35G 



BEN NEVIS OBSERVATORY. — LOG-BOOK. 



[1887. 



At 4 h fog-bow, radius inside, 37° 10'; outside, 40° 20'. The 

 upper joint was put on ladder-stand at 15 u 15 m . The 

 earth shadow was seen at 8 b 35 m and again at 1 6 h . A glory 

 was seen as 10 h . At 16 1 ' 30 m gaps (streamer-like) were 

 observed in the piuk afterglow that filled the western sky, 

 small bits of cir.-str. were seen very near the western 

 horizon at same time. 



Dec. 31. — The summit was clear and sky cloudless till 

 2 h . At 3 1 ' thin fog was passing, and at 4 h and for the rest 

 of the day the summit was enveloped. During the fore- 

 noon there was a " misty feel " in the fog, and at 15 h , 16 h , 

 and 17 h it was distinctly mist that enveloped the top, yet 

 the temperature of the air was about 22°. At 3 h , 4 h , and 

 5 h corona? were seen, and a fog-bow was noted at 7 h . At 

 3 h the following measurements of coronse were obtained : — 





1st set. 



2nd set. 



3rd set. 



Radius of first red, 



1°4£' 



l°2i' 



0° 59-|' 



„ of second red, 



2° 2' 







,, of third red, 



2° 50' 







(measured to outside of red in each case.) 



Instruments in use during 1887. 



Barometers. — No. 1385 was in use during the whole of 

 1887. No. 1252, though not in use, was hanging in position 

 ready for use at any time. The Barograph worked most of 

 the year; the note anent its scale error on page 343 above 

 is still applicable. 



Thermometers.— As Dry and Wet, Nos. 192660, 192672, 

 192671, 192677, 50850, and 50852 were used (for makers 

 see pages 334 and 343 above). 



As Self-Registering. — Max. No. 117293, and Mins. 

 116918, 138545, 138533 were in use, the Max. and first 

 Min. in " old clock box, " and the other two in ladder-stand 

 boxes. 



Rain-Gauges.— Mr Omond's patterns of 5-inch Gauges 

 were used, the deep-rimmed or the shallow-rimmed as the 

 season and kind of precipitation required. 



Anemometers. — For direction, Chrystal's Anemometer 

 continued in use, and worked fairly well. 



For Velocity. — After August 3 Robinson's Cup Anemo- 

 meter was used when the weather permitted, i.e., when it 

 was not freezing. Till August 3 it was out of gear. 

 When regeared (August 3) an arrangement of bevel 

 pinions was put instead of upper flexible part of shaft 

 that communicates revolutions to counter. About the 

 beginning of December one of its arms was broken, 

 but it was put in working order again before the end 

 of that month. 



Sunshine Recorder. — The repaired Sunshine Recorder 

 (see p. 343) was used, and worked well. 



Mr Omond's pattern of Chrystal's Hygrometer was used 

 several times during the year, and worked satisfactorily ; 

 but it was broken in September, and since then it has been 

 out of repair. 



From June 4 till Oct. 11 the Thermometers in use were 

 placed in the old clock box ; for the rest of the year in 

 small boxes on ladder-stand. 



The depth of Snow was always measured at post A. 



The measurements of Rainfall were several times inter- 

 rupted, and often rendered unsatisfactory, by drifting ; and 

 the Ozone Tests were occasionally blown away and occasion- 

 ally bleached. 



With the above exceptions, the record for the year is 

 continuous ; though once or twice the observation, or part 

 of it, was a few minutes late. 



The Seismometer is still unsatisfactorily mounted (see 

 p. 343). No results have been obtained from it during the 

 year. 



The Thermograph and Hair Hygrometer were not in 

 use. 



The Black Bulb in vacuo used was No. 186. 



The Cosmic Dust Collector was out several times dur- 

 ing the year. 



For observing the rainband Hilger's pocket Spectroscope 

 was used. 



The permament staff of the Obvervatory consists of R. T. 

 Omond, A. Rankin, J. Miller, and since Oct. 7, A. 

 Drysdale. 



From Aug. 3 till Sept. 21, Mr C. E. Gray acted as 

 telegraph clerk at the Observatory. 



Messrs William Hay, A. J. Herbertson, and J. Duncan 

 took the places of some of the staff at various times. 



ERRATA. 



Page 13. Mean 12 h , instead of 5-083, read 5 '038. 

 ,, 43. Mean Midnight, instead o/5'692, read 5-685. 

 „ 202. Amount 17th, instead of 0-039, read 0-038. 



