On July 4, 1836, the Patent Office became its own organization within the
Department of State under the
Patent Act of 1836.
Henry Leavitt Ellsworth became its first commissioner. He started construction of a new
fire-proof building, after the previous building had burned down in a disastrous fire. Architect
Robert Mills was given instructions by
Congress to design the building using fireproof construction material. Mills used masonry vaulted ceilings that spanned the interior spaces for an
open floor plan, cement plastered walls, and
cantilevered stone staircases from floor level to floor level. Construction of the building was finished in 1864. The
Patent Office fire started at about 11 am on September 24, 1877. It was reported in the newspaper that the fire started in the room that held the
patent models. There was a considerable amount of flammable material in that area. Spontaneous combustion of patented chemicals has been given as one of the theories for the start of the fire. Another theory was that a lens might have caught the sun's rays and focused them on a combustible object. Others claim that it was an unseasonably cold morning, and that a fire started by some copyists in their office grate emitted sparks that fell onto the roof and caught a wooden
gutter screen on fire. The roof was constructed of wood, which led to a rapid ignition and a fast-moving disastrous building fire. The
Evening Star reported that the spectacle of the building going up in flames became extraordinarily shocking to the spectators as it turned into a calamity. Despite the fire-proof construction efforts the fire consumed the building and devoured some 87,000 patent models with their associated documents. Some of the important artifacts were saved, however, due to the extraordinary efforts of the Patent Office staff and some valiant firemen. ==Models destroyed==