They say that the Ancient Chinese did not keep time with clocks or dials, but rather with incense. One length of smelling stick would be burned after another of the same duration, in succession, and each day in the same order. Lavender after Juniper after Cardamom after Camphor, perhaps. So might the people tell each other, "I will meet you in the market when the wind smells strongly of Cassia," and have no fear of a missed engagement.
I myself have smelled Muscadet and Vouvray and Santorini all this morning, so I know that it must be high summer.