The Influence of High Winds on the Barometer at the Ben Nevis Observatory

The question of the effect of wind on the readings of the barometer was first examined by Sir Henry James in a paper read to the Society on March 15, 1852. The observations were made during the succession of gales from the south-west which occurred in January and February of that year, at his house in Granton, with an aneroid barometer, laid horizontally in succession on the table of his room in the cottage, on the seat of the open summerhouse, and on the surface of the ground close to the summer-house, all at the same level. The anemometer employed was of a very simple construction, being on the same principle as the instrument used for weighing letters, the weight or pressure being indicated by the compression of a spiral spring in a tube. A table of results is added, giving the depression of the barometer in decimals of an inch for the velocity of the wind from 14 to 40 miles per hour. At 14 miles the barometric depression was 0.010 inch, and increased gradually to a depression of 0.045 inch at 40 miles per hour. Unfortunately, the number of observations on which the depression for each wind-velocity has been deduced are not given, and the observations in the cottage and those at the open summer-house are combined into one result.