66 Lord Kelvin on the Age of the 



V. The Age of the Earth as an Abode fitted for Life. 

 By the Eight Hon. Lord Kelvin, G.C.V.O. * 



§ 1. rilHE age of the earth as an abode fitted for life is cer- 

 JL tainly a subject which largely interests mankind in 

 general. For geology it is of vital and fundamental impor- 

 tance — as important as the date of the battle of Hastings is 

 for English history — yet it was very little thought of by 

 geologists of thirty or forty years ago ; how little is illus- 

 trated by a statement f, which I will now read, given originally 

 from the presidential chair of the Geological Society by 

 Professor Huxley in 1869, when for a second time, after a 

 seven years' interval, he was president of the Society. 



" I do not suppose that at the present day any geologist would he found 

 ... to deny that the rapidity of the rotation of the earth may be 

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

 be cooling. Most of us, I suspect, 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." 



§ 2. I believe the explanation of how it was possible for 

 Professor Huxley to say that he and other geologists did not 

 care for things on which the age of life on the earth essen- 

 tially depends, is because he did not know that there was 

 valid foundation for any estimates worth considering as to 

 absolute magnitudes. If science did not allow us to give any 

 estimate whatever as to whether 10,000,000 or 10,000,000,000 

 years is the age of this earth as an abode fitted for life, then 

 1 think Professor Huxley would have been perfectly right in 

 saying that geologists should not trouble themselves about 

 it, and biologists should go on in their own way, not en- 

 quiring into things utterly beyond the power of human 

 understanding and scientific investigation. This would have 

 left geology much in the same position as that in which 

 English history would be if it were impossible to ascertain 

 w T hether the battle of Hastings took place 800 years ago, or 

 800 thousand years ago, or 800 million years ago. If it were 

 absolutely impossible to find out which of these periods is 

 more probable than the other, then I agree we might be 

 Gallios as to the date of the Norman Conquest. But a 



* Communicated by the Author, being the 1897 Annual Address of the 

 Victoria Institute with additions written at different times from June 

 1897 to May 1898. 



t In the printed quotations the italics are mine in every case, not so 

 the capitals in the quotation from Page's Text-book, 



