Our understanding, moreover, labours under the fault of bestowing its attention chiefly on things, whose beauties are not to be perceived at first sight, and of inadvertently slighting others, because clear as day: images of this kind, like a ship on the waves, leave but momentary traces in our memory. Hence the ideas of our childhood are the most permanent, because every common occurrence then seems extraordinary. Thus, if nature herself instructs us, that she is not to be moved by common things, let art, as the Orator, ad Herennium, advises us, follow her dictates. Every idea increases in strength, if accompanied by another or more ideas, as in comparisons; and the more still as they differ in kind: for ideas, too analogous to each other, do not strike: as for instance, a white skin compared to snow. Hence the power of discovering a similarity, in the most different things, is what we commonly call wit; Aristotle, “unexpected ideas”: and these he requires in an orator[195]. The more you are surprized by a picture, the more you are affected; and both those effects are to be obtained by allegory, like to fruit hid beneath leaves and branches, which when found surprizes the more agreeably, the less it was thought of. The smallest composition is susceptible of the sublimest powers of art: all depends upon the idea. Necessity first taught the artists to use allegory. No doubt, they began with the representation of single objects of one class: but as they improved, they attempted to express what was common to many particulars; _i. e._ general ideas. All the qualities of single objects afford such ideas: but to become general, and at the same time sensible, they cannot preserve the particular shape of such or such an object, but must be submitted to another shape, essential to that object, but a general one. The Egyptians were the first, who went in search of images of that kind. Such were their hieroglyphicks. All the deities of antiquity, especially those of Greece, nay, their very names, were originally Egyptian[196]. Their personal theology was quite allegorical; and so is ours. But the symbols of these inventors, partly preserved by the Greeks, were often so mysteriously arbitrary, as to make it altogether impossible to find out their meaning, even by the help of those authors that are still extant; and such a discovery was looked upon as a nefarious profanation[197]. Thus sacredly mysterious was the pomegranate[198] in the hand of the Samian Juno: and to divulge the Eleusinian rites, was thought worse than the robbery of a temple[199].