After this we find him a prisoner in the hands of the Americans and French at Yorktown, Virginia. As on the former occasion, he was treated with all imaginable kindness; and, being released on parole, returned to Europe early in 1782, and proceeded by way of Cork, Dublin, and Greenock to Edinburgh, where he abode for a short time. Thence he started for London: and, desirous of testing the best way of sustaining physical strength during long marches, and urged perhaps also by economical considerations, he resolved to make the journey on foot. His West Indian and American experience had taught him that spare diet consisted best with pedestrian efficiency, and it was accordingly his practice, during this long walk, to abstain from animal food until the close of day, nor often then to partake of it. He would walk some fourteen miles before breakfast--a meal of tea and bread; rest then for an hour or an hour and a half; then pace on until bedtime--a salad, a tart, or sometimes tea and bread, forming his usual evening fare. He found that on this diet he arose every morning at dawn with alacrity, and could prosecute without inconvenience his laborious undertaking. By way of experiment he twice or thrice varied his plan--dining on the road off beefsteaks, and having a draught of porter in the course of the afternoon; but the result justified his anticipations. The stimulus of the beer soon passing off, lassitude succeeded the temporary strength it had lent him; and, worse than all, his disposition to early rising sensibly diminished.
His stay in London, which he reached in this primitive fashion, was not long. His kind friend Dr. Stuart, who had exchanged into the Royal Horse-Guards, gave him the shelter of his roof; but so poor was Mr. Jackson, that, although ardently desirous of improving himself in his profession, he was unable to attend any one of the medical schools with which London abounds.
The peace of 1783 having opened the continent to the curiosity of the British traveller, Jackson curtly announced to his friends, that "he was going to take a walk." His poverty allowed him no other mode of locomotion; so off he set on the grand tour, carrying with him a map of France, a bundle of clothes, and a scanty supply of money. Crossing the Channel, he reached Calais, a place which Horace Walpole, writing from Rome, declared had astonished him more than any thing he had elsewhere seen, but in which our adventurer found nothing more astonishing than a superb Swiss regiment. He proceeded to Paris, and thence through Switzerland, by Geneva and Berne, into Germany, at a town of which--Günz in Suabia--he met with a comical enough adventure.