39 
BRITISH MEAN TEMPERATURES. 
By W. L. DALLAS, or the Meteorological Oefice. 
J N the Himalayas, the Andes, and other great mountain chains 
within the tropics, a phenomenon may be witnessed which is 
always interesting and instructive. A traveller climbing one of 
these ranges advances first across valleys and small hills covered 
with the jungle and luxurious vegetation of the tropics. As he 
continues the ascent he leaves behind him the beautiful palms 
and immense cotton trees, the brilliantly marked birds, reptiles, 
and insects, the inhabitants of the tropics, and reaches the oak, 
the elm, and the birch, the growth of the temperate zone. 
These, in their turn, give way first to the larch and the fir, then 
to low bushes and scrub- wood, then to lichens and mosses, and 
finally to the region of perpetual snow. The whole of the flora and 
fauna have changed. Even in this short time a journey has in 
reality been effected from the equator to the pole ; yet the lie 
of the land is the same, and the air is the same, the whole at- 
mospherical conditions are only slightly modified, with one 
great exception — and that exception is, temperature. 
Difference of temperature is thus shown to be sufficient to 
gather the products of all the different zones of the earth into 
one small region, demonstrating practically and plainly the 
importance of temperature to every inhabitant of this world. 
Any contributions, then, which are made to our knowledge of this 
the most important factor in climate, must deserve and receive 
interest and attention from every one. More particularly is this 
the case when the contribution is made by the Meteorological 
Office, as in the case of the recently-published Tables; for, 
coming from such a quarter, it carries a guarantee that the 
observations have been taken with that regard to uniformity 
both of instruments and exposure which is so necessary for a 
proper comparison of the temperatures of different places. In- 
structions for taking temperature observations have been pre- 
pared ; and in many cases every effort has been made to secure 
uniformity in the hours of observation, the nature of the screen, 
and in the instruments from which the observations are to be 
