ILLUSTRATIONS 
TEXT FIGURES 
Fig. 1. Forces of restitution acting on an unshared shell electron, upon 
radial displacement. 
2. Composition of forces of restitution acting on a shared electron. 
3. Symmetrically weak union; loose electron. 
4. Unsymmetrical weak union; firm electron. 
5. The attraction between two non-reacting molecules. 
6. The attraction between two reacting molecules. 
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