STATIC MODELS 
133 
6t 
ix. 5] 
realized. A number of asymmetrical configurations of the helium 
atom have been worked out, but none of the cases considered 
gives exact agreement with the experimental value, the nearest 
approach being 77*26 volts, this value involving the use of half 
quantum numbers. 
The existence of a helium molecule is required for the explana 
tion of the band spectrum, though no doubt the molecule is 
unstable and only has a transitory existence. The moment of 
inertia calculated is of the same order of magnitude as that 
determined by Curtis from observations of the band spectrum. 
We may conclude that although the static models here con 
sidered may not possess all the advantages possessed by the 
dynamic models, they may be usefully employed for certain 
purposes owing to the comparative simplicity of the mathematical 
processes and the physical conceptions involved. 
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