1889.] 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



137 



clogged with ice, and refused to work. The measure- 

 ments of chief bow were : — 





Outside. 

 42° 57' 



Inside. 

 37° 3' 





42° 0' 



37° 46' 











42° 28' 



37° 24' 



At the time the fog-bow was measured, the mist was thin 

 and very wet, and formed a coat of ice on all exposed 

 surfaces. Air temperature at time, 28° - 4, the minimum 

 for the day ; the maximum being 31°"9. 



March 18. — At 18 h 20 m the thermometer box was 

 shifted. 



March 19. — Brown fog crystals forming all forenoon. 

 At 19 h there was about half an inch of white fog crystals 

 over the brown ones of the morning. 



March 21. — Air moderately clear to-day. Barra and 

 Western Isles to N. and S. of Eig visible. Heather 

 burning to S.W. in distance to-day. Thermometer box 

 shifted after 10 h . Rather squally in early morning. 



March 23. — Thermometer box shifted after 12 h . 



March 26.— The sky was cloudless at 21 h , 22 h , and 

 midnight, but thin fog kept passing at intervals till 23 h . 

 At midnight a faint aurora was observed near the horizon. 



March 27. — The thermometer box was shifted at 

 Qii 25 m . The summit was clear all day. No lower 

 clouds all day, but various amounts of cir. types on sky 

 from 5 h onwards. These radiated at 6 h from N.N.W. 

 and S.S.E., at 13 h from N. and S., and at 17 h from 

 N.N.W. and S.S.E. again, and were moving at 8 h and 

 10 h from N.N.W. The air was saturated at l h , and 

 midnight, but very dry during the rest of day — mean 

 humidity for day 27, maximum for time air was dry 31, 

 and minimum 9. The dry and wet readings entered at 

 12 h were taken at 12 h 7 m , the wet bulb not having 

 cooled down at 12 h , after having been wetted a few 

 miuutes previously. The dry and wet readings at 21 h 

 were carefully checked at the time of observation. An 

 aurora was seen at l h , 3 h and 23 h . A solar halo was 

 seen at 1 2 h and 1 3 h . The depth of the snow 

 wreath between the "wreath post" and edge of cliff 

 was to-day found to be 148 inches at its highest point. 

 In the evening a snow-bunting was seen about the 

 door. [It has been seen several times since last noted 

 in the 4th inst.] 



March 28. — The top was clear only at 7 h and 17 h , and 

 at both hours there was str. fog all round below. At 7 h 

 a corona and glory were seen. Snow thawing quickly 

 about the observatory to-day. 



April 3. — The top cleared at 23 h last night, and 

 remained clear till 6 h to-day, the sky being all the time 

 overcast. The thermometer box was shifted at 2 h 15 m . 

 White fog crystals forming about 12 h , but at 14 h those 

 forming were brown. 



April 9. — Since the 4th the wind has blown a 

 moderate breeze from E. or E.S.E., and there have been 

 only few breaks in the fog, and no sunshine till to-day. 

 Top clear several times in forenoon and most of the 

 afternoon; sky, except at T3 h , overcast. The ther- 

 mometer box was shifted after 12 h . Heather-burning 

 going on to W. to-day. 



April 10. — At midnight there was a depth of 3 or 4 



inches of loose dry snow on surface, which consisted of 

 small starry crystals. About mid-day (12 h ) the crystals 

 were falling singly, and in flakes. As soon as the flakes 

 touched anything they broke up, and left the individual 

 crystals detached and separate. The crystals falling then 

 were white (having the ordinary appearance of snow), but 

 at and after 18 h , they were glassy and transparent — 

 glistening aud reflecting light. Calm or almost so all 

 afternoon. 



April 11. — Except from 2 h to 4 h the summit was clear 

 all forenoon. Variable amounts of cirri types on sky, 

 radiating from N.N.E. and S.S.W. The snow-bunting 

 has been seen daily about the observatory for hours 

 at a time, since 1st of month. To-day it was photo- 

 graphed. 



April 12. — Fog crystals brown all morning, and sooty 

 in taste. Clearing overhead at times to-day, showing cir. 

 and cir.-c. above, lying E. and W.; and heavy cum.-s. 

 ' masses all around. 



April 13. — At l h radiating points of cir. were W. by 

 N. and E. by S., and at 2 h N.W. by W. and E.S.E. A 

 lunar corona seen at 23 h . 



April 14. — At 7 h and 8 h an irregular broken corona 

 was seen on cir. clouds ; order of colours : — sun, glare, 

 red, blue, red at 7 h ; and at 8 h , sun, glare, blue, green, 

 red. At 12 h it was noted that there was no glare or 

 brown colour in sky about the sun, the sky being 

 uniformly blue almost up to the sun all round. 



April 15. — Top clear for greater part of day. Fog all 

 round below till noon, when it rose above level of summit, 

 and formed cum. clouds. Heather burning in various 

 directions to-day, which caused a good deal of haze all 

 round. 



April 17. — A halo was seen at 9 h . Except at this 

 hour there was mist on the top till ll h , but clear for the 

 rest of the day, and after 14 h cloudless as well; but 

 thick mist on surrounding hills all day. Air dry all 

 afternoon. At 13 h radiating points of cir. were S.S.W. 

 and N.N.E. 



April 18.— Top clear till 10 h . Cloudless till 6 h , but 

 fog on lower hills all morning, which rose and enveloped 

 summit also from ll h onwards. From 16 k yesterday till 

 8 h to-day, the wet bulb had to be moistened about 10 

 miuutes before each observation. White icy fog crystals 

 forming all afternoon. 



April 22. — Summit clear at 6 h , at times about mid-day 

 and from 17 h till 23 h , sky cloudy or overcast, but no fog 

 on hills. At 21 h and 22 h the radiating points of cir.-s. 

 were N.W. and S.E. The thermometer box was shifted 

 after 13 h . 



April 24. — Barometer pumping heavily — over a tenth 

 of an inch, in the strong northerly squalls. The rain- 

 gauge was useless to-day owing to the drift ; most of the 

 loose snow lying on the top was blown away. 



April 25. — Fog over the lower hills in forenoon ; 

 about noon it rose and covered Ben Nevis also with fog 

 and scud. Thermometer box shifted at 12 h 20 m . Solar 

 corona seen about 13 h . The outside part of the 22 k 

 observation was about 2 minutes late owing to lamp 

 going out. 



April 27. — Thermometer box shifted at 13 h 20 m . Air 

 clear all round in afternoon ; no fog in valleys nor on 

 hills. 



