail fell heavily till 4 h . Top 

 cleared after 9 h . Very fine all afternoon, and air very- 

 dry. Patches of fog among hills in afternoon, and 



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