W. A. Norton—Force of Effective Molecular Action. 847 
attractive and repulsive —_— fand /. I have made a series 
of calculations of the values of F for various assigned values of 
curve that may be termed a curve of ¢ e molecular action. 
4. 
Fig. 1 is such a curve answering to k= 5-428. In F 
curve c, the same curve is shown on a smaller scale has 
horizontal and vertic eal). Curve a in this figure answers to 
k=1 ive , and curve 6 answers to k= 9-44. Fig. ge 
force obtaining at other distances z. The distance 
» 
is that which obtains when no extern _ force of stress is in 
as Oe, that may gh e when a pressive stress 
is aie to the body, effective Lo. er, is repulsive. 
When a tensile stress is in Seiten increasin distance , 
the effective force, as 2s, becomes attractive, and increases in in- 
tensity to the maximum value bm, at the moment of rupture. 
At greater distances, as 08, the ‘effective attraction falls off ; 
and passes into a repulsion when the distance becomes greater 
than Oc. This repulsion increases with the distance to a maxi- 
mum dn, and then diminishes continually to an indefinite dis- 
