This guitar is an early Martin 0-27 and is almost identical to another already posted on this website, with the exception that it is fitted with brass tuners instead of ivory friction pegs.
Most collectors are familiar with 2-27 guitars that make up the large majority of style 27 guitars made. Size 0 guitars in style 27 are quite rare: only thirty-nine 0-27 guitars were made between 1856 and 1863, a total of 27 of these having brass tuners.
Many collectors are also aware that the style 27 guitars have an abalone sound hole ring. This is the normal feature for smaller body style 27 guitars but, for a brief period between 1856 and 1858, 0-27 guitars had an ivory sound hole ring like a period style 28. It is a little hard to tell for certain but the switch back to the abalone sound hole ring for the 0-27 guitars seems to have taken place in 1858.
Considering the zig-zag back stripe on this guitar, it might be suggested this guitar is actually a 0-28 where style 27 purfling was substituted for the usual herringbone but the brass tuners clearly point to this being a style 27 guitar. See the entry for the 0-27 guitar with ivory friction pegs.
This guitar also has some interesting writing under the top. Near the bottom of the guitar there is a penciled note "Repaired by D. Mojica/San Francisco/1866" indicating the back of the guitar was removed at that time for a repair.
Back and sides: Brazilian rosewood
Top: Red spruce (Adirondack)
Purfling: Style 27
Back stripe: Zig-zag pattern
Brass tuners with ivory buttons
Other period features:
Ebony belly bridge
Ebony neck reinforcement
1-7/8" neck width at nut
C. F. Martin stamp on back of headstock
No style stamp