I knew this would catch your attention :). Here is the text from the exhibit announcement. I haven't seen it yet, but the photo with the announcement shows a leather diary with a flap the full length of the diary. The owners are from the Austin area. There doesn't appear to be a direct link to the announcement from the museum page.

James Alexander Lowrey (1841-1917), a Union soldier during the Civil War, a member of Company G in Iowa’s 36th infantry. Lowrey was a miller when he enlisted on August 11, 1862 at Centerville, Iowa. His lasting legacy is the diary he carried with him during the war that offers a look into the life of a soldier during the epic conflict. Lowrey’s company was captured at the battle of Marks’ Mills (April 25, 1864) in Arkansas. His notes on that battle are simple: “Left camp 6 O’clock. Marched till 10 O’clock and was then drawn into fire of battle. Fought about 2 hours and then had to surrender the whole command. Two of our boys killed on the field and several wounded. Know nothing of some of them.” After surrendering, Lowrey and the rest of the company marched for 20 straight days to Camp Ford in Tyler. His May 15, 1864 diary entry notes, “Got to camp 4 O’clock. Had our names taken and marched inside the stockade. Have no shelter. Out in the hot sun.” Charliss Cabe, James Lowrey’s great-great-granddaughter who owns the diary along with her two siblings, said, “we knew that the Bullock had an exhibit on the Civil War and the place [Camp Ford] where he was held, so it was an easy decision for us [to loan the diary]. We live here and have gone to the Bullock many times and felt a kinship with the museum. It was our first choice.” Lowrey remained imprisoned until March 1865, when his regiment was released, probably in an exchange for captured Confederate soldiers, a common practice at the time.