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BEN NEVIS OBSERVATORY-LOG-BOOK, 1900. 



Jan. 1. — Summit clear for a few hours before sunrise. 

 E.S.E. winds after 6 h , increasing to gale force at night. 

 Tower Thermometer used at 23 h as observer's lamp was 

 blown out. 



Jan. 2. — E.S.E. gale blowing most of the day, with 

 showers of snow after 14 1 '. Tower Thermometer used at 

 l h , 2 h , and 4' 1 . Throughout the day the measurements of 

 precipitation are doubtful owing to drift. 



Jan. 4. — Observer's lamp blown out at thermometer 

 box at l h and Tower Thermometer used then and at 3 h . 

 Thermometer box changed at 23 b 15 m 



Jan. 5. — Summit clear till 17 h , but sky overcast, or 

 nearly so, with cirro-cumulus and no sunshine recorded. 



Jan. 6. — Strong S.E. breezes, with showers of snow till 

 17 h . Air almost calm thereafter. Summit clear at times 

 though sky overcast, with a strip of green sky on the 

 horizon to N.N.W. at 15\ 



Jan. 9. — Summit clear after 21A Two sharp clicks 

 on the telephone instrument at 16 h 43 m . 



Jan. 10. — Summit clear after 16 h , but air saturated till 

 21 b when a slightly dry reading was obtained. At 22 h 

 the sky was overcast by cir.-stratus, with lunar halo and 

 air was saturated. At 23 h the cloud had thickened and 

 sunk somewhat, the moon gleaming without a halo or 

 corona and the humidity was 29 per cent. At midnight 

 it was snowing and air almost saturated again. Ther- 

 mometer box changed at 17 h 30 ra . 



Jan. 11. — Temperature rose above freezing-point at 

 17 h . This is the first hourly reading above 32° since 

 noon on December 7th 1899. The thaw continued for 

 exactly 24 hours, reducing the depth of snow 5 inches. 

 Icy fog crystals were forming in the early morning and 

 there were some slight showers of drizzling rain at night. 

 The thermometer box was changed at 10 h 15 m . 



Jan. 18. — Summit clear at 16 h . Sky cloudy, with 

 cirrus moving from N.W., and the horizon to S.S.W. was 

 a vivid green. Snow lying to about 600 feet above sea 

 level. Thermometer box changed at 16 h 15 m . Fog was 

 on again at 17 h . Two ravens seen at bucket stage at 16 k . 

 Drift very bad at midnight. 



Jan. 19. — Squally south westerly winds, with heavy 

 snowfall and very bad drift in forenoon. The measure- 

 ments up to 13 h amounted to just over 4 inches, though 

 they are somewhat doubtful owing to drift. The centre 

 of the storm passed about ll 1 ' 20 m . The wind then 

 shifted to W. or N.W. and the temperature fell consider- 

 ably. There was a distinct thaw in the forenoon, though 

 there was no hourly reading above 32°. There were 

 frequent showers of snow and snow-hail after noon, ami 

 St Elmo's Fire — not very strong — was observed at 22 1 ' 

 and miduight — snow-hail falling on both occasions. At 

 midnight the observer in holding a pick, point upward, 



felt a distinct shock up the arm. At l b the rain guage 

 was found lying on its side full of drift and the amount 

 at l h is therefore interpolated. At 3 h , 4 h , and 5' 1 , the 

 Dry and Wet bulbs — stems, bulbs and casings — were 

 found completely buried in snow. Clicks on the tele- 

 phone instrument due to earth-currents were heard 

 frequently throughout the day — strong at 8 h 30 m , 

 12 h 25 m , 16' 1 30 m , 18 h 55 m , and 22 h 31 m , and moderate 

 at 10 h 40 m , 10 h 45 ,n , 19 h 40 m , and 21 h 45 m . 



Jan. 20. — Heavy showers of snow and snow-hail most 

 of the day. St Elmo's Fire pretty strong at 2 h . Dry 

 and Wet thermometers in box changed at 10 h 10 m . 



Jan. 21. — Temperature rising to 29°"8 at 16 h , when 

 drizzling rain was falling and ice forming on exposed 

 surfaces. Temperature fell thereafter with a shift of 

 wind from S.W. to N.N.W. and there were heavy showers 

 of snow during the rest of the day. A slight click was 

 heard on the telephone instrument at 23 h 51 m . 



Jan. 22. — Exceptional amount of precipitation all day; 

 snow and snow-hail till S h , rain thereafter, an inch and a 

 half fell in two hours ending 10 h , and over 4 inches in 

 the eight hours ending 14 h . Total rainfall for the day 

 6812 inches. This is, with the exception of October 3rd 

 1890, the wettest day on record here. 



Jan. 23. — Glazed frost from 8 h to 18 h . Thaw before 

 and after. Showers of rain and drizzle throughout the 

 day. Depth of snow down 3 inches. Rainfall for 24 

 hours ending 2 h to-day, 7T38 inches. 



Jan. 24. — Summit clear at 5 h , but sky cloudy with 

 cirro-stratus and cirro-cumulus. Thick fog-heaps, with 

 irregular contours on hills below. Clear again at 17 1 ' and 

 18 h , sky overcast with pall of cumulo-stratus which over- 

 hung the hills all round. 



Jan. 25. — In early morning, squally north easterly 

 winds, with showers of snow and bad drifting. Tempera- 

 ture rose to 30° at noon and remained pretty steady 

 thereafter. Glazed frost with showers of rain and drizzle 

 till midnight — when the temperature was 32°. 



Jan. 26. — Showers of rain and sleet all morning, with 

 strong squally S. to S.W. winds, blowing with gale force 

 at 9 h , 10 h and 11\ The centre of the storm passed 

 about ll h 30 m , the usual indications of the passage being 

 very clearly marked ; the rise in pressure was exceptionally 

 abrupt. Ice forming at times before noon, the tempera- 

 ture up to ll h ranging between 3T2 and 32*1, it fell 

 thereafter to 19° -3 at 19 h , and then remained almost 

 steady. Earth currents at 14 h 15 m , \i h 43 m and 20 1 ' 29 m . 

 27. — Thermometer box changed after 13 h . 

 above snow not altered. 



29. — Thermometer box changed after 5 h and 

 raised one step on ladder. Height above snow altered 

 from 20 inches to 41 inches. 



Jan. 

 Height 

 Jan. 



