Public domain
New machine to speed up statistics of census of 1940. Washington, D.C., Dec. 2. Back in 1870, it took 7 years to compile statistics from the facts taken by census takers, but in the next 10 years, Herman Hollerith invented a 'unit tabulator,' shown on left of photo being operated by Operator Ann Oli
From the collection of Library of Congress. Free to download, adapt and use — no permission needed.
Credit lineNew machine to speed up statistics of census of 1940. Washington, D.C., Dec. 2. Back in 1870, it took 7 years to compile statistics from the facts taken by census takers, but in the next 10 years, Her. 1939-01-01. Harris & Ewing. Harris & Ewing Collection, Library of Congress. Public domain.