ON METEOROLOGICAL OBSERVATIONS ON BEN NEVIS. 63 



north of west, and the quantity diminishes as we go round the compass 

 in both directions, until the driest point is reached a httle south of east, 

 the east again having a very low value. The dryness of S.E. winds is 

 remarkable. They seem mostly to occur when an area of high pressure 

 is moving off and a cyclonic stoi-m approaches from the west ; and this 

 dry character indicates that the wind shifts when the storm actually 

 reaches the observatory and the rain begins to fall. 



For the past two years much attention has been given by Mr. A. 

 Rankin, the first assistant, in making rainband observations, and he has 

 discussed them in an interesting paper, recently read before the Scottish 

 Meteorological Society, which, along with Mr. Omond's paper on the 

 Rainfall and Winds, will shortly appear in the Society's journal. 



A series of elaborate hygrometric observations was made at the obsei'- 

 vatory during August, September, and October 1885 by Mr. H. N. 

 Dickson, under the direction of Professor Tait and Mr. Buchan. The 

 observations have been discussed by Mr. Dickson in a paper recently 

 read before the Royal Society of Edinburgh. The results are of consider- 

 able value in determining how far Glaisher's factors, so largely used by 

 meteorologists in hygrometric inquiries, can be safely used. As regards 

 the i-emarkably dry states of the air, which form so prominent a feature 

 in the climate of Ben Nevis, Glaisher's factors are found to be altoge- 

 ther inapplicable, and the hygrometric observations will therefore require 

 a specially constructed set of tables. Copies of this and the other papers 

 referred to above will, when published, be forwarded to the Association. 



Third Report of the Committee, consisting of Professor Balfouu 

 Stewart {Secretary), Professor Stokes, Professor Schuster, 

 Mr. G-. Johnstone Stoney, Professor Sir H. E. KoscoE, Captain 

 Abney, and Mr. G-. J. Symons, appointed for the purpose of 

 considering the best methods of recording the direct Intensity 

 of Solar Radiation. 



The Committee, in conformity with their last report, have had con- 

 structed by Mr. Casella an instrument of the following description : — 



It consists of a cubic copper enclosure, 3^ inches square outside, the 

 faces of which are § of an inch thick. This cube is packed round with 

 felt, y^y of an inch thick, and the whole is faced outside with thin polished 

 brass plates, y^ of an inch in thickness. 



In that vertical face of the cube which is intended to face the sun two 

 holes are bored into the copper from above. These holes are equally 

 distant from the centre on each side, and are intended to receive the cylin- 

 drical bulbs of two delicate thermometers wrapped round with tin foil 

 so as to be in metallic contact with the copper. Let us call these thermo- 

 meters A and B. In the opposite face of the cube there is one such hole 

 bored centrally into the copper, also intended to receive the bulb of a 

 thermometer, which we shall call C. Finally, in the very centre of the 

 enclosure there is placed the bulb of a thermometer similar to the above 

 which we shall call D. 



This last thermometer occupies the position that will ultimately be occu- 

 pied by the interior flat bulb thermometer upon which the sun is to play 



