November 4, 1921] 



SCIENCE 



423 



know something about what he has done for 

 humanity. 



If every annual crop of starch- or sugar- 

 containing plants can furnish us an abundance 

 of liquid fuel and solvents under the form of 

 alcohol, we may look at this from another point 

 of view and call it simply the stored-up energy 

 of the sun. The photochemical action of the 

 sun rays under the influence of the chlorophyl, 

 or green matter of the plant leaves, brings 

 about the most subtle creative chemical synthe- 

 sis. Carbon dioxide, a product of combustion, 

 one of the ultimate destruction products of 

 plant or animal life, combines with water under 

 the action of sunlight. Dead matter reenters 

 the process of life. The first, or one of the first 

 products of this synthesis is formaldehyde ; the 

 latter, in its turn, inaugurates a succession of 

 further chemical syntheses which result in the 

 formation of sugars, starch, cellulose, and other 

 carbohydrates. 1^0 sun, no photochemical 83ra- 

 thesis, no crops — no life ! So that, after all, the 

 whole living world is dependent upon a delicate 

 photochemical reaction. Starvation, on one 

 hand, or abundance of crops and foodstuffs, 

 on the other, all within the range of photo- 

 chemistry. 



In the same way, our vast coal beds and our 

 petroleum wells and our natural gas, are merely 

 the result of light energy stored up from the 

 plant or animal life of former geological 

 periods. This, in itself, ought to impress us 

 with the enormous possibilities of photochem- 

 ical synthesis. And yet, here is a field where the 

 scientist or engineer has accomplished next to 

 nothing. In the utilization of this marvelous 

 energy, we have not gone much beyond the art 

 of making photographs. 



So here is a power, an energy, which has been 

 much neglected by scientist and engineer alike. 

 Where is the Faraday, the Ampere, the Leon- 

 ardo da Vinci, where is the Archimedes who 

 shall show us how to use the sun rays for charg- 

 ing our electrical storage batteries, or who 

 will teach us how to handle the photochemical 

 action of sunlight, or to emulate nature in her 

 synthesis of plant life? Who will utilize this 

 delicate method instead of our hitherto brutal 

 processes of synthesis. Nature in her methods 



of plant life synthesis does not treat with boil- 

 ing solutions of alkalies or strong acids; she 

 uses no high temperatures nor strong electric 

 currents. If we want to be successful in this 

 direction, we shall have to utilize equipment 

 possessing large exposed surfaces similar to 

 the leaves of plants. We may have to operate 

 in rather dilute solutions instead of the con- 

 centrations which are ordinarily used in our 

 present methods. We may have to find means 

 for rapidly separating the formed products as 

 fast as they accumulate. We may be compelled 

 to work within narrow ranges of temperature, 

 perhaps not exceeding those outside of which 

 plant life stops. 



But who knows what surprises are in store 

 for us and how we may simplify all this after 

 the subject once begins to receive enough atten- 

 tion. 



In the past, scientists have taught the engi- 

 neers how to transmute the forces of nature, 

 but this took a very long time. About a cen- 

 tury and a half ago, Lavoisier, by his memor- 

 able work in chemistry, got as far as to ex- 

 claim : " In Nature nothing is created, nothing 

 is lost, there are only transformations." But 

 he was thinking of maMer as such. It took 

 almost a century more before Mayer and Joule 

 proclaimed the same truth in physics as far as 

 forces of Nature or energy are concerned. Our 

 present conception of the conservation and 

 transformation of energy are of rather recent 

 date. Nor were these fundamental truths 

 readily accepted without opposition. Since 

 then, progress has been rapid. Scientists and 

 inventors alike have taught the engineer how 

 to transmute the forces of Nature. 



Let us take, for instance, a well-known chem- 

 ical reaction— the oxidation of carbon and 

 hydrogen; whether this oxidation be accom- 

 plished simply by the burning of coal, gas, or 

 oil in furnaces under a steam boiler, or by the 

 internal combustion in any variety of a gas 

 engine, it gives heat which in turn is trans- 

 formed into motion or motive power, which 

 runs our factories, our ships, our trains, our 

 automobiles, our flying machines. Or, in- 

 versely, motion can be turned into an equiva- 

 lent amount of heat by friction or otherwise, as 



