Ernst Mach of experimental physics concentrated on the interference, diffraction, polarization and refraction of light in different media under external influences. From there followed important explorations in the field of supersonic fluid mechanics. Mach and physicist-photographer Peter Salcher presented their paper on this subject in 1887; it correctly describes the sound effects observed during the supersonic motion of a projectile. They deduced and experimentally confirmed the existence of a shock wave of conical shape, with the projectile at the apex. The ratio of the speed of a fluid to the local speed of sound "v"/"v" is now called the Mach number. It
Mach: The First Colony a 32-page book, and a 16-page book. Mach: The First Colony Mach: The First Colony is a role-playing game published by Alliance Publications in 1983. "Mach: The First Colony" is a science-fiction system in which the players are mercenaries on a frontier planet. The planet, its societies, and mixed technologies are described in detail. The first book (32 pages) covers character creation and combat; the second (32 pages) covers skills and creatures. The game includes an introductory scenario (16 pages). "Mach: The First Colony" was designed by Michael Lange with Martin Miller, and published by Alliance Publications in 1983 as