What Happened on April 3rd

John Napier--a Scottish mathematician most famous for inventing logarithms and an early calculating device called Napier's Bones--dies at age 67. Napier's Bones consisted of multiplication tables inscribed in strips of wood or bone, making for quick calculations. (They were called "bones" because of the material used to make the better quality versions--bone or ivory.). His logarithmic system provided the basis for the invention of the slide rule around the same time and logarithms were the principal means by which calculation was performed until the advent of the digital computer. Napier was born in Merchiston, Scotland in 1550.