Smell is perhaps more closely intertwined with memory than sight, sound, or any other of our senses. Indeed, scents are an incredibly important part of history and culture. That's why Cecilia Bembibre and her colleagues at the UCL Institute for Sustainable Heritage are working to preserve certain smells for the ages. After all, smells are "the olfactory heritage of humanity," she says. ”From the BBC:

But how do you capture something as intangible as a historical scent? One method involves exposing a polymer fibre to the odour, so that the smell-causing chemical compounds in the air can stick to it. Then Bembibre analyses the sample in the laboratory, dissolving the compounds stuck to the fibre, separating them and identifying them. The resulting list of chemicals is effectively a recipe for the scent.

Another method separates and identifies the compounds directly from the gas sample – an approach commonly used in the perfume, food and beverages industry, as it allows volatile odour-active compounds to be identified. A third way is to use the nose itself, either by asking panels of people to describe certain smells, or by asking expert “noses”, who may be perfumers or scent designers.

“We characterise the smell from the human point of view,” adds Bembibre. “This is important because if we want to preserve it for the future, it depends on many factors. Not only the chemical composition but also our experience.”

Bembibre has chemically extracted the smells of old leather gloves, ancient books and mould Bembibre has chemically extracted the smells of old leather gloves, ancient books and mould, among other things.

In 1974, Upper Arlington, Ohio public library launched a program to link their card catalog and shelved books by odor. The project was called: "Stick Your Nose in the Card Catalog." From Weird Universe:

The idea was that the card in the catalog would have a scent, and then the book on the shelf would have a matching scent. So you could find your books by smell. There were about 60 scents in total, including apple, chocolate, garlic, lemon, roses, root beer, leather, pizza, orange, strawberry, candles, pine, cheddar cheese, clover, and smoke.

The library says that they "aren't sure what exactly happened to the scented catalog, but we guess that the cards eventually lost their scent over time, but remained part of the catalog until it was decommissioned" for a digital system in 1989. Read the rest

The smell of old books is instantly recognizable but hard to describe. Thanks to mass spectrometry and good old fashioned smell tests, University College London researchers have created a Historic Book Odour Wheel. Read the rest

The answer lies in another question. How can PVC — polyvinyl chloride, a commonly used type of plastic — be the stuff that makes tough, rigid sewer pipes and, simultaneously, be the stuff that makes floppy vinyl signs and cheap Goth pants?

"PVC is hard stuff. But if you put in a lot of plasticizer, you can get it to be soft," explains John Pojman, a chemistry professor at Louisiana State University. At a molecular level, PVC is a dense thing. Imagine a slinky in its stiff, compressed state. The plasticizers are chemical compounds derived from coal tar. Mix them with PVC and the small molecules of plasticizer shove their in between the densely packed PVC molecules. Imagine stretching the slinky out so that its coils are now wobbly. Same thing happens here. The more plasticizer you add, the less rigid the PVC.

And it's the plasticizers that produce that smell — the one we associate with the vinyl interior of a new car.

Image: 365:37 - Mar 29 - that new car smell, a Creative Commons Attribution Non-Commercial No-Derivative-Works (2.0) image from waldengirl's photostream

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