 The two drip sounds were obtained by pinging two different-sized pieces of brass and glass tubes against the palm of the hand.The drain sound was created by air blowing through a tube into water and then amplifying the bubble sound through a metal tube.After Habberfield captured each sound effect, she mixed them in different combinations by trial-and-error until she found the leitmotif that would accompany Sidney Stratton and his bubbling apparatus in the film.