Fig. 28
9. The Electric Engine ([Fig. 27]).—This toy, with one dry battery cell, develops power enough to run several other toy machines. The diagram in [Fig. 28] will make its plan of operation plain. B is the battery cell, c the electro-magnets, a an armature of iron. By a rod this armature is connected with a crank on the axle which carries the fly wheel f. Another crank, d, upon the same axle serves like a push button to close the electric circuit at the right instant. The wire g from the battery cell encircles the electro-magnet c and then is connected to the iron base of the toy. When the crank d touches the conductor e, which is a spring, the electric current passes around the magnet, the magnet pulls the iron armature a, and this gives an impulse to the wheel f whose momentum carries it around during that portion of the revolution when d is separated from e and a is receding from the magnet.
It is customary to say that the circuit is closed through the base of the machine, but this language requires interpretation. It means that a way is provided for the electric current to pass through the base. A person who is expert in language but not in electricity might expect us to say "the circuit is open through the base."
Fig. 29
10. The Telegraph Sounder ([Fig. 29]).—This was a toy half a century ago, but since the days of Samuel Finley Breese Morse it has become of vast commercial importance. The Western Union Telegraph Company in 1909 had 211,513 miles of poles and cables, 1,382,500 miles of wire, 24,321 offices, sent 68,053,439 messages, received $30,541,072.55, expended $23,193,965.66, and had $7,347,106.89 in profits. In the United States more than 93,000,000 and in the world at large more than 600,000,000 messages are sent annually, and there are men still living who scoffed at Morse's ideas as impracticable.
It is interesting to contemplate what would happen to the Stock Exchange, to the newspapers, to the railroads, to the congressman addressing his constituents from the floor of a legislative chamber, to business in general, if the world were deprived of the telegraph.
A few years ago a telegraph despatch was sent from New York to San Francisco, Tokio, London, and back to New York, 42,872 miles, in three minutes less than an hour. Electricity can travel around the world in a fraction of a second, the time was consumed in repeating the message. I once sent a message from New York to New Haven to announce that I was coming, and afterward took my train and reached New Haven in time to receive my own message and pay the messenger boy. But I have never lost faith in the beneficent results of Morse's labours.
Morse (1791–1872) was an artist and the first President of the National Academy of Design. He was likewise a professor in New York University and constructed his first experimental telegraph line upon the University campus in 1835. His first public line was built from Washington to Baltimore in 1844. The Western Union Telegraph Company was incorporated in 1856. Of course the work of Morse rested upon that of Oersted, in Copenhagen, who, in 1819, discovered electro-magnetism, and upon that of Joseph Henry of Albany, who in 1827 first insulated the wires.