Clarence King. 235 



maze of phenomena successfully, but I prefer to build no 

 farther until the underlying physics are worked out." He 

 was at that time already very strongly impressed with the 

 imperfection of the then existing knowledge of terrestrial 

 thermo-dynamics and the indispensability of more exact data 

 in this branch of science for a rational discussion of the funda- 

 mental problems of geology. 



This idea found a practical outcome a few years later in the 

 establishment of a physical laboratory, immediately after his 

 assumption of the Directorship of the United States Geologi- 

 cal Survey. His earnestness and energy is shown by the fact 

 that instead of waiting for the slow action of Congress, he 

 defrayed the cost of the delicate apparatus necessary for this 

 work out of his own pocket. The credit of the brilliant 

 physical investigations carried on in that laboratory is naturally 

 due to Professors Barus and Hallock, who conducted them, but 

 it was King's acumen and good judgment that was responsible 

 for their selection, and his action that made it possible for them 

 to carry on their work. To himself, as he says ten years later 

 in his paper on the Age of the Earth (this Journal, vol. xlv, 

 Jan. 1893), he reserved the privilege of " making geological 

 applications of the laboratory results." The experiments on 

 the physical constants of rocks contemplated were to be directed 

 to the determination (a) of the phenomena of fusion, (b) of 

 those of elasticity and viscosity, and (c) of those of heat con- 

 ductivity, each considered with special reference to their 

 dependence on temperature and pressure. 



The paper on the Age of the Earth, mentioned above, is his 

 only published result, and was but an earnest of what he had 

 planned to do. This was an attempt to advance to new pre- 

 cision Kelvin's estimate of the earth's age deduced from terres- 

 trial refrigeration. It consists mainly of a mathematical 

 discussion of the earth's thermal age as determined from 

 various postulates presented by Laplace, Geo. H. Darwin, and 

 Lord Kelvin, and based on Barus' determinations of the latent 

 heat of fusion, specific heat, melted and solid, and volume of 

 expansion between the solid and melted state, of the rock 

 diabase. This is followed by a critical examination of other 

 methods of determining the earth's age — by tidal retardation, 

 by sun-age, and by variations of eccentricity. After a careful 

 scrutiny of all the data on the effect of pressure on the temper- 

 ature of consolidation, King concluded that, without further 

 experimental data, " we have no warrant for extending the 

 earth's age beyond 24 millions of years," an estimate which, 

 as the result of a somewhat more extended discussion, was 

 afterwards confirmed by Lord Kelvin himself. (Smithsonian 

 Beport, 1897, p. 345.) 



