The quality and quantity of the force of a man are able to give birth to other forces, which will be proportionally greater as the motions produced by them last longer.
[Footnote: Only part of this passage belongs, strictly speaking, to this section. The principle laid down in the second paragraph is more directly connected with the notes given in the preceding section on Physiology.]
860.
Why does not the weight o remain in its place? It does not remain because it has no resistance. Where will it move to? It will move towards the centre [of gravity]. And why by no other line? Because a weight which has no support falls by the shortest road to the lowest point which is the centre of the world. And why does the weight know how to find it by so short a line? Because it is not independant and does not move about in various directions.
[Footnote: This text and the sketch belonging to it, are reproduced on Pl. CXXI.]
861.
Let the earth turn on which side it may the surface of the waters will never move from its spherical form, but will always remain equidistant from the centre of the globe.
Granting that the earth might be removed from the centre of the globe, what would happen to the water?
It would remain in a sphere round that centre equally thick, but the sphere would have a smaller diameter than when it enclosed the earth.
[Footnote: Compare No. 896, lines 48-64; and No. 936.]