722 REPORT—1899. 
these things,” being of opinion that, true or fictitious, they have made fio practical 
difference to the earth, during the period of which a record is preserved in stratified 
deposits.’ 4 
ior the indifference which their advocate thus professed on their behalf most 
geologists believed that they had ample justification. The limits within which the 
physicist would circumscribe the earth’s history were so vague, yet so vast, that 
whether the time allowed were 400 millions or 100 millions of years did not seem 
to them greatly to matter. After all, it was not the time that chiefly interested 
them, but the grand succession of events which the time had witnessed. That 
succession had been established on observations so abundant and so precise that it 
could withstand attack from any quarter, and it had taken as firm and lasting a 
place among the solid achievements of science as could be claimed for any physical 
speculations whatsoever. Whether the time required for the transaction of this 
marvellous earth-history was some millions of years more or some millions of years 
less did not seem to the geologists to be a question on which their science stood in 
antagonism with the principles of natural philosophy, but one which the natural 
philosophers might be left to settle at their own good pleasure. 
For myself, I may be permitted here to say that I have never shared this feel- 
ing of indifference and unconcern. As far back as the year 1868, only a month 
after Lord Kelvin’s first presentation of his threefold argument in favour of limit- 
ing the age of the earth, I gave in my adhesion to the propriety of restricting the 
geological demands for time. I then showed that even the phenomena of denuda- 
tion, which, from the time of Hutton downwards, had been most constantly and 
confidently appealed to in support of the inconceivably vast antiquity of our globe, 
might be accounted for, at the present rate of action, within such a period as 
100 millions of years.? To my mind it has always seemed that whatever tends to 
give more precision to the chronology of the geologist, and helps him to a clearer 
conception of the antiquity with which he has to deal, ought to be welcomed by 
him as a valuable assistance in his inquiries. AndI feel sure that this view of - 
the matter has now become general among those engaged in geological research. 
Frank recognition is made of the influence which Lord Kelvin’s persistent attacks 
have had upon our science. Geologists have been led by his criticisms to revise 
their chronology. They gratefully acknowledge that to him they owe the intro- 
duction of important new lines of investigation, which link the solution of the 
problems of geology with those of physics. They realise how much he has done 
to dissipate the former vague conceptions as to the duration of geological history, 
and even when they emphatically dissent from the greatly restricted bounds within 
which he would now limit that history, and when they declare their inability to 
perceive that any reform of their speculations in this subject is needful, or that 
their science has placed herself in opposition to the principles of physics, they none 
the less pay their sincere homage to one who has thrown over geology, as over so 
many other departments of natural knowledge, the clear light of a penetrating and 
original genius. 
When Lord Kelvin first developed his strictures on modern geology he expressed 
his opposition in the most uncompromising language. In the short paper to which 
reference has already been made he announced, without hesitation or palliation, 
that he ‘ briefly refuted’ the doctrine of Uniformitarianism which had been espoused 
and illustrated by Lyell and a long list of the ablest geologists of the day. The 
severity of his judgment of British geology was not more marked than was his 
unqualified reliance on his own methods and results. This confident assurance of 
a distinguished physicist, together with a formidable array of mathematical 
formule, produced its effect on some geologists and paleontologists who were not 
Gallios. Thus, even after Huxley’s brilliant defence, Darwin could not conceal 
the deep impression which Lord Kelvin’s arguments had made on his mind. In 
one letter he wrote that the proposed limitation of geological time was one of his 
1 Presidential Address. Quart. Journ. Geol. Soc. 1869. 
2 Trans. Geol. Soc. Glasgow, vol. iii. (March 26, 1868), p.189. Sir W. Thomson 
acknowledged my adhesion in his reply to Huxley’s criticism. Op. cit. p. 221. 
