The times., 1900-12-23


condition of vapor. and that it formed an
enormous nebulous mass many times
larger than the then known dimensions
Of the planetary sphere. He showed how'
under the influence of gravitation, this
nebula would condense and that such
irregularities of motion and density as
would be sure to exist would lead to ro-
tation of the mass. Under the law of
zravitation this would lead to outer rings
being left behind by the contraction OF
the central mass, which rings would az
later period become drawn together AT
some point of initial greater density and
thus form planets. The whole process is
admitted to be automatically demon
| strabIe given the initial conditions; but
| recent extensions of our knowledge OF the
| interplanetary and interstellar spaces
have shown that the supposed void Is
! really full OF invisible solid matter. rang
| ing from The bulk of the smaller planets
| down to the finest dust, and 1t is very
| difficult to imagine any possible causes
which could keep all the solid matter OF
| the system in a state OF vapor, when
| subject on the confines of the mass, TO
the cold of interstellar space. The ante
cedent condition of our system is now
thought TO have been either wholly or
| partially meteoritic, but in either case
we have a genuine theory Of its evolu-
| ton which has now been so extended as
! to include the appearance of comets and
| Ineteors, of nebulae and star clusters, OF
| temporary, periodic and colored stars.
| and many other phenomena OF the stellar
universe. 1t is no objection to these
| grand theories 20 urge that they do not
explain the origin of the matter of the
| universe, either what it is or how it came
| to be where we now find it. We can only
| taIe one step at a time; and even II in
these greater problems any further ad-
vance should be as yet denied us, 1t is
| still great thing to have been able to
| take even one secure step into the vast
and mysterious depths of the interstellar
| spaces.
EVOLUTION OF TIE EARTH'S CRUST.
Although Pythagoras $500 B. c. believed
that sea and land must often have changed
places. and few other observers at diff
| ferent epcchs came to the same conclu-
sion. yet till quite recent times the earth
was generally supposed to have been al
ways very much as it is now; people spoke
of 'the eternal hills" and the great
mountain ranges, the mighty ravines and
preeipices, as well as the deep seas and
oceans, were believed to be the direct
work of the Creator.
1t was only In the latter half Of the
eighteenth century that few obs eryers
began to see the Importance Of studying
the nature of the earths crust, so far as
it could be reached in ravines, quarries,
and mines; and one OF the most earnest
of these students. Dr. iutton of Edjn-
burgh, after more than thirty years Of
| travel and study, published his great
work. THE Theory of the Earth which
must be considered to be the starting
point of modern geology. He maintained
that 1t was only by observing causes nov
in action that we can explain the phenom-
ena presented by the stratifed and igne-
Gus rocks; he showed that the former
must have been laid down by water. and
that the larger part Of them, containing
must have been deposited on the sea bot
tom. He showed how rain and rivers,
frost and snow. wind and heat disinte-
| grated the hardest rocks and would in
| tine excayate the deepest valleys; while
earthquakes, however small an elevation
any one of them might produce, would in
time raise up the sea bottom sufficiently
high to form, when denuded. mountain
ranges plains. and valleys like those we
row see everywhere upon the earth's sur
face. He also showed that the most an
cient stratifled rocks. those that lie at the
very base OF the series. presented ever.
indication of having been formed in ex-
actIy the same way as the most recent
oaes Hence he stated a conclusion which
excited a storm of opposition, in these
words: 'fIn the economy of the world
can find no traces Of beginning. no pros
pect of an end" This was thought tC
imply a denial of creation, and was quite
sufficient at that period to prevent the
work of any man of science from being
judged impartially.
But although Playfair and a few other!
upheld Hutton's views, they were too move
to receive much support by his contempo-
raries, and eis was especially the cast
as regards the slow and continuous actor
Of existing causes being sufficient to &C.
count for all the known phenomena pre-
sented by the crust of the earth. Hence
the belief in catastrophes and cataclysms-
in great commissions tearing mountains
asunder, and vast floods sweeping oveI
whole ontinents-continued to prevail, til
finally hanished by the genius and perse-
verance OF one man-Sir Charles Lyell
His "Prirciples of Geology" was first pub
lished in $780, and successive editions, re-
vfsed and cften greatly extended. continued
to appear till the authors death forty-fivC
years later As this work affords q fine
example OF the application OF the prin-
ciples Of evolution to the later phases o
the earth's history, and as 1t not onl!
rcvoIntlonized scientific opinion in its Owl
domain, but prepared the way for the ac-
ceptance OF the still more novel and start
ling application OF the same principles K
the entire organic world. It will be neces
sary to show what opinions prevailed al
the time it first appeared in order that We
may understand how great was the chang
it effected
, In the earlier years OF the nineteenth
century the standard geological work
/ both in Great Britain and on the Contin
ent, was Cuvier's Essay on the Theor
Of the Earth" In 1927 a fifth edition o
the English translation appeared, aLt
there was German translation so lat
, as 1s30-suficient proofs of its wide popu
larity. Yet this work abounds in state