If - and the thing is wildly possible - the charge of writing nonsense were ever brought against the author of this brief but instructive poem, it would be based, I feel convinced, on the line (in p.4) "Then the bowsprit got mixed with the rudder sometimes." In view of this painful possibility, I will not (as I might) appeal indignantly to my other writings as a proof that I am incapable of such a deed: I will not (as I might) point to the strong moral purpose of this poem itself, to the arithmetical principles so cautiously inculcated in it, or to its noble teachings in Natural History - I will take the more prosaic course of simply explaining how it happened.