in a ceremony where he donned a Mohawk headdress and danced traditional dances. 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. Work with the deaf Bell's father was invited by Sarah Fuller, principal of the Boston School for Deaf Mutes (later to become the public Horace Mann School for the Deaf) to introduce the Visible Speech System by providing training for Fuller's instructors, but he declined the post in favour of his son. Travelling to Boston in April 1871, Bell proved successful in training the school's instructors. He was subsequently asked to repeat the programme at the American Asylum for Deaf-mutes in Hartford, Connecticut, and the Clarke School for the Deaf in Northampton, Massachusetts. Returning home to Brantford after six months abroad, Bell continued his experiments with his "harmonic telegraph". The basic concept behind his device was that messages could be sent through a single wire if each message was transmitted at a different pitch, but work on both the transmitter and receiver was needed. Unsure of his future, he contemplated returning to London to complete his studies, but decided to return to Boston as a teacher. His father helped him set up his private practice by contacting Gardiner Greene Hubbard, the president of the Clarke School for the Deaf for a recommendation. Teaching his father's system, in October 1872, Alexander Bell opened his "School of Vocal Physiology and Mechanics of Speech" in Boston, which attracted a large number of deaf pupils, with his first class numbering 30 students. While he was working as a private tutor, one of his pupils was Helen Keller, who came to him as a young child unable to see, hear, or speak. She was later to say that Bell dedicated his life to the penetration of that "inhuman silence which separates and estranges". In 1893, Keller performed the sod-breaking ceremony for the construction of Bell's new Volta Bureau, dedicated to "the increase and diffusion of knowledge relating to the deaf". Throughout his lifetime, Bell sought