With these all-powerful magicians--an expected result and the willingness to credit a marvel--clearly in mind, let us proceed from those instances in which they have least effect up to the point where they form the chief factor. First come a host of conjuring tricks performed on the stage in slightly modified forms, but which are presented as "spiritualistic." So simple a trick as scratching a name on one's hand with a clean pen dipped in water, then writing the name on a slip of paper, burning the slip and rubbing the part with the ashes, thus causing the ashes to cling to the letters formed on the hand and reveal the name, has been offered as a proof of spirit agency. Whenever an article disappears or rapidly changes its place, the spiritualist is apt to see the workings of hidden spirits; and over and over again have the performances of professional conjurers been declared to be spiritual in origin in spite of all protest from the conjurers themselves. Here everything depends upon the possession of certain technical knowledge; judging without such knowledge is apt to be mere prejudice. Another very large class of phenomena consists of those in which the performer is placed in a position apparently inconsistent with his taking any active part in their production; rope-tying tests, cabinet séances, the appearance of a "spirit-hand" from behind a screen, locking the performer in a cage, sewing him in a bag, and so on. The psychologist has very little interest in these; their solution depends upon the skill with which knots may be picked, locks unfastened, and the other devices by which security may be simulated. The chief interest in such performances is the historical one, for these have done perhaps more than anything else to convince believers of the truth of Spiritualism. Here, where everything depends upon the security of the fastenings (for once free, the medium can produce messages from the spirit-land limited only by his ingenuity and boldness), upon the particular moment when the examination was permitted or the light turned down, upon the success with which an appearance of security and intactness of seals and knots may be simulated, it might be supposed that all possible precautions had been taken to control and eliminate these possibilities; while, as a matter of fact, the laxity of most investigators in this regard is well known. These performances deceive because people overlook the technical acquisitions needed to pronounce upon the possibility or impossibility of a fastening having been tampered with and apparently restored without detection. If manufacturers of safes were equally credulous, and gave equally little time to the study of the security of locks, "safe" would be an ironical expression indeed.