1890.] 



BEN NEVIS OBSERVATORY.— INSTRUMENTS, ETC. 



227 



INSTRUMENTS, ETC., 1890. 



Barometer No. 1385 was in use during the whole of 

 1890, No. 1252 being kept as a reserve instrument. 

 The latter is supposed to have a trace of air in its 

 vacuum. 



The following Dry and Wet Bulbs were used : — Nos. 

 192660 and 192672, 192671 aud 192677 (these are now 

 only used in the Tower Screen). Up to 4th June 50850 

 and 50852 were used occasionally, but were then sent 

 down to the Low Level Observatory. Nos. 535541 and 

 535542 (new instruments) have been in use since 4th 

 June. Max. 117293 and Min. 116918 were used in the 

 large screen in summer, and Mins. 138533 and 138545 

 in the small screens in winter. 



Up to 11th June midnight the thermometers were 

 placed in small screens on ladder stand No. 2 ; as also 

 after 4th November ll h . Between these dates the large 

 screen, old clock-box, was in use, except from 16th 

 October 14 h to 22nd October midnight, when a small 

 screen was used. 



The usual 5-inch raingauges, rain or snow pattern 

 according to circumstances, were in use. 



The Campbell-Stokes Sunshine Recorder has been used 

 all through the year. 



Max. Black Bulb in vacuo No. 186 has been used 

 when possible, and for several months in summer Black 

 Bulb No. 484108 — common thermometer in vacuo. 



The Direction and Force of the wind have been 

 estimated, as usual, on the roof at the hourly observations, 

 and the Robinson H. C. and Chrystal Direction Anemo- 

 meters used when practicable, but the clock of the latter 

 has been disconnected, and now serves as office clock. 



On 17th July the Standard clock was sent to Ritchie 

 aud Son for further repairs. Since its return it has been 

 kept at the Low Level. 



The Rainband has been estimated daily, as usual, with 

 a direct vision spectroscope. 



The Stephanome was employed for measuring glories, 

 halos, corona?, etc., as usual. 



Several Photographs have been taken. 



The Richard Barograph has been used throughout the 

 year. 



The Richard Thermograph was not used, and on 5th 

 June was sent down to the Low Level Station. 



The Depth of snow was taken at Post A., except for a 

 short while in October, when it was taken near Ladder 

 Stand No. 2. 



The Telegraph instrument worked well ; in the month, 

 of June the wire was extended to the Low Level Station. 

 On the evening of 5th January, the telegraph cable was 

 damaged during a thunderstorm, and communication was- 

 not restored till the afternoon of the 10th. 



The Ozone test papers have been frequently blown away 

 or bleached, and the raingauge measurements interrupted 

 by drift. At 7 h , on 18th January, the Dry and Wet 

 Bulbs were not read, it being found impossible to keep 

 the lantern alight in the heavy squalls blowing. With 

 the above exceptions the record is complete, though the 

 observation, or part of it, was occasionally a few minutes 

 late. 



On 8th August a doorway was cut in the S.E. side 

 of upper story of tower, and an arrangement made by 

 which a screen could be exposed there in stormy weather. 

 No use has been made of it yet, but preliminary trials 

 show that at night, in strong winds, the error introduced 

 by using it instead of the ordinary screen would never 

 exceed half a degree. 



On 24th February a portable Dust Counter was 

 brought up, and on 4th December it was sent down to 

 the Low Level. 



On 5th June a larger Dust Counter was erected in the 

 middle room of tower, with pipes leading to the outer 

 air at the N.N.W. and S.E. sides. 



The Lightning Conductor was bent during a severe 

 gale on 19th January, and is still leaning over to one 

 side. 



The Staff of the Observatory consists of R. T. Omond, 

 A. Rankin, J. Miller, and since 17th January, S. Nisbet. 

 W. Wilson went down on 1st January. Messrs R. C. 

 Mossman, J. Macdonald, Alex. Drysdale, J. Duncan, and 

 Wm. Stewart have taken the places of the observers at 

 various times. From 16th August to 30th September 

 R. Crerar acted as telegraphist. 



