Pleasant smells have long been associated not only with health, wealth and good hygiene but also sound moral character; bad smells indicate lack of cleanliness, ill health, poverty ‒ and immorality. Throughout history, people have applied scents to their bodies and clothing. They have carried perfumed objects, worn scented jewellery, sent scented letters, even exchanged scented coins. Aromas have been used to perfume private houses and public...