897 
attractive force continued to increase up to 6, after which it sud- 
Total force F. 
/; fa 
Fig. 3. 
denly (hence discontinuously) changed into a repulsive force, with 
another constant of intensity ¢ than that of the attractive force vie 
whereas now we suppose a continuous change of force at o with a 
single constant f. 
Analytically this may be expressed — as far as e.g. the action of a 
force, exerted on P by M, is concerned —- by a formula of the form 
: |,—6,—2 
i, = (el, =F 2) pen aes (1a) 
in which «= OP, and the indices 1 all refer to distances from M,, 
measured towards the left; and this instead of simply PF, = /(e,— 
—(/,—2,)) as we put formerly (loc. cit. p. 1188 et seq.), i.e. the 
attractive force proportional to the distance from the moving point 
P to the boundary of the sphere of attraction 9, (of M‚), so that 
F,=0, when P lies on the boundary of this sphere or outside it. 
In consequence of this the attraction, after having reached a maximum, 
again becomes = 0 at 5, (hence (tr = /,—o,), reverses its sign, and 
again changes into a repulsion, which would become infinite at s, 
(« =/,—-s,). From the other molecule .M, P is subjected to an 
attraction 
’ 
ies & 
: l,—o,+e 
eee a) cares, (15) 
in which # is again = OP, and the indices now refer to distances 
from M,, measured to the right. 
Hence after some reductions the total action exerted on P to the 
right (see Fig. 3), (with omission of the indices, because /, = /, = /, 
etc.) is now found to be: 
Ff Ff! |. Be Ab lef) 
(ls)? — a? 
instead of simply (= F — F,=/. 2x, as before (p. 1188). 
