54 THE INTER-RELATIONS OF
exterior, though imperceptible, by continuous action through long
periods of time, alter the configuration of land and sea, and give or
take away from the area of the habitable surface of the globe. The
eastern part of England is so little elevated above the level of the
sea, that a subsidence of 100 fathoms would practically place it all
below the waves of the German Ocean, and change Great Britain
into an archipelago of islands, while the county of Essex would cease
to exist.
The production of wind and of the great denuding agents, rain
and rivers and ice, due to rarefaction, evaporation, condensation,
and solidification, to say nothing of thunder-storms, takes us again
into Physics, which science thus appears to be intimately associated
with climate and weather. The "Times" each morning reminds its
readers, by the weather reports received by electricity from places
around our coasts and from the other side of the Atlantic, of the
great assistance now given to the science, though certainly not yet
the exact science, of Meteorology, by electricity. The remarkable
statement was made the other day that on Tuesday last the temper-
ature at Aberdeen was a degree warmer than at Biarritz and 30
warmer than at Nice ; and that at Shields the temperature was 190
warmer than at Lyons, and no less than 270 warmer than at Berne
in Switzerland. Such a statement of a fact so opposed to all our
forefathers' knowledge and to a latitudinal gradation of temperature,
could not have been made before the days of the electric telegraph,
and thus electricity is shown to be a most valuable factor in deter-
mining and making generally known the true climate of various parts
of the globe, and Physics is seen to be, in this indirect manner also,
strikingly associated with Meteorology.
CHEMISTRY AND GEOLOGY.
The science of Chemistry, like that of Physics, is also usually
excluded from the Natural History sciences, but it must be obvious
that chemistry is a great agent in producing both biological and geo-
logical results. In biology, chemistry is accompanied by that force
which altogether transcends human knowledge, vitality, and so in
botany and zoology its operations are occult and cannot apart from
the vital energy be observed. But in geology, chemistry pure and
simple confronts the student on every side.
The first character that arrests the attention of an observer of
any rocky mass is its colour, and this when not white is due to