The company's name is Banghart & Fischer, and it sold "construction materials for schools, papers, leathers, tools, etc."
Mabelle "Mabel" Spofford was born on May 29, 1883 to Frank Melvin Spofford (1854-1936) and Clara Todd (1855-1936) in Danvers, MA. She had one brother: Ralph Prescott Spofford (1881-1949). She graduated from Mass Normal Art School in 1902 and began an art teaching career in 1906, first in Vermont, then other local MA towns, before settling in Gloucester, MA in 1922 where she stayed until she retired in 1950. At some point she also achieved her life long dream of traveling throughout Europe so she could see the art and architecture she studied in person. She then moved back to her home town of Danvers, and later died there on November 21, 1981.
The letter is addressed to Miss Mabel Spofford, (1883-1981), a local young public art school teacher who appears to have written Baumgarten & Co. with a request for additional supplies. In the company's reply they grant her request for "color pads in red, green, black, purple, and blue at 5 cents each .... in lots of 1 dozen we will allow a discount of 20%". At the end, they add that in addition to the Animal Stencils they also make a set of "Brownie Stencils consisting of 10 different figures". Measures 8 1/4" x 7 1/4" General wear. Crease folds.