Unification of Energies 19 



spun, and we find that in spite of all its multitudinous 

 diversity it is all the same. 



The qualitative differences between different kinds 

 of things turn out to be quantitative, since they de- 

 pend on differences in the number and orbits of the 

 revolving electrons and on the number of hydrogen 

 nuclei or protons in the center of the atom. This must 

 not lead us to overlook the fact that newness in the 

 truest sense may emerge from new collocations of the 

 same components. Out of Carbon, Hydrogen, Oxy- 

 gen, Nitrogen (C, H, 0, N) — the "Big Four" ele- 

 ments — may be made a poison or a tonic, an ex- 

 plosive or a food, a medicine or an aroma. Out of the 

 same bricks and mortar — and a few girders — you 

 may build a street of hovels or a Westminster Cathe- 

 dral. 



§10. The Unification of Energies. 

 Another great unification of recent times concerns 

 the energies. Benjamin Thomson or Count Rum- 

 ford was one of the early investigators to grasp at 

 the idea that heat is a mode of motion. Motion gives 

 rise to heat and heat gives rise to motion. It was 

 plain that part of the energy of an incandescent body 

 may be given off as light, and it was reserved for 

 Faraday and Clerk Maxwell to discover the electro- 

 magnetic nature of light. Thus light, electricity, 

 magnetism come into one series of energies. But a 

 further great unification follows from Einstein's 

 theory, — for gravitation also comes into line with 

 the other powers, — and the world is unified in its 

 energy as well as in its matter. 



