Little wonder, then, that he found the Mompesson and Somerset cases material to his hand and that he seized upon them eagerly as irrefutable proof of demoniacal agency. His first task, indeed, was to prove the alleged facts; these once established, they could be readily fitted into a comprehensive scheme of reasoning. In 1666 he issued a small volume, _Some Philosophical Considerations touching Witches and Witchcraft_. Most of the first edition was burned in the fire of London, but the book was reprinted. Already by 1668 it had reached a fourth impression.[4] In this edition the work took the new title _A Blow at Modern Sadducism_, and it was republished again in 1681 with further additions as _Sadducismus Triumphatus_, which might be translated "Unbelief Conquered."[5] The work continued to be called for faster than the publisher could supply the demand, and went through several more revisions and reimpressions. One of the most popular books of the generation, it proved to be Glanvill's greatest title to contemporary fame. The success of the work was no doubt due in large measure to the collection of witch stories; but these had been inserted by the author as the groundwork of his argument. He recognized, as no one on his side of the controversy had done before, the force of the arguments made by the opposition. They were good points, but to them all he offered one short answer--the evidence of proved fact.[6] That such transformations as were ascribed to the witches were ridiculous, that contracts between the Devil and agents who were already under his control were absurd, that the Devil would never put himself at the nod and beck of miserable women, and that Providence would not permit His children to be thus buffeted by the evil one: these were the current objections;[7] and to them all Glanvill replied that one positive fact is worth a thousand negative arguments. Innumerable frauds had been exposed. Yes, he knew it,[8] but here were well authenticated cases that were not fraud. Glanvill put the issue squarely. His confidence in his case at once wins admiration. He was thoroughly sincere. The fly in the ointment was of course that his best authenticated cases could not stand any careful criticism. He had been furnished the narratives which he used by "honest and honourable friends." Yet, if this scientific investigator could be duped, as he had been at Tedworth, much more those worthy but credulous friends whom he quoted.