Having now described the principal slate tricks which mediums use to entangle the unwary for their own ends, we come to other tricks which are used from time to time to impress the credulous with the idea that the medium is imbued with supernatural power and can perform what are, in effect, miracles. These tricks are legion, and they vary from clumsy attempts at mystification to the use of elaborate pieces of magical apparatus which call for rare mechanical genius in their design and construction. The present chapter will deal more particularly with what might be termed mind reading tricks and the reading of concealed writing. Of these tricks one of the most perplexing is that of reading sealed communications, or answering questions placed in an envelope which is well sealed. If I were to tell you that I could read whatever was written on a card inclosed in an envelope, and that envelope not only well sealed, but also stitched or sewn through with a thread and needle or machine, and the thread sealed to the envelope also, without removing the seal, stitches, etc., you would hardly credit the assertion. It is nevertheless true, and is easily and readily accomplished by very simple means. Prepare a sponge with alcohol. With this you rub or brush the envelope, which immediately becomes transparent as glass, thus enabling you to see through it and read what is written on the card. It takes but a few seconds for the alcohol to evaporate and leave the envelope in the same condition as before, without leaving a trace as to what or how it has done. This test was used most successfully for years by a celebrated Philadelphia medium. [Illustration: Fig. 20.--The Thumb Pencil Carrier.] We now come to a test often employed. A card is given by the medium to a skeptic with the request to write a question on it. The medium now holds the card in his hand against his forehead. Presently he hands the card back to the spectator, and on it, in writing, is found an answer to the question. The medium accomplishes the above feat by means of a little apparatus which is easily attached to the tip of the thumb. Part of it goes under the thumb nail and the lower part has a small needle point which embeds itself in the flesh. In the center of this little apparatus is a tiny piece of lead pencil. With this clever bit of mechanism the medium does the writing with the thumb of the hand holding the card. (Fig. 20.)