Prof. Tyndall has also given the world (in his “Fragments of Science,” published in 1871) some account of his attempt to investigate these phenomena. Again, we have a minute record of a séance which was a failure, and in which the Professor, like Lord Amberley, easily imposed on some too credulous Spiritualists by improvising a few manifestations of his own. The article in question is dated as far back as 1864. We may therefore conclude that the Professor has not seen much of the subject; nor can he have made himself acquainted with what others have seen and carefully verified, or he would hardly have thought his communication worthy of the place it occupies among original researches and positive additions to human knowledge. Both its facts and its reasonings have been well replied to by Mr. Patrick Fraser Alexander, in his little work entitled “Spiritualism; a Narrative and a Discussion,” which we recommend to those who care to see how a very acute yet unprejudiced mind looks at the phenomena, and how inconclusive, even from a scientific standpoint, are the experiences adduced by Prof. Tyndall. The discussion in the Pall Mall Gazette in 1868, and a considerable private correspondence, indicates that scientific men almost invariably assume that, in this inquiry, they should be permitted, at the very outset, to impose conditions; and if, under such conditions, nothing happens, they consider it a proof of imposture or delusion. But they well know that, in all other branches of research, Nature, not they, determines the essential conditions, without a compliance with which no experiment will succeed. These conditions have to be learnt by a patient questioning of Nature, and they are different for each branch of science. How much more may they be expected to differ in an inquiry which deals with subtle forces of the nature of which the physicist is wholly and absolutely ignorant! To ask to be allowed to deal with these unknown phenomena as he has hitherto dealt with known phenomena, is practically to prejudge the question, since it assumes that both are governed by the same laws.