1885.] 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



333 



too faint to measure. During the day whitish glare all 

 round horizon above the haze that filled the valleys ; this 

 turned brown at sunset, but was white again at night. 

 Faint brown colour under moon again to-night. 



Nov. 17. — Thick haze in valleys all day, but thinning a 

 little at night. At 7 h bright red. Yellow and green 

 colours at eastern horizon. Brown colour under sun all 

 day, and more faintly under moon at night. At 16 h , just 

 before sunset, red look all round horizon. At 16 h 35 m 

 red, orange, and yellow at western horizon, and pink upper 

 glow reaching to about 30° altitude. At 17 h fog on Mull, 

 and at night fog all up Loch Linnhe. At midnight white 

 belt round horizon from W.N.W. to N.N.E., and more 

 faintly as far as E. About 3° high, apparently very thin 

 cirro-stratus. 



Nov. 18. — At l h fog low down on Loch Linnhe and 

 Locheil, and haze in valleys to northward. At 3 h fog on 

 Loch Lochy. Fog on Locheil continued till 10 h . At 

 sunrise fog on Moor of Rannoch, and haze over Atlantic 

 and Moray Firth. Brown colour under sun all afternoon. 

 At 19 h , 20 h , and 21 u aurora seen ; — several arches, the 

 lowest being composed of vertical wavy streamers, the 

 higher ones of simple streaks of light. Height to bottom 

 of first arch, 6° 12'; top, 17° 30'. Green band in spectro- 

 scope very distinct. Shortly before 22 1 ' thin fog began to 

 blow over the top of Ben Nevis. At 23 h double lunar 

 corona, red outside. The size varied very much ; at times 

 the two sets of colours merged into one misty corona, a 

 second forming gradually outside as these shrank into one. 



Nov. 19. — Lunar fog-bow (no colours), seen in early 

 morning. Loose feathery white fog crystals forming freely 

 all afternoon and night. 



Nov. 20. — Dense fog blowing in waves over the hill 

 top till 18 h , very thick, but not reaching high up. Dark 

 roll-cum. at horizon at night. Thermometer box shifted 

 at 22 h 15 m . 



Nov. 21. — Detached patches of fog on hills to south- 

 ward all morning. The surface of the snow on the hill 

 top was found to-day to be all roughened by the fog 

 crystals on it. They were 2 to 6 inches in length, and 

 quite dry. 



Nov. 22. — At 8 h it was observed that the fields near 

 the sea-level were white with hoar frost. Sun much en- 

 larged and elongated when rising ; the vertical and 

 horizontal diameters appearing as 3 to 5. At 14 h brown 

 colour under sun. Haze and fog on Locheil and in 

 Caledonian Valley, rising higher at night and getting 

 thicker to northward. Earth shadow observed at sunset. 

 Sunset colours weak, and little or no afterglow. At 18 h 

 brown colour under moon. Sky covered more or less 

 with cirro-cumulus till midnight. On this a faint, badly- 

 defined lunar corona was observed at 19 h and 20 h . At 

 Pale red ^0 h , c °l°urs somewhat as in margin, but 



Yellow very badly defined. At 19 h only one red- 



Bluish-white dish ring. Radius to inside, 1° 54' ; out- 

 } side, 4° 18'. At 20 h , radius of red, 2° 54'; 



yellow, 2° 35'; outside of blue, 1° 42'. Blue much broader 

 than the red or yellow, and with no defined inner margin. 



Nov. 23. — Double corona on cir.-cum. at 4 h . Badly 

 Bed defined, but of normal form. Radius of 



Green outer red, 6° 48' ; inner red, 3° 7' ; yellow, 



Y e j: 2° 42'. Yellow, a narrow line ; green, a 



Bluish broad belt. White fog crystals forming 



J freely all day. 



Nov. 26. — At 9 h , as it was blowing very hard, one of 

 the old rain-gauges of heavier make was put out. The 

 gauge was taken in at 14 h , and not put out again to-day, 

 as it was impossible to manage it in the strong wind. At 

 \7 h began to use lantern fitted inside an oilskin coat. At 

 22 h note-book blown away when re-entering tower door. 

 At 14 h it was observed that the upper part of the snow- 

 post A had been blown away. 



Nov. 27.— Thermometer box shifted at 22 h 20 m . 



Nov. 30. — At 6 h St Elmo's fire observed on lightning 

 conductor, both anemometers, and on top of ladder lead- 

 ing up tower outside. No sounds heard, even when quite 

 close to the conductor. 



Dec. 1. — Heavy showers of snow, sleet, and hail all day. 

 Louvres of thermometer box badly choked. 



Dec. 2. — At 13 h the rain-gauge was taken in, as it was 

 getting choked with drift. It was put out again at 15 h . 

 Thermometer box shifted at 17 h 15 m . 



Dec. 3. — At 20 h the rain-gauge was found leaning over 

 to windward, having been under-cut by the wind, and 

 full of drift. 



Dec 5. — Thermometer box shifted at 2 h 25 m . 



Dec. 6. — At 8 h bright pink upper glow to E., horizon 

 yellow ; no red colour visible. Snow down to about 600 

 feet. Sunset colours at 1 6 h weak. No afterglow. Well- 

 marked auroral arch all night ; no streamers. Height of 

 top of arch above horizon at 19 h , 12°. The dry-bulb 

 readings at 15 h and 17 h being below 10° — the limit of 

 Glaisher's Tables — the factor was assumed to be 8 - 8, and 

 the dew points calculated by that. 



Dec. 7. — Faint aurora similar to last night, visible from 

 19 h to midnight. 



Dec. 9.— Thermometer box shifted at 15 u 20 m . 



Dec. 10.— At O' 1 8 m thermometers shifted. 



Dec. 12. — Thermometer box shifted at 15 h 20 ra . 



Dec. 14.— Started Robinson at 16 h 20 m , but tied it up 

 again just after midnight. 



Dec. 15. — At 12 h faint brown colour under sun. Dense 

 rolling fog on hill top all round. At 17 h moon shining 

 faintly through cir.-str. clouds, but no halo visible. 



Dec. 16. — Double corona at 20 h ; colours as iu margin ; 

 Outer yellow very faint. Formed on scud; 

 no corona when scud clears off. Radius of 

 outer red, 3° 48' ; inner red, 1° 58' ; outer 

 yellow, 3° 38'; inner yellow, less than 1° 40'. 

 Very faint traces of third ring at times. 

 Similar corona at 22 h . When the scud got 

 very thick, the outer part was more yellow, 

 and less blue-looking. Radius of outer red, 3° 33' ; 

 inner red, 1° 53' ; outer yellow, 3° 0' ; inner yellow, 

 1° 23'. 2 m afterwards, outer red, 3° 8'; inner red, 1° 42'. 

 At midnight lunar fog-bow ; no colours. 



Dec. 17. — Faint afterglow at 16 h . At 17 h western 

 horizon still coloured red, yellow, and green. Fog on 

 hills to 3000 or 4000 feet all afternoon and night. 

 Double lunar corona at 20 h , formed on very thin mist or 

 scud blowing over the hill, flashing into sight and dis- 

 appearing again ; outer ring blue, and inner yellow both 

 reds well marked. Too fleeting to measure. Very faint 

 lunar halo at 22 h . 



Dec. 18. — At 7 h deep, soft, blood-red and scarlet colours 

 at horizon to E.S.E. At 8 h 20 m upper glow to S.E. and 

 S.S.E., the northern side having well marked long 

 streamers. Sun rose 8 h 45 m . At 8 h 40 m the upper 



Bed 

 Yellow 

 Bluish-green 

 Bel 

 Yellow 

 d 



