schwit1 writes: 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.