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BEN NEVIS OBSERVATORY.— LOG-BOOK. 



67 



covered the hill top before 2 h , and continued on the top 

 till 21 h , shortly after which it cleared off, leaving a cloud- 

 less sky. This fog lingered longest on the hills to E. and 

 S.E. Thermometer box shifted at 23 h 15™. 



March 1. — The fog that began to blow across the hill 

 top at 4 h seemed to be local, as none had been observed 

 before. After the top cleared at 8 h , however, fog still lay 

 to about 4000 feet all round. It broke up into detached 

 portions after noon. A glory was seen at 8 h . No unusual 

 colours near sun during the day. The earth shadow and 

 shadow of Ben Nevis seen after sunset. This afternoon 

 the snow at the first gorge was found to be overhanging 

 the edge for 140 inches. At 18 h the tracks of a hare were 

 seen near the thermometer box. 



March 2. — The wet bulb reading at 2 h is rather 

 doubtful as the bulb had got somewhat dry. After this 

 time the bulb was wet at the half-hour as long as the air 

 continued dry. A faint lunar halo was seen at 3 h and a 

 corona at 4 h . At 4 h detached fog was lying among the 

 hills to S. At 5 h it was over all the hills to 4000 feet, 

 except those to S.E., and at 6 h on the top. 



March 4. — Between 15 h and 16 h , snow crystals, with 

 six blunt-pointed rays, each ray feathered with smaller 

 crystals, observed to be falling. 



March 5.— Thermometer box shifted at 2 h 15 m . At 

 7 h the shadow of Ben Nevis was seen to W. Stratus fog 

 lay at about 2000 feet or less among the hills to S. and 

 W. At 8 h this fog was in detached portions, but was 

 blowing over the Cairn Dearg. 



March 6. — The snow which fell this afternoon was heavy 

 granulated stuff, which hardly drifted at all. Between 13 h 

 and 14 h the wind on Maclean's Steep and the Plateau was 

 W.N.W., though on the top it was between N. and N.E. 



March 12. — Star-shaped flakes of snow falling in 

 afternoon — too little to show in gauge. 



March 14. — At 4 h the lamp was blown out just after 

 reading dry bulb ; the wet bulb was assumed to be the 

 same. At 23 h all the outside observations were 4 m 

 late, owing to lantern being blown out. The jacketed 

 lantern was used all night. It was impossible to stand 

 on the roof during the strongest wind at night. At 15 h 

 the pressure of the wind was tested by holding the blade 

 of a shovel, measuring 16 inches by 12 vertically, and 

 measuring the pressure by a spring balance. The max. 

 observed was 26 lbs. on the square foot (35 lbs. on shovel), 

 the estimated force at the time being 10. 



March 15. — The vane of direction anemometer was 

 heavily coated with fog crystals till after 15 h , and did not 

 point truly to windward. At midnight the dry bulb was 

 below its scale, and its temperature was assumed to be the 

 same as the wet bulb. 



March 16. — At l h the dry bulb was below its scale, and 

 its temperature was assumed to be the same as the wet 

 bulb. At l h 10 m dry and wet shifted. At 2 h the fog 

 broke to N., and an aurora was seen. At 10 h 10 m 

 thermometer box shifted. No fog in valleys all afternoon, 

 but horizon very hazy — this was partly due to the heather 

 burning that was going on all round. At 16 h some cumulus 

 clouds under sun, with very ragged edges, were coloured 

 red and green on their upper edges, the red being next 

 sun. Distance of red from sun about 7°. Aurora was 

 seen at night. At 20 h and 21 h it consisted of a single 

 arch without streamers, but at 22 h the arch was broken 



up, and there were long narrow streamers rising from all 

 parts of it and reaching to about 45° altitude. At 23 h 

 and midnight it was again a single arch without streamers. 

 All evening an earth current in telegraph cable kept the 

 needle over to clash side. During this afternoon and 

 evening the dry read frequently below the wet bulb. It 

 was observed to be covered with fine spicules of ice, 

 which although wiped off continually gathered on it again. 



March 17. — At l h double arch aurora seen, and at 2 h 

 faint aurora still visible. Loose, dry, white fog crystals 

 forming in afternoon. At 7 h star-shaped crystals falling. 

 They were roughly about T ^ inch diameter. 



March 18. — Aurora seen faintly at l h and 2 h . At 6 h the 

 upper glow was seen. Detached cumulus over hills in 

 forenoon, but no fog in valleys all day. Horizon rather 

 hazy, due partly to heather burning. The sun set at 

 18 h 40 m . After glow and earth shadow seen. At 23 h 

 faint auroral light seen to N. 



March 19. — The earth shadow and shadow of Ben Nevis 

 were seen before sunrise at 6 h 30 m . Some detached 

 cumulus over hills again to-day, but no fog in valleys. 

 Horizon again hazy ; large tracts of heather burning. 

 No unusual colours were observed in the sky either 

 yesterday or to-day. At sunset the after glow and earth 

 shadow were seen. 



March 20. — A faint aurora, consisting of a siogle arch 

 low down and without streamers, was seen at 2 h , 3 h and 

 4 h . The earth shadow was seen before sunrise. A snow- 

 bunting was seen flying about on the hill top at ll h . 

 The earth shadow and the after glow were seen after 

 sunset at 19 h . At 20 h the W. horizon still showed faint 

 sunset colours. There was no fog in the valleys or on 

 the hills to-day, but thick haze, mixed with smoke from 

 burning heather, covered everything to about 4000 feet. 

 Above this were a few patches of cumulus. Air intensely 

 dry all night. 



March 21. — At 6 h roll-cum. was seen low down to 

 W. and N.W. ; at 7 h it had come nearer, and at 8 h had 

 covered the sky overhead. The upper glow and earth 

 shadow were seen before sunrise. 



March 22. — At 9 h the mist that had covered the top 

 all morning sank down to about 4000 feet, but the sky 

 overhead was covered with stratus which seemed to join 

 the mist all round. At ll h fog-bow seen, white with 

 faint red outside. Also at ll h 10 m glory with one band 

 of colour — too faint to measure. 



March 23. — At 14 h the top was clear though sky 

 overcast with low stratus. No fog in valleys. At 15 h 

 crystals of snow falling, mixed with small, hard, shapeless 

 snow. 



March 24. — No raingauge was out from 6 h to 9 h , but 

 apparently no snow fell. All measurements of amount of 

 snow doubtful, owing to drift. Louvres of thermometer 

 box badly choked with fine drift and fog crystals most of 

 the day. 



March 25. — At 8 h a layer of cloud of fog about the 

 level of the hill top extended in all directions. Ther- 

 mometer box shifted at ll h 30 m . For several hours after 

 this the readings of the dry and wet were very mild, but 

 the air was apparently saturated. At 14 h snow crystals 

 falling, as varying from —^ to ^ inch diameter. A few of 

 them had points projecting in different planes in addition 

 to the usual six. Similar crystals falling at 15 h , but, on 



