Introduction

Abstract

Giambattista delia Porta, a Renaissance scientist, was the author in 1558 of Magia Naturalis (Natural Magic), a book in which he discusses many subjects, including demonology, magnetism, and the camera obscura. The book mentions an imaginary device that has since become known as the “sympathetic telegraph.” This device was to have consisted of two circular boxes, similar to compasses, each with a magnetic needle. Each box was to be labeled with the 26 letters, instead of the usual directions, and the main point was that the two needles were supposed to be magnetized by the same lodestone. Porta assumed that this would somehow coordinate the needles such that when a letter was dialed in one box, the needle in the other box would swing to point to the same letter.