The Simile also is a metaphor; the difference is but slight. When the poet says of Achilles that he
this is a simile; when he says of him 'the lion leapt', it is a metaphor -- here, since both are courageous, he has transferred to Achilles the name of 'lion'. Similes are useful in prose as well as in verse; but not often, since they are of the nature of poetry. They are to be employed just as metaphors are employed, since they are really the same thing except for the difference mentioned.
The following are examples of similes. Androtion said of Idrieus that he was like a terrier let off the chain, that flies at you and bites you -- Idrieus too was savage now that he was let out of his chains. Theodamas compared Archidamus to an Euxenus who could not do geometry -- a proportional simile, implying that Euxenus is an Archidamus who can do geometry. In Plato's Republic those who strip the dead are compared to curs which bite the stones thrown at them but do not touch the thrower, and there is the simile about the Athenian people, who are compared to a ship's captain who is strong but a little deaf; and the one about poets' verses, which are likened to persons who lack beauty but possess youthful freshness -- when the freshness has faded the charm perishes, and so with verses when broken up into prose. [1407a] Pericles compared the Samians to children who take their pap but go on crying; and the Boeotians to holm-oaks, because they were ruining one another by civil wars just as one oak causes another oak's fall. Demosthenes said that the Athenian people were like sea-sick men on board ship. Again, Demosthenes compared the political orators to nurses who swallow the bit of food themselves and then smear the children's lips with the spittle. Antisthenes compared the lean Cephisodotus to frankincense, because it was his consumption that gave one pleasure. All these ideas may be expressed either as similes or as metaphors; those which succeed as metaphors will obviously do well also as similes, and similes, with the explanation omitted, will appear as metaphors. But the proportional metaphor must always apply reciprocally to either of its co-ordinate terms. For instance, if a drinking-bowl is the shield of Dionysus, a shield may fittingly be called the drinking-bowl of Ares.