1893.] 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



93 



was somewhat cloudy. After 22 h a dark cloud came up 

 from S., with haze below, and fog was passing summit at 

 23 h and midnight. The radiating points of cirrus bands 

 on sky at 19 h were W. and E., well marked. 



June 29. — Mist till 23 h , when summit cleared, the 

 mist falling below level of top, and sky cloudless overhead. 

 Heavy showers of rain in morning, and slight drizzle most 

 of the day. 



June 30. — Sky cloudless, except for a little cirrus at 5 h 

 and 6 h , and again after 2 l h . Fog lay all round below in 

 early morning, but gradually vanished in the course of fore- 

 noon, leaving tbin haze in valleys till 19 h , when a thick haze 

 bank was seen approaching from S.E. and S. This haze 

 was all around by 22 h , and reduced " V " from 3 previously 

 to 1 at and after 22 h . 



Jul]) 1. — Summit clear and air dry all day, but thick 

 haze all round, with some broken cum. fog among it to E. 

 and S. A solar halo was seen at 5 h . 



July 2. — Fog or mist on summit from 4 U till ll h , and 

 fog hanging about hill top and passing at times till 20 h ; sky 

 nearly cloudless thereafter. Thick haze below in early 

 morning. 



July 3. — Top clear, but sky cloudy, and fog and haze 

 all round below all forenoon. Overcast, and mist on 

 summit, with heavy showers of rain in afternoon. Dew on 

 roof in early morning. 



July 4. — Fog and mist on or passing over the summit 

 till 20 h , but clearing a little at times in the afternoon. 

 At 21 h the fog sank below level of Ben, leaving sky 

 almost overcast with cir.-str. Air slightly dry since noon. 

 A fog-bow and glory were seen at 12 h 30 m . 



July 5. — Top clear all day, but sky overcast till 9 h . It 

 then gradually cleared, and after 14 h the sky was cloudless, 

 except for a very little cum. forming and reforming in it. 

 Fog all round in morning to about 4000 feet ; this 

 gradually sank, and finally disappeared at 14 h , leaving a 

 thick haze in valleys, which diminished somewhat later in 

 the day. At 21 h str. fog began to form in valleys to N. 

 and E. among the haze. 



July 6. — Sky almost cloudless till 3 1 ', except for a little 

 cirrus which gradually overspread the sky, and in the 

 afternoon it was completely covered by dense, hard-packed 

 cir. -stratus, and continued so the rest of the day. Haze 

 and a little stratus fog in valleys in morning, which cleared 

 somewhat in the afternoon, when the visibdity was birely 

 3. After 15 h the haze increased very much, and at 21 h 

 fog began to form on it to the E. and S. 



July 7. — Cloudy or overcast sky all day, with fog 

 passing at times till ll h . Yesterday's very thick haze 

 continued all day, reducing the visibility to 1. At 19 h 

 there was observed to the S. a layer of lumpy, thundery- 

 looking cumulus, from which loose scud came drifting over 

 our sky, whilst the horizon was covered all round with 

 dense, hard-packed strato-cirrus. At 22 h 30 m lightning 

 was observed illuminating the whole of the southern 

 horizon, each flash being followed by a peal of thunder. 

 By 23 h the sky was overcast with cumulo-stratus, and 

 very heavy rain began to fall shortly afterwards, whilst St. 

 Elmo's Fire was seen and heard from the tops of every 

 post, ladder, anemometer, as well as Observer's pencil, cap, 

 etc. Between 23 h and midnight frequent flashes of 

 lightning were seen playing all round the Ben, each 

 followed by a peal of thunder. The storm by this time 



appeared to have passed over us awa}r to the N., and 

 nothing was seen or heard till 0' 1 45 m , when very vivid 

 flashes, followed by thunder, began to play in the 

 neighbourhood of the North Cliff, and continued to be seen 

 till 2 h 35 m on the 8th. All through the storm the tele- 

 graph instrument was clicking loudly, as many as eight 

 and nine clicks being heard at one time, the last occurring 

 about 2 h 45 m on the 8th. By midnight the wind, which 

 had been S. and of a slightly squally nature all clay, 

 increased somewhat in force, and began to blow in fitful 

 gusts from the S.E. Air slightly dry ail day, lowest 

 humidity 81 per cent, at 15 h , 19 h , and 20 h . St. Elmo's 

 Fire was observed at each hourly observation from 23 h on 

 7th to 2 h on 8th inclusive. 



July 8. — Sky cloudy or overcast, with mist on or pass- 

 ing over the summit all day, and thick haze all round. 

 Temperature falling slightly 51° to 49° till 6 h , after which 

 it rose to 57°'l at ll h , and fell slowly the rest of the day 

 to 47° - 9 at midnight ; air slightly dry from 6 h to 14 h , but 

 saturated the rest of the day, except at 18 h , when the 

 humidity was 99 per cent. After 10 h strong earth currents 

 were observed in the telegraph cable, causing the needle to 

 click repeatedly. At noon and 13 h very heavy cumulus 

 clouds and thick haze were observed to E. At 14 h thirty 

 brilliant flashes of lightning followed by thunder were 

 seen, the hill being then enveloped in mist. A slight 

 crackling sound was heard inside the office at 14 h 50 m , 

 and eight minutes afterwards a brilliant flash of light- 

 ning was seen which eutered the Observatory, producing a 

 bright flash and smart crack at the telegraph connections 

 in the office; no damage done, the line-wire being dis- 

 connected at the time. Mr. Craig saw simultaneously a 

 flash, followed by a crack, in the dust-room of the tower, 

 the lightning having apparently entered from the outside 

 by the south brass tube, connected with the aspirator, 

 which was being used at the time. Nothing further was 

 seen or heard, but the telegraph instrument was kept dis- 

 connected for several hours afterwards. Very heavy 

 showers of rain were experienced during the storm. 

 Strong squally S.E. winds till 19 h , when it backed to the 

 E.S.E., becoming more steady, and increasing to a 

 moderate gale (force 7-8) at midnight. 



July 10. — Mist all day, except at 18 h , wheu the 

 summit cleared — -after a heavy shower of rain — for a short 

 time. Thunder was heard to N. from 16 h 40 m to 17 h 10 m , 

 whilst the telegraph needle was clicking for some time 

 before and after this. When the summit cleared at 18 h a 

 very thick haze and gloomy appearance was observed 

 to the N.E., and detached fog and thinner haze all round 

 in valleys. 



July 11. — Summit clear from 2 h to 4 h , but sky cloudy 

 and fog all round and passing at times. At 5 h mist came 

 on, and continued till ll h , when the top cleared again, 

 but sky was overcast or nearly so, and heavy showers 

 of rain fell at times all afternoon. Frequent peals of 

 thunder were heard to the S.E. and S. from 12 h 35 m till 

 17 h , and a flash of lightning was seen to S.E. at 13 h 20 m , 

 apparently about four miles off. St. Elmo's Fire was 

 heard hissing from 15 h 30 m till 15 h 50 m , and the telegraph 

 needle was clicking all afternoon. Very light E. winds 

 all day, and temperature ranging from 42° to 47°. 



July 12. — Sky cloudy and fog all round below till 4 h , 

 when the summit became enveloped in fog, which changed 



