Lieutenant Worden was kept a prisoner until the 13th of the following
November, when, his health having broken down, he was exchanged and sent
North. There he remained, slowly regaining his strength until March,
1862, when it fell to his lot to become a leading actor in one of the
most famous naval engagements in all history.

When war had fully begun the Union forces in charge of the Norfolk Navy
Yard saw they were not strong enough to prevent its capture by the
Confederates, who were arming for that purpose. They therefore set fire
to the numerous and valuable shipping there. Among the vessels scuttled
and sunk was the steam frigate _Merrimac_, at that time the finest
vessel in the service. In truth, she went down so quickly that very
little damage was done to her. The Confederates raised her, fastened a
huge iron snout or prow at the front, cut down her deck and encased her
with railroad iron, which sloped at an angle of forty-five degrees, and
was smeared on the outside with grease and tallow. Her enormous weight
made her draw more than twenty feet of water and when she was moving
slowly through the bay or river her appearance suggested the mansard
roof of a vast house. From what has been said it will be noted that the
_Merrimac_ was a genuine ironclad, something which had never been heard
of before.

[Illustration: BLOCKADE RUNNER--THE "MONITOR"--CAPTAIN ERICSSON.]

Regular news of the building of the _Merrimac_ (called the _Virginia_ by
the Confederates) was telegraphed to Washington by friends of the
Government. The authorities felt some uneasiness, but were far from
suspecting the terrible power for destructiveness possessed by the
monster. Captain Ericsson, the famous Swedish inventor, was constructing