This is a letter from G. D. Isett to Singer Manufacturing Company. It is a bit hard to read, but here goes:
Letterhead - "Office of Etna Iron Works - G. D. Isett & Bro. Manufacturers of No. 1 Charcoal Blooms, Slabs and Pig Iron - Yellow Springs, Blair Co., PA"
Date - "July 10 ~ 1872"
Body - "Singer Mnf-Co- Enclosed please find one dollar - we got a ? doz for machines - any ? .50 cts send needels for no 50 thread union ? machine - Yours ? G. D. Isett & Bro"