MCGE E 



tension of human faculty to pu-rposive pre-combinations of such 

 sort as to afford prompt verification of inferences and confident 

 demonstration of natural relations ; so that this first pillar of 

 Science may be deemed the gift of Astronomy as to material, 

 and of Chemistry as to structure and useful setting. 



The doctrine of the indestructibility of matter was at once 

 the fruit of a philosophical renovation and the seed of an in- 

 tellectual reformation ; for, as it ripened in mind after mind and 

 was sown broadcast by the slow but persistent processes of 

 the times, it generated new inquiry and experiment, which at 

 the same time gave sustenance to many hungry minds and fur- 

 nished fresh seed for yet other minds. Among the conse- 

 quences of the intellectual quickening were certain exper- 

 iments by Benjamin Thompson, or Count Rumford, which, 

 when described in 1798, served to transfer the discussion of 

 temperature from the domain of metaphysics to that of physical 

 inquiry and to demonstrate that heat is a manifestation of mo- 

 tion ; Thompson was soon followed by Sir Humphry Davy 

 and half a century later by Dr. J. P. Joule, who repeated and 

 extended the experiments and fixed the mechanical equivalent 

 of heat. Then came a brilliant coterie of physicists, Grove, 

 Faraday, Helmholtz, Tyndall, and others, who verified the de- 

 terminations by means of special experiments and by compar- 

 ison with general human experience, established the inter- 

 changeabiHty (or correlation) of forces, and gradually organized 

 their growing knowledge in a system revealing another cardinal 

 principle — the conservation of energy, or (preferably, in view 

 of Thompson's terminology and of later researches) The Per- 

 sistence of Motion. This new principle met a mental need, 

 and found so many applications that it came to be regarded as 

 the most important discovery of the centur}^. Originally the 

 gift of Physics, it was soon extended into the realm of organic 

 life by Liebig and others in Germany and by Carpenter in 

 Britain, and only a few years later it was pushed into the realm 

 of mental action by LeConte and Barker in America. For 

 half a century the inconstructible and indestructible motion en- 

 livening the universe was assumed to be constant only in the 

 universe as a whole and constantly variable in the constituent 



