The lectures present a practical, experiment-focused introduction to wave phenomena across media, beginning with surface waves and ripples on liquids and the principles of wave motion, wavelength, velocity, reflection, refraction, and interference. They then examine waves generated by moving bodies and ship-wave resistance, illustrating fluid flow, vortices, and model testing. Subsequent chapters treat sound as longitudinal air waves, its production, propagation, hearing range, and devices like sirens and the phonograph. Throughout, visible demonstrations and mathematical rules are used to connect water and air waves to more abstract electromagnetic waves in the proposed æther, emphasizing comparative physical principles and experimental methods.