Nov. 3, 1881 | 
NAL ORE 
IE 
METEOROLOGY OF BEN NEVIS 
ee cairn on the top of Ben Nevis marks, as is well 
known, the highest spot in the British Islands, and 
when the question of high-level meteorological observa- 
tions came to be seriously entertained some years ago, 
attention was drawn to this position as the best afforded 
in these islands for a first-class meteorological observatory 
which would form one of the more important members in 
the network of the high-level stations of the Continent. 
The advantages of the situation are enhanced by the con- 
sideration that the mountain rises directly from the level 
of the sea to a height of 4406 feet, and that its summit 
stands from 2000 to 3000 feet clear above the mountain 
ridge to westward which lies between it and the Atlantic. 
The mountain thus raises its head in the very midst of 
the west-south-westerly winds from the Atlantic, which 
exercise so preponderating an influence on the meteorology 
of Europe. 
at this elevated situation the more important to be looked 
for are those which relate to the greater movements of the 
atmosphere, particularly the upper currents in their rela- 
tions to the cyclones and anti-cyclones of Europe, the 
data for the investigation of some of the laws regulating 
these movements being obtained by a comparison on the 
one hand of observations made on Ben Nevis with those 
made at the other high-level stations of Europe, and on 
the other with those made at lower levels, and published 
in the different Daily Weather Reports. 
When therefore the Scottish Meteorological Society 
(last spring) accepted the handsome offer of Mr. Clement 
L. Wragge to ascend Ben Nevis every morning in time to 
make observations on the top at 9 a.m., every care and 
precaution was taken as regards the quality of the instru- 
ments procured, and in the arrangements made for their | 
exposure and protection, so as to make the observations 
first-class, as far as this could be secured without constant | 
residence on the top or the erection of continuously re- | 
cording instruments. Further, as it is contemplated to 
build an observatory on the top, the arrangements regard- | 
ing the instruments and their positions were carried out, 
so that all that will be required to complete the observa- 
tory is simply the erection of a suitable residence for the 
observers. 
That Mr. Wragge possessed not only enthusiasm, but 
also strength of will, skill, and readiness of resource, was | 
soon manifested. He met the Council of the Society in 
Edinburgh on May 26 and 27, was in Fort William on 
the following day, and on Tuesday, the 31st, fixed and 
secured the instruments in proper position on the top of 
the Ben, including a massively-built cairn for the recep- 
tion of the barometer. On June 1, at 9 a.m., the obser- 
vations were regularly begun, and have since been con- 
tinued without the break of a single day up to the disas- 
trous storm of October 14. This continuity, so extremely 
desirable in such a series of observations, was guaranteed 
by Mr. Wragge securing at the outset the services of a 
well-qualified assistant, whom he trained to the work, as 
well as a second assistant, whom he also trained, to meet 
any emergency that might arise. 
The instruments are these :—A barometer inclosed in a 
cairn, 63 feet high and 17 feet in circumference, which in- 
closes a strong box fastened with lock and key, with a second 
door protecting the box from heavy rains and the gusts 
of wind which blow up the narrow gullies of the tremen- 
dous precipices, 1800 feet high, only a few paces off, and 
sweep over the instruments with terrific fury. A Ste- 
venson’s screen, with maximum, minimum, dry and wet- 
bulb thermometers, the bulbs of which are 4 feet above 
the mountain stone; the box opens to north, and also 
contains the ozone tests. The other instruments are a 
terrestrial minimum radiation thermometer, a solar 
maximum radiation thermometer, 4 feet high, and a rain- 
gauge, 8 inches in diameter, and its rim 1 foot high. 
Fig. 1 shows Stevenson’s thermometer screen in elevation, 
Among the results from observations made | 
erected on four stout posts, having angle-sloping stan- 
chions, by which the box was securely and immovably 
fixed. 
This arrangement continued till the end of July, when, 
as the tourist season was then setting in, a more effectual 
protection of the thermometers was necessary, so as to pre- 
vent the possible occurrence of any crowding of tourists 
immediately around the thermometers, or any other inter- 
ference which might vitiate the readings made daily at so 
heavy an expenditure of time and trouble. In order to 
afford the required protection, Mr. Stevenson designed a 
strong wire cage, measuring five feet each way, the wire- 
netting being supported by strong iron rods continued 
downwards beyond the cage, and bent below at right 
angles. The horizontal projecting rods below are weighted 
with heavy blocks of stone, so as to secure complete 
stability to the structure. In the interior of the cage the 
Stevenson screen, with the thermometers and ozone tests, 
is placed, and firmly secured with supports. 
Fig. 2 is a sketch of the station, kindly prepared by Mr. 
Wragge, which will explain, better than any verbal descrip- 
tion could do, the arrangements which have been carried 
out with regard to the instruments, and also the remark- 
able character of the plateau at the top of Ben Nevis. A 
is the barometer cairn ; B, the wire cage, with the ther- 
mometer screen seen inside ; C, the solar maximum radia- 
tion thermometer, a black-bulb in vacuo, the terrestrial 
radiation thermometer being placed on one of the stones 
adjacent; D, the rain-gauge; and E, the hut, covered 
Fic, 1.—Stevenson’s thermometer screen as fixed on Ben Nevis shown in 
elevation. 
with tarpaulin and built of the surrounding stones for 
shelter to the observer. The cairn of the Ordnance Sur- 
vey is distant twenty-five paces north-westwards from the 
barometer cairn. 
Under instructions from the Council of the Scottish 
Meteorological Society I inspected the station on the top 
of the Ben on July 28, and on the following day the station 
at Fort William, where observations are carefully and 
intelligently made by Mrs. Wragge as nearly as possible at 
the same instant of time that observations are made at 
the top and at the different points on the outward and 
homeward journeys. We left Fort William about half- 
past five on Thursday morning, the party consisting of 
Mr. Wragge, Dr. Sanderson, the Society’s honorary 
treasurer, Mr. R. C. Sanderson, and myself, as well as 
Mr. Wragge’s Newfoundland dog, Renzo, that daily ac- 
companies him in his ascents. The instruments are read 
at Fort William before starting, and the first observation 
on the journey is made at a peat bog, which was reached 
at 6.12 a.m., Mr. Wragge dismounting and reading his 
aneroid and sling thermometer, and noting the wind, 
clouds, and other observations of the weather. The lake 
was reached at 7.23 a.m., where the third set of observa- 
tions were made, including the temperature of the water 
of the lake, which was 48°3, being 3°°0 higher than that 
of the air. Here our ponies were left, and Mr. Wragge 
pushed on, in order to reach the top in time for the regular 
| 9 a.m. observation, while we followed more at leisure. 
