sentences:  One of his friends was William Dowd, who had an interest in early instruments, and together they constructed a clavichord.This connection, with his interest as an amateur violinist in violin making and the location of his library reading stall near the stacks holding books on musical instruments, led to Hubbard's interest in the historic harpsichord.While pursuing graduate study at Harvard, Hubbard and Dowd both decided to leave to pursue instrument-making.