420 



BEN NEVIS OBSERVATORY. 



ANEMOMETER 



Miles per hour. 



The following tables give the readings of the Robinson Hemispherical Cup Anemometer 

 at Ben Nevis Observatory for such times as it was working. The anemometer is mounted 

 on the roof of the tower of the Observatory and stands 5 feet above the roof of the tower, 18 

 feet above the flat roof of the main part of the Observatory, and about 32 feet above the 

 ground. It has 4 cups, 5 inches in diameter, mounted on arms measuring 15 inches from 

 centre of spindle to centre of cup, and its records are reduced to miles per hour by the factor 

 2-841. 



The anemometer can only be used when the temperature is above the freezing point, 

 or on the rare occasions when it passes below the freezing point with a dry atmosphere. 

 The presence of fog or mist when the temperature is below 32° at once chokes the 

 mechanism with ice, and either stops it, or so retards its motion as to render the readings 

 misleading. The tables printed here contain all the satisfactory records from 1888 to 1892 

 inclusive. In the spring of 1889 the instrument was under repair and was only started 

 on 16th July : during the whole summer of 1892 it was in the maker's hands for repairs and 

 alterations. The other breaks in the record are due to frost. 



Each month in which any record was got is printed separately. At the right hand 

 side is given, 1st the mean value of all days on which records were got for the whole 24 

 hours, on broken days no mean is given, and 2nd the maximum hourly value of every da}^ 

 whether complete or not — of course on the incomplete days this gives only the maximum of 

 the time the anemometer was working. The highest maximum value for each month is put 

 in bold faced type. At the foot of each month are the mean values for each hour ; in 

 computing these, only the entries on complete days are taken. 



WIND. 



Miles per hour. 



MAY 1888. 





1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 



16 



17 



18 



19 



20 



21 



22 



23 m t 

 night. 



Mean. 



1 

 Max. j 



1 



2 

 3 

 4 

 5 



6 



7 



8 



9 



10 



11 

 12 



; 13 



14 

 15 



i 16 

 17 



! is 



i 19 

 1 20 



21 

 22 

 23 

 24 

 25 



26 

 27 

 28 

 29 

 30 



Mean 



28 

 13 



12 



40 

 31 



20 

 

 3 

 6 

 5 



12 

 5 



16-1 



33 

 12 



5 



40 

 16 



18 

 1 



1 

 5 

 4 



10 

 6 



14-2 



26 

 15 



4 



42 

 13 



13 





 2 

 7 

 3 



6 



4 



12-4 



14 

 8 



39 



17 



12 

 

 5 

 2 

 o 



7 

 2 



10-9 



18 

 9 



42 

 14 



12 

 

 8 

 1 

 2 



12 

 



12-1 



25 

 12 



44 

 6 



8 







10 







7 



11 

 



12-8 



25 

 9 



42 



7 



11 





 12 







9 



6 

 



12-4 



24 

 11 



62 

 7 



5 



1 



12 







4 



7 

 1 



13-6 



24 

 15 



66 



8 



1 



2 



10 







O 











12-7 



25 

 14 



67 

 12 



2 

 

 C 

 

 2 





 



12-7 



21 

 14 



61 



12 



4 

 

 1 

 

 2 



i 



6 



11 -3 



20 

 15 



57 

 14 



4 

 

 

 

 



4 

 



11-0 



26 

 9 



67 

 11 



7 

 

 3 

 

 



4 

 



13-1 



29 

 9 



55 

 6 



9 

 1 

 3 

 1 



2 



5 

 



12-3 



27 

 13 



59 

 65 



7 



6 

 1 



4 

 1 

 4 



7 

 1 



13-6 



17 

 24 



12 



49 

 60 

 11 



6 

 

 6 

 4 

 5 



5 



3 



13-6 



18 

 22 



15 



49 



55 



6 



1 

 

 6 

 2 

 5 



2 

 6 



11-0 



18 

 22 



22 



54 



63 



4 





 

 8 

 

 3 





 



11-1 



18 



18 



7 

 24 



62 



64 



5 



1 

 2 

 7 

 



2 



1 

 11-1 



20 

 15 



10 



69 



57 



6 





 5 



10 

 



1 



1 

 10-6 



23 

 12 



7 



68 



68 



5 





 2 

 12 

 

 6 



2 

 11-9 



19 

 13 



4 



61 



51 



6 





 

 7 

 

 5 



4 

 9-6 



23 

 14 



7 



55 

 45 



12 



3 





 9 

 

 6 



4 

 10-3 



25 

 13 



12 



44 

 38 

 15 







2 



11 



1 



5 



6 

 10-1 



22 



54 

 10 



6 

 1 

 6 

 1 

 4 



5 

 12-1 



25 

 33 



15 



12 

 24 



69 1 



68 

 31 



20 



5 

 12 



7 



9 



12 

 6 



