Do you know any application of those magnets?

They are employed in a great variety of electrical apparatus, principally in telegraphy.

When was the first telegraph established?

It was made in 1836, being invented by Prof.  Steinheil, of Munich, and adopted by the government of Bavaria.  It was 12 miles long, and the signals were made by small bells.

Who was the inventor of the telegraph in this country?

Samuel F.B.  Morse, who was born at Charlestown, Mass., April 27, 1791.  He began life as a painter, but did not give his whole attention to art—­chemistry and experiments in electricity and galvanism claiming much of his time.  He first conceived the idea of the telegraph in 1832, and exhibited his invention to Congress in 1837.  He struggled on with scanty means, and was about to give up in despair when Congress appropriated $30,000 for an experimental line, which was opened on May 12, 1844, between Washington and Baltimore.  Prof.  Morse died in 1872, but not before he had reaped honors and fortune from his invention.

How rapidly does the electric current travel through the wires?

From experiments made it appears to be about 15,400 miles in a second.

Can more than one message be sent at the same time on the same wire?

Yes; it is possible now to send several messages at the same time.

What is a Cable?

It is a telegraph wire under water.  Prof.  Morse, in 1842, laid a wire insulated by a covering of hemp coated with pitch-tar and India-rubber between Governor’s Island and the Battery, New York.  Several attempts were made in other countries.

What was the greatest telegraphic undertaking?

That of connecting Europe with America by a submarine cable spanning the ocean, which was commenced in 1857 and completed August 5, 1858.

To whom do we owe this grand undertaking?

This honor is entirely due to Mr. Cyrus W. Field.  Mr. Field was born at Stockbridge, Mass., on November 30th, 1819.  In 1853 he became interested in ocean telegraphy, and after many reverses succeeded in laying the first cable in August, 1858.  The message sent by Queen Victoria to the President of the United States, consisting of 99 words, occupied 67 minutes in transmitting.  In September of the same year this cable ceased to work, but the energy of Field restored confidence, and another cable was made and laid down in July, 1865, but after 1200 miles were deposited it was lost.  In 1866 another was made and successfully laid in July.  In August the lost cable was found and spliced, and carried to the western shore.

What is a Dynamo-electric machine?

A machine by which very powerful currents can be obtained directly from mechanical power.  In these, by means of a steam-engine or other power, a number of coils of wire called the armature are set into rapid revolution between the poles of powerful electro-magnets.  All currents are caused to flow from the armature in one direction by means of a contrivance called the commutator.  Very successful machines of this sort are the Gramme machine, the Siemens, and, principally, the so-called Brush machine.  By these the electric light is now generally produced.