resumed. A cholera epidemic began in Columbus, prompting widespread flight to the countryside by residents. Once the epidemic subsided, work on the Statehouse continued, interrupted only by intermissions during the harsh Ohio winters. Comparing plans of the various architects it is apparent that perhaps the most striking change and one that has endured in the finished building, was the fact that West and Sawyer eliminated the rounded dome that all previous designers had suggested for the building, instead replacing it with a low conical roof. Fire consumed the old two-story capitol building in 1852, which created a new urgency to complete the Statehouse project as government offices were forced to relocate to various buildings around Columbus. While some suspected arson, the exact cause of the fire remains a mystery to this day. With the Statehouse exterior nearing completion by 1854, Columbus architect Nathan Kelley was hired to supervise the design and construction of the building's interiors. One of his major tasks would be to provide a system for heating and ventilation in the building, which had not been considered previously. An innovative steam heating system was constructed, with warmed air moved through the building in what Kelley called "air sewers"—small passages made of bricks that linked the various floors of the building. With great fanfare, the new Statehouse opened to the public on January 7, 1857, and soon thereafter the Ohio General Assembly convened in their new chambers. Most of the building was completed, with the notable exception of the rotunda. Although actual work on the building was proceeding smoothly, government officials were deeply dissatisfied with Kelley, citing problems with his working methods and aesthetic choices. Isaiah Rogers, a well known architect based in Cincinnati at the time, was recruited to supervise the final stages of the Statehouse's construction. During his tenure, Rogers oversaw completion of the building's interior and coordinated work on the distinctive rotunda and its enclosing cupola. One of the building's most distinctive exterior features is the low, conical roof atop the cupola, positioned where many viewers expect to see a dome. In the long span between beginning construction on the Statehouse and its completion, the "finished" design changed many times and various proposals included a round dome atop the building. Rogers, in deciding not to use a dome, was actually reverting to a design scheme by architects West and Sawyer. In the end, the building featured