Here is one of the few harp guitars made by Martin in the early 20th century. Serial number 9392 was shipped to Grinnell Brothers in Detroit on April 18, 1902. It was based on the then relatively new 000 size body.
Martin made harp guitars with either 10, 12 or 16 strings. One was even made with 18 strings.
The guitar has ivory friction pegs instead of tuning machines. Wood bushings, into which the friction pegs were fitted, are visible on the back side of the peg head.
Style 21 features:
Back and sides: Brazilian rosewood
Top: Red spruce (probably West Virginian)
Sound hole decoration: Herringbone
Other period features:
Ebony pyramid bridge (for 10 pins)
Slotted square Japan pearl fingerboard inlays
Ivory friction pegs
Serial number stamped in top of peg head (as well as on neck block)
“C. F. Martin & Co.” stamp in back of the head stock
No style stamp
Photos courtesy of Elderly Instruments