apple gel; apple honey

[cheerpul]

I work at a living history museum in NW Ohio, where we have been celebrating our apple butter fest all week. I had a gentleman approach me asking what I knew about apple gel. He said that he had three crocks of this in his basement, covered with paper and a board with a rock on it dated 1937, which appears to be unspoiled. He said that he'd been told that they only made apple gel when they had a bumper crop and that it was very concentrated. He thought that it could be cut with juice or water to make apple butter.

I have found a couple of obscure references to apple honey or spread. One, at www. botanical.com; A Modern Herbal by Mrs. M. Grieve states:

"It is also possible to make a very delicious preserve called Apple Honey, by boiling apples slowly for a very long time without any addition of sugar. The people of Denmark make this in hayboxes, thus saving fuel. When cooked long enough it is thick and brown, and very sweet, and will keep any length of time. "
Can anyone help me find out more about this type of preserve?