Besides Diderot, the band of the _Philosophes_ included many famous names. There was the brilliant and witty mathematician, Dalembert; there was the grave and noble statesman, Turgot; there was the psychologist, Condillac; there was the light, good-humoured Marmontel; there was the penetrating and ill-fated Condorcet. Helvétius and D'Holbach plunged boldly into ethics and metaphysics; while, a little apart, in learned repose, Buffon advanced the purest interests of science by his researches in Natural History. As every year passed there were new accessions to this great array of writers, who waged their war against ignorance and prejudice with an ever-increasing fury. A war indeed it was. On one side were all the forces of intellect; on the other was all the mass of entrenched and powerful dullness. In reply to the brisk fire of the _Philosophes_--argument, derision, learning, wit--the authorities in State and Church opposed the more serious artillery of censorships, suppressions, imprisonments, and exiles. There was hardly an eminent writer in Paris who was unacquainted with the inside of the Conciergerie or the Bastille. It was only natural, therefore, that the struggle should have become a highly embittered one, and that at times, in the heat of it, the party whose watchword was a hatred of fanaticism should have grown itself fanatical. But it was clear that the powers of reaction were steadily losing ground; they could only assert themselves spasmodically; their hold upon public opinion was slipping away. Thus the efforts of the band of writers in Paris seemed about to be crowned with success. But this result had not been achieved by their efforts alone. In the midst of the conflict they had received the aid of a powerful auxiliary, who had thrown himself with the utmost vigour into the struggle, and, far as he was from the centre of operations, had assumed supreme command.