When investigators bring their own marked slates with them, screwed tightly together, and sealed, the medium has to adopt different tactics from those employed in the tests before mentioned. He has to call in the aid of a confederate. The audacity of the sealed-slate test is without parallel in the annals of pretended mediumship. For an insight into the secrets of this phase of psychography, the reading public is indebted to a medium, the anonymous author of a remarkably interesting work, “Revelations of a Spirit Medium.” Many skeptical investigators have been converted to Spiritualism by these tests. They invariably say to you when approached on the subject: “I took my own marked slates, carefully screwed together, to the medium, and had lengthy messages written upon them by spirit power. These slates never left my hands for a second.” I will quote what the writer of “Revelations of a Spirit Medium” says on the subject:
“No man ever received independent slate-writing between slates fastened together that he did not allow out of his hands a few seconds. Scores of persons will tell you that they have received writing under those conditions through the mediumship of the writer; but the writer will tell you how he fooled them and how you can do so if you see fit.
“In the first place you will rent a house with a cellar in connection. Cut a trap-door one foot square through the floor between the sills on which the floor is laid. Procure a fur floor mat with long hair. Cut a square out of the mat and tack it to the top of the trap door. Tack the mat fast to the floor, for some one may visit you who will want to raise it up.
“Explain the presence of the fur by saying it is an absorbent of magnetic forces, through which you produce the writing. Over the rug place a heavy pine table about four feet square; and over the table a heavy cover that reaches the floor on all sides. Put your assistant in the cellar with a coal-oil stove, a tea-kettle of hot water, different colored letter wax and lead pencils, a screw driver, a pair of nippers, a pair of pliers, a pair of scissors and an assortment of wire brads. You are ready for business.
“When your sitter comes in you will notice his slates, if he brings a pair, and see if they are secured in any way that your man in the cellar can not duplicate. If they are, you can touch his slates with your finger and say to him that you can not use his slates on account of the ‘magnetism’ with which they are saturated. He will know nothing of ‘magnetic conditions’ and will ask you what he is to do about it.
“You will furnish him a pair of new slates with water and cloths to clean them. You also furnish him paper to write his questions on and the screws, wax, paper and mucilage to secure them with. He will write his questions and fasten the slates securely together.
“You now conduct him to your séance-room and invite inspection of your table and surroundings. After the examination has been made you will seat the sitter at one side of the table with his side and arm next it. If he desires to keep hold of the slates a signal agreed upon between yourself and your assistant will cause the spirit in the cellar to open the trap door, which opens downwards, and to push through the floor and into position where the sitter can grasp one end of it, a pair of dummy slates. This dummy your assistant will continue to hold until the sitter has taken hold of it after the following performance:
“Your assistant lets you know everything is ready by touching your foot. You now reach and take the sitter’s slates and put them below the table, and under it, telling the sitter to put his hand under from his side and hold them with you. He puts his hand under and gets hold of the dummy slates held by your assistant.
“Your assistant holds on until you have stood the slates on end, leaning against the table leg, and have got hold of the dummy. He then takes the sitter’s slates below and closes the trap. He proceeds to open them, read the questions, answer them and refasten the slates.
“You will be entertaining your sitter by twitching and jerking and making clairvoyant and clairaudient guesses for him.