Sir W. Temple, in his "Essay on Poetry," seems to derive the idea from the Runic incantations, for, after speaking of them in various ways, he adds, "and the proverb of rhyming rats to death, came, I suppose, from the same root."
According to a superstitious notion of considerable antiquity, rats leaving a ship are considered indicative of misfortune to a vessel, probably from the same idea that crows will not build upon trees that are likely to fall. This idea is noticed by Shakespeare in "The Tempest" (i. 2), where Prospero, describing the vessel in which himself and daughter had been placed, with the view to their certain destruction at sea, says:
"they hurried us aboard a bark, Bore us some leagues to sea; where they prepared A rotten carcass of a boat, not rigg'd, Nor tackle, sail, nor mast; the very rats Instinctively have quit it."
The _Shipping Gazette_ of April, 1869, contained a communication entitled, "A Sailor's Notion about Rats," in which the following passage occurs: "It is a well-authenticated fact that rats have often been known to leave ships in the harbor previous to their being lost at sea. Some of those wiseacres who want to convince us against the evidence of our senses will call this superstition. As neither I have time, nor you space, to cavil with such at present, I shall leave them alone in their glory." The fact, however, as Mr. Hardwick has pointed out in his "Traditions, Superstitions, and Folk-lore" (1872, p. 251), that rats do sometimes migrate from one ship to another, or from one barn or corn-stack to another, from various causes, ought to be quite sufficient to explain such a superstition. Indeed, a story is told of a cunning Welsh captain who wanted to get rid of rats that infested his ship, then lying in the Mersey, at Liverpool. Having found out that there was a vessel laden with cheese in the basin, and getting alongside of her about dusk, he left all his hatches open, and waited till all the rats were in his neighbor's ship, and then moved off.
_Snail._ A common amusement among children consists in charming snails, in order to induce them to put out their horns--a couplet, such as the following, being repeated on the occasion:
"Peer out, peer out, peer out of your hole, Or else I'll beat you as black as a coal."