establishment of physical facts. But where can any other field be found of equal interest? Difficulties and perplexities meet the explorer in abundance. But they exist in order to be overcome by the same steady persistence which has attained its reward in many another direction. With regard to two other chapters I desire also to make a special remark--those on "Materialisations" and "Spirit Photography." Both are physical phenomena. But I desire to make it plain that no claim is made of being able to present evidence with regard to either of these subjects which should satisfy the reasonable demands of science. It may be asked--Why then introduce them at all? For two reasons: (1) Because the evidence in favour of both is only just outside the boundary of scientific demonstration. (2) Because of the extreme interest of the phenomena themselves. As to "Materialisations." Out of an immense mass of testimony, most of it of no evidential value, one case has been selected where more than ordinary care seems to have been taken. But the phenomenon is so marvellous, especially in its more perfect alleged phases, when the "materialised" form is scarcely distinguishable from a living breathing human being, that the inquirer is bound to hold his judgment in suspense until the last possible moment. Again as to "Spirit Photography." The term "Psychic Photography" would be far preferable, as implying no theory. The experiences of Mr. J. Traill Taylor, which I have selected as the sole illustration, appear to leave no moral doubt but that under certain circumstances photographs are produced which known laws are unable to explain. Definite and recognisable human figures and faces are thus obtained. But this is a very long way from proving that "spirits" sit or stand before the camera for their photographs to be taken! If some trained experimenter in scientific research, who possesses an unbiassed mind, would devote himself for two or three years to the study of either of these classes of phenomena, it is almost a certainty that he would be richly rewarded. Is there no one who will enter upon the task?