THE PEOGBESS OF SCIENCE. 



221 



more prominent men in science. The 

 various papers are quite largely devoted 

 to statements of the unsolved practical 

 and theoretical problems, in so far as 

 they are capable of statement. 



In the line of theory and research 

 the most promising field seems to be 

 the development of the electron theory 

 which has been in the past mainly built 

 up on experimental studies of the elec- 

 trical discharge in gases. This theory is 

 an attempt to represent all electrical 

 phenomena in terms of the conception of 

 the electron, an excessively minute 

 charged particle, a thousand times 

 smaller than an atom. This theory has 

 already given a remarkably clear in- 

 sight into the electrical properties of 

 gases, and tentative explanations of the 

 most promising kind of the ultimate 

 constitution of matter, and of tlie na- 

 ture of gravitation, two of the most 

 stupendous problems of the present day 

 in physics. 



Among the purely practical prob- 

 lems, purely practical because the scien- 

 tist has, one might almost say, given it 

 up in despair, is the production of elec- 

 trical energy direct from coal. One can 

 say almost to a certainty that if one 

 is to transform a large percentage of the 

 latent energy of coal into electrical en- 

 ergy the coal must not be burned. The 

 mischievous waste at present endured 

 seems to be inherent in the burning 

 process, but the wildest dreamer has 

 never imagined that coal can be of any 

 use other than for feeding a fire! There 

 does seem to be a difficulty here, and per- 

 haps the example of the scientist who 

 revels in thermodynamics might just as 

 well be followed by the inventive prac- 

 tical man. One thing, however, is cer- 

 tain and that is that the solution of this 

 problem depends upon the invention of 

 a new kind of fire which can be stopped 

 in mid air, as it were, by a turn of the 

 hand, each atom of carbon and each 

 atom of oxygen stopping its mad whirl 

 to begin it again at our pleasure, stand- 

 ing in the meantime in a state of quiet 

 expectancy. Such a fire the physicist 

 would call a reversible fire. The burn- 



ing of zinc in a voltaic cell is indeed 

 such a fire, and most of the attempts to 

 transform the latent energy of coal into 

 electrical energy efficiently liave been 

 attempts to construct a voltaic cell 

 which will burn coal. Another kind of 

 reversible fire might be realized in the 

 gas engine if we had materials, to build 

 a gas engine of, which would stand ex- 

 cessively high temperatures and exces- 

 sively high pressures. In such a gas 

 engine a mixture of gas and air could 

 be enormously compressed and made so 

 hot that it could not burn, then by ex- 

 panding the mixture combustion would 

 slowly take place and in such a way 

 that to stop expanding would be to 

 stop the combustion. Such combustion 

 would be reversible, for to recompress 

 the mixture would literally unburn it. 

 Such a gas engine would have a very 

 high efficiency if one could keep the 

 cylinder from being cooled by the sur- 

 rounding air. 



The burning of food in the body of 

 a Avork horse is a case in which an un- 

 usually large percentage of the latent 

 energy of the fuel, or food, is converted 

 into useful work, and thermodynamics 

 tells us beyond peradventure that this 

 high efficiency must be due to a state of 

 affairs something like the following: 

 Let us imagine the muscles built up of 

 enormously complicated molecules, like 

 the molecules of albumin for example, 

 and let us imagine that as a muscle con- 

 tracts these complicated molecules are 

 distorted slowly, and that as they be- 

 come distorted some of the atoms of 

 carbon and hydrogen are slowly bulged 

 out of the molecular structure and gin- 

 gerly allowed to approach the atoms of 

 oxygen in the blood in such a way that 

 the process would be arrested at any 

 moment by a cessation of the contrac- 

 tion. If such a process could be com- 

 pletely realized and if the atoms of 

 oxygen could also be kept at bay by 

 being themselves involved in some 

 fashion in the bulging process of the 

 muscular structure, then the efficiency 

 of muscular action would be one hun- 

 dred per cent. It is in fact much less 



