282 REPORT— 1698. 



different heights above and below the level of the intermediate station. 

 The observer takes with him dry and wet bulb thermometers (Assmann's) 

 with which the temperature and humidity are observed. Special atten- 

 tion is given to the particular height where at the time the more rapid 

 changes of temperature and humidity occur, which are so strikino' 

 features on the slopes of Ben Nevis, of the cyclones and anticyclones as 

 they sweep past the mountain. These observations will continue to be 

 made for some time at short intervals, to which are added eye observa- 

 tions, such as mist and ha/e as they appear or disappear ; of marked 

 changes of wind, both direction and force ; of the heights of the clouds 

 on the neighbouring heights and mountains, of the rainfall, ifcc. 



Mr. Omond has undertaken a discussion of tlie hourly observations 

 at the three observatories, carried out in sequence froni day to day, witli 

 the view of ascertaining, among other points, the times which elapse 

 between the tirst appearance of the indications of a cyclone or anti- 

 cyclone, and its actual arrival in the British Islands. 



Dr. Buchan has been for some time engaged in the preparation of a 

 paper on the annual rainfall of Scotland, and its variations from year to 

 year in different parts of the country. In carrying out this inquiry, the 

 relation of the whole subject to the sun-spot period of eleven years is 

 under consideration. The last four periods, commencing respectively 

 1855, 1866, 1877, and 1888, are alone dealt with. The result is that the 

 mean annual variation of the rainfall of Scotland, considered as a whole, 

 from 1855 to 1897, shows a course of variation for the eleven years period 

 closely accordant Avith the variation of the sun spots. As the sun spots 

 increase from the minimum to the maximum in the si.\th year of* the 

 period, the rainfall is under the average ; but as they fall from the 

 ma.ximum to the minimum during the next five years, the rainfall is 

 above the average. 



The averages have been calculated for upwards of 300 stations in 

 Great Britain, and the remarkable result has been arrived at that, for 

 stations in the west, well open to the westerly winds from the Atlantic — • 

 and such stations are numerous — the above relation between the distribu- 

 tion of the rainfall and the sun spots during the eleven years periods 

 obtains without exception in the strongest marked form. 



An examination of the annual direction and force of the wind for the 

 eleven years period has been made, and sorting the results into two 

 groups, comprising respectively N.W., N., N.E., and E. winds, which 

 may be regarded as dry winds, and S.E., S., S.W., and W. winds as 

 wet or rain-bringing winds, the following is the striking result : the 

 maximum occurrence of the dry winds is coincident with the years when 

 sun spots are increasing to the maximum and the rainfall is under the 

 average ; and the maximum occurrence of the wet winds is coincident 

 with the years when sun spots are diminishing towards the minimum and 

 the rainfall is above the average. 



Further, the minimum force of the wind is during the former half of 

 the eleven years period when the sun spots are increasing, and the maxi- 

 mum when they are falling to the minimum. 



In your Committee's last report it was intimated that there is in 

 course of construction a map for each day of each of the years over which 

 the Ben Nevis Observations extend, on which is entered the amount of 

 the day's rainfall at 120 places in Scotland ; the storms of wind from the 

 night and day observations at the Scottish Lighthouses ; hours of sun- 



