"This second volume, like the first, shall contain many materials, some suggestions, few opinions. On such a subject as this, dogmatism, whether in affirming or denying, is unpardonable. There is, perhaps, no human inquiry, as to which Bacon's wise aphorism is more applicable: 'If a man will begin with certainties, he shall end in doubts; but if he will be content to begin with doubts, he shall end in certainties.' "If even the opinions and suggestions I may offer should fail in accuracy, the materials will remain valuable, if care and industry may avail judiciously to select them. From these each reader can deduce his own conclusions; and thus, perhaps, such incidental puzzles as the seeming investment with clothing of apparitions may be relieved from the imputation of absurdity, if they do not find full solution. "A word, in conclusion, as to the alleged abandonment of what is called Spiritualism by certain persons named by you. You adduce the reported defection of such seceders as conclusive argument against the cause they desert. But it proves nothing, except, perhaps, that one extreme often results in its opposite. If these men, forsaking common sense, ran off into wild extravagance, little wonder that they repented. And if their case be otherwise, their secession, if secede they did, has still no weight. Weak men adopt opinions, and again discard them, alike on insufficient evidence. We sometimes turn back, confused, in the very path of progress. Du Fay, the discoverer of the fact that there are two kinds or states of electricity, repudiated his own brilliant discovery. "I am, my dear sir, "Faithfully yours, "ROBERT DALE OWEN. "PRESIDENT C. C. FELTON."[13]