Mechanical Calculators 1600's Blaise Pascal : Pascaline Calculator (1642) Gottfried Wilhelm Leibniz: The Leibniz Wheel (1673) 1630: Puritans establish the Massachusetts Bay Colony 1619: A Dutch Ship brings the first Africans to Jamestown 1690: John Locke publishes Essay Concerning Human Understanding Step Reckoner, Pascal's machine, courtesy of http://www.maxmon.com Photos of Pascal & Leibniz, courtesy of http://www-groups.dcs.st-and.ac.uk Ilhan Kucukaydin