Under this head may be arranged the Baron Schilling’s at St. Petersburg, consisting of 36 magnetic needles, and upwards of 60 metallic conductors, and invented, it seems, at the same date with my electro magnetic telegraph, in the autumn of 1832. Under the same head comes that of professors Gauss and Weber, of Göttingen, in 1833, who simplified the plan by using but a single needle and a single circuit. Professor Wheatstone’s of London, invented in 1837, comes under the same category; he employs five needles and six conductors. Professor Steinheil’s, also invented in 1837, employs two needles and two conductors. But there was another discovery, in the infancy of the science of electro magnetism, by Ampère and Arago, immediately consequent on that of Oersted, namely: the _electro magnet_, which none of the savants of Europe who have planned electric telegraphs ever thought of applying, until within two years past, for the purpose of signals. My telegraph is essentially based on this latter discovery. Supposing my telegraph to be based on the same principle with the European electric telegraphs, which it is not, mine, having been invented in 1832, would still have the precedence, by some months at least, of Gauss and Weber’s, to whom Steinheil gives the credit of being the first to simplify and make practicable the electric telegraph. But when it is considered that all the European telegraphs make use of the deflection of the needle to accomplish their results, and that none use the _attractive power of the electro magnet to write in legible characters_, I think I can claim, without injustice to others, to be the first inventor of the _electro magnet telegraph_. In 1839, I visited London, on my return from France, and through the polite solicitations of the Earl of Lincoln, showed and explained its operation at his house, on the 19th of March, 1839, to a large company which he had expressly invited for the purpose, composed of Lords of the Admiralty, members of the Royal Society, and members of both Houses of Parliament. Professor Wheatstone has announced that he has recently (in 1840) also invented and patented an _electro magnetic telegraph_, differing altogether from his invention of 1837, which he calls his _magnetic needle telegraph_. His is, therefore, the first European electro magnetic telegraph, and was invented, as is perceived, eight years subsequent to mine, and one year after my telegraph _was exhibited in the public manner described at the Earl of Lincoln’s residence in London_.