DIVISIBILITY is that property of quantity, matter, or extension, through which it is either actually or potentially separable into parts. Whether matter is or is not indefi nitely divisible, is a question which has occupied the minds of philosophers since very early times. See ATOLL There is no doubt that, abstractly speaking, it is indefinitely divisible. We cannot conceive any body or space so small but that we can subdivide it in imagination, and thus figure to ourselves bodies and spaces still smaller; and prac tically, we know that the subdivision of matter is carried in nature far beyond appre ciation either by our senses or by calculation. The diffusion of odors through the air for long periods from odoriferous bodies without their suffering auy sensible change of weight, and the tinging of great quantities of fluid by very minute portions of color ing matter, are cases commonly appealed to in proof of the extreme fineness of certain material particles; while, by experiment, it is shown that there is no practical limit to the divisibility of even the most solid substances. Thus, an ounce-weight of silver, gilt
over with eight grains of gold, has been drawn out into a wire 13,000 ft. long, which was all its length covered with the gold; and a tube of glass presented to the blow-pipe has been drawn out till it became as fine as a silk fiber, or of an inch thick, still retaining its character as a tube with a distinct interior and exterior surface. In fact, in theory, great and small are mere terms of relation; under the microscope, objects invisible to the eye appear of considerable bulk; and as sir John Herschel, in his cele brated Introduction, to the Study of the Physical Sciences, has put it, there is no reason why a mote in a sunbeam should not be in itself a world. With regard to the indefinite divisibility of space, it may be demonstrated geometrically; and perhaps, after all, it is the feeling that space is infinitely divisible, which compels our minds most strongly to resist the not-ion of ultimate atoms with definite forms, as conceived in the corpuscular theory.