1893.] 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



91 



April 30. — Thermometer box raised one step on ladder 

 at h 15 m . 



May 1. — Fog clearing off summit at times in the fore- 

 noon, and after 20 h top quite clear of fog. Sky about half- 

 covered with cirro-stratus, and fog over bills all round. 

 Air dry at 23 h and midnight. Humidity about 80 per 

 cent. 



May 4. — Top clear after 17 h , but sky overcast with 

 cir. and cir.-str., and heavy strata-cum. above horizon all 

 round, and detached cum. fog on lower hills, and tbin haze 

 in valleys ; after 21 h no fog was seen below. At midnight 

 fog was on summit again. A solar halo was seen at 1 8 h 

 and 19 h , with mock suns. Thermometer box was lowered 

 one step on ladder at h 15 m . 



May 5. — Air dry after 4 h . Sky overcast during day, 

 but clearing somewhat in the evening. Patches of fog lay 

 in valleys most of the day, at times rising and passing 

 over Ben Nevis. A strong south and south-east breeze 

 blowing all day. Haze all round. A solar corona seen at 

 ll h and 12 h , and solar halos were observed at 10 h , 13 h , 

 1&\ and 19 h . 



May 6. — Sky overcast, except at 5 h and 6 h , when fog 

 was on summit, till 20 h , when sky began to clear, and it 

 was almost cloudless at midnight. In the early morning 

 fog gathered in valleys to S.E. and S. ; but during the 

 forenoon this all disappeared, and no fog was seen in 

 valleys after 6 h . Thick haze around all day. Solar 

 halos were seen at 8 h and 17 h . 



May 7. — Strong S.E. winds all day, increasing in force 

 to a moderate gale in the evening. Temperature falling 

 unsteadily all day. Fog lay in valleys to S. and E. in the 

 early morning, and blowing over summit till 9 h . Sky 

 was almost cloudless till 21 h ; but fog off and on summit 

 thereafter. Cir.-str. above horizon to W. and N.W. 

 almost all day, and haze all around. 



May 8. — The strong S.E. winds of yesterday continued 

 to blow till 2 h . Fog and overcast sky, or nearly so, all day, 

 with occasional sunny intervals in the forenoon ; after 22 h 

 fog cleared off Ben Nevis, leaving sky cloudless. Solar 

 halos were seen from 9 h to 12 h . 



May 9. — Thin cirro-stratus covered the sky till 20 h . 

 Solar halos were seen on it from 6 h to 16 h . . Aurora 

 seen at 23 h and midnight. No streamers. 



May 10. — To-day the large screen (summer pattern) 

 began to be used at l h . Aurora seen at l h ; there was no 

 arch, and streamers were just visible. Solar halos 

 formed on cir.-str. were observed from 6 h to 12 h . Haze 

 all round. After 18 h mist came on with slight drizzling 

 rain the rest of the evening. 



May 13. — Mist cleared off and sunk below summit 

 after 8 h , leaving cloudless sky till 13 h , but rose again to 

 level of Ben Nevis, and blowing over the summit all after- 

 noon till 20 h ; continuous fog thereafter. 



May 14 — Summit clear after 3 h , but sky very cloudy 

 till night, with cirrus and cirro-str., on which solar 

 halos were seen from 8 h till 13 h . After 22 h sky was 

 cloudless ; but at midnight there was fog in valleys to 

 S.E., and a little blowing over summit at times. Variable 

 W. aud S.W. breezes till 14 h , and calm till 18 h ; light 

 S.E. winds thereafter. 



May 15. — Temperature high, and air dry all day. Sky 

 very cloudy or almost overcast with cir. aud cir.-str., on 

 which solar halos formed almost all day. Detached fog 



in valleys to N. and E. in the forenoon, but after 13 h no 

 fog was seen below. A little fog was seen on hills to 

 N.E. and S. at and after 19 h . Thick haze around all day. 

 Solar corona? seen at ll h and 12 h . 



May 16. — Sky overcast all day, except at 19 h and 20 h , 

 when fog enveloped summit, and air saturated at those 

 hours. Detached fog in valleys all day, and thick haze all 

 round. Slight showers of rain fell in the afternoon. 

 Solar halos seen at ll h and 13 h . 



May 17. — Sky cloudy or overcast with cir.-s. till 6 h , fog 

 and mist thereafter, but summit clear at times in the 

 afternoon, and thick strato-cum. fogs on hills to E. aud 

 S. Solar coronse seen at 7 h and 12 h . 



May 19. — Mist or fog all day, except at 14 h and 15 b , 

 when summit was clear and sky half-covered with cum., 

 and cum. all round above horizon. Showers of rain all day. 

 At 15 h 30™ a peal of thunder was heard down to S.E. 

 At this time summit was clear, but the appearance to the 

 S.E. was very ugly, thick banks of cum.-str., and below 

 this nimbus just tipping hill tops came rolling up, and at 

 15 h 45 m enveloped summit, accompanied with a heavy 

 shower of hail and rain. The mist on the summit at this 

 time was very thick, and inside the Observatory it was 

 very dark. This continued till 16 h 10 m . 



May 20.— Mist, till 16 h ; summit clear at times there- 

 after, but sky cloudy or overcast with cum.-s. and nimbus, 

 with heavy showers of rain. The general appearance of 

 the sky to the S.E. and W. was very thundery. Earth 

 currents in telegraph cable in the afternoon • a click of 

 the needle of telegraph instrument was heard at 16 h 30 m ; 

 but no lightning was seen and no thunder heard. 



May 21. — Mist or overcast sky all day, with light 

 showers of rain and hail. Temperature pretty low all day, 

 and much colder than has been experienced during the 

 past fortnight, the temperature at midnight being 32°. 

 Thunder was heard frequently from ll h 50 m till 15 h 40 m , 

 but no lightning was seen. During the above time strong 

 earth currents were observed in telegraph cable. 



May 23. — Strong earth currents in telegraph cable all 

 afternoon. 



May 30. —Summit clear and air dry almost all day, 

 but temperature low throughout, and falling decidedly at 

 night. Fog below level of summit to N. and E. in early 

 morning, which by midday all disappeared, leaving the 

 air very clear in every direction. 



June 1. — Summit clear most of the day, but sky 

 cloudy. Solar halos seen at 5 h and 15 h 45 m . 



June, 2. — Air was not saturated — humidity 92 to 99 

 per cent. — to-day till noon, although a thin fog covered 

 the summit all the time. This fog cleared off in afternoon, 

 but came on again at night. Thick haze all round in 

 evening. A solar halo was seen on very thin filmy cirrus 

 at 15 h and 19 h . 



June 6. — Summit clear till 3 lj , and no fog below, but 

 sky overcast, except for a clear strip at N.E. horizon, 

 which at 3 h was gorgeously coloured, as was also the 

 lower surface of cloud. The clouds fell to level of 

 summit by 4 h , and enveloped it as a wet mist, with 

 drizzling rain till 19 h . After this the top was clear at 

 times, but air not dry, while the sky was overcast, and all 

 the hills below were covered in mist, which occasionally 

 rose and covered summit also. The wind veered from 

 S.S.E. in early morning to S.W. by noon and W.S.W. 



