Sir A. Geikie—Age of the Earth. 457 



Nearly four years later he emphasized his dissent from what he 

 considered to be the current geological opinions of the day by 

 repeating the same argument in a more pointedly antagonistic form in 

 a paper of only a few sentences, entitled "The Doctrine of Uniformity 

 in Geology briefly refuted." ' 



Again, after a further lapse of about two years, when, as President 

 of the Geological Society of Glasgow, it became his duty to give an 

 address, he returned to the same topic and arraigned more boldly 

 and explicitly than ever the geology of the time. He then declared 

 that " a great reform in geological speculation seems now to have 

 become necessarj'," and he went so far as to affirm that " it is quite 

 certain that a great mistake has been made — that British popular 

 geology at the present time is in direct opposition to the principles 

 of natural philosophy." ^ In pressing once more the original 

 argument derived from the downward increase of terrestrial 

 temperature, he now reinforced it by two further arguments, the one 

 based on the retardation of the earth's angular velocity by tidal 

 friction, the other on the limitation of the age of the sun. 



These three lines of attack remain still those along which the 

 assault from physics is delivered against the strongholds of geology. 

 Lord Kelvin has repeatedly returned to the charge since 1868, his 

 latest contribution to the controversy having been pronounced two 

 years ago.^ While his physical arguments remain the same, the 

 limits of time which he deduces from them have been successively 

 diminished. The original maximum of 400 millions of years has 

 now been restricted by him to not much more than 20 millions, 

 while Professor Tait grudgingly allows something less than 

 10 millions.* 



Soon after the appearance of Lord Kelvin's indictment of modern 

 geology in 1868, tlie defence of the science was taken up by Huxley, 

 who happened at the time to be President of the Geological Society 

 of London. In his own inimitably brilliant way, half seriously half 

 playfully, this doughty combatant, with evident relish, tossed the 

 physical arguments to and fro in the eyes of his geological brethren, 

 as a barrister may flourish his brief before a sympathetic JLiry. He 

 was willing to admit that " the rapidity of rotation of the earth may 

 be diminishing, that the sun may be waxing dim. or that the earth 

 itself may be cooling." But he went on to add his suspicion that 

 " most of us are Gallios, ' who care for none of these things,' being 

 of opinion that, true or fictitious, they have made no practical 

 difference to the earth, during the period of which a record is 

 preserved in stratified deposits." * 



For the indifference which their advocate thus professed on their 

 behalf most geologists believed that they had ample justification. 



1 Proc. Roy. Soc. Edin., yoI. v, p. 512 (Dec. 18, 1865). 



2 Trans. Geol. Soc. Glasgow, vol. iii, pp. 1, 16 (February, 1868). 



^ " The Age of the Earth," being the Annual Address to the Victoria Institute, 

 June 2, 1897: Phil. Mag., January, 1899, p. 66. 

 * " Pecent Advances in Physical .Science," p 174. 

 ^ Presidential Address, Quart. Journ. Geol. Csoc., 1869. 



