NO. II STRUCTURE OF THE ATOM — PARSON 6 1 



we have V=4.$x io~ 4 volts. Complications apart, this is within the 

 range of the most sensitive electrometers, but a practical study of the 

 problem shows many difficulties. However, experiments on this 

 matter are in progress. 



Langmuir's recent work on atomic Hydrogen opens up another 

 line of attack, for the H atom should have the same moment as one 

 magneton. Langmuir found that these atoms could be made to 

 travel some distance from the point of their dissociation without 

 recombining, and could then increase the resistance of a coil of fine 

 platinum wire in which they'dissolved. The present author proposes 

 to study the effect of a non-uniform magnetic field on their move- 

 ments. 



Although there has not as yet been any direct detection of the 

 moment of the magneton, it is possible to make a rough calculation of 

 the heat of dissociation of the H 2 molecule from the assumptions of 

 this theory. 



In §5 was given a diagrammatic representation of the H 2 molecule. 



Using the original assumption that the radius of the magneton is 



about half that of the H atom, we see that the two 



<&■ r\ magnetons in this molecule are about twice the length 



of their radius (V) apart. 



Let the distance from the circumference of one mag- 

 neton to the center of the other be nr. 



Now the field due to one magneton, at a point lying on its axis and 

 distant by nr from its circumference, is 



M . r 2 _ 2M 



77-r 2 (nr) 3 n 3 r 3 ' 

 Hence the magnetic work done in bringing the other magneton from 

 infinity up to this point is roughly 



2M 2 _ 2X(3.5) 2 XiQ' 38 

 n 3 r 3 w 3 X (i.5) 3 XIO~ 27 

 7.5 Xio -11 

 = L tf er g s > 



and for a gram-atom of Hydrogen this amounts to 



4.SX10 13 



^ D „ ergs. 



n 3 



Substituting the values 1, 2 (most probable), and 3 for n, we have 



4.5X10 13 , 5.6X10 12 , i.7Xio 12 ergs 



for the heat of dissociation. Now Langmuir's calculations from 

 experiment give as the probable value about 77,000 cal. 1 or 



3.2 xio 12 ergs. 



"Phil. Mag., 27, 188, 1914. 



