Some of his accounts show curious lapses. In one experiment an accordion is placed in a cage under the table and Mr. Home puts his hand into the top of the cage to do psychic things with the instrument. The temperature of the room is carefully recorded (that doesn't matter, but imparts a scientific flavour to the observations) although we are not told why the experiment was done under the table instead of in a more convenient position on top of it, though 'my assistant went under the table, and reported that the accordion was expanding and contracting,' and 'Dr. A. B. now looked under the table and said that Mr. Home's hand appeared quite still.' Sir William would never have made such an omission if he had been using the same reasoning powers that he used in his scientific descriptions. It is noticeable that the chief 'scientific' supporters of spiritualism are eminent in physical science; they have been trained in a world where honesty is assumed to be a quality of all workers. A laboratory assistant who played a trick upon one of them would find his career at an end, and ordinary cunning is foreign to them. When they enter upon the world of Dissociates, where deceit masquerades under the disguise of transparent honesty, these eminent men are but as babes--country cousins in the hands of confidence-trick men--and their opinions are of less value than those of a smart schoolboy. Spirit photographs are useful to people who desire to show material evidence for their beliefs, and for more than fifty years the desire has been met by periodical outbreaks of this particular manifestation, with occasional exposures of fraud. The spirit effects can be produced by double exposure of one plate or by printing on one paper from two negatives, so that the declaration that a photograph is that of a spirit carries no proof with it and one must examine the circumstances under which the photograph is obtained. A friend of mine, with a decided tendency to belief in the reality of spirit photography, was good enough to show me photographs of himself with spirit forms beside him, and undertook to repeat his visit to the photographer--who is accepted as genuine by leading spiritualists and appears to be the chief exponent in the art of spirit photography in this country--and take with him plates supplied by myself. The photographer allows you to bring your own plates, goes with you into the dark-room, and allows you to initial the plate before it is put in the frame (whether it is your plate which you mark depends upon the will and dexterity of the artist, aided by the darkness and a preliminary hymn and prayer which should remove all doubts from your mind). Then the plate is put in the camera and, whilst attendant ladies pass into a trance, an exposure is made with yourself as the sitter. Next the plate is developed under your eyes and perhaps a spirit form is revealed.