One of my most precious posessions is The Green Cookbook.
It's actual title is "Cooking for American Homemakers", and it was published by the Culinary Arts Institute of Chicago in 1965.
My mom received it as a gift from her mother, and she gave it to me. It has instructions for all sorts of basic things that people take for granted - like how to cook eggs in their shells, or how to cut fresh bread easily (use a hot knife). It has recipes for things we wouldn't consider 'regular food', like roasted squirrels and calf's brains (I'm serious). However, it also has information about everything basic to cooking ... like what "heated to the hard-crack stage" means when you're talking about candymaking.
I found an online recipe for mullein cough drops, and, since I grew mullein in the garden this year, I wanted to try it. I was stumped, however, by the directions. "Heat to the hard crack stage" means .. what?
Well, the Green Cookbook had the answer. The hard crack stage means the sugar mixture has been heated to 300 degrees Farenheit, or, when dropped into very cold water it separates into threads which are hard and brittle.
I did manage to make mullein cough candy today - it tastes a lot like molasses, and even if I did make a rather large mess of the kitchen, it was a good practice run.