.<^().u/r coxTF.MroR.iRy .ii>i:i.\( is i\ riivsus- /.v m7 



iniulil li\ till' l.uM.s of llir Sl.ili()H.ir>- St.itrs.'' (Oiild we lur iiisLinci- 

 ^11 sli,i|H- llu- first proN iso, lOiilil Zi.r choose such local ions for Ihc electrons 

 iissumcd stationary, tluit tlu' sodium atom (for instaiuv) would dispKiy 

 onI\' those i-nerny-valui's whicli the spectrum of sodium allows for its 

 Stationar>- States, and no others? 



IndouhtedK' we coidil. The sodium atom is supposed to ronsist 

 (>! i'le\en eleelrous surrouiuliiij; a luieleiis of charge + 1 \e. If the elec- 

 trons were all stationary in assigned positions about the nucleus, we 

 could calculate the energy of the arrangement. The energy-values of 

 the vaiious Stationary States being known, it would not beditTicult to 

 tind, for each one of the Stationary States, at least one arrangement of 

 the eleven electrons identical with it as to energy-value. Having done 

 this, we could lay it ilown as a law that the electrons shall stand still in 

 e.ich and any one of these arrangements; but not in an\- other ar- 

 rangement whatsoevei. 



But would this be an explanation of the Stationary Stales? Not. 

 I think, in any significant sense of that valuable word. It could 

 justly be designated as an explanation, as a theory, only if the various 

 arrangements so prescribed for the various Stationary States should 

 turn out to be interrelated according to some law — to be goxerned 

 by some unifying principle — to display some intrinsic quality of 

 simplicity and elegance and beauty, distinguishing them from all 

 the other and rejected arrangements. This has not been achieved. 



Let mc now take up the other of the two suggestions which were 

 made above. Suppose that we accepted the nuclear atom-model, 

 with the proviso that the electrons should revolve in closed orbits 

 planetwise, without radiating any of their energy, and without gliding 

 by a spiral path into the nucleus. Could we so shape this second 

 proviso, could we choose such orbits for the electrons assumed revolving, 

 •icilhout loss of energy, that the sxlium atom or the hydrogen atom (for 

 instance) would display only those energ\-values which the spectrum 

 of sodium or the spwctrum of hyflrogen prescribes for the Stationary 

 States, and no others? 



.Again, there is no doubt that we could; but the value of the achieve- 

 ment, again, would depend on whether oi not the orbits which we thus 

 selected were interielated according to some law, or governed by some 

 unif\ing principle, or distinguished from all the other orbits by some- 

 thing seemingly fundamental. Consider Rutherford's nKnlel for the 

 hydrogen atom, which consists of a nucleus and an electron. If we 

 adopt the proviso which was just set forth, and suppose that the elec- 

 tron may revolve around the nucleus in circular orbits without radiat- 

 ing any of its energy, then we can select particular circular orbits, such 



