Here are the bases of three Ball quarts attributed to the F.C. Ball Machine because of the offset neck seams. However these are three completely distinct moulds. The base with the number "1" has a seam that circles the outside of the base and a deep quarter sized valve mark and the neck is topped with a rounded bead. The base with the two 2's has no base seam with a fine shallow quarter sized valve mark and the top ot the neck is flattened and slopes inward. The jar with the number "4" has no base seam and a double groove quarter sized valve mark and the top of the neck is slightly rounded. Other than sharing the offset neck seam these jars would appear to have been made on totally different machines. Are they infact all F.C. Ball jars?