hide Matching Documents

The documents where this entity occurs most often are shown below. Click on a document to open it.

Document Max. Freq Min. Freq
Knight's Mechanical Encyclopedia (ed. Knight) 10 0 Browse Search
Thomas Wentworth Higginson, Carlyle's laugh and other surprises 4 0 Browse Search
Harper's Encyclopedia of United States History (ed. Benson Lossing) 2 0 Browse Search
Thomas Wentworth Higginson, Atlantic Essays 2 0 Browse Search
James Russell Lowell, Among my books 2 0 Browse Search
View all matching documents...

Browsing named entities in Harper's Encyclopedia of United States History (ed. Benson Lossing). You can also browse the collection for Ampere or search for Ampere in all documents.

Your search returned 1 result in 1 document section:

Harper's Encyclopedia of United States History (ed. Benson Lossing), Electricity in the nineteenth century. (search)
currents. Curiously, even in 1802 the fact that a wire conveying a current would deflect a compass needle was observed by Romagnosi, of Trente, but it was afterwards forgotten, and not until 1819 was any real advance made. It was then that Oersted, of Copenhagen, showed that a magnet tends to set itself at right angles to the wire conveying current and that the direction of turning depends on the direction of the current. The study of the magnetic effects of electric currents by Arago, Ampere, and the production of the electro-magnet by Sturgeon, together with the very valuable work of Henry and others, made possible the completion of the electric telegraph. This was done by Morse and Vail in America, and almost simultaneously by workers abroad, but, before Morse had entered the field, Prof. Joseph Henry had exemplified by experiments the working of electric signalling by electromagnets over a short line. It was Henry, in fact, who first made a practically useful electro-magnet