The letter referred to was a fair sample of the sort of criticism which he wrote on the subject, and which he was willing to retail out to others, and then decline to face any fair discussion with a highly honorable opponent, at least his equal in public and social position, who had unanswerably answered his bitterly libellous language. It is open to question whether Mr. Owen's delicacy was not excessive in respecting the privacy of Professor Felton's volunteered letter of controversial attack upon his book, and whether he would not have been perfectly justified in publishing it, as he asked permission to do, side by side with the masterly reply which it elicited. This reply, which I now proceed to publish, will suffice to show how little the Harvard dignitary, however learned in Greek, was a match in logical controversy for Mr. Owen, who had been a distinguished member of Congress, and who had recently vacated the post of U. S. Minister at the court of Naples. The Professor stated that he had fully "investigated the subject both in this country and in Europe, and that the conclusion at which he had arrived was that the alleged physical phenomena, such as moving of tables without the ordinary application of physical force, _never take place_ under conditions which absolutely prevent the action of delusion or fraud." He is not the only man who has claimed to have "investigated," when he has visited a few mediums with the eyes of his mind so shut and sealed with hostile prejudice that what he calls his investigation had been but an idle farce. Then again, in the same letter, he declares, in relation to the investigation in Boston, that "the whole thing failed, failed utterly." I refrain from designating this as it deserves. I refer my readers to the history of that sham investigation for them to give it its proper designation. He knew the statement was not true of the manifestations during the investigation, if his own committee could be believed. The letter says, "If I ever have time I shall prepare a volume on the subject." He did not, however, have time before he followed the course of Nature, and he has now found out for himself many things not falling within the scope of his studies as Professor of Greek, which he did not know before. After this outpouring, he goes on to sanction the same thing in Christian Revelation. He says the cases are different. Yes, we have the absolute facts here, and that is better than those of long ago. The fact is, Prof. Felton never gave it one hour of fair investigation. Though Prof. Felton refused permission for the publication of his letter, I am under no restraint for the publication of Mr. Owen's masterly reply to it; with which, as it has not before been published (to my knowledge), I am glad to be able to enrich this volume. "PHILADELPHIA, November 12, 1860. "MY DEAR SIR: