The French frigate _Thetis_, having captured the brigantine _Eliza_, of New York, a seaman named Henry Doughty, a native-born citizen of Boston, was placed with a number of English sailors who had been captured, and was then delivered to the British in exchange for French sailors. Using American sailors in effecting exchanges became a common practice with the French naval commanders. The crews of American vessels taken to the West Indies were commonly turned ashore without clothing (except what they were wearing), or food, or means of procuring either. On November 10, 1797, seven captured American vessels were lying at Petit Guave, three-fourths of the crews of which had died because of the hardships they had suffered when thus turned ashore. In some cases the crews were imprisoned. Captain Breard, of the schooner _Zephyr_, of Portsmouth, who ventured to go on board the privateer that had captured him and there beg for a little of the food of which he had been robbed, was thrown over the rail. Captain Codwise, of the brig _Glasgow_, was thrown into prison at Leogane and kept for thirty-six hours without food. A more cheerful picture of the life at sea in American ships at that time is found in a letter (written in 1799) from Captain Elias Hasket Derby, Jr., to his father. The young man was in command of the Salem ship _Mount Vernon_, and he had arrived at Gibraltar after a passage of seventeen and a half days. "The first of our passage was quite agreeable; the latter, light winds, calm, and Frenchmen constantly in sight for the last four days. The first Frenchmen we saw was off Tercira--a lugger to the southward. Being uncertain of his force we stood by him to leeward on our course and soon left him. July 28th, in the afternoon, we found ourselves approaching a fleet of upwards of fifty sail, steering nearly N. E. We run directly for their center; at 4 o'clock found ourselves in their half-moon; concluding it impossible that it could be any other than the English fleet, continued our course for their center to avoid any apprehension of a want of confidence in them. They soon dispatched an 18-gun ship from their center, and two frigates, one from their van and another from their rear, to beat towards us--we being to windward. On approaching the center ship under easy sail I fortunately bethought myself that it would be but common prudence to steer so far to windward of him as to be a grapeshot's distance from him, to observe his force and maneuvering. When we were abreast of him he fired a gun to leeward and hoisted English colors. We immediately bore away and meant to pass under his quarter, between him and the fleet showing our American colors. This movement disconcerted him, and it appeared to me he either conceived we were either an American sloop of war, or an English one in disguise, attempting to cut him off from the fleet; for while we were in the act of wearing on his beam he hoisted French colors and gave us a broadside.