1896-97.] T. S. Muir on Observing Station on Ben Nevis. 283 
The greatest depression was '041 inch lower at noon on the 
17th, followed by a heavy rainfall, which was greatest at Fort- 
William and least at the summit. The greatest excess was '023 
inch higher at 18 h. on the 3d, followed by six days of fine 
weather. 
Temperature, Table III. — The maximum temperature, 59° - 5, 
occurred between noon and 16 h. on the 13tli, and the minimum, 
35°'0, between 21 h. on the 20th and 9 h. on the 21st. At the 
latter hour the thermometer stood at 36*9. The range at the 
intermediate station was thus 24 *5. The 13th was an exceedingly 
warm day, with bright sunshine, the maximum for the month 
being also recorded at Fort- William. On the night of the 
20th-21st, temperature ruled low at all three places, the mini- 
mum being observed both at the summit and Fort- William. 
Thunder and lightning occurred on the 14th, while the 21st was 
cold, but fine and rainless. 
Subjoined is a table giving the mean differences of temperature 
for the six standard hours. 
S = Summit, I = Intermediate, B = Base. The first column gives 
the mean September differences for three years ; the others for 
September 1-23, 1896. 
S. and B. 
S. and B. 
S. and I. 
I. and B. 
9 
15'4 
15-3 
7'2 
8'1 
10 
15-8 
16'4 
7'7 
87 
12 
16'5 
18*3 
8-7 
9*6 
14 
16'8 
18'8 
9'5 
9'3 
18 
16'4 
17'2 
8'8 
8*4 
21 
14'6 
15'9 
8'3 
7 '6 
Mean, 
15'9 
17*0 
8'4 
8'6 
From it we find that from 9 to 12 in the morning the inter- 
mediate temperature came nearer to that of the summit, and from 
noon till 21 h. it was closer to that at Fort-William; while the 
mean day difference was as nearly as possible half of that between 
the summit and the base. It is probable, however, that during 
the night it is nearer to the summit temperature, and that the 
