August 15, 1919] 



SCIENCE 



145 



that they were actually emitted by a spark in 

 his laboratory, and could easily be detected 

 across the room and at greater distances. 

 This made wireless telegraphy possible. After- 

 wards it was only a question of perfecting the 

 transmitting and receiving devices in order to 

 increase their range. This was no light task, 

 and we owe much to Marconi and others for 

 accomplishing it. But it is plain that wire- 

 less telegraphy could not have been even 

 imagined before the discovery of electric waves 

 in the ether by Maxwell and Hertz. 



Some advances in science are less direct in 

 their application, but even more significant. 

 Of what benefit to the world is astronomy, the 

 oldest of the sciences? I need not dwell on 

 its obvious applications in the measurement 

 of time, in accurate surveys of the earth's 

 surface, in the determination of positions at 

 sea. These uses render astronomy invaluable, 

 but they do not represent its greatest contri- 

 bution to the world. 



To appreciate this, we must turn to the 

 pages of Henri Poincare, in his little book on 

 " The Value of Science." The basis of scien- 

 tific progress is law, and we owe the conquest 

 of law to astronomy. Where would our mod- 

 em civilization be, asks Poincare, if the earth, 

 like Jupiter, had always been enveloped by 

 clouds? Our remote ancestors were creatures 

 of superstition, surrounded by mysteries, 

 startled at every display of incomprehensible 

 forces, accustomed to attribute all natural phe- 

 nomena to the caprice of good and evil spirits. 

 To-day we no longer implore the aid of nature : 

 we command her to do our bidding, because 

 we have learned some of her secrets, and are" 

 constantly solving others. We command her 

 in the name of laws which she can not repu- 

 diate, because they are her own. Recognizing, 

 as we do, the unchangeable basis of these laws, 

 we do not foolishly demand that they be 

 changed, but submit ourselves to them, and 

 utilize them to the advantage of mankind. 



Astronomy taught us the existence of the 

 laws of nature. The Chaldeans, first to ob- 

 serve the heavens attentively, perceived har- 

 mony of motion and sequence of phenomena. 

 Day and night, the round of the seasons, the 

 phases of the moon, the periodic wanderings 



of the planets, held their attention and en- 

 couraged their study. Their work was con- 

 tinued by the Greek astronomers, who dis- 

 covered rule after rule with the simple in- 

 struments at their command. Tyeho Brah'e, 

 Copernicus, Kepler and Galileo pushed for- 

 ward the advance at an accelerating rate, imtil 

 Newton finally announced the oldest, the most 

 accurate, the simplest and the most general of 

 all natural laws. 



Encouraged by these never-ending successes, 

 students turned their attention to the phe- 

 nomena of the earth's surface, and found in 

 their apparent disorder the same harmony and 

 the same reign of law. But the infinite va- 

 riety of nature, the confiict of forces, and the 

 extreme complexity of terrestrial phenomena 

 would have greatly delayed progress if the 

 simple and easily-discovered rules of the 

 heavens had not pointed the way. Faced with 

 discouragement, the physicist or the zoologist 

 could fall back upon the assurance, which as- 

 tronomy had repeatedly afforded, that nature 

 does obey laws. Their task, therefore, was 

 to discover these laws, and to persist in their 

 endeavors until the difiiculties had been over- 

 come. 



I wish that time permitted me to follow 

 Poincare further and to show how the world's 

 debt to astronomy rests not merely upon her 

 initial discovery of natural laws, but also upon 

 her proof that these laws-, once accurately 

 determined, are unchangeable through the 

 centuries, and that they apply in every part 

 of the visible universe. I might also show 

 ,how Copernicus and Galileo, when they dem- 

 onstrated that the sun and not the earth is 

 at the center of our system, smashed into 

 fragments the medieval mode of thought, and 

 reestablished the true methods of science, pre- 

 viously used in more restricted form by the 

 Greeks. If it were still maintained that the 

 task of astronomy has been accomplished, I 

 might point out that only yesterday it demon- 

 strated that the elements and some of the 

 compounds of the chemist are not confined to 

 the earth, but are present in the most distant 

 stars, and that the latest developments of 

 electrical theory and the most recent investi- 

 gations on the nature of matter are tested by 



