290 Proceedings of Royal Society of Edinburgh. [sess. 
midnight blew at the rate of 40-50 miles an hour from the south- 
east, then changed to north, and became calm. The heaviest fall 
took place between midnight and 7 h. ; on the other hand, at the 
middle station the wind was almost calm from 16 h. onwards. 
At 21 h. there was a light air from the north. At Fort-William 
the wind was also northerly. 
The observations having been considered separately, it only 
remains to point in a word to any noteworthy connections as 
shown by the Tables. It is the rule to find any striking change 
of pressure or temperature in one case echoed in a lesser degree by 
the other two, hut the apparent irregularities are numerous. 
The sudden risings and fallings of temperature on the first two 
days of the month are probably due to the fact that on those days 
the station was visited by passing fog, punctuated by gleams of 
sunshine. 
There was a wave of colder weather, lasting from the 5th to the 
8th, broken only at the summit on the morning of the 6tli. This 
was during the period of fine weather. 
Thunder and lightning occurred on the 14th. The fall and 
sudden rise of the barometer was accompanied by a rise and 
equally sudden fall of the thermometer, which was most marked 
at the summit. 
Lightning on the evening of the 1 6th was accompanied by a drop 
in the temperature at 16 h., followed by a temporary rise. 
On the next day, the 17th, the barometer fell rapidly as tem- 
perature rose quickly, and the subsequent rise of the former was 
balanced by the fall of the latter. The wind at the middle station 
that day varied from 20 to 60 miles an hour ; while at the top, from 
14 to 19 h., it varied from 30 to 70 miles an hour. 
My residence at the intermediate station was rendered comfort- 
able and almost luxurious by the assiduous kindness and fore- 
thought of Mr Rankin, superintendent of the Observatory ; and I 
am indebted to Professor Tait, Dr Buchan, and Mr Omond for 
many valuable hints in the preparation of this paper. 
