In 1780 he was captured by a British seventy-four, when taking a prize into port and sent with other prisoners to England.  On the passage, the prisoners—­amounting to about sixty—­were confined in the most loathsome of dungeons, without light or pure air, and with a scanty supply of provisions.

They thought when they arrived at Plymouth, that their privations were at an end; but they were only removed to another prison-ship, which, although dirty and crowded, was, in some measure, better than the one they had left.  From this, contrary to expectation, as soon as they were so much recovered as to be able to walk, they were brought on shore and confined in Mill prison, where they met the anxious faces of several hundred American prisoners, who had undergone the same privations as themselves.

This prison was surrounded by two strong walls, twenty feet apart, and was guarded by numerous sentries.  There were small gates in the walls, and these were placed opposite each other, the inner one generally remaining open.  The prisoners were allowed the privilege of the yard nearly all day, and this set the inventive mind of Barney upon the scheme, which, in the end, terminated in his liberty; not, however, without infinite danger and trouble.  He set about finding out some small chance which might afford the least hope of release; and having discovered one of the sentries that had served in the United States, and remembered the kindness with which he had been there treated, Barney and he formed the means of escape.  It was arranged that Barney should affect to have hurt his foot and obtain a pair of crutches, and thus lull suspicion.

On the 18th of May, 1781, he habited himself in the undress uniform of a British officer, the whole covered with a old greatcoat, and, by the aid of the sentinel, cleared the prison; when he threw off the coat, and soon arrived at the house of a well known friend to the American cause, in Plymouth.  That he might not be soon missed, he got a lad, who, after answering to his own name, was to get out, and answer to Barney’s, in the yard, which little stratagem succeeded admirably.  When Barney arrived at the friend’s house, he made preparations to leave as soon as possible, well knowing that if any of the British were detected harboring him, they would be convicted of high treason.  In the evening, therefore, he departed to the house of his friend’s father, at a considerable distance, where he would be safer.  On arriving there, he was surprised to find two of his old friends—­Americans—­who had been, for some time, anxiously waiting for an opportunity of returning home, and now thought that the time had arrived.