I found the answer to my question! Google is my friend :).

>In this style of lid, the seal was not on the rim of the jar mouth but on the shoulder, below the threads.

...which explains something else I have always wondered about -- why older jars have a more pronounced 'lip', below the threads.

The quote is from here: http://www.backwoodshome.com/forum/vb/showthread.php?t=17067

That page also has a detailed quote from an old BBB on the topic :).

The old zinc jars have a wider edge on the top and the newer lids don't work as well.

I use mine as seed jars.

>I use mine as seed jars.

You plant them and more jars grow? Cool!

(I do a lot of seed saving, too, but ran out of room for jars. Ziploc bags fit my little house better :).

haha, it seems like it, here. I have SO many. I bought a narrow bookcase years ago for $2, it's 6' or 8' long and 3' high, with shelves just perfect for qt and 1/2 gal jars. That's where I put the seed jars for years.

Ziploc's allow condensation that isn't good for the seed. Just 1 bit of moisture and the entire bag is gone.

Yeah, ziplocs are not ideal. I dry the seed very dry, and finish them off in a warm oven. And I only store seeds that way at room temp if I have an enormous supply of one thing.

Most of my seed varieties are in the fridge. Way more seeds than food in there :).

I am thinking I might set up a dedicated seed fridge, but it would have to be a little dorm-style one, and that would mean not frostfree, so a less dry environment. What do you think?

I used to find pieces of that white glass in the garden where I used to live. Always wondered what it was for until I found zinc lids with the glass still intact. Then it all made sense.

Huh, I wonder what the story was behind that, how they ended up broken and in the yard.

When I got it, it was horse pasture on a hill. My garden spot was in the middle on one of the terraces they created when the pasture was created. Long and narrow, 20 ft x 60 or more long. I believe it was all trees at one time. I don't really know.

In the "old days" they used to burn or bury all their trash. I figure at some point, these were buried or got buried over time. They weren't deep either. Not more than 6 or 8 inches.

The other place they used to dispose of things were in outhouses. Relic hunters look on old home sites for old outhouse sites in search of old glass bottles and relics of the past. I doubt there was an outhouse there, but that dirt might have been excavated when terracing or clear cutting for the pasture. I dunno.

Of course, it could have been from years of passersby tossing things in the woods at the time and they just happened to land there. Or maybe it was an old moonshine still site. Not too far from the creek... :-)