How to make a bra out of two handkerchiefs, c1921

How to make a 'camisole'(in fact an early bra) out of a pair of handkerchiefs. It may be similar to the one made by the New York socialite, Mary Phelps-Jacob, - later patented by her, with a more complex form - in 1914. Almost certainly the model wears it over her shift for reasons of cinematic propriety. British Pathe archivist dates it to around 1921.