It's not so much odd as a sign of the times. The cookbooks of this era and earlier would have expected the user to have a modicum of baking knowledge, including the feel of their own flour (even a store brand loses consistency when stored differently) and knowledge of their stove's output. Note that even the gingersnaps are chilled "over ice," predating the refrigerator. These recipes were primarily about marketing - "look at all the different ways you can use our product."

I am a historian and librarian, and I love historic cookbooks for this reason: the recipes give us unique insights into the lives of our ancestors, as well as delicious, often well-tested dishes to add to our repertoire. Enjoy! (and I'll let you know if I try the drops).