These are about 10" a side, and are based on the size of the piece of terrycloth, and not being too big to hold or to put in the microwave easily. If you want to make one, buy seed corn and put in enough for it to be a solid layer of corn when the bag's on its side, and to fill the bag half or less when it's held by the corner.
This morning, Keith sent me a link to a blog entry on medieval bed-warming techniques, and one of the things was a bag of cherry pits heated in a low oven. Bed warmers puzzle & answers
That led me to an image search, because it said the cherry-pit bags are becoming popular again:
Once when we were in Minneapolis (Keith was working on a contract, and living in an apartment) Holly was cold, and we hadn't brought a corn bag. I put rice into one of Keith's white cotton socks and put an overhand knot in the top. That worked, and so Keith kept it for future visits. We still have it, somewhere. Corn stays warm longer, though, and when the corn is new there's humidity with it too. I suppose cherry pits were good because the heat would last a while and heat up without destroying the seed (in those pre-microwave days of yore).
The blog is worth saving and exploring.
Old & Interesting, history of domestic paraphernalia, household antiques in use.
Antique household equipment, furnishings, utensils - housekeeping as part of social history. Domestic life, household management - how people organised their homes and did the daily chores. Yesterday's everyday objects are today's antiques or museum pieces, and we may view them with nostalgia or curiosity about past ways of life. Old & Interesting takes a look at how these everyday things were actually used, how people managed their home life - and more. Alongside articles illustrated by excerpts from advice manuals, period novels and other literature, this page is updated every couple of weeks. RSS feed or email will let you know about new articles.