Vignette from a lithographic plate showing people sealing letters with sealing wax which contains cochineal. This natural dye is obtained from the bodies of female cochineal bugs, which contain a pigment called carminic acid. The insects are crushed and then steamed or dried. The dye is expensive as it requires large numbers of insects to produce a relatively small amount of dye. Taken from 'The Cochineal and Lac Insecrs' in 'Graphic Illustrations of Animals - Showing Their Utility to Man', illustrated by Benjamin Waterhouse Hawkins and R K Thomas, printed by J Graf, C Graf, Day & Haghe, and published by Thomas Varty.
© Science Museum / Science & Society Picture Library