Wig Powdering Closet.

Wigs were stored and powdered in these small closets. The fashion for men's powdered wigs was very much in vogue until around 1770, and bedrooms and guest rooms often had a space where people could re-powder their wigs with finely ground starch, scented with essence of lavender or flower water. When wigs and powdered hair pieces fell out of fashion towards the end of the 18th century, a trend possibly hastened by a tax on hair powder, these small closets were often turned into chamber pot repositories. This dual role explains why toilets were traditionally referred to as 'powder rooms' and the term 'powdering one's nose' was used by polite ladies when excusing themselves from mixed company.
I found this interesting little room in Cambridge Folk Museum.