Demeter's Rain is the cleanest and most delicate of all our fragrances. Step outside after the first storm after a dry spell and it invariably hits you: The sweet, fresh, powerfully evocative smell of fresh rain. If you've ever noticed this mysterious scent and wondered what is responsible for it, you're not alone. What you really smell comes not from the air, but the ground! Plants release oils that enter the soil and blend with the other earthy odors. These odors are released into the air when the relative humidity at ground level exceeds 75 percent. Moist humid air will transmit odors far better than dry air. In these moist humid conditions, we notice these odors more readily. And since rain is so often connected with moist humid air, we tend to associate one with the other. Demeter Fragrance Rain captures this complex sensory moment perfectly. But apart from the specific chemicals responsible, there's also the deeper question of why we find the smell of rain pleasant in the first place. Some scientists have speculated that it's a product of evolution. Anthropologist Diana Young of the University of Queensland in Australia, for example, who studied the culture of Western Australia's Pitjantjatjara people, has observed that they associate the smell of rain with the color green, hinting at the deep-seated link between a season's first rain and the expectation of growth and associated game animals, both crucial for their diet. She calls this "cultural synesthesia"-the blending of different sensory experiences on a society-wide scale due to evolutionary history. It's not a major leap to imagine how other cultures might similarly have positive associations of rain embedded in their collective consciousness-humans around the world, after all, require either plants or animals to eat, and both are more plentiful in rainy times than during drought. If this hypothesis is correct, then the next time you relish the scent of fresh rain, think of it as a cultural imprint, derived from your ancestors.