TRANSACTIONS OF SECTION A. 923 
The reasons for this remarkable dryness he then discusses, and adds to what 
has been already advanced by local medical men, the elevation of Malvern above 
the stratus—tfog level of the low country, the effect of rising above which he 
compares, though on a far smaller scale, to rising above the north-east wind’s cloud 
level on the Peak of Teneriffe. 
Several other circumstances are then detailed, which all tend to enhance the 
mean temperature, check the variations or range of temperature, and decrease the 
strength of the winds at Malvern, combining altogether to produce the most 
genial and healthy atmosphere yet ascertained in Great Britain. 
16. The Annual Rainfall of the British Islands. By AunxanpER BucHAN. 
As regards the British Islands, the greatest differences in local climates arise 
from differences in the rainfall. Ifthe climate of Skye be compared with that of 
the coasts of the Moray Firth, in no month will the mean temperatures be found to 
differ so much as 2°0, and for several months of the year they are nearly identical. 
But the annual rainfall of Skye rises to, and in many places exceeds 100 inches; 
whereas from the mouth of the Spey to Tain, the rainfall is little more than a 
fourth part of that amount; and this difference in the rainfall, with the clear skies 
and strong sunshine which accompany it, renders the southern shores of the 
Moray Firth one of the earliest and finest grain-producing districts of Scotland, 
whereas Skye is one of the latest and poorest grain-producing districts. Hence 
the paramount importance of the rainfall in the climatology of a country. 
The temperatures of comparatively few places are required, in order to draw, 
with approximate correctness, the lines of mean atmospheric pressure and tempera- 
ture for any particular region. But with the rainfall it is very different, this being, 
of meteorological data, the most difficult to represent cartographically, and there is 
no other way to arrive at a tolerable approximation to the average rainfall of a 
district than by numerous rain-observing stations. This inquiry, the results of 
which are represented on the map exhibited, is based on observations of the rain- 
fall made at 1,080 stations in England and Wales, 547 in Scotland, and 213 in 
Treland—in all 1,840; and while it cannot be said that any district is overstocked 
with rain-gauges, large districts remain wholly, or at least very imperfectly, 
represented. 
The period which has been selected for this inquiry is the twenty-four years 
extending from 1860 to 1883, it being only in 1860 that fairly adequate data for 
the whole of the British Islands began to be available by the appearance of 
Symons’ ‘ British Rainfall.’ In Mr. Symons’ energetic hands, aided for some years 
by grants from the British Association, the stations for observation of the rain- 
fall, and the publication, have increased year by year, till in 1884 the stations 
number nearly 2,600, and the publication occupies 242 pages. While the returns 
published by the Meteorological Societies of Hngland and Scotland, and returns 
from other sources have been utilised, it is mainly on Mr. Symons’ invaluable 
annuals that this inquiry is based. 
The methods of discussion employed, and the average annual rainfall of the 
different stations, are detailed at length in the ‘ Journal of the Scottish Meteoro- 
logical Society,’ recently published. 
The distribution of the rainfall for the twenty-four years over the British Islands 
is shown by six shadings indicating the districts where the annual rainfall does not 
exceed 25 inches; is from 25 to 30 inches; from 30 to 40 inches; from 40 to 60 
inches; from 60 to 80 inches; and lastly above 80 inches. 
The regions of heaviest rainfall, marked off by an average of 80 inches or up- 
wards annually, are four—Skye and a large portion of the mainland to the south- 
east as far as Luss on Loch Lomond; the greater part of the Lake district; a long 
strip including the more mountainous part of North Wales; and the mountainous 
district in the south-east of Wales. 
The West Highlands present the most extensive region of heaviest rainfall in 
the British Islands. The mountain masses along whose slopes the rainfall is pré- 
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