It cannot be too strongly insisted upon how slight may be the clue that holds the key to the explanation, how easy it is to overlook it, how mysterious the performance becomes without it. It may be the difference between placing the slate in a given position and starting to do so when the hand of the medium naturally comes forward to receive it; it may depend upon whether the slates were examined just before or just after a certain detail in the performance which was carefully not made prominent; it may depend upon the difficulty of really seeing a quick and unexpected sleight-of-hand movement on the part of a skilled performer; it may depend upon whether the question asked was really of your own choosing, or was deftly led up to; it may depend upon a score of other equally insignificant details upon which the assurance of the average person, that such mal-observation or misdescription did not occur, is almost worthless. These are some of the slighter factors in the case; there may be much more serious ones which lead not merely to exaggeration but to elaborate falsification and distortion of truth, and to the emphatic assertion of the most extravagant miracles, coupled usually with the assurance that there was no possibility or room for deception. Mr. Davey's performance was relatively a matter-of-fact test with critical and intelligent sitters; hence we should expect the divergence between report and reality to be far less serious than when the question at issue is the demonstration of the supernatural by an appeal to the religious fervor and to the emotional susceptibilities of would-be believers and sympathetic propagandists. I shall return to this difference of attitude in discussing the prepossession in favor of the belief in Spiritualism; for the present, it is sufficient to notice that under the most favorable combination of circumstances--that is, an able, educated, and experienced observer witnessing a definite performance in a calm, critical mood, and carefully preparing a written account of his observations--the difference between actual fact and the testimony of the witness is still considerable, and the divergence often upon essential points. We are accordingly justified in making allowance for double or treble or a hundredfold more serious divergence between fact and report, when we pass to decidedly less favorable conditions, such as those of the ordinary spiritualistic test or séance; for these surely present conditions least conducive to accuracy of observation or of record.