I think he is meaning an instrument consisting of small bars of wood, flat at the bottom and rounded at the top, and resting on the edges of a kind of open box.
The Interesting Narrative of the Life of Olaudah Equiano study guide contains a biography of Olaudah Equiano, literature essays, quiz questions, major themes, characters, and a full summary and analysis.
The Interesting Narrative of the Life of Olaudah Equiano essays are academic essays for citation. These papers were written primarily by students and provide critical analysis of the autobiography of Olaudah Equiano.