A message in a bottle, which has floated on the waves of time for 90 years, has been found by French archaeologists.

The beer bottle contained a letter sent to an American soldier fighting in the First World War from his “Aunt Pete” in Oklahoma City. It was discovered by accident by archaeologists exploring a 6th and 7th century Merovingian settlement, at Messein in Lorraine.

The letter gives a jaunty, unthinkingly racist account of life in the US Midwest in July 1918, four months before the end of the war. “Its [sic] all most [sic] impossible to get help of any kind and those you do get are likely to be called any time,” Aunt Pete writes. “There is a big bunch of darkeys going tomorrow night. They had a big parade today and are going to have a big dance tomorrow at the colored park: we lost our porter.”

The letter appears to have reached Sergeant Morres Vickers Liepman, of D Battery, 130th Field Artillery, who was serving with the 35th Division of the American expeditionary force in Lorraine.

Sgt Liepman, who survived the war, placed the letter in the bottle and buried it. He may have been trying to preserve it during a German bombardment.

Officials from Inrap have tried to trace Sgt Liepman’s descendants without success. The US embassy in Paris has discovered that Morres V Liepman studied in Pittsburgh, Kansas, and enlisted on 25 July 1917. He reached Le Havre in June 1918 and fought in the battles of the Argonne, Saint-Mihiel and the Vosges. In the autumn of 1918 his unit was stationed in the Haye Forest sector not far from the Noires terres where his letter was found. He returned to the US in 1919. Aunt Pete’s second name is unknown. The only address on her letter is that of the Robert M Scott drugstore in Oklahoma City.