NATURAL PHILOSOPHY — SWANN 241 



everything were maofnified in mass so that the electron attained 

 a mass of four ounces, that four ounces woukl on the same scale 

 of magnification become as heavy as the earth. 



Before the discovery of electrons we had cause to believe that 

 there were such things as atoms and molecules, but nobody ven- 

 tured to picture their structure, and we felt we had gone far in 

 penetrating nature's mysteries when we were able to say that, on 

 the basis of certain plausible considerations, it was probable that if 

 a drop of water were magnified to the size of the earth, the mole- 

 cules would become as large as small shot. The discovery of the 

 electron gave a fresh impetus to man's hojoe of understanding the 

 atom, and before long the second fundamental brick of nature's 

 structure revealed itself — the fundamental unit of positive electric- 

 ity — the proton, whose natural home is in the nucleus, the heart 

 of the atom. The proton is two thousand times as heavy as the 

 electron, but it is two thousand times as small, so that if the proton 

 were magnified to the size of a pinhead, that pinhead would, on the 

 same scale of magnification, attain a diameter equal to the diameter 

 of the earth's orbit around the sun. 



At the end of the last century Rontgen discovered X rays. The 

 property by which they first claimed attention was their power to 

 pass through flesh and so show shadows of the bones of the body. 

 Soon, however, it was realized they were endowed with many other 

 properties of a most important and interesting kind, properties 

 which were bound up with the atom's structure and whose study, 

 therefore, served to throw further light upon that structure. 



Until the end of the last century, one of the most firmly established 

 beliefs was that of the permanence of the atoms. However, near its 

 close, Becquerel found certain curious properties of uranium oxide 

 which suggested that this substance was continually emitting some 

 kind of a radiation which could pass through screens opaque to light, 

 and affect a photographic plate. Several other substances were dis- 

 covered possessing this property, and many other characteristics of 

 these substances were discovered, characteristics which could only be 

 harmonized on the belief that the atoms of these substances were in 

 a continual state of spontaneous disintegration — of atomic explosions 

 if you will — and that the phenomena observed were the symbols of 

 these explosions. 



One may naturally be led to inquire how far discoveries in pure 

 physics and mathematics find their reflections in the things of every- 

 day life in the sense which we call useful. If in a great city we 

 should set out on our travels with the intention of visiting all the 

 places within the field of our immediate interests to the exclusion oi 

 others, and if we should refuse to walk along any street which did 

 not itself contain many of these places, then, even as regards those 



