218 THE CLIMATE OF THE NORTH COAST OF WALES. 
Quarterly Report, and compared it with Dr. Nicot’s Returns 
from Llandudno for the same period, and taken from the same 
source. The rain-fall is taken from Mr. GuarsHEeR’s own returns 
at Blackheath, and my own at Colwyn Bay for the ten years 
ending December 31st, 1890. Both these stations are nearly the 
same height above the sea—Blackheath being 168 feet, and 
Nant-y-Glyn 180 feet. In place of ‘‘ mean temperatures,” I have 
used the ‘‘mean maximum ” and ‘‘mean minimum” tempera- 
tures, or the mean of all the daily highest and lowest tempera- 
tures respectively. The use of the “ mean temperature,” which 
is obtained by adding together the mean maximum and mean 
minimum, and dividing by two, is very misleading. For 
instance, a locality where the mean maximum was 80°, and 
the mean minimum 20°, would give a mean temperature 
of 50°. So also would another locality where the mean 
maximum was 60°, and the mean minimum 50°; yet the climates 
of the two places would be very different in their effects upon 
animal and vegetable life. 
The result of a comparison between the above-named localities 
may be thus briefly summarized :—It is hotter in summer, and 
colder in winter, near London, than on our Coast, while the 
average rain-fall of the former is 23°36 inches, against 30°77 
inches at the latter. 
The accompanying diagrams (see Tables I. and II.) will show 
the differences between the mean minima and maxima at 
Greenwich and Llandudno respectively, for the four quarters 
of the year. A much greater difference however is shown if we 
take the extreme temperatures on both sides reached during 
the nine years. The highest shade temperature at Greenwich 
was 94°-2 in August, 1884, and the lowest 12° in January, 1891. 
The highest at Llandudno was 84° in August, 1887, and the 
lowest 2U° in December, 1890, and January, 1891. There was thus 
a difference of 10°°2 in the extreme maxima and 8° in the extreme 
minima of the two localities. The extreme range of temperature 
in nine years is therefore 82° at Greenwich and 64° at Llan- 
dudno. In Australia a range of 56° im a single day has been 
recorded (Heat as a Mode of Motion, page 407.) There the air 
j8 extremely dry. 
The usual explanation given for the higher winter tempera- 
ture of the North Wales coast is our old friend the so-called 
“ Gulf Stream,’’ which however is not the true Gulf Stream, but 
a warm current from the Equatorial region of the Atlantic 
Ocean, which strikes our shore and saves us from the rigours 
of a Labradorian winter. And no doubt this is quite true as 
regards our islands as a whole, but it is not easy to see why it 
should be of so much more benefit to us than to the Estuary of 
the Thames, or even (as is the case) to the south-east coast of 
England. In the latter case, the distance, say, from Land’s End 
to Brighton is about the same as to Llancudno, while Brighton 
