Existing comment:
Receipt book
Manuscript, compiled ca 1600
This book is a compilation of medical remedies and household secrets. Tucked between a trick for preventing fruit from rotting on the tree and an aid for female dieting, the page on the left includes two recipes for invisible ink; one uses ink made with rock alum that becomes visible when the paper is dipped in water, and the other uses ink made with lemon or onion juice that becomes visible when the paper is held before a flame. |