42
Gallileus Of the
But yet for all this, any great Mass swimming in a standing Lake, may be moved by any petit force; only it is true, that a lesser force more slowly moves it: The parts of Liquids, so farre from resisting Division, that they contain not any thing that may be divided.but if the waters Resistance of Division, were in any manner sensible, it would follow, that the said Mass, should, notwithstanding the percussion of some sensible force, continue immoveable, which is not so. Yea, I will say farther, that should we retire our selves into the more internall contemplation of the Nature of water and other Fluids, perhaps we should discover the Constitution of their parts to be such, that they not only do not oppose Division, but that they have not any thing in them to be divided: The Resistance a Solid findeth in moving through the water, like to that we meet with in passing through a throng of people:so that the Resistance that is observed in moving through the water, is like to that which we meet with in passing through a great Throng of People, wherein we find impediment, and not by any difficulty in the Division, for that none of those persons are divided whereof the Croud is composed, but only in moving of those persons sideways which were before divided and disjoyned: Or in thrusting a Stick into an heap of Sand.and thus we find Resistance in thrusting a Stick into an heap of Sand, not because any part of the Sand is to be cut in pieces, but only to be moved and raised. Two kinds of Penetration, one in Bodies continuall, the other in Bodies only contiguous.Two manners of Penetration, therefore, offer themselves to us, one in Bodies, whose parts were continuall, and here Division seemeth necessary; the other in the aggregates of parts not continuall, but contiguous only, and here there is no necessity of dividing but of moving only. Now, I am not well resolved, whether water and other Fluids may be esteemed to be of parts continuall or contiguous only; Water consists not of continuall, but only of contiguous parts.yet I find my self indeed inclined to think that they are rather contiguous (if there be in Nature no other manner of aggregating, than by the union, or by the touching of the extreams:) and I am induced thereto by the great difference that I see between the Conjunction of the parts of an hard or Solid Body, and the Conjunction of the same parts when the same Body shall be made Liquid and Fluid: See what satisfaction he hath given, as to this point, in Lib. de Motu. Dial. 2.for if, for example, I take a Mass of Silver or other Solid and hard Mettall, I shall in dividing it into two parts, find not only the resistance that is found in the moving of it only, but an other incomparably greater, dependent on that vertue, whatever it be, which holds the parts united: and so if we would divide again those two parts into other two and successively into others and others, Great difference betwixt the Conjunction of the parts of a Body when Solid, and when fluid.we should still find a like Resistance, but ever less by how much smaller the parts to be divided shall be; but if, lastly, employing most subtile and acute Instruments, such as are the most tenuous parts of the Fire, we shall resolve it (perhaps) into its last and least Particles, there shall not be left in them any longer either Resistance of Division, or so much as a capacity of being farther divided, especially by Instruments more grosse than the acuities of Fire: and what Knife or Rasor put into well melted Silver can we finde, that will divide a thing which surpasseth the separating power of Fire? Certainly none: because either the whole shall be reduced to the most minute and ultimate Divisions, or if there remain parts capable still of other Subdi-
visions
