The Hackers' letters appear to be a nearly complete record of their service from enlistment to just after the death of Philip in January, 1863. These letters, 114 from Philip and 149 from Rohloff, plus Rohloff's diaries provide an excellent picture of life in the Union Army during the opening stages of the war and during the campaigns of 1862.
Among the most valuable letters in the collection are Rohloff's written during the summer of 1861. These provide an excellent sense of life in the camps defending Washington, going beyond descriptions of the routine of camp life to discussions of morale, officers, and the preparedness of soldiers on both sides. Rohloff describes the equipment and uniforms issued to his Regiment -- late and in poor condition -- in great detail, and their involvement in skirmishes and in the 1st Battle of Bull Run. He displayed an unusual zeal in soldiering, remarking that he did not hesitate in firing at Confederate soldiers, even the first time, and making a number of caustic remarks about Confederate soldiers. The amusing rivalry he and Philip carried on through their correspondence with home over their regiments and relations with friends and women decreased after the First Battle of Bull Run, and seems to have ended altogether after the Peninsular Campaign, when both their moods turned darker and more serious. The brothers both wrote informative letters during the Peninsular Campaign, particularly during the siege of Yorktown, the Battle of Williamsburg, and the Seven Days' Battles. The letters describing the Battle of Fredericksburg are also absorbing, particularly Philip's account of his own wounding. Somehow, through their experiences, which included a number of disastrous defeats at the hand of the enemy, both brothers unwaveringly maintained their faith in their country and their religion.
Rohloff and Philip wrote clearly and succinctly, and both were sensitive to the larger issues of the conflict and to the effect of war on the participants and civilians. Both commented occasionally on strategy and the leadership of the Union Army. Philip's letters are somewhat more polished than Rohloff's. The majority of the brothers' letters were written to family members, with most addressed to their father and mother, William and Barbara Woll Hacker, their younger siblings, Serena and Theodore, or their sister and brother-in-law Augusta and Alpheus Macomber in various combinations. Rohloff also wrote more than 30 letters to his former employers, E.F. Albright and C. Thomson, or Mrs. Albright.
The collection contains letters of several other Michigan soldiers, most of who served with the Hackers, or were friends of the Hacker family from Brighton. Among these are four letters from Peter Smith (Co. G, 2nd Michigan), reminiscing about his friendship with Rohloff and describing visits to his grave; five from Newton J. Kirk (Co. E, 26th Michigan Infantry); four from Capt. John C. Boughton (Co. G, 2nd Michigan), two letters of Edward R. Bliss (4th Michigan Infantry), and six letters written in February and March, 1863, by W. H. Pratt, a Sergeant in the hospital in which Philip Hacker was dying (probably William H. Pratt, Co. E, 26th Michigan Infantry).
Finally, there is an important series of 16 letters written between 1863 and 1866 by Julia Susan Wheelock (b. 1833), an agent for the Michigan Soldiers' Relief Association in Washington and northern Virginia. Wheelock's letters contain excellent descriptions of the activities of a woman in a soldiers' relief society, and she is mentioned appreciatively in the letters of several soldiers in the Hacker brothers' collection for her efforts. Her letters to Mrs. Hacker are particularly interesting in that Mrs. Hacker appears to have been a home-front coordinator for the charitable activities of the Soldiers' Relief Association. In 1870, Wheelock published a memoir of her war-time experiences, The boys in white; the experience of a hospital agent in and around Washington.
The collection also contains The Congregational Psalmist: A Collection of Psalm Tunes, three soldier's bibles, two belonging Rohloff C. Hacker and one from Alexander Reuben that also has Philip W. Hacker's name in it, a leather wallet with Philip Hacker and William A. Ferguson's name on it, and a sewn cloth case. Miscellaneous items such as newspaper clippings, stamps, hunting licenses, currency, 4 photographs, and photographic negatives are also included. A small selection of 20th century family correspondence about the Hacker brothers supplement the collection.