Plutarch Quaestiones Convivales 3.9.1

[1] WHEN I had said this, Aristo cried out aloud, as his manner was, and said: I see well now that there is opened a return again of measures unto feasts and banquets; which measures, although they are most just and democratical, have for a long time (I wot not by what sober reason) been banished from thence, as by a tyrant. For, as they who profess a canonical harmony in sounding of the harp do hold and say, that the sesquialteral proportion produceth the symphony diapente ( διὰ πέντε), the double proportion the diapason ( διὰ πασῶν), and that the accord called diatessaron ( διὰ τεσσάρων), which is of all most obscure and dull, consisteth in the epitrite proportion; even so they that make profession of skill in the harmonies of Bacchus have observed, that three symphonies or accords there are between wine and water, namely, diapente, diatrion ( διὰ τριῶν), and diatessaron; and so they say and sing,—Drink either five or three, but not four. For the fifth has the sesquialteral proportion, three cups of water being mingled with two of wine; the third has the double proportion, two cups of water being put to one of wine; but the fourth answereth to the epitrite proportion of three parts of water poured into one of wine. Now this last proportion may be fit for some grave magistrates sitting in the council-hall, or for logicians who pull up their brows when they are busy in watching the unfolding of their arguments; for surely it is a mixture sober and weak enough. As for the other twain; that medley which carrieth the proportion of two for one bringeth in that turbulent tone of those who are half-drunk, for it suffereth a man neither to be fully sober, nor yet to drench himself so deep in wine as to be altogether witless and past his sense; but the other, standing upon the proportion of three to two, is of all the most musical accord, causing a man to sleep peaceably and forget all cares, and, like the corn-field which Hesiod speaks of, stilling and appeasing all proud and disordered passions within the heart, and inducing instead of them a peaceable calm and tranquillity.