Brand: Joseph Dixon
Looks like an older Dixon's. A. G. stands for American Graphite......M is a reference to the lead degree.
Began as the "Joseph Dixon Crucible Company" (Joseph Dixon: 1799-1869) with its main manufacturing facility in Jersey City, New Jersey. Dixon was an inventor who received patents in 1850 for the use of graphite crucibles in pottery and steel manufacturing. He died in 1869. Dixon’s son-in-law, Orestes Cleveland, took over as president of the company in 1858. Cleveland served as both mayor of Jersey City as well as a short stint in the U.S. House of Representatives (1869-1871). In 1873 the company bought the American Graphite Company located in Ticonderoga, New York, and in 1913 began integrating the name into its brand as "Dixon Ticonderoga." In 2005, Dixon Ticonderoga was acquired by Italian-based FILA.
Learn more about the company’s long history at dixonusa.com. Also check out my blog post about the famed Dixon Ticonderoga.