499 
NATURE 
[March 22, 1883 
parison-pressure by aneroid, temperature of air and 
evaporation (dry and wet bulbs), maximum and minimum 
shade temperature, and ozone for periods of 6 and 18 
hours, temperature of ground at depths of 1 and 2 feet; 
temperature of lake; wind and force; kind of cloud, 
amount and velocity; hydrometeors and remarks in full 
detail as before each time. Rainfall on Ist, 8th, 15th, 
and 22nd of each month. 
BROWN’S WELL.—Position : 2200 feet above sea, 3m. 
If, on a grassy patch with springs and swamps, on the 
main slopes of Ben Nevis. Boulders and stones of fine- 
grained granite graduatiog into felsite lie around. Slope 
to westward estimated at 35°. 
Ffours.—7.30 a.m. and 0.30 p.m. 
Elements.—Pressure by aneroid, temperature of air 
and evaporation (dry and wet bulbs), temperature of 
well; wind and force; kind of cloud, amount and 
velocity; hydrometeors and remarks in full detail as 
before each time. 
RED BURN CROSSING.—Posztion : 2700 feet above sea, 
3m. 2f., above the general limit of vegetation in the deep 
ravine of and close beside the Red Burn; boulders and 
debris of porphyritic rock on all sides; slope to westward 
estimated at 4o°. 
Hlours.—7.55 a.m. and noon. 
Elements.—Pressure by aneroid, temperature of air 
and evaporation (dry and wet bulbs), temperature or 
burn; wind and force; kind of cloud, amount and 
velocity; hydrometeors and remarks in full detail as 
before each time. 
BUCHAN’S WELL.—Position : 3575 feet above sea, 
3m. 5f., source of the Red Burn: entirely in a region of 
rocks, fragmentary stones, and debris; completely open, 
and ground more undulating, with comparatively gentle 
slope to westward. 
ffours.—8.30 and 11.30 a.m. 
Elements.—Pressure by aneroid, temperature of air 
and evaporation (dry and wet bulbs), temperature of well; 
wind and force; kind of cloud, amount and velocity ; 
hydrometeors and remarks in full detail as before each 
time. 
BEN NEVIS, SuMMIT OBSERVATORY.—Position : 
4406 feet above sea, 4m. 6f, in the centre of a rough 
rocky plateau, covered with felstone lavas and volcanic 
agglomerates (see Figs. 3 and 4). 
Hours.—9, 9.30, 10, 10.30, and 11 a.m, 
Elements.—Pressure by mercurial barometer, com- 
parison-pressure by aneroid, temperature of air and 
evaporation (dry and wet bulbs), wind and force ; kind of 
cloud, amount, and velocities of strata ; hydrometeors 
and remarks in fullest detail as at the sea-level and inter- 
mediate stations at all the above times. 
Maximum and minimum shade temperature, solar 
maximum and terrestrial minimum temperature, and rain- 
fall by four gauges at 9 a.m. 
Temperature of Wragge’s Well and of ground at depths 
of 1 and 2 feet between 9 and 11 a.m. 
Ozone for periods of 4 hour, 1 hour, 1} hour, and 
2 hours between 9 and 11 a.m., also by two differently 
exposed tests for 24 hours ending 9 a.m. 
Actinism of the sun’s rays and of daylight by Dr. 
Angus Smith’s apparatus for 24 hours ending 10.17 a.m. 
Hygrometric conditions prevailing about 9 o’clock the 
previous night by self-registering dry and wet bulbs, were 
noted at 10,50 a.m. 
A moment’s consideration, then, will show that the 
observations at the sea-level station were in every case 
simultaneous with those at the summit and intermediate 
stations, and that the hours at the latter were so arranged 
as to “mean” to the Io a.m. readings at the base and 
summit of the mountain, and also at the Peat Moss. 
Rainband by Browning’s spectroscope was observed at 
various altitudes, and its indications proved of consider- 
able value. Full notes were taken of the cloud limits, 
and of any important changes observed between the 
stations. 
Of course my first business was to get the main obser- 
vations—pressure, temperature, hygrometric conditions, 
wind, cloud, &c.—into full swing by June 1; and as I 
felt my way and got my hours and distances well under 
command I added to my work. Thus the ozone observ- 
ing-system and the three extra rain-gauges on the summit 
were added on June 15, and the delicate operations for 
measuring the actinism of light on July 9. The additional 
gauges were established to discover if and to what extent 
the rainfall varies in connection with the wind at different 
points of the plateau from the centre to the edge of the 
great precipice. 
During June, Stevenson’s screens were in use only at 
the sea-level, lake, and summit; and hence at the other 
places the dry and wet bulbs had to be swung and the 
latter moistened afresh from adjacent water at each 
swinging. But aching wrists and sore fingers soon made 
me determine to have louvred screens at all the stations, 
and by July 1 they were in their places and dry and wet 
bulbs supplied by Hicks and Negretti and Zambra fixed 
permanently in each. So above all was accuracy the 
better insured, and the whole system went like clockwork. 
I left Achintore before 5.30 a.m., and returned about 
3 p-m., and the rate of ascending and descending was so 
regulated as to insure punctuality usually within a few 
seconds—often to the second—at the various stations. 
The new screens were a trifle smaller than the others. 
I need hardly add that the instruments at all stations 
were the best observing-standards procurable, and that 
the arrangements in every respect were those approved 
by the Meteorological Office and the English and Scottish 
Meteorological Societies. The condition of the wet bulbs, 
fixing of ozone tests, clamping self-registering instruments 
to prevent vibration in gales, levelling rain-gauges, and 
numerous other matters of important detail required the 
closest attention. The Beaufort wind and cloud scales 
were in use, and the ozone tests were Moffat’s. Two 
assistants, educated by Mr. Colin Livingston of Fort 
William—a sufficient guarantee for their ability—and 
trained by myself, helped in the work; and relieved me 
in the ascent of the mountain three times a week, and on 
these occasions I took the sea-level station. One of the 
greatest difficulties I had to contend with in the Ben 
Nevis routine was as to the pony on which I rode to and 
from the Lake, where it was left to graze and await my 
descent. Occasionally the stable-boy overslept, and I 
had to make up for lost time,—no easy matter, as the 
wretched track leads over deep ruts and treacherous 
swamps, and the poor brute had a trying time of it. Still 
more frequently the person to whom it belonged gave me 
rotten saddlery in spite of all remonstrance; and on 
commencing the ascent the girth would break, and I had 
to turn the animal airift and plod on to the Lake my 
fastest. This was decidedly hard, inasmuch as I was 
obliged to climb afoot some 2500 feet from the tarn in 
less than two hours by a circuitous route and over rough 
rock stopping to observe at the other intermediate sta- 
tions. Again, the pony often wandered in his hobbles or 
having broken the tethering rope had made off to the 
moss; so also on the homeward journey I had sometimes 
to leave him and run my hardest over ruts and through 
swamps, by a short cut, to get my readings at the next 
station. Other trying parts of the work consisted in the 
journeys between Buchan’s Well and the top in the 
allotted time, in having the two hours’ exposure on the 
summit in bad weather, and in becoming chilled after 
profuse perspiration. The rude hut, with its walls full of 
holes of all shapes and angles through which the wind 
whistles and the snow-drifts drive, afforded but a poor 
shelter from the drenching rain and cold, and it was im- 
possible to keep anything dry. My hands often became so 
numbed and swollen, and my paper so saturated that I had 
