The relief of American prisoners in England was another thing which continually taxed the attention of Franklin during the Revolutionary War. "I was sick, and in prison, and ye visited me not," was a reproach that no one of them could justly address to him. His nature was a truly compassionate one, and, in few respects, does it show to greater advantage than in his unceasing efforts to secure the exchange of his unhappy countrymen, confined at Portsmouth and Plymouth, or, that failing, to provide them with all the pecuniary succor in his power, in addition to that so generously extended to them by many kind hearts in England.[40] In his friend, David Hartley, a man, whose peaceful and humane instincts even the vilest passions of war could not efface, he had an agent in a position to reach the ear of the English Ministry for the purpose of promoting the exchange of prisoners. For different reasons, the task was a painfully slow one. In the beginning, all American prisoners were committed to prison upon the charge of high treason, a charge entirely inconsistent with the idea of exchange. Besides, England was reluctant to relinquish the advantage that she had, until the treaty of alliance between France and America was consummated, in the fact that American ships had nowhere to confine their prisoners except under their own hatches. They tried to meet this difficulty by releasing English prisoners on parole on their each promising that they would secure the release of an American prisoner, but the English Admiralty, after some hesitation, finally refused to surrender a single American prisoner in exchange for such paroled Englishmen. Commenting upon this fact, along with another incident, Franklin wrote to James Lovell, "There is no gaining anything upon these Barbarians by Advances of Civility or Humanity." At last, however, several cartels were agreed upon, and he enjoyed the great happiness of seeing some hundred or so American captives brought over to France and released. He was still, however, to incur a great disappointment when, owing to the fear on the part of Holland of provoking English resentment, the five hundred prisoners, transferred to Holland by John Paul Jones, after his engagement with the _Serapis_, had to be exchanged for French instead of American prisoners. The French Ministry promised to make this disappointment good by advancing to Franklin an equal number of English prisoners taken by French ships, but the English Ministry promptly met this promise by refusing to exchange American prisoners for any English prisoners except such as had been captured by American ships. It was also a great disappointment to Franklin that he could not induce the English Ministry to give its assent to a formal proposition from him that prisoners, taken by either country, should be immediately released upon the understanding that an equal number of prisoners held by the other should also be released. The high-minded