206 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1937 



knowledge and art the very existence of which had hitherto been 

 unsuspected. The discoveries of Galileo, Faraday, and Pasteur are 

 such instances. But, to my notion, no such instance has been so 

 dramatic as the discovery of the electron, the tiniest thing in the 

 universe, which within one generation has transformed a stagnant 

 science of physics, a descriptive science of chemistry, and a sterile 

 science of astronomy into dynamically developing sciences fraught 

 with intellectual adventure, interrelating interpretations and practical 

 values. 



I take particular pleasure in mentioning these practical values, for 

 even the most unimaginative and short-sighted, hard-headed, "practi- 

 cal" business man is forced to admit the justification for the pure 

 research^of no preconceived practical use whatsoever in the minds 

 of those who led in its prosecution, and of all degrees of success and 

 significance — which has been directed at the electron. For out of 

 this research have come the following thmgs which all can understand 

 and appreciate: a growing business in manufacture of electronic de- 

 vices which now amounts to 50 million dollars a year in America alone; 

 a total business of some hundreds of millions of dollars a year which is 

 made possible by these electronic devices; innumerable aids to health, 

 safety, and convenience; and an immense advance in our knowledge 

 of the universe in which we live. 



THE BACKGROUND 



In science, as in human afTairs, great events do not occur without a 

 background of development. The electron had an ancestry which 

 can be traced back through the centuries. Its immediate progenitors 

 were the electromagnetic theory of light, spectroscopy, and the leak- 

 age of electricity through gases. First cousins were X-rays and radio- 

 activity and quantum theory, for, out of a background of long investi- 

 gation of bewildering and apparently unrelated phenomena, there burst 

 upon the scientific world the X-ray in 1895, radioactivity in 1896, 

 and the electron in 1897 — all while investigators in the older fields 

 of heat radiation and thermodynamics were finding those bothersome 

 inconsistencies in these hitherto respectable subjects which led to that 

 unexpected extension of Newtonian mechanics now called quantum 

 mechanics. The concept of the electron, behaving according to the 

 laws of quantum mechanics, is now the basis of most of our interpreta- 

 tion of all that falls under the good old name of natural philosophy. 



That only the pioneers of the scientific world were prepared for 

 these discoveries, however, is \vitnessed by the fact that a standard 

 textbook of chemistry \videly used m my student days in 1904 stated 

 that, "Atoms are the indivisible constitutents of molecules," and so 

 late as 1911 a prominent physicist warned his colleagues not to be too 

 hasty in accepting these new-fangled ideas. 



