SUMMARY AND CONCLUSION 565 



all of recorded pre-Pleistocene time seem to me to present a very strong 

 presumptive case for a source of heat supplied by the earth itself. I am, 

 of course, perfectly well aware that this view is counter to the pronounce- 

 ment of the physicists and mathematicians, who are very emphatic in 

 their opinion that the earth could never have supplied more than a small 

 increment of the heat that is obviously called for. On the other hand, it 

 seems to me absolutely impossible, from the data as presented in the fore- 

 going pages, that the sun could have supplied the heat requisite to warm 

 the early oceans. We are told that at the present time the snn supplies 

 more than 2,000 times as mnch heat as is supplied by the earth itself; 

 yet since Pleistocene time, when the present system of solar control is 

 believed to have been established, it has not been able to warm the oceans 

 as they were certainly warmed in pre-Pleistocene time. Furthermore, 

 solar control is fatal to non-zonal climates, polar geniality, and tropical 

 or subtropical glaciation. If the sun was the dominant factor in main- 

 taining temperatures on the earth during all recorded geologic time, how 

 or Avhy did it fail in Pleistocene time? I can not escape the conviction 

 that more weight must be attached to the contention that the earth itself 

 has supplied a greater amount of heat than is now admitted to be possi- 

 ble. I do not see how the ascertained facts can otherwise be explained. 

 Whether this heat came from the original earth heat, or from some aug- 

 mented form of radioactivity, or from a combination of both sources, I 

 am not prepared to say. If the mathematicians and physicists had al- 

 ways been right in their pronouncements on earth history, we might have 

 more faith ; but, to mention only one recent instance, after the experience 

 in the fallibility of these arguments in determining the age of the earth, 

 which has been so completely upset by the newly discovered factor of 

 radioactivity, it is at least unwise or unsafe to put a too rigid dependence 

 on them. As Huxley once said : 



"Mathematics may be compared to a mill of exquisite workmanship, which 

 grinds jou stuff of any degree of fineness ; but nevertheless what you get out 

 depends upon what you put in ; and as the finest mill in the world will not 

 extract wheat-flour from peascods, so pages of formulae will not get a definite 

 result out of loose data." 



Therefore, it seems to me to be well within the limit of possibility that 

 there may be factors in this problem of earth heat that are not properly 

 evaluated or are unsuspected or undetected which may vitiate or modify 

 previous results. 



