BY MOLECULAR COALESCENCE. 21 
spherules as before contact, and therefore will exhibit 
nearly the same appearance under the microscope as if 
these spherules were apart. Whilst, on the contrary, the 
molecules contained in the inner hemespheres, coming 
within the attractive influence of both spherules, and being 
simultaneously drawn in the direction of their centres by 
two variable forces, whose sum is always a constant quan- 
tity, will be brought under the mechanical conditions 
required to give them an elliptical form, as shown in 
diagram fig. 2, whose axis major is the line 4, B, and axis 
minor c, D, and whose foci are the points ¢, c’, the centres 
of the coalescing spherules and the coordinates of the 
curve are the lines c, p, and ¢’, p. And hence the dumb- 
bell-shaped particle made up of these several molecules 
will refract the rays of light passing through the peripheral 
portion as a sphere would, and those passing through its 
central elliptical portion as an ellipse would. Hence these 
rays, being transmitted differently, will render these parts 
distinguishable one from the other by the microscope, 
each according to its peculiar laws of transmission of 
light. As the coalescence of two such spherules as those 
just described progresses, the dumb-bell shape will 
gradually disappear, the spherical form of the remote 
hemespheres becoming changed into that of an ellipse, 
so that now, the exterior outline having become also 
elliptical, there results a form presenting two ellipses, one 
situated within the other. (See fig. 2, c.) The still 
further coalescence of these once spherical particles is 
attended only with a gradual diminution of the eccentricity 
of these ellipses, until, their foci coimciding, one perfectly 
spherical calculus results. When, as was before observed, 
the molecules will all become quiescent, being now 
balanced between equal and opposite attractive forces, and 
