These records consist almost exclusively of the business records of Zachau's many mercantile enterprises. They include a barely-legible letterbook, daybooks, account books, and cash books dealing with Zachau's business ventures, 1857-1914. The daybooks deal with sales at his general store and with his hauling and plowing operations, and include a daily recording of the weather and the tasks of employees, most of whom were family members. Only the last six years of the records, 1907-January 1914, document personal activities and family events.
