252 REPORT—1899, 
past years. At the top of the mountain the absolutely highest pressure 
for the year was 25°992 inches on June 10; and at Fort William 
30°458 inches on January 23. 
The differences from the mean monthly barometric pressure greatly 
exceeded the averages in January and July, the excesses being respec- 
tively for Fort William 0-231 inch and 0°196 inch, and at the top of Ben 
Nevis 0°227 inch and 0°183 inch. On the other hand the reverse held 
good in February and April, when the defects from the averages were: 
respectively for Fort William 0:174 inch and 0-146 inch, and at the top 
of Ben Nevis 0:177 inch and 0-104 inch. The excesses occurred when 
the general type of weather was anticyclonic, and the defects from the 
pressure when it was cyclonic. 
The following shows the deviations of the mean temperature of the: 
months from their respective averages :— 
Fort Top of 
William. Ben Nevis, Difterence: 
Oo ° fo} 
January . 5:2 55 0-3 
February 03 15 18 
March 02 O-4 0:2 
April 18 2:3 05 
May 21 17 0-4 
June O1 0:5 0:4. 
Jnly 06 03 03 
August : ; 06 0-9 03 
September : 5 27 46 9 
October . ; 4:0 ay O1 
November 06 03 0-9 
December 37 3:2 0-4 
Year 12 14 0-2 
The absolutely highest temperature for the year recorded for Fort: 
William was 79°-7 on September 6, and at the top 62°°6 on the same date. 
The absolutely lowest temperature was 21° on November 29 at Fort 
William, and 9°-6 on February 20 at the top of the mountain. A notice- 
able feature of these maximum temperatures in September, when the type 
of weather was strongly anticyclonic, was the lateness of the season when 
they occurred, and, besides, they far exceed any previously recorded in 
September at either of the Observatories. 
In Table IT. are given for each month the lowest observed hygrometric 
readings at the top of Ben Nevis :— 
Tas_e IT. 
= Jan. | Feb. | Mar. | April} May | June} July | Aug. | Sept. | Oct. | Noy. | Dee. 
| 
o { ° °o ° ° | °o ° ° ° o co] ° 
Dry Bulb . » | 25:0 | 193 | 25:0 | 388] 31:0 | 45°5 | 47:2 | 34:1 | 53°0 | 57-1 | 41°4 | 20°2 
Wet Bulb + «| 82:2 | 17°3 | 22°6 | 30:7 | 24:3 | 32:0 | 33:2 | 26:3 | 36:5 | 46°3 | 30°0 | 16:9 
Dew-point . ~ edo: | + 27 93 | 20:2 62 | 15°38 | 175 | 12:3 | 20:0 | 36:4 | 15°2 | -6°5 
Elastic Force . - | °079 | *049 | -065 | °109 | °057 | -089 | *096 | -075 | -108 | °215 | °086 | 032 
Relative Humidity 59 47 49 46 33 29 23 38 27 46 33 29 
(Sat.=100) | 
Day of Month 3 3 24 30 22 6 28 9 9 24 3 19 8 
Hour of Day . + (6 am. |3 a.m. | 8 a.m.'6 a.m./11p.m.7 a.m. /9 a.m. |4 a.m.} 1 p.m.'5 Pe p.m./9 a.m. 
Of these lowest relative humidities, the lowest 23 occurred in July with 
a dew-point of 17°°5, and the highest 59 in January with a dew-point of 
