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SCIENCE. 



[N. S. Vol. XVII. No. 434. 



final attempt to press into the citadel of a 

 cardinal truth may cost more effort than 

 all of the approach through the outer 

 works. 



However, we have gained a store of 

 knowledge about materials, energy and 

 organic life, and have organized it in such 

 a way that it seems to point to a few great, 

 generalized facts. We apparently have 

 learned that nature is never idle, but that 

 she is a persistent worker with a steady, 

 cumulative activity in which there is ever 

 a unity and no discontinuity; that there 

 is an ever-present ' dovetailedness ' as Dick- 

 ens, I think, put it. Nature's activities 

 are not isolated and independent of each 

 other, but are apparently all in intimate 

 relation, and governed by the same all- 

 pervading fundamental laws. This is the 

 foundation on which the engineers of the 

 present century have to work. Meager as 

 it is, it is far in advance of that occupied 

 by their predecessors of one century ago. 



Of fundamental laws we seem to have 

 proved two — the law of the conservation 

 of energy, as it is called, and the law of 

 organic evolution, which controls the de- 

 velopment of life through the 'survival of 

 the fittest.' I spoke of these as proved, 

 and so they have been as far as they relate 

 to the problems of our daily life ; but they 

 have been rather deduced by inference, as 

 far as the universe at large is concerned, 

 than established by demonstrations. The 

 law of evolution has been so widely dis- 

 cussed in type and speech, that I may as- 

 sume on the part of each of you some 

 knowledge of its doctrine, and I win at 

 once pass on. 



The law of conservation of energy as- 

 serts that energy can not be created nor 

 destroyed. We may transform energy in 

 any manner within the compass of our in- 

 tellect, but we finish with the same amount 

 of energy as we started with. We may 

 transform the chemical energy of coal, by 



combustion in a boiler furnace, into heat 

 energy, and this may be utilized to 'raise 

 steam.' The energy in the steam may be 

 transformed into mechanical energy by 

 means of a steam-engine, and this into 

 electrical energy by a dynamo. The elec- 

 trical energy will be less than the original 

 chemical energy because some of the heat 

 has gone to contribute warmth to the sur- 

 rounding air and solid bodies, but the 

 available electrical energy added to all of 

 this heat (which has not been destroyed,- 

 mind you, but continues to exist as heat) 

 makes a sum which exactly equals the 

 original chemical energy in the coal. 



Another fundamental law has been or- 

 dinarily accepted as governing ; this relates 

 to matter. You all know that matter is 

 apparently indestructible. Transform it 

 as we may; change, by combination, the 

 matter which we call hydrogen and that 

 which we call oxygen into that which we 

 call water ; again, combine this with metal- 

 lic sodium to form caustic soda; again, 

 form other combinations or compounds — 

 through them all we have apparently 

 transformed matter without gain or loss, 

 and hold the same mass at the end of our 

 transformations as we held at the begin- 

 ning. The chemists have been making a 

 very thorough study of this idea for years 

 past, and they do not seem convinced that 

 it represents a universally applicable law; 

 but for all present purposes of the engineer 

 it may be safely accepted. 



In accordance with these laws relating 

 to matter, energy and life, and their 

 myriad corollaries, the professional en- 

 gineer must carry on his work through the 

 discovery of scientific principles and their 

 useful combinations. Invention is no 

 longer a mere question of designing a 

 working machine. That may now be safely 

 left to the skilled mechanic; while the 

 engineering inventor must discover new 

 combinations of scientific principles and 



