"At the end of my first treatise, already finished in manuscript in the course of August, 1877, I called attention to the circumstance that a certain number of physical phenomena, which, by 'synthetical conclusions _à priori_' might be explained through the generalized conception of space and the platonic hypothesis of projection, coincided with so-called Spiritualistic phenomena. Cautiously, however, I said:--'To those of my readers who are inclined to see in Spiritualistic phenomena an _empirical_ confirmation of those phenomena above deduced in regard to their _theoretical_ possibility, I beg to observe that from the point of view of idealism there must first be given a precise definition and criticism of _objective reality_'" etc. Now this reference to Spiritualistic phenomena was made before Zoellner had seen anything of the kind, and his attitude was evidently a receptive one. Moreover, we have Professor Scheibner's testimony to the fact that during the whole investigation his attention was entirely directed towards the subject of the fourth dimension, and an experimental demonstration of its existence. Bearing in mind, therefore, the mental attitude in which, and the object with which, Zoellner approached this investigation, we cannot look upon any subjective, or emotional, mental disturbance, which results, as described, in making him narrow his attention more and more upon a few ideas, and disregard or find it difficult to observe what seems contrary to them, as without objective significance, particularly where we know the man to be a total stranger to investigations of such a nature as this one, and not only quite ignorant as to possible methods of deception, but unwilling to doubt the integrity of the Medium. (3.) There are things in Zoellner's own accounts which indicate a certain lack of caution and accuracy on his part, and tend to lessen one's confidence in his statements. As an instance of inaccuracy, I may mention the statement he makes in his article in the _Quarterly Journal of Science_ as to the opinions of his colleagues. Professor Zoellner says: "I reserve to later publication, in my own treatises, the description of further experiments obtained by me in twelve séances with Mr. Slade, and, as I am expressly authorized to mention, in the presence of my friends and colleagues, Professor Fechner, Professor Wilhelm Weber, the celebrated electrician from Goettingen, and Herr Scheibner, Professor of Mathematics in the University of Leipsic, who are _perfectly_ convinced of the reality of the observed facts, altogether excluding imposture or prestidigitation." Here the attitude of the four men is not correctly described, and Professor Zoellner's statement does them injustice, as Professor Scheibner remarked. At least two of the men were merely _inclined_ to accept the facts, and to these two the words "_perfectly_ convinced" will not apply.