April 27, 1877 was a Friday
April 27, 1977 was a Wednesday
U.S. patent dates are Tuesdays Possibly English or Canadian?
Spaces to count sheets of paper or cardstock?
CORRECTION --thickness of material, cord, thread, or fabric? Patents describe improvements on a sewing machine, but abstract & drawings are not available. CANADIAN
CA 7.392 William W. Whitcomb
Sewing Machine
April 27, 1877
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CA 7.393 Israel M. Rose
Sewing Machine
April 27, 1877