For the rest, he professes himself indifferent whether his assertions meet with credence or not. He has done his best to test the phenomena for himself, regarding them critically, and not at all in a spirit of credulity; and he has endangered his reputation by undertaking what he regards as a plain duty, that of setting down under his own name, for the world to accept or reject as it pleases, a statement of the experiences to which he has devoted so much time and attention, and of the actuality of which, though he in no way professes to understand them, he is profoundly convinced. Equally convinced of their occurrence is Professor Richet, who has had an opportunity of observing many of them, and he too regards them from the same untheoretical and empirical point of view; but he has explained his own attitude in a Preface to the French edition, as Dr. Maxwell has explained his in ‘Preliminary Remarks,’—both of which are here translated—so there is no need to say more; beyond this:— The particular series of occurrences detailed in these pages I myself have not witnessed. I may take an opportunity of seeing them before long; but though that will increase my experience, it will not increase my conviction that things like some of these can and do occur, and that any other patient explorer who had the same advantages and similar opportunity for observation, would undergo the same sort of experience, that is to say, would receive the same sensory impressions, however he might choose to interpret them. That is what the scientific world has gradually to grow accustomed to. These things happen under certain conditions, in the same sense that more familiar things happen under ordinary conditions. What the conditions are that determine the happening is for future theory to say. Dr. Maxwell is convinced that such things can happen without anything that can with any propriety whatever be called fraud; sometimes under conditions so favourable for observation as to preclude the possibility of deception of any kind. Some of them, as we know well, do also frequently happen under fraudulent and semi-fraudulent conditions; but those who take the easy line of assuming that hyper-ingenious fraud and extravagant self-deception are sufficient to account for the whole of the facts, will ultimately, I think, find themselves to have been deceived by their own _a priori_ convictions. Nevertheless we may agree that at present the Territory under exploration is not yet a scientific State. We are in the pre-Newtonian, possibly the pre-Copernican, age of this nascent science; and it is our duty to accumulate facts and carefully record them, for a future Kepler to brood over.