In the War for the Union Captain Wilkes commanded the James River squadron, was made commodore in 1862 and was retired in 1864 and made rear-admiral on the retired list.

[Illustration:  THE “SAN JACINTO” STOPPING THE “TRENT.”]

The scientific expedition of which Lieutenant Wilkes was given command was intended, to quote the words of Congress, “for the purpose of exploring and surveying the southern ocean, as well to determine the existence of all doubtful islands and shoals as to discover and accurately fix the position of those which lie in or near the track of our vessels in that quarter and may have escaped the observation of scientific navigators.”

Lieutenant Wilkes sailed from Hampton Roads on the 19th of August, 1838, his flagship being the 18-gun sloop-of-war Vincennes, the 18-gun sloop-of-war Peacock, the 12-gun brig-of-war Porpoise, the storeship Relief, the tender Sea Gull and the tender Flying Fish.  Since one of the main objects was scientific research, the expedition was provided with a philologist, naturalists, conchologists, mineralogist, botanist, draughtsmen and a horticulturist.

A halt for a week was made at the Madeira Islands, when the ships headed southward, reaching Rio Janeiro late in November.  In January, 1839, they halted at Orange Harbor, Terra del Fuego, and made it their base of operations.  On the 25th of February Lieutenant Wilkes, in the Porpoise, accompanied by the Sea Gull, started for the South Pole.  On the 1st of March considerable ice and snow were encountered and an island sighted, but the men could not land because of the surf.  The next day the Ashland Islands were discovered and soon after the two vessels reached Palmersland.  The following is the account of Lieutenant Wilkes: 

“It was a day of great excitement to all, for we had ice of all kinds to encounter, from the iceberg of huge quadrangular shape, with its stratified appearance, to the sunken and deceptive masses that were difficult to perceive before they were under the bow.  I have rarely seen a finer sight.  The sea was literally studded with these beautiful masses, some of pure white, others showing all shades of the opal, others emerald green and occasionally, here and there, some of deep black.  Our situation was critical, but the weather favored us for a few hours.  On clearing these dangers we kept off to the south and west under all sail, and at 9 P.M. we counted eight large islands.  Afterward the weather became so thick with mist and fog as to render it necessary to lie to till daylight, before which time we had a heavy snowstorm.  A strong gale now set in from the southwest; the deck of the brig was covered with ice and snow and the weather became exceedingly damp and cold.  The men were suffering not only from want of sufficient room but from the inadequacy of the clothing.”