.901.] 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



365 



Fog since. Slight haze below all round in forenoon. 

 Earth shadow seen at 7 h . 



March 5. — Strong S. W. and N.W. winds in early 

 morning. Tower thermometer read at 2 h and 3 h . 



March 6. — Thermometer box changed at 7 h . 



March 14. — Summit clear all day. Thick cum.-fog 

 lying all round below. 



March 15. — Fine day, but thick haze all round. 



March 20. — Fog on summit till noon. Clear since, 

 with exception of slight passing fog. Glories seen at first 

 gorge. Earth shadow seen. Raven and hawk seen. 



March 21. — Air very clear and dry, humidity being as 

 low as 26. Earth and Ben shadows seen. 



March 23. — Somewhat hazy, but air dry ; lowest 

 humidity 17% at 19\ Glories seen at 8 h . 



March 25. — Lunar corona seen. Eagle seen flying 

 over summit during afternoon. 



March 27. — Stevenson Screen changed after 13 h . 



March 28. — Fog in the morning, which cleared off 

 during the day, leaving a cloudless sky towards midnight. 

 Thermometers changed at 15 h . 



March 29. — Strong S.E. wind after 21 ''. Summit clear, 

 with foggy intervals, till 17 h . Fog thereafter. Temper- 

 ature taken from tower thermometer at 21 h and 24 h . 



March 30. — The gale continued to blow, with a velocity 

 of about 100 miles an hour, till 6 b , but moderated 

 thereafter. Tower thermometer in use till 6 h . 



March 31. — Lunar corona at 21 h , but too faint to 

 measure. 



April 1. — Lunar corona at 22 h — radius of red = 5° 54' 

 30". Thermometer box changed after 16 h . 



April 2. — Lunar corona at l h and lunar halo at l b and 

 2 h . Tower thermometer used at 8 b , 9 h , 10 h , 13 h , and 14 h . 



April 3. — Thermometer screen changed after 19 h . 



April 5. — Fog, with sunny intervals. Faint lunar 

 corona at 4 h . Thermometer screen changed after 8 h . 

 Height of bulbs above snow 43 inches. 



April 7. — Thermometer screen changed after 19 h . 



April 9. — Thermometer screen changed after ll h . 

 Height above snow 37 inches. Depth of snow to-day 

 69 inches. 



April 10. — Fog or mist most of the day, but the summit 

 was clear from 18 h to 21\ Earth shadow seen at 19 h 30 m . 

 Thermometer screen changed at 6 h 15 m . The screen is now 

 on the highest step of the tallest ladder. Height of bulbs 

 above snow 47 inches. 



April 12. — A snow-bunting was seen at the bucket 

 stage to-day. Thermometer screen changed after ll h . 

 Height above snow 45 inches. 



April 15. — Thermometer screen changed after 23 h . 



April 16. — Thermometers changed at 12 h . To-day a 

 joint was added to the ladder on which the screen is 

 placed, the height of bulbs above snow being 53 inches. 



April 17. — Summit clear for the greater part of the 

 day, and the air very dry at times, the lowest humidity 

 being 28%. The earth and Ben shadows were seen 

 to-day. 



April 19. — Thermometer screen changed after 6 1 '. A 

 raven was seen to-day, near the N.E. buttress. 



April 20. — Fine and sunny weather, although thick 

 haze has persisted all day. 



April 21. — A raven was observed near the Observatory 

 to-day. Thick haze all round. 



April 22. — Thermometer screen lowered one step on 

 the ladder after 6 h . Height of bulbs above snow 41 inches. 



April 23. — Mist or fog till 20 h , cir. and cir.-s. there- 

 after. Lunar halo at 22 h , 23 h , and 24 h , radius 20° 

 29' (approximate). Thermometer screen changed after 

 21 h . 



April 24. — Summit clear most of the day. Earth and 

 Ben shadows seen at 5 h . Raven seen on the summit in 

 the afternoon. 



April 25.— Summit clear all day, but sky mostly 

 cloudy. Hazy all day. 



April 26. — Sky cloudless, or almost so, during the 

 greater part of the day. To-day the cat caught a young 

 rat in the Observatory. 



April 27. — Clear all day, except at 15 h , when the 

 summit was covered with thin fog. Earth and Ben 

 shadows seen in morning, and a lunar halo observed at 

 22 h and 23 u , radius 21° 7'. Thermometers changed after 

 l h . Today a number of snow-buntings were seen near 

 the Observatory. 



April 28. — A raven was observed at ll h . Thermo- 

 meters changed after 12 h . Height above snow 53 inches. 



April 29. — Thermometers changed at 10 h 15 m . 

 Height above snow 53 inches. A raven and a number 

 of snow-buntings were seen flying past the Observatory 

 this afternoon. 



April 30. — Summit clear at l h , 2 h , and 3 h , fog or mist 

 thereafter, till midnight, when the fog sank below the 

 level of the hill. To-day the Stevenson Screen was shifted 

 to the highest step of the shortest ladder. Height of bulbs 

 above snow 45 inches. 



May 1. — Summit clear, but very thick haze around till 

 22 h , when it cleared somewhat. 



May 2. — In the morning the sky was cloudless, while 

 low fog covered Glen More and Rannoch Moor. At 10 h 

 cumulus clouds appeared in the sky and remained during 

 the rest of the day. A raven and a number of snow- 

 buntings seen to-day. 



May 3. — A slight fall of hail and rain occurred in the 

 afternoon. Thunder heard at 15 h . 



May 8. — A number of snow-buntings were seen near 

 the Observatory. The cat caught a mouse to-day. 



May 13. — Fine sunny weather, but very hazy. Sky 

 almost cloudless, there being no lower clouds whatever. 



May 17. — The wet bulb of the thermometers, when 

 read at 9 h to 13 h inclusive, and at 15 h , 18 h , and 19 h , was 

 much lower than the dry bulb. In the daily sheet these 

 readings have been taken as saturated, the clouds at the 

 time being mist or fog. At 18 h the thermometers were 

 changed. A snow-bunting was seen close to the Obser- 

 vatory during the afternoon. 



May 18. — At 16 h the thermometers were tested together. 

 It was found that both sets were reading correctly. 



May 19. — At ll h 15 m the dry and wet bulbs were 

 changed. 



May 20. — After 15 h the Stevenson Screen was shifted 

 on to the shorter ladder. Height of bulbs 46 inches 

 above snow. 



May 21. — Extremely hazy all day. At 20' 1 the sky 

 became cloudy and continued so till midnight. 



May 22. — Sky cloudless, but extremely hazy. 



May 24. — Very hazy at times. A considerable amount 

 of cirrus cloud in the sky to-day. At 22 h and 23 h lunar 



TRANS. ROY. SOC. EDIN. — VOL. XLIV. 



3 A 



