THE PROGRESS OF PHYSICS IN TWENTY-FIVE 

 YEARS— 1891-1915 



Frank P. Whitman 



Early in the year 1901 Professor T. C. Mendenhall wrote 

 — for the Nezv York Sun, I think, — an excellent summary of 

 the progress, or I might almost say. the creation, of physics in 

 the 19th century. He classifies the subject under the familiar 

 rubrics of energy, heat, light and electricity, and summarizes the 

 extraordinary development of each. It is a familiar story, but 

 it brings to the mind in a way that is still impressive the fact 

 that i)hysical science as we know it today, heat and its laws, in- 

 cluding the dynamical theory, light with its two huge wings of 

 infra-red and ultra-violet radiation, electricity with its marvelous 

 theoretical development and its two capital discoveries of the 

 electromagnet and the induced current, the extraordinary theo- 

 retical structures of the molecular nature of matter on the one 

 side and the all pervading ether on the other, had not only their 

 great development, but with small exceptions their very begin- 

 nings within these hundred years. l>ut another thought comes 

 with fully as much force as one reads this record ; the familiarity 

 of it all. All these things have l^een known to us — to the oldest 

 of us — from our youth up. Rumford and Davy, Fourier, 

 Mayer, Helmholtz, Kelvin, Joule, laid the foundations and reared 

 the superstructure of the doctrine of heat by the middle of the 

 century ; the great experimental and theoretical bases of optics 

 recall the names long gone by, of Young, Fresnel, Mains, Wol- 

 laston, Kirchoff and Bunsen ; electricity was brought to its full 

 strength under the hands of Oerstedt, Ampere, Faraday, at a 

 comparatively early period, and the genius of Maxwell welded 

 the two sciences together before the century was three quarters 

 gone. We come up to the period at which our review begins 



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