A website from the Massachusetts Historical Society; founded 1791.

Browsing: Papers of John Adams, Volume 6

This foot note contained in document ADMS-06-06-02-0087
5. The proclamation of 9 May, mentioned above, was intended to prevent incidents such as Gustavus Conyngham's capture of the French brig Graciosa in 1777 and the Swedish brig Honoria Sophia in 1778 and stemmed from a report on illegal seizures by American armed vessels, that is, privateers, contained in a letter of 30 Nov. 1777 from the Commissioners that the Committee for Foreign Affairs had received on 2 May ( JCC , 11:486; Cruises of Conyngham, ed. Neeser, p. xl, xliii–xlv, prize list facing p. 152; Wharton, ed., Dipl. Corr. Amer. Rev. , 2:433–436; see also Evans, Nos. 16121, 16122). It required American privateers to observe the “rights of neutral powers and the usage and custom of civilized nations” and prohibited the seizure of vessels belonging to allies of the United States, unless carrying contraband or enemy soldiers, as well as those of the enemy located within the territorial waters of a neutral state and thus enjoying the protection of that nation.
The Committee clearly believed that the proclamation of 9 May and the ratification of the Franco-American treaties would produce a fundamental change in the future operations of American privateers. They would be able to operate more freely because of the clear definition of what constituted a lawful prize and the removal of the hindrance posed by French regulations, even if only pro forma, designed to prevent a premature rupture between England and France. In other words, neutral ships would no longer be taken and there would be no repetition of the incident in which the Harwich packet Prince of Orange and the brig Joseph, both taken by Gustavus Conyngham in May 1777, were returned to their British owners in response to a sharp protest by the British ambassador in Paris against the blatant use of French ports by American privateers at a time when France was ostensibly a friendly power, bound by the 1713 Treaty of Utrecht which prohibited such practices ( Cruises of Conyngham , p. xxx–xxxii).
The Committee's conclusion was further supported by the arrival, on 2 May, of a letter from the Commissioners dated 28 Feb. 1778. The Commissioners reported that the French government had agreed to pay 400,000 livres to the owners of the privateers Boston and Hancock to compensate them for the seizure and return to their English owners, “for Reasons of State,” of two British West Indiamen. While the seizure was ostensibly the result of a false declaration of origin (the prizes were said to be from St. Eustatius), it was, in reality, apparently the result of too much talk on the part of the privateer captains, Babson and Hendricks, which forced the hand of the French government (Wharton, ed., Dipl. Corr. Amer. Rev. , 2:507–509; Deane Papers , 2:110, 216). Silas Deane later stated, in his defense before Congress, that the compensation to the owners of the Boston and Hancock amounted to 450,000 livres and resulted solely from the efforts of Le Ray de Chaumont and himself ( Deane Papers , 3:169).