My Trails into the Past

My paternal great-uncle, Jack C. Sullivan, left for France aboard the Martha Washington from Hoboken, New Jersey. He held the rank of sergeant in the 4 th Engineers, Co. E of the Fourth Division (Regular). [1]  Now I have a new question. When was he promoted? He had to have been promoted while still in the United States. Unfortunately, his service record was part of those records destroyed in the 1973 fire at the National Personnel Records Center in St. Louis. [2] When I requested his file, I was offered a copy of the final pay voucher for his unit. I learned he enlisted on 4 June 1917. [3] The 4 th Engineers were formed at Camp Lewis in Washington. Jack sent home a letter to his sister reporting he had enlisted. [4] FamilySearch has a wonderful database, “United States, World War I, military muster rolls and rosters, 1916-1939.” They are not indexed but each regiment is listed in a pseudo-alphabetical order, starting with the 101 st Ammunition Tr. 26 Div, 5 th Compa...