THERE is nothing else to be done, but to beat the Iris, and pass it through a Sieve: That Powder is very good for Hair, and smells naturally of Violets; there is no other of that Smell, because the Violet has not strength enough." "Violet powder" was popular during the 17th and 18th centuries for powdering the hair, a fashion among the wealthy, and then in the 19th century as scented powder to use on the skin after bathing. It comes, not from the violet, but from the root of a type of iris flower: Iris florentina. Today it is called "orris root" and is often used in perfumery to preserve other scents, although it does have a lovely scent of its own.
Sources: The French Perfumer by Simon Barbe, 1696, and The Artifice of Beauty by Sally Pointer, 2005.