The author of Sergeant Lamb's America continues the fictionalized account of an Irish soldier fighting for the British during the Revolutionary War.   This is the second in a two-book series telling the story of Sgt. Roger Lamb, a non-commissioned officer in the British Army, who served in America during the American War of Independence. Captured with Gen. Johnny Burgoyne after the Battle of Saratoga, he made a daring escape and later served under General Cornwallis.   Following closely to Sergeant Lamb's personal memoirs, renowned poet, classicist, and novelist Robert Graves traces the sergeant's harrowing time in the service, providing a compelling, only barely fictionalized eyewitness account of a crucial point in American history.