19. A victorious army opposed to a routed one, is as a pound's weight placed in the scale against a single grain.
Literally, “a victorious army is like an 鎰 i (20 oz.) weighed against a 銖 shu (1 oz.); a routed army as a shu weighed against an i.” The point is simply the enormous advantage which a disciplined force, flushed with victory, has over one demoralised by defeat. Legge, in his not on Mencius, I. 2. ix. 2, makes the 鎰 to be 24 Chinese ounces, and corrects Chu Hsi’s statement that it equalled 20 oz. only. But Li Ch‘üan of the T‘ang dynasty here gives the same figure as Chu Hsi.
20. The onrush of a conquering force is like the bursting of pent-up waters into a chasm a thousand fathoms deep. So much for tactical dispositions.
The construction here is slightly awkward and elliptical, but the general sense is plain. The T‘u Shu omits 民也. A 仞=8尺 or Chinese feet.