When I turned my attention to cooking historic recipes, I never realized how different it would be. It is nowhere near as simple and straightforward as it was to follow recipes from modern cook books.
The first thing you learn is that the recipes themselves are not written in the same way. The modern form of recipe, with a list of ingredients followed by the instructions, was developed in the late 19th Century, and at first was only common in the cook books from the more prominent cooking schools. True common use of that format did not come until the early 20th Century. The vast majority of recipes before then were written as a single paragraph, with the ingredients, measurements and instructions all in-line.
The next thing you learn, is that what instructions there are, are often incredibly incomplete. Cook books were written for people who already knew how to cook. These books were most likely aimed at young women who were just married and starting their own households, but had already learned how to cook from their Mothers and Grandmothers from when they were children. Thus, the things that everyone knows were left out. This includes everything from how to mix ingredients, to how long and what temperature to cook it, to what type, size and number of pans to use. For very old recipes, the amounts of the ingredients may be left out as well.
Then, you come down to obscure ingredients, ingredients that were known by other names, ingredients that have themselves changed in size or quality. And, as the title of this site implies, the wonderful vagueness of the measurements themselves.
These are the obstacles that I had to overcome, and hopefully, will be able to make less frustrating for you. After all, this should be fun!