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The Mid-Station on Ben Nevis. By R. T. Omond. 



In the year 1896 the Directors of the Ben Nevis Observatories arranged that a 

 temporary observing station be opened at the hut on the road half-way up the hill. A 

 barometer, rain-gauge, and set of thermometers were provided, also a Richard barograph, 

 thermograph, and hygrograph. The hut stands on steeply sloping ground facing west- 

 ward, and is 2190 feet above sea-level. The barometer and barograph were placed in 

 the hut ; and two Stevenson screens for the thermometers, the thermograph, and the 

 hygrograph were placed on the hill-side in its vicinity along with the rain-gauge. 

 Though the site was not an ideal one for the purpose, being on the side of a hill and not 

 on a peak, it was considered that valuable information as to the condition of the air 

 between the level of the sea and that of the summit might be obtained by occasional 

 periods of observation at this Mid- Station. This expectation has been realised, especially 

 as regards the distribution of temperature in summer. 



In the summer of 1896 Mr T. S. Mum resided and took observations at the Mid- 

 Station for six weeks. Mr Mum was also at the Mid-Station in the summers of 1897 

 and 1898 ; he was assisted and his work supplemented in the former year by Mr Alex. 

 Drysdale and Mr Alex. Aitken, and in the latter by Mr Campbell Irons and 

 Mr Aitken. In 1899 Mr D. W. Wilton observed for some weeks in summer, and 

 in August 1902 Messrs J. H. Maclagan Wedderburn and Robert Aitken carried 

 on a very complete series of observations at the Mid-Station along with temperature 

 readings at three other places on the side of Ben Nevis. 



Mr MuiR discussed the observations made during the first three years in a paper 

 communicated to the Scottish Meteorological Society and published in their Journal.* 

 In this paper he dealt mainly with the differences of temperature between the Mid- 

 Station and the Summit and Base Stations, and the connection of the variations in these 

 differences with varying types of weather. There are many interesting and important 

 results brought out in Mr Muir's paper, one of which may be mentioned. Referring 

 to periods of high and low barometric pressure, he says : " An approaching change for 

 the better is indicated from two to three days beforehand by the summit temperature 

 approaching nearer than usual to that of Fort- William during the day, while the Mid- 

 Station temperature follows in agreement, but more sluggishly. Such a phenomenon, 

 when strongly marked in the afternoon during the heat of the day, and when maintained 

 for some days, indicates a longer period of fine weather. On the other hand, an 

 approaching depression is shown first by the Mid-Station temperature, then more 

 slowly by the Ben Nevis temperature, becoming lower relatively to that of Fort- 



* Journal of the Scottish Meteorological Society, vol. xii. p. 152, " Temperature Observations at the Mid-Station on Ben 

 Nevis," T. S. Mum, M.A. 



