D'Alembert was a great mathematician. His literary taste was extremely cold: he was not worthy of reading Richardson. The volumes, if he ever read them, must have fallen from his hands. The delicate and subtle turnings, those folds of the human heart, which require so nice a touch, was a problem which the mathematician could never solve. There is no other demonstration in the human heart, but an appeal to its feelings: and what are the calculating feelings of an arithmetician of lines and curves? He therefore declared of Richardson that "La Nature est bonne à imiter, mais non pas jusqu'à l'ennui." But thus it was not with the other two congenial geniuses! The fervent opinion of Rousseau must be familiar to the reader; but Diderot, in his éloge on Richardson, exceeds even Rousseau in the enthusiasm of his feelings. I extract some of the most interesting passages. Of Clarissa he says, "I yet remember with delight the first time it came into my hands. I was in the country. How deliciously was I affected! At every moment I saw my happiness abridged by a page. I then experienced the same sensations those feel who have long lived with one they love, and are on the point of separation. At the close of the work I seemed to remain deserted." The impassioned Diderot then breaks forth:--"Oh, Richardson! thou singular genius in my eyes! thou shalt form my reading in all times. If forced by sharp necessity, my friend falls into indigence; if the mediocrity of my fortune is not sufficient to bestow on my children the necessary cares for their education, I will sell my books,--but thou shalt remain! yes, thou shalt rest in the _same class_ with MOSES, HOMER, EURIPIDES, and SOPHOCLES, to be read alternately. "Oh Richardson, I dare pronounce that the most veritable history is full of fictions, and thy romances are full of truths. History paints some individuals; thou paintest the human species. History attributes to some individuals what they have neither said nor done; all that thou attributest to man he has said and done. History embraces but a portion of duration, a point on the surface of the globe; thou hast embraced all places and all times. The human heart, which has ever been and ever shall be the same, is the model which thou copiest. If we were severely to criticise the best historian, would he maintain his ground as thou? In this point of view, I venture to say, that frequently history is a miserable romance; and romance, as thou hast composed it, is a good history. Painter of nature, thou never liest! "I have never yet met with a person who shared my enthusiasm, that I was not tempted to embrace, and to press him in my arms!