Things can be identified by their smell. Of all our senses, smell is the least understood. Scientists have calibrated sound and light waves so that a piano tuner can make sure that your B b keys play B b . Your ophthalmologist can measure the sensitivity of your retina to the color purple.
Science knows practically nothing.
Odors reach into all our emotional lives, drawing from the deepest caves in our minds. Odors suggest, stimulate associations, evoke, frighten, arouse us, but they seem to be just below conscious thought. Smells arouse us. When you look at a pencil, touch a book, you probably don't get an emotional response. But there is nothing quite like an odor to drive your emotions.