Ernst Mach was born in 1838 in what was then part of Austria and now part of the Czech Republic. He was a physicist and philosopher and studied wave dynamics, fluid mechanics and shock waves. He was the first to study super-sonic motion. Multiples of the speed of sound are now designated by numbers named after him. The speed of sound is known as “mach 1″ and twice the speed of sound is “mach 2″ and so on. Mach also did work in the areas of optics and mechanics. “Mach’s Principle” suggests that inertia is the result of an interaction between the body exhibiting inertia and all other bodies in the universe, including those at extreme distances.
1856 – Tesla