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communicated to the Academy his observation that the galvanic conductors attracted needles that were not magnetised.
It deserves here to be remembered that, from Aldini’s book, it was known that the chemist Giuseppi Mojon, at Genoa, had, before 1804, observed in unmagnetised needles, exposed to the galvanic current, a sort of polarity. Izarn repeats this also in his “Manuel du Galvanisme,” which book was one of those that, by order, were to be placed in the library of every Lycée in France.
Ampère, who, as is well known, bestowed most particular attention on the subject brought, in 1820, before the scientific world through Oersted, mentioned that it might perhaps be possible to make use of the deviation of the needle for telegraphic purposes, but neither he nor any one else then constructed such an instrument.
It was reserved for Baron Schilling, at St. Petersburg, to make the first electro-magnetic telegraph. Having become, as we know, through Soemmerring, at Munich, passionately fond of the art of telegraphing by means of galvanism, he now used for it the deflection of the needle, which he placed within the multiplier of Schweigger horizontally on a light vertical axle hanging on a silken thread,
