Task: Question Answering
Input (English): Passage: Joseph and Mary lived with their son Joseph, Jr. and his family in a small house while theirs was being built. Mary Priestley was primarily responsible for the design of the couple's new home and her family inheritance may have helped finance it, but she died before it was completed. By 1797, Joseph's laboratory was completed—the first part of the home to be finished. It was the first laboratory that "he had designed, built, and outfitted entirely himself" and was probably the first "scientifically-equipped laboratory" in the United States. Joseph continued his scientific and scholarly work in his new laboratory, identifying carbon monoxide (which he called "heavy inflammable air"). In 1798 Joseph Jr., his wife, and their children moved into the new house with Joseph Priestley. The house also held Priestley's library, which contained about 1600 volumes by his death in 1804 and was one of the largest in America at the time. The Priestley family held Unitarian church services in the drawing room and Joseph educated a group of young men until the local Northumberland Academy that he helped found was completed.The house proper was completed in 1798, with a Mr. Jones of Northumberland employed acting as master carpenter. Built in an 18th-century Georgian style, the "balance and symmetry" of the architecture signaled "subdued elegance". The house was accented with Federalist highlights, such as "the fanlights over the doors and the balustrades on the rooftop belvedere and main staircase", marking it as distinctly American. Douglas R. McMinn, in the National Register of Historic Places nomination for the Northumberland Historic District, calls it a "mansion" that is "probably the finest example of the Federal style in the region". As William N. Richardson, the site administrator for the Joseph Priestley House in the 1990s, notes, Priestley's American home did not resemble his "high-style Georgian town house" that was destroyed in Birmingham; rather, it was "plain" and built in the "American vernacular".The house has a two-and-half story central section, which is 48 feet (14.6 m) by 43 feet (13.1 m), and two one-story wings on the north and south sides that are each 22 feet (6.7 m) by 21 feet (6.4 m). The first and second floors have a total area of 5,052 square feet (469 m²). The north wing was the laboratory and the south wing (which had an attached woodshed) was the summer kitchen. The cellar, first, and second floors of the central section are each divided into four rooms, with a central hall on the first and second floors; the first floor also has an intersecting hall that leads to the laboratory. The attic has three rooms for servants and a larger room for storage. A paint analysis done in 1994 revealed that the house had no wall paper initially and that the walls and woodwork were painted "a brilliant white". 
Question: What is the last name of the person in whose new laboratory Joseph continued his scientific and scholarly work?
Output (English): Priestley.