In his American Dictionary of the English Language (New York: s. Converse, 1828) Noah Webster gave one definition of "wafer" as: "A thin leaf of paste, or a composition of flour, the white of eggs, isinglass, and yeast, spread over with gum-water [gum being sticky tree secretions], and dried; used in sealing letters." By wetting a wafer, one reactivates the sticky nature of it, and when again it dries, the letter is sealed. He also listed "wafer" as a verb, meaning "to seal or close with a wafer." The Complete Letter-Writer (Thomas Cushing: Salem, 1797) warned that one should NOT seal a letter with a wafer unless it is to an inferior. No doubt sealing wax was thought the "proper" and polite way to seal a letter, though as another advice book pointed out, never where you have written the most important part of your epistle, as opening may destroy that section. Certainly we have hundreds of letters in our collection of original documents that were sealed with red or sometimes black wax... which leads me to sealing wax. The Encyclopedia Britannica of 1910-11 said just about the same thing as the Encyclopedia, or a Dictionary of Arts, Sciences, and Miscellaneous Literature, published in Philadelphia in 1798, so the decade of the 1830s is safely bracketed.

MEDIEVAL sealing wax was Venice turpentine (a yellow or green-yellow oleoresin [oil-resin mixture] from the European Larch tree [i.e., cooked evergreen sap], although sometimes regular resin was mixed with regular spirits of turpentine and sold as Venice turpentine) mixed with Beeswax and coloring, usually vermilion, a red mercury compound. By modern, as in post-medieval times, the stuff contained NO WAX. The 1798 receipt said the best stuff was made with two parts shellac, one part resin, and one part vermilion, heated slowly over a moderate fire in an earthen pot. The sealing wax would then be molded into sticks in oiled tin molds, then heated over a charcoal fire or spirit flame to smooth and glaze them. Cheaper versions were made by substituting Venice turpentine for resin, and seed lac (a less refined version of shellac) for shellac. ("Lac" is the dried resinous secretions of an insect found mostly in India, and goes by different names at different stages of refining.) Still courser versions had less shellac and more resin, and red lead was substituted for part of the vermilion. Red was the most common color, but black (from ivory black) or other mineral pigments were also used. The early 20th century reference states that chalk, magnesia carbonate, and other minerals were sometimes used as "fillers" in cheaper grades. The coarser grades were used for sealing wine bottles, packages, and such, and a softer kind was made for "official" seals on documents such as charters and the like. By re-heating it, sealing wax becomes plastic again, so a drop on a letter would seal it tenaciously. A watchkey, ring, or any little unique device, even one made expressly for the purpose, could then be pressed in it while still soft to personalize it. This traditionally ensured authenticity of an important document, or more practically, ensured that no one had secretly opened your letter and resealed it.