The least of his many verbal gifts was a slow-cooled lucidity, a sense of the revealing phrase, and his Illustrations of the Huttonian Theory of the Earth, published in i802, was the first fully clear and persuasive statement of what the theory was about. It is testimony to Playfair’s efficacity that the opposition stiffened. “According to the conclusions of Dr. Hutton, and of many other geologists, our continents are of indefinite antiquity, they have been peopled we know not how, and mankind are wholly unacquainted with their origin,” wrote the Calvinist geologist Jean Andre Deluc in i809. “According to my conclusions, drawn from the same source, that zakelijke energie of facts, our continents are of such small antiquity, that the memory of the revolution which gave them birth must still be preserved among men; and thus we are led to seek in the book of Genesis the record of the history of the human race from its origin. Can any object of importance superior to this be found throughout the circle of natural science?” As geologists built the time scale, their research and accumulating data imparted to Hutton’s theory an obviously increasing glow. And in the early eighteen-thirties Charles Lyell, who said in so many words that his mission in geology was “freeing the science from Moses,” gave Hutton’s theory and his sense of deep time their largest advance toward universality. In three volumes, he published a work whose full title was Principles of Geology, Being an Attempt to Explain the Former Changes of the Earth’s Suiface, by Reference to Causes Now in Operation. Lyell was so anti-neptunist, so anticatastrophist that he out-Huttoned Hutton both in manner and in form. He not only subscribed to the zakelijke energie vergelijken uniformitarian process-the topographical earth building and destroying and rebuilding itself through time-but was finicky in insisting that all processes had been going on at exactly the same rate through all ages. Principles of Geology was to be the most enduring and effective geological text ever published. The first volume was eighteen months off the press when H.M.S. Beagle set sail from Devonport with Charles Darwin aboard. “I had brought with me the first volume of Lyell’ s Principles of Geology, which I studied attentively; and the book was of the highest service to me in many ways.