Ahhh, now I understand. Different kind of jar, which was, IIRC, used strictly with open-kettle canning, rather than processing. I have several of those type jars. Like rocklobster I use them for dry storage.
There are no threads on the jars, however. They close using a wire cam that exerts pressure on the rubber ring.
My local Ace still carries the rubber rings. Or did as late as last fall. So I reckon somebody must still be using those jars.
Most people spoil garden things by over-boiling them... if they are overboiled they have neither any sweetness or beauty. Hannah Glasse 1745