An ongoing two-year renovation of the University of Virginia’s Rotunda has revealed a chemical lab designed by Thomas Jefferson that dates from the 19th century.

Workers uncovered the early science classroom behind a wall on Monday, according to the university.

The room was sealed in one of the lower-floor walls of the iconic Rotunda in the mid-1840s and protected from a fire in 1895 that destroyed much of the building’s interior.

The chemical hearth inside was originally built as a semi-circular niche in the Rotunda, with two fireboxes that provided heat. Brick tunnels underneath the building led fresh air to fireboxes and workstations, while ducts carried away the fumes and smoke.

Students at the time worked at five workstations cut into stone countertops.

The school’s senior historic preservation planner, Brian Hogg, said the chemical hearth may have been used by John Emmet, the school's first professor of natural history, who worked with Jefferson to equip the space.

“This may be the oldest intact example of early chemical education in this country,” Hogg said in a news release.

The university believes the chemical hearth may have been sealed behind the wall when the chemistry laboratory was moved to an annex of the Rotunda before the 1895 fire.

“The hearth is significant as something of the University’s early academic years,” said Mark Kutney, an architectural conservator in the University Architect’s office. “The original arch above the opening will have to be reconstructed, but
we hope to present the remainder of the hearth as essentially unrestored, preserving its evidence of use.”

Once the renovations are completed on the Rotunda, the chemical hearth be on full display behind a barrier.