Opinion on Harbor Defense.

April 4, 1863.

On this general subject I respectfully refer Mr.________ to the Secretaries of War and Navy for conference and consultation. I have a single idea of my own about harbor defense. It is a steam ram, built so as to sacrifice nearly all capacity for carrying to those of speed and strength, so as to be able to split any vessel having hollow enough in her to carry supplies for a voyage of any distance. Such ram, of course, could not herself carry supplies for a voyage of considerable distance, and her business would be to guard a particular harbor as a bulldog guards his master's door.