In exploring the operations of the mind, some of which are extremely nice and slippery, it is necessary to proceed with the utmost circumspection. And after all, seldom it happens that speculations of this kind afford any strong conviction. Luckily, in the present case, we have at hand facts and experiments that support the foregoing theory in a satisfactory manner. In the first place, the opposing a small object of one species to a great object of another, produces not, in any degree, that effect of contrast, which is so remarkable when both objects are of the same species. There is no difference betwixt these two cases that promiseth to have any influence, but only that the former is common, the latter rare. May we not then fairly conclude, that surprise from the rarity of appearance is the cause of contrast, when we find no such effect where the appearance is common? In the next place, if surprise be the sole cause of the effects that appear in making a comparison, it follows necessarily that these effects will vanish so soon as a comparison becomes familiar. This holds so unerringly, as to leave no reasonable doubt that surprise is the prime mover in this operation. Our surprise is great the first time a small lapdog is seen with a large mastiff: but when two such animals are constantly together, there is no surprise; and it makes no difference whether they be viewed separately or in company. We put no bounds to the riches of a man who has recently made his fortune. The opposition betwixt his present and past situation, or betwixt his present situation and that of others, is carried to an extreme. With regard to a family that for many generations hath enjoyed great wealth, the same false reckoning is not made. It is equally remarkable, that a simile loses its effect by repetition. A lover compared to a moth scorching itself at the flame of a candle, is a sprightly simile, which by frequent use has lost all force. Love cannot now be compared to fire, without some degree of disgust. It has been justly objected against Homer, that the lion is too often introduced in his similes. All the variety he is able to throw into them, is not sufficient to keep alive the reader’s surprise.