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the spoken word does not carry far enough: hence the institution

of gongs and drums. Nor can ordinary objects be seen clearly

enough: hence the institution of banners and flags.

24. Gongs and drums, banners and flags, are means whereby the

ears and eyes of the host may be focussed on one particular

point.

[Chang Yu says: "If sight and hearing converge simultaneously on

the same object, the evolutions of as many as a million soldiers

will be like those of a single man."!]

25. The host thus forming a single united body, is it impossible

either for the brave to advance alone, or for the cowardly to

retreat alone.