ly to
affect his powers of observation, the following points may throw some
light.

(2.) It is evident, both from what Zoellner has himself printed and from
what Professor Scheibner has said, that Zoellner's interest in the
investigation centered in his attempt to prove experimentally what he
already held to be speculatively true as to a fourth dimension of space.
In a paper published in the _Quarterly Journal of Science_, for April,
1878, he says:

"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
_a 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 i