Tiré de Discorsi e dimostrazioni matematiche intorno a due nuove scienze, ici en anglais à partir de la page 100 : Dialogues Concerning Two New Sciences, As I was scraping a brass plate with a sharp iron chisel in order to remove some spots from it and was running the chisel rather rapidly over it, I once or twice, during many strokes, heard the plate emit a rather strong and clear whistling sound ; on looking at the plate more carefully, I noticed a long row of fine streaks parallel and equidistant from one another.
