1897.] 



BEN NEVIS OBSERVATORY.— LOG-BOOK. 



465 



with 



ice. 



All exposed surfaces were coated thickly 

 Showers of snow, sleet, and drizzle fell. 



Feb. 9. — Temperature between 28-4 and 30-0 with 

 mist and drizzling rain till 5 a.m., temperature falling 

 steadily the rest of the day, with fog and showers of snow? 

 Feb. 10.— Summit clear from 8 h till 10 h , but sky 

 overcast. Clear again and sky almost cloudless except for 

 a little cirrus at 22 h and 23 h . Fog on again at midnight. 

 Lunar corona seen at 23 h . Thermometer box changed at 

 22 h 15 m . Height not altered. 



Fek 11.— Thin fog till 8 h ; sky cloudless since, except 

 for thin fog passing over summit frequently. Fog all 

 round below to about level of Ben Nevis, but at 22 h fog 

 had completely disappeared. Air dry in the afternoon? 

 Coronse seen at l h , 2 h and 21 h . Fogbows seen at l h , 2 h 

 and 14 h . 



Feb. 12.— Sky cloudless all day except for a little 

 cirrus in the morning and afternoon. Thick haze all 

 round below all day. At 2 l h cum.-fog above, haze to W., 

 and at 22 u fog passing, thereafter settling down on 

 summit. Temperature showing considerable range ; 20° "0 

 to 32° - 6. It is the first time the temperature has been at 

 32° since 31st December 1896. Air very dry all day, the 

 humidity being as low as 14% at 7\ 'Lunar halo seen 

 at 20 h and 22 h . 



Feb. 15. — Mist or fog all day except at 6 h and 7 h 

 when sky was almost cloudless, but mist below all round 

 to about level of summit and passing at times. Slight 

 showers of drizzling rain during the day. Temperature 

 very steady all day between 29°T and 31°-6. Glazed 

 frost forming almost all day. 



Feb. 16. — Fog crystals (white) forming in forenoon. 

 Temperature pretty steady ; between 29° and 32° all day. 

 Drizzling rain after 21 h . Glazed frost forming all after- 

 noon. 



Feb. 17. — Summit dear frequently between 13 h and 

 1 6 h , but sky somewhat cloudy with cirrus. Showers of 

 drizzling rain till 10 h , and again at midnight. Glazed 

 frost forming till noon and at midnight. 



Feb. 26. — -Thermometer box changed at 23 h 15 m . 

 Height not altered. 



Feb. 28. — Strong S.E. breeze in the afternoon and 

 brown fog-crystals forming from the fog. Summit clear, 

 but sky pretty cloudy and fog on hills in distance. Air 

 slightly dry at 10 h . Slight showers of snow in after- 

 noon. Strong earth currents in telephone during evening. 



March 2. — A gale from S.E. almost reaching hurricane 

 force in the afternoon. Wind veering to S.W. and 

 W., moderating in force after 17 h . Barometer falling 

 rapidly all day. Tower box in use at lb h and 16 h . No 

 correction applied to it, as it read almost the same as 

 Stevenson Screen, double readings having been taken 

 previous to these hours and afterwards. From 15 h to 18 h 

 inclusive measurements of rainfall are interpolations. 

 Apparently snowing heavily in afternoon. Barometer 

 pumping from 13 h to 17 h . During the height of the 

 gale slight damage was done. The collar round and 

 half-way up kitchen chimney (the part that stays are fixed 

 to) gave way. The chimney was also somewhat off the 

 plumb, but was put right in the evening. Ventilator 

 in kitchen passage was blown down, and all the roofing 

 of snow-porch was carried away. 



March 3. — Fug till 5 h . Summit clear and sky almost 



cloudless except for a little cirrus and fog on hills in the 

 distance. Fog came on again at 7 h . Stars gleaming 

 at 23 h , and the streamers of an aurora seen. 



March 4. — Strong S.E. gale from 7 h to 13 h , moderating 

 in force thereafter. Tower box in use from 8 h to ll u 

 inclusive. No correction applied to readings. Read- 

 ings were taken from tower box and Stevenson box 

 when the storm began, and both were reading almost 

 the same. 



March 5. — Summit clear from 6 h till 13 h , except for a 

 little fog passing at times. Sky slightly clouded with 

 cirrus. Wet fog around and lower layer of cum.-fog lying 

 over Lochiel and Caledonian Canal. Coronse seen at 

 6 h and 12 h and glories at 8 b . Thermometer box changed 

 at 7 h 15 m . Height not altered. 



March 7. — Thermometer box changed at 10 h 15 m . 

 Height not altered. 



March 9. — Strong earth currents in telegraph cable 

 between 20 h and 21 h . 



March 10. — St Elmo's Fire seen at l h on kitchen 

 chimney and on top of tower. 



March 12.— Strong gale from S.E. till 5 h , backing to 

 E.S.E. and E. Maximum force 10-11 and minimum 

 force 5-7. Slight showers of snow fell from 7 h till 17 h , 

 but no rain gauge out all day. The entries of amount 

 from 7 h till 17' 1 are interpolations. Tower Screen in use 

 at 4 h , 5 h , 7 h , 8 h , 9 h and 10 h . The following double 

 readings were taken : — 



His. 



Stevenson. 



Tower. 



Diff. 



Hrs. 



Stevenson. 



Tower. 



Diff. 



1 



25-9 



25-3 



+ -6 



13 



24-7 



24-0 



+ '7 



2 



25-2 



24-7 



+ -5 



14 



24-8 



24-2 



+ '« 



3 



23-3 



22-9 



+ -4 



15 



24-0 



24-2 



-2 



6 



247 



24-0 



+ -7 



16 



23-8 



24-0 



— -2 



11 



24-8 



24-0 



+ -8 



17 



23-8 



23-8 



•o 



12 



24-7 



24-0 



+ -7 











giving a mean correction of -|-0 - 4 which was applied 

 to the tower readings at such hours as the Stevenson 

 Screen was not read. Dry and wet bulbs changed at 

 14 h 5 m . 



March 17. — At midnight when the observer was out 

 taking the observation and half-way between Tower and 

 thermometer box, a small dark object rose up from the 

 surface — a bird probably — and flew off in the direction 

 of the cliff. At the spot it rose from there was a hole 

 scooped out sufficient to shelter a small bird. 



March 20. — Thermometer box changed at 8 h 15 ra . 

 Box was raised one step on ladder. Height above snow 

 now 51 inches. 



March 24. — Brilliant display of St Elmo's Fire seen 

 on top of kitchen chimney and on instruments on roof of 

 Tower. The jets of light seen on all objects were fully 2 

 inches long. 



March 29. — Fog till ll h . Summit clear since. Sky 

 pretty cloudy till 19 h ; almost cloudless since. Heavy 

 shower clouds in the afternoon to N.E. and S. Aurora 

 seen at 21 h , 22 h and 23 h . A raven seen at 16 h . Ther- 

 mometer-box changed at 13 h 15 m . Height above snow 

 48 inches. 



TRANS. ROY. SOC. EDIN. — VOL. XLIII. 



3 N 



