Task: Question Answering
Input (English): Passage: The American Chemical Society (ACS) has used the Joseph Priestley House as a place to mark special celebrations. On July 31 and August 1, 1874, "seventy-seven chemists made a pilgrimage to the site to celebrate the centennial of chemistry". The date was chosen to mark the hundredth anniversary of Priestley's experiment producing oxygen by heating mercuric oxide with a magnifying lens and sunlight. These chemists came from 15 US states and the District of Columbia, Canada, and England, and their meeting at the house and a local school "is now recognized as the first National Chemistry Congress, and many ACS historians believe it led to ACS's formation two years later on April 6, 1876". On September 5, 1926, about 500 ACS members met again at the home to dedicate the small brick museum and to celebrate the meeting 50 years earlier (two survivors of that first meeting were present).Representatives of the ACS were present at the October 1970 dedication of the house as a museum. On April 25, 1974 around 400 chemists from the ACS Middle Atlantic Regional Meeting in Scranton came to visit the home. The Priestley Medal, the highest and oldest honor awarded by the ACS, was awarded to Paul Flory at the house that day. (A replica of the Priestley Medal is on display at the house.) On August 1, 1974—what has been labeled the bicentennial of the discovery of oxygen—over 500 chemists attending the third Biennial Conference on Chemical Education at State College traveled to the house to celebrate "Oxygen Day". In October 1976, the ACS celebrated its own centennial with a celebration in Northumberland. A 100-plus piece replica of Priestley's laboratory equipment, made by universities, corporations, and the Smithsonian Institution, was presented to the house for display. On April 13, 1983, ACS President Fred Basolo spoke at the house to celebrate Priestley's 250th birthday and as part of a first day of issue ceremony for the United States Postal Service's Joseph Priestley commemorative stamp. In 2001 the ACS again met at the house to celebrate the 125th anniversary of the society, and reenacted parts of the 1874 and 1926 celebrations, including a march to Priestley's grave, at which each participant left a red rose. 
Question: On what date was a 100-plus piece replica of Priestley's laboratory equipment presented to the Joseph Priestley House for display?
Output (English): October 1976.