1890.] 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



221 



and gradually spread to those to W., after 13 h Ben 

 Nevis was also covered almost continuously, but the sky 

 appeared to be clear above. 



Feb. 13. — This afternoon it was noticed that the fog 

 •crystals were slightly brown in colour. 



Feb. 14. — Thin fog blowing over the hill top, but 

 sky apparently clear above most of the day. A light, 

 probably auroral, was seen to N. at 22 h . 



Feb. 15. — Sky pretty clear, but fog blowing over the 

 hill top till ll h , and continuous fog after that. Faint 

 aurora seen at 2 h and 3 h . Thermometer box shifted at 

 10 h 10 m . Height above snow not altered. 



Feb. 16. — At 21 h streak of light under clouds at N. 

 horizon, probably auroral. 



Feb. 18. — During both yesterday and to-day the strong 

 ■S.E. wind and thick fog has covered all exposed surfaces 

 with masses of fog crystals ; on the anemometer posts and 

 the spare thermometer stand they are fully 3 feet long. 



Feb. 19. — Sky seen occasionally in the middle of the 

 day about three-fourths covered with cirro-cumulus. Fog 

 ■crystals still growing rapidly. 



Feb. 20. — In afternoon the top of tower was partly 

 cleared of fog crystals ; they filled the entire top, except 

 a small portion to the N.W., the growths from the three 

 anemometer shafts and the chimney having joined. The 

 crystals on the Robinson anemometer were fully 7 feet 

 long. Crystals have also formed on the surface of the 

 ground, hiding the old hard snow, and mixing with the 

 slight sprinkling that fell to-day. 



Feb. 21.— Thermometer box shifted at 7 h 10 m . 

 Height above snow not altered. Very thick dazzling 

 fog in the middle of the day, but sky clear at night 

 ■occasionally, though always fog blowing over the hill top. 

 Thermometer box shifted again at 22 h 15 m . Height 

 above snow not altered. 



Feb. 22. — Top clear in afternoon and air dry, but fog 

 on hills round at about 4000 feet, and sky partly covered 

 with cirrus and cirro-cumulus moving from the N.W. and 

 N. The fog came on again before sunset, and at 22 h 

 had turned to damp mist. 



Feb. 23. — Thin mist and drizzling rain most of the 

 day, but clear sky seen above at night. 



Feb. 24.— Thin mist with slight drizzle of rain, coating 

 all exposed surfaces with ice till 3 h , but stars seen gleam- 

 ing through it. From 5 h on war' Is the air was dry, 

 exceedingly so in the afternoon. Fog lay over the hills 

 below at from 3000 to 4000 feet height all day, but 

 broke into detached portions at night. The after- 

 glow and earth shadow were seen at sunset. Thermo- 

 meter box shifted at 4 h 15 m . Height above snow not 

 altered. To-day Mr. A. Rankin returned to the obser- 

 vatory bringing with him Mr. Aitken's dust counter 

 (portable form). 



Feb. 25.— Summit clear, and sky entirely cloudless 

 all day. Air very dry to-day, the maximum humidity 

 being only 58 (at noon), while the minimum was 25 

 (at 7 a.m.), 97 per cent, of the possible sunshine was 

 recorded. A glory (two rings) was seen at 8 h , and the 

 earth shadow at sunrise and sunset. Fog lay on the E. 

 and N. hills most of the day, and a little haze was seen 

 low in valleys to S.W. in afternoon. 



Feb. 26. — Cloudless till 6 h . All morning fog lay on 

 'northern hills, and after 4 h it gradually spread south- 



wards and rose in height, till at and after 7 h it enveloped 

 Ben Nevis also. 



Feb. 27.— Thermometer box shifted at 17 h 10 m . 

 Height above snow not altered. 



March 1. — Summit clear almost all day. Air dry at 

 times in afternoon. The thermometers (not the box) 

 were changed at 8 h 10 m . A lunar halo was seen at 

 midnight on very thin filmy cirrus, which radiated 

 from N.E. and S.W. 



March 2. — Hill top clear all day. Small quantities 

 of cirrus on sky, radiating points at 16 h being E.S.E. 

 and W.N.W. After 20 h this cirrus was very filmy, 

 and on it the moon formed a corona, but no halo. A 

 glare of 20° radius surrounded the moon all night. Air 

 very dry at midnight. Humidity = 36. 



March 3. — The filmy cirrus, lunar corona, and glare 

 continued on sky till 5 h . Till 2 h the hills around were 

 very clear, but at 3 h sheets of str. fog were seen to N., W. 

 and S., which became very general at 4 h and 5 h , and 

 enveloped the Ben at 6 h and during the rest of the 

 day. In the evening a mouse was seen in the lumber 

 room. 



March 4. — From ll h till 13 h heavy rain fell, the 

 temperature being close to the freezing point (32°'0 to 

 32° '3). During the rest of the day, snow or hail was 

 falling somewhat heavily at times. 



March 5. — Most of the afternoon and night the tempera- 

 ture was between 30° and 32°, and thin drizzling rain 

 was falling, which formed a thick crust of ice on all 

 exposed surfaces — badly choking the thermometer box. 



March 6.— Thermometer box shifted at 7 h 20 m . Height 

 above snow not altered. 



March 7. — Thermometer box shifted at 16 h 15 m . 

 Height above snow 44 inches. Heavy rain fell at 16 h 

 and 17 h , and heavy -snow during the rest of the day. 



March 9. — Str.-cir. observed at 2 h and 3 h radiated 

 from N.E and S.W., and moved from N.W. Ben clear 

 most of the forenoon, but fog on, except at 14 h and 15 h , 

 during the afternoon. Thermometer box shifted at l h 

 15 m . Height above snow not altered. Snow covered 

 the country all round to-day to sea-level. 



March 11. —Raining heavily all day. At 3 h and 4 h 

 the hourly amounts measured were 0*500 in. and 0*526 

 in. respectively. For six consecutive hours (l h — 7 h ) the 

 hourly amounts exceeded 0*300 in. The total for the 

 day was 5*210 inches. 



March 17. — Thermometer box shifted at 13 h 15 m . 

 Height above snow not altered. The zodiacal light was 

 seen in the West at 21 h . 



March 1 8. — At. 1 5 h , observed that this morning's grow th 

 of fog crystals was brown. 



March 19. — Ben clear from 3 h till 23 h . Thermometer 

 box shifted at 4 h 15 m . Haze all round to-day, very thick 

 in forenoon, moderately so in afternoon. Three snow- 

 buntings seen flying about hill top at 8 h . Zodiacal light 

 seen at 21 h . 



March 21. — Thermometer box shifted at 9 h 10 m . At 

 19 h and 20 h , light drizzling rain falling, the air tempera- 

 ture being 27*9 and 27*4. 



March 23. — Thermometers shifted after the 7 h obser- 

 vation. The dark part of the moon was unusually distinct 

 this evening. 



March 24. — Brown fog crystals forming to-day. 



