OcTOBER 13, 1898. ] 
know must have existed, though no vestige 
of them may remain. 
It may be further asserted that, while it 
was Hutton who first impressed on modern 
geology the conviction that for the adequate 
comprehension of the past history of the 
earth vast periods of time must be admitted 
to have elapsed, our debt of obligation to 
him is increased by the genius with which 
he linked the passage of these vast periods 
with the present economy of nature. He 
first realized the influence of time as a 
factor in geological dynamics, and first 
taught the efficacy of the quiet and unob- 
trusive forces of nature. His predecessors 
and contemporaries were never tired of in- 
voking the more vigorous manifestations of 
terrestrial energy. They saw in the com- 
position of the land and in the structure of 
mountains and valleys memorials of num- 
berless convulsions and cataclysms. In 
‘Hutton’s philosophy, however, ‘it is the 
little causes, long continued, which are con- 
sidered as bringing about the greatest 
changes of the earth.’”* 
And yet, unlike many of those who de- 
rived their inspiration from his teaching, 
but pushed his tenets to extremes which he 
doubtless never anticipated, he did not look 
upon time as a kind of scientific fetich, the 
invocation of which would endow with effi- 
cacy even the most trifling phenomena. As 
if he had foreseen the use that might be 
made of his doctrine, he uttered this re- 
markable warning: ‘“‘ With regard to the 
effect of time, though the continuance of 
time may do much in those operations 
which are extremely slow, where no change, 
to our observation, had appeared to take 
place, yet, where it is not in the nature of 
things to produce the change in question, 
the unlimited course of time would be no 
more effectual than the moment by which 
we measure events in our observations.”’} 
* Theory of the Harth, Vol. II., p. 205. 
Tt Op. cit., Vol. I., p. 44. 
SCIENCE. 
515 
We thus see that in the philosophy of 
Hutton, out of which so much of modern 
geology has been developed, the vastness of 
the antiquity of the globe was deduced from ~ 
the structure of the terrestrial crust and the 
slow rate of action of the forces by which 
the surface of the crust is observed to be 
modified. But no attempt was made by 
him to measure that antiquity by any of 
the chronological standards of human con- 
trivance. He was content to realize for 
himself and to impress upon others that the 
history of the earth could not be understood, 
save by the admission that it occupied pro- 
longed though indeterminate ages in its 
accomplishment. And assuredly no part 
of his teaching has been more amply sus- 
tained by the subsequent progress of re- 
search. 
Playfair, from whose admirable ‘ Illustra- 
tions of the Huttonian Theory’ most geol- 
ogists have derived all that they know di- 
rectly of that theory, went a little further 
than his friend and master in dealing with 
the age of the earth. Not restricting him- 
self, as Hutton did, to the testimony of the 
rocks, which showed neither vestige of a 
beginning nor prospect of an end, he called 
in the evidence of the cosmos outside the 
limits of our planet, and declared that in 
the firmament also no mark could be dis- 
covered of the commencement or termina- 
tion of the present order, no symptom of 
infancy or old age, nor any sign by which 
the future or past duration of the universe 
might be estimated.* He thus advanced 
beyond the strictly geological basis of rea- 
soning, and committed himself to state- 
ments which, like some made also by 
Hutton, seem to have been suggested by 
certain deductions of the French mathe- 
maticians of his day regarding the stability 
of the planetary motions. His statements 
have been disproved by modern physics ; 
distinct evidence, both from the earth and 
* Illustrations of the Huttonian Theory, 2118. 
