Given the question: Extract the answer to the question from the following context. Question: __ was born in 1821. Context: After setting up his workshop, Bell continued experiments based on Helmholtz's work with electricity and sound. He also modified a melodeon (a type of pump organ) so that it could transmit its music electrically over a distance. Once the family was settled in, both Bell and his father made plans to establish a teaching practice and in 1871, he accompanied his father to Montreal, where Melville was offered a position to teach his System of Visible Speech.
The answer is:
Helmholtz