But to judge by perception is a comparatively rare accomplishment, and so most critics continued to employ the foot-rule as if they were measuring flat surfaces, while occasionally going so far as to recognize the existence of certain mountain-peaks as "irregular beauties." In a more or less conscious distinction from the criticism of external rules there developed also during the eighteenth century what its representatives were pleased to call metaphysical criticism, to which we should now probably apply the term psychological. This consisted in explaining poetic effects by reference to strictly mental processes in a tone of calm analysis eminently suited to the rationalistic temper of the age. It methodically traced the sources of grandeur or of pathos or of humor, and then illustrated its generalization by the practice of the poets. It could thereby pride itself on going back of the rules to the fundamental laws of human nature. Kames's Elements of Criticism, written in 1761, became a work of standard reference, though it did not impose on the great critics. In commending it Dr. Johnson was careful to remark, "I do not mean that he has taught us anything; but he has told us old things in a new way."[37] But in general Kames was considered a safer guide than the enthusiastic Longinus, who throughout the century was looked upon with distrust. "Instead of shewing for what reason a sentiment or image is sublime, and discovering the secret power by which they affect a reader with pleasure, he is ever intent on producing something sublime _himself_, and strokes of his own eloquence." So runs the complaint of Joseph Warton.[38] The distrust was not without ground. The danger that the method of Longinus in the hands of ungifted writers would become a cloak for critical ignorance and degenerate into empty bluster was already apparent.[39] Only rarely was there a reader who could distinguish between the false and the true application of the method. Gibbon did it in a passage which impressed itself upon the younger critics of Hazlitt's generation. "I was acquainted only with two ways of criticising a beautiful passage: the one, to shew, by an exact anatomy of it, the distinct beauties of it, and whence they sprung; the other, an idle exclamation, or a general encomium, which leaves nothing behind it. Longinus has shewn me that there is a third. He tells me his own feelings upon reading it; and tells them with such energy, that he communicates them."[40] That vital element, the commentator's power of communicating his own feelings, constituting as it does the difference between phrase-making and valuable criticism, did not become prominent in English literature before the nineteenth century.