148 ANNUAL REPORT SMITHSONIAN INSTITUTION, 194 



If you drive an automobile you have no doubt experienced a time 

 when the car developed engine trouble. The motor sputtered and 

 backfired; it ran haltingly and noisily. You took the car to a 

 garage where a trained mechanic rolled up his sleeves and got out 

 an assortment of tools and wrenches. He regulated the carburetor 

 and made other minor adjustments. Soon the engine began to run 

 smoothly and quietly, quickly gaining its full efficiency. 



It may be that every human being is like the automobile engine 

 that is not quite correctly adjusted. It may be that tiny adjustments, 

 if we knew how to make them, would open up the potentiality of 

 genius for every child. Perhaps that hope is extravagant, but 

 there seems every reason to believe that the time is coming when 

 far more will be accomplished to insure stronger bodies, healthier 

 nerves, stabler dispositions, and keener minds for every child than 

 at the present time. 



V 



Physics derives its fourth great cultural value from the fact that 

 it is the foundation stone of all attempts to understand the universe. 

 We have just been considering the basic relationship which physics 

 bears to chemistry and biology. That relationship applies equally 

 to astronomy and cosmogony. I attempted to trace this essential 

 unity of the universe in my first book. The Story of Science (9). 



The universe is one. The same fundamental laws that govern 

 the electrons in the atom control the stars in the Milky Way. 

 Modern science has achieved its greatest triumph in tracing the 

 organization of the universe from the tiny electron to the great clouds 

 of galaxies. This has been done with the aid of physics. Perhaps 

 it was in tliis field that the importance of physics was first most 

 clearly realized. Galileo was an astronomer as well as a physicist 

 and the laws which he and later Newton developed were seen at 

 once to apply to the heavens as well as the earth. Appropriately 

 enough the study of planetary motions was christened "celestial 

 mechanics." 



Newton in his law of universal gravitation stated a rule that 

 applies as truly to the double star 500 light-years away as it does 

 to the apple falling from the branch of a tree. 



The kinship of physics and astronomy became clearer with the 

 investigations of the nature of light and the invention of the spectro- 

 scope, and this kinship was duly celebrated with the christening 

 of this branch of study as "astrophysics." 



In his attempts to solve the problem of the evolution of the galaxy, 

 the genesis of the sun's heat, the origin of the solar system, and 

 many other fascinating problems of the heavens, the astronomer 

 turns to the knowledge which the physicist has accumulated about 



