the elements of physiological physics the elements of physiological physics an outline of the elementary facts principles and methods of physics and their applications in physiology elementsofphysio00mgre year 1884 chap xxxti the siren 425 the siren of cagniard de la tour fig 186 permits the number of vibrations producing sounds of different pitch to be accurately estimated it consists of a brass air chamber b the top of which is perforated with fifteen holes disposed at regular intervals from one another above the perforated lid is a circular plate d finely pivoted capable rwthf4.jpg from egland xxxti View Photo