Put a plate of zinc into one cheek, and a plate of silver, (a crown piece) into the other, at a little distance from each. Apply the cheeks to them as extensively as possible. Thrust in a rod of zinc between the zinc and the cheek, and a rod of silver between the silver and the other cheek. Bring their outer ends slowly into contact, and a smart convulsive twitch will be felt in the parts of the gums situated between them, accompanied by bright flashes in the eyes. And these will be distinctly perceived before contact, and a second time on separating the ends of the rods, or when they have again attained what may be called the striking distance. If the rods be alternated, no effect whatever is produced. Care must be taken, not to press the pieces hard to the gums; this either hinders us from perceiving the convulsion, or prevents it. I find too, that one rod, whether zinc or silver, is sufficient for the communication, and even bringing the two pieces together, will do as well, or perhaps better. But the rods are easier in the management. Asking pardon for the liberty I have taken, without having the honour of your acquaintance, I am, With great regard, SIR, Your most obedient Humble servant, JOHN ROBISON. ------------------------------------ F I N I S. ------------------------------------------------------------------------ Transcriber’s notes: Obvious typographical errors were repaired. This included one word duplicated across page boundaries. Non-obvious “misspellings” were left alone. Possible old spellings inside quotations were left alone. End of the Project Gutenberg EBook of Experiments and Observations Relative to the Influence Lately Discovered by, by Richard Fowler