Many years ago the then Duke of Newcastle, who took the ground of being a believer in the truth of Christianity, said to his chaplain, the Rev. Mr. Leslie, that he was not satisfied with the ordinary methods of proving the truth of Christianity. He thought they were too lengthy and complicated, and that ordinary people had neither the leisure nor the patience to master them. Knowing Mr. Leslie's abilities, he urged him to produce something plain and simple and yet conclusive on the subject.
In the extraordinarily short space of three days, Mr. Leslie presented the Duke with a rough draft of a remarkable treatise, entitled, "Short and Easy Method with the Deists." This so appealed to the Duke that he declared, that, though he had hitherto believed himself to be a Christian, now he was sure of it, and ever after spoke of Mr. Leslie's treatise with great appreciation, and never met him without asking his blessing. This interesting anecdote comes from the late Captain Leslie, a son of the author of "Short and Easy Method with the Deists."
Under the title, "Short and Easy Method with the Deists," Mr. Leslie's treatise was published. In course of time the pamphlet got out of print. Years after the late Sir Edward Denny Bart., an earnest Christian, was so struck by the unanswerable character of the proof that he got it republished under the title, " Leslie's Four Marks," adding remarks of his own. This again went out of print. The present writer then obtained permission to use Mr. Leslie's argument on the condition that the title of his pamphlet should be different, and that the argument should be presented in his own language.