'Among the many foibles of the human race, we may justly reckon this to be one, that when they have once got any thing really useful, they apply it in all cases, proper or improper, till at last they make it quite ridiculous. Nothing can possibly be more useful than a just and accurate _definition_, because by this only we are able to distinguish one thing from another. It is obvious, however, that _in definitions we ought always to define a thing less known, by one which is more so, and those things which are known to every body, neither can be defined, nor ought we to attempt a definition of them at all; because we must either explain them by themselves, or by something less known than themselves, both of which give our definitions the most ridiculous air imaginable_. 'A certain right reverend gentleman, not many miles from Edinburgh, and whom, out of my great regard for the cloth, I put in the first place, gave the following definition of a thief. "A thief," says he, "my friends, is a man of a _thievish disposition_." Now though this definition is somewhat imperfect, for a thief also exerts that _thievish disposition_ which lurks in his breast, I intend to take it for my model, on account of its great conformity to many of the definitions given by the most celebrated authors.--I remember to have seen in one of the Reviews a definition of _Nature_, which began in the following manner. "Nature is that _innate_ celestial fire."--The rest has in truth escaped my memory, though I remember the Reviewers indecently compared it to the following lines, which they say were a description of a dog-fish. 'And his evacuations Were made _a parte post_. _A parte post!_ these words so hard In Latin though I speak 'em, Their meaning in plain English is, He made pure _Album Graecum_.