Derby never married and led a solitary existence, living mostly in hotel rooms. After the failure of an invitation by the state government of
Bahia, he returned to Rio de Janeiro and committed
suicide in a hotel room, on November 27, 1915, a few months after gaining Brazilian citizenship. He was 64 years old. After Derby's unexpected death, staff of the survey realised that they did not have any recent picture of him. They dispatched some men to Derby's hotel room, where they cleaned him up, sat him in a chair and photographed him, holding his eyes open with matchsticks. ==References==