A friend of mine told me of a medium he once went to see, who gave him a most remarkable test. He brought his own slate, and, as he afterward said, there could have been no trick about it. The medium took the slate for a moment, and with a pencil covered the slate with writing on both sides, just to see, so he said, if it would be good enough for the test. He then cleaned off the slate on both sides and gave it back to my friend, requesting him to hold it close against his breast, and then in a short time remove it, and, when he did so, he was thunderstruck to find writing on it on the side nearest to him. This struck me as being a most astounding proof of spirit writing. I had a meeting with the medium, who gave me the same test. It seemed strange to me that he should want my slate to write on and wash it off again, for the same reason as he gave my friend, and that was to see “if it was good enough for the spirits to work with.” I received a message on the slate, after it was washed, and saw that there was none on there after it was cleaned and handed to me. I went home puzzled, and experimented to no avail. I had another sitting with the medium, but he did not give me the same test; so I returned home again and tried to fathom the mystery, and was eventually successful. The trick was mainly in the pencil. It was pointed at both ends. (Fig. 16.) One end was a genuine slate pencil, the other end was a silver nitrate, or caustic pencil. In writing on the slate he wrote the lines quite a little distance apart with the slate pencil; in between these lines he wrote with the caustic pencil, the writing of which was invisible. The sponge the slate was cleaned with, was dipped in salt water. That part of the slate containing the writing done with the silver nitrate was just lightly tapped with the sponge, the rest of the slate was thoroughly cleaned. The salt water, when the slate becomes dry, brings out the silver nitrate white like a slate pencil mark. I consider this trick as ingenious and clever a one as it has been my good fortune to witness, and one that caused me much mental effort to solve. [Illustration: Fig. 17.--Writing with the Toes.]