*Attraction between Floating Globules.—The “Devouring” Globule.* When globules of different liquids are floating on the same water surface, a tendency to coalesce is sometimes noticed, but is by no means general. I will show one example which possesses striking features, showing as it does the remarkable results which may be brought about by surface forces. First of all, we form a number of active orthotoluidine globules on the surface of a dish of water, which you see wriggling about in their characteristic fashion. After their activity has subsided somewhat, I float on to the surface a large globule of dimethyl-aniline. Attraction of some kind is at once apparent, for the nearest globule of orthotoluidine immediately approaches the intruder. And now comes the process of absorption. The large globule of dimethyl-aniline develops a protuberance in the direction of its victim (Figs. 42 and 43), and the small globule of orthotoluidine coalesces with this “feeler,” which then shrinks back into the large globule, conveying with it the entangled orthotoluidine. This, however, by no means satisfies the devouring globule, as a second victim is at once appropriated in the same manner; and you will notice a nibbling process at work round the edges continuously, which is due to the absorption of the smaller globules of orthotoluidine. The action continues until the whole of the surface has been cleared of orthotoluidine, after which the large globule floats tranquilly in the centre of the vessel, apparently resting after its heavy meal. The interaction of the forces which gives rise to this phenomenon is difficult to fathom; there are no doubt several tensions, constantly changing in magnitude, which in the result cause the liquids of the large and small globules to intermingle. Separate globules of a single liquid sometimes unite in this manner, but this is not common, it being more usual for the scattered units to remain apart. [Illustration: __Fig._ 42.—The “devouring” globule. Five stages._] [Illustration: __Fig._ 43.—Photograph of one globule absorbing another._]