the Hydrogen Molecule. 



1033 



order to obtain a correct value o£ P with a high degree of 

 accurac} r , the distance between the two hydrogen atoms in 

 the molecule must be sought from some other source. 

 When the problem can be managed using some crystal, like 

 the diamond say, where these distances are well known, this 

 will afford a good value for the small residuum, P, and fix 

 the property of the electron with considerable approximation. 



Fig-. 3. 



z 2 =i.o 



Fig. 2 changes into this figure when the value of P (26) is that given in 

 (31). The coefficients of the r~ 6 and r~ 8 terms are now small but 

 do not vanish. The curves are plotted from equation (17), the 

 scale being the same as that of fig. 2. There is now a stable equi- 

 librium position where the x- and z-curves of zero force intersect 

 at an angle of 39° 49' (Z 2 = -41), and at distance r=-81x 10-s cm. 

 The equilibrium distance for the z-force on the axis has increased 

 from 1-18x10-8 cm. in fig. 2 to 1-83x10-8 cm. here. 



In the case of gases it is believed that not much more is 

 known about the distances between atoms in molecules than 

 a rough approximation to their order of magnitude. 



