Considered great improvements to their predecessors of the era, their design included oscillating engines,[5] water tight bulkheads,[6] and wire bulwarks, to reinforce the sides against the force of rough seas.

[12] It was the Arago which, in December 1859, returned Senator Seward from his eight-month tour of Europe and the Middle East, to begin his unsuccessful bid for the Republican Presidential nomination.

[13] Due to the outbreak of the American Civil War, government contracted mail service ceased with the Arago's last voyage in this capacity, beginning from New York on March 30, 1861.

The steam ships Arago, Vanderbilt, Illinois and Ericsson, were ordered to Hampton Roads where, using their better speed and newly installed iron prows, were to ram the Virginia should she again put out to open water.

After the Virginia was scuttled to prevent her capture following the Confederate retreat from Norfolk, the Arago was removed from this duty and, with a civilian crew, returned to transporting troops and equipment for the Union army.

After watching the ship speed up and drop cotton bales and other items over the side, Captain Gadsden, after consulting the military officers on board, gave chase.

Arago delivered the flag and its entourage to Fort Sumter where, four years to the day it was lowered in surrender by then Major Anderson and Private Hart, it was again raised by them in celebration of the Union's victory.

[26][27] Following the war her owners, the New York and Havre Line, gave her a general overhaul, including new boilers, repainting inside and out, and newly furnished staterooms and cabins.

With the hope for her to regain her pre-war transatlantic glory, Arago left New York on November 25, 1865, with Captain Henry A. Gadsden still in command, with 40 cabin passengers and a cargo of cotton.

Shortly after Arago's departure for Peru in early May, and before changing her flag, claims were made she had loaded up with mercenaries, arms and supplies to support revolutionists in Cuba.