from The Lowell Tribune, May 3, 1917, page 4 (page 8 on micorfilm), column 2:
Two More Enlist
Two more Lowell boys, Charles Tanner, son of Mr. and Mrs. Fred Tanner, and George Minninger, son of the late Mat Minninger, have enlisted in the army, both boys going into the coast artillery service. They will leave today for Ft. Wayne and from there will go to Columbus, Ohio.