Diderot was certainly of all men most fitted to organize and uphold this great work and to carry it to triumphal completion. He said once of himself that he belonged to his windy countryside of Langres; “the man of Langres has a head on his shoulders like the weathercock on the top of the church spire--it is never fixed at one point.” He was scarcely just to himself; with all his emotional vivacity and his readiness to receive new impressions, there was in him also an infinite patience and a tenacity to hold on to the end in spite of all. Both his versatility and his patience were called for here. He was indefatigable, for ever animating the waverers, stimulating the slow-paced, fighting with timid publishers, himself having a hand in everything, ever ready to suggest new ideas or to spend months in studying the details of machines or factories, or anything else that had to be done; knowing all the time that at every moment he might be exiled or imprisoned. The personal qualities of the man, even more than his varied abilities, carried him through. Someone speaks of “his eyes on fire and the prophetic air which seemed always announcing the enthusiasm of actual labour;” we hear of his “éloquence fougueuse et entraînante;” and, with this, of his feminine sensibility, his wit and tact and fertility of resource. We divine these qualities in his head as it has come down to us, though his characteristics do not easily lend themselves to brush or chisel. He has himself some remarks on this point. In his _Salons_ he comes upon his own portrait by Van Loo, and, after some good-humoured criticism, he adds: “But what will my grandchildren say when they come to compare my sad books with that smiling, mincing, effeminate old flirt? My children, I warn you that I am not like that. I had a hundred different faces in one day, according to the thing that affected me. I was calm, sad, dreaming, tender, violent, passionate, enthusiastic, but I was never as you see me there. I had a large forehead, very bright eyes, tolerably large features, a head quite like that of an ancient orator, a _bonhomie_ which approached stupidity, and an old-fashioned rusticity. I wear a mask which deceives the artist, whether it is that there are too many things mixed together, or that the mental impressions which trace themselves on my face succeed one another so rapidly that the painter’s task becomes more difficult than he expected. I have never been well done except by a poor devil called Garand, who caught me as it happens to a fool who utters a _bon mot_.” Meister, Grimm’s secretary, who knew Diderot well, says of him: “The artist who would seek an ideal head for Plato or Aristotle could hardly meet a modern head more worth his study than Diderot’s. His large forehead, uncovered and slightly rounded, bore the imposing imprint of his large, luminous, and fertile spirit. The great physiognomist, Lavater, thought he detected there some