[1] He was in continuous service during the peace of 1748–56, and on the outbreak of the Seven Years' War served with Admiral Edward Hawke in the Basque Roads in command of HMS Achilles.

In the Havre-de-Grace expedition of the same year Barrington's ship carried the flag of Rear-Admiral George Brydges Rodney, and in 1760 sailed with John Byron to destroy the French Fortress of Louisbourg in Nova Scotia.

He was appointed in 1768 to the frigate HMS Venus as governor to the Duke of Cumberland, who remained with him in all ranks from midshipman to rear admiral.

Between 1772 and 1775 he accompanied Captain John Jervis to Russia where they spent time in St Petersburg and inspected the arsenal and dockyards at Kronstadt, and took a tour of the yacht designed by Sir Charles Knowles for Catherine the Great.

Barrington and Jervis then took a private cruise along the Channel coast calling at various harbours including Brest and making and improving their charts as they went.

[3][4] After a change of government, Barrington was again appointed second in command of the Channel Fleet in 1782, this time under Admiral Richard Howe.

James Marshall and Marie-Louise Osborn Collection, Beinecke Rare Book and Manuscript Library, Yale University.