he could not resist the temptation to try his
hand at inventing a machine which should properly engrave the plates he
was drawing. It was pure delight to him to exercise his wits on such a
problem, and as a result in a short time he had made a machine for
engraving plates which was used successfully in preparing the
illustrations for his book on "Canals."

The youth had now won wide recognition throughout Sweden for his
inventive skill. But his own country offered him small opportunities,
devoted though he was to the land and the people. There was more chance
for such a man in a country like England, and there he now went.
Stephenson was working then on his steam-engine, and Ericsson studied
the same subject, and built an engine which in many ways was superior to
the Englishman's. In whatever direction he turned his mind he was able
to find new ideas for improving on old methods.

Ericsson soon built a locomotive for the directors of the railway
between Liverpool and Birmingham which was the lightest and fastest yet
constructed, starting off at the rate of fifty miles an hour. He could
not find the opportunities he wished, however, in England, and went to
Germany, and from there came to the United States.

It was in America that Ericsson won his greatest triumphs. He had
invented a screw propeller for boats, and found a splendid market for
this type of machinery. He built the steamship _Princeton_, the first
screw steamer with her machinery under the water line. This was a great
improvement on the old top-heavy style of steamboats, but how great was
only to be known when war showed that ironclads with machinery safely
sunk beneath the water line and so out of reach of the enemy's guns
were to revolutionize naval warfare.

By the time of the American Civil War men in all countries were
experimenting with these new ideas for ships which Ericsson had launched
upon the world. News came to Washington that the Confederate government
had an all-iron boat, low in the water, which could ram the high-riding
wooden ships of the Union navy, and would furnish little target for
their fire. The Union was in great alarm, for it looked as though this
small iron floating battery could do untold damage to the Union
shipping. There was only one man to appeal to if the North were to
offset this Southern ship, which had been christened the _Merrimac_.
John Ericsson was the man, and he agreed to build an ironclad which
should be superior