Dating kerr canning jars
Since the first Ball jar was produced in Buffalo 125 years ago, the company has made many variations of the glass jar including the Mason’s Patent 1858, the Perfect Mason, the Mason Improved, the Sure Seal, the Ideal, the Eclipse, the Standard, and of course, the Special. Kerr opened the Hermetic Fruit Jar Company, producing some of the first wide-mouth jars, which were easy to fill and empty.
Prior to that time, flat tin lids were attached to the jars with wax rings.
The difference is a raised lip to help keep the jar from cracking.
This was called the “Strong Shoulder” and was similar to the Mason jar.
Later versions (after around 1936) were made in clear glass, and some (usually from the 1950s) in brown amber.
More rarely, jars will turn up in darker shades of green.