# On This Day

• ### 6-1-1658

Pascal posed his six questions related to the cycloid as challenge problems. They dealt with area, volume of solids of revolution, and center of gravity. (For the complete list, see Scripta Math. 26 (1963), pages 297-298.)

Blaise Pascal
Cycloids
• ### 6-1-1890

First U.S. Census compiled by machine was completed by the Hollerith Tabulator. The previous census took nearly a decade to compute. The 1890 census recorded the U.S. population at 62,979,766.