xii
1812. “Baron Schilling’s operations with a subaqueous
galvanic conducting cord, through the river
Neva, at St. Petersburgh.”—(P. 16.)1815. 3rd August (p. 34.)—Baron Schilling
communicated to Soemmering the “Manuel du Galvanisme,” a book printed at Paris in 1805,
mentioning Romagnosi’s discovery.Baron Schilling may, therefore, be supposed to have known from this date the fact, that a galvanic current deflected a magnetic needle; although Dr. Hamel comes to the conclusion (p. 34), that neither Soemmering or Schilling had any idea of a practical application of Romagnosi’s discovery until 1825 or 1826, five years after Ampère’s suggestion.
1820. Oersted directed the attention of the scientific
world, more effectually than Romagnosi had done, to the influence of a voltaic current on a magnetic needle. Dr. Hamel supposes him to have been acquainted with Romagnosi’s
discovery of 1802.—(P. 35.)1820. Ampère suggests “that it might be possible to
make use of the deviation of the needle for
telegraphic purposes.”—(P. 40.)