“Being on a lunchbox was awesome, and being on a thermos was pretty cool too.”

— Zach Galligan

Actor, Gremlins (1984)

“Now I only have two things: my friends, and… um… my thermos.”

— Steve Martin

Actor, The Jerk (1979)

Having school-aged children means finding time to do things together with your spouse. My wife works for the chemistry department at Ohio Wesleyan, and since we’re both in town, we try to have a lunch date once a week during the school year.

During one of those recent lunches, she mentioned to me that she was waiting for delivery of a “Dewar” flask. I had no idea what she meant. Heck, I didn’t even know how to spell it. Was there a “u” in there? Was it named for someone? She knew the spelling, and as is often my habit now, I went immediately to Google to see what I could find.

The flask, it seems, is named for its inventor, Scottish physicist and chemist James Dewar. And the story of his invention, failed attempt to patent it, and resulting lawsuit, have a fascinating and major impact on modern American marketing.

Dewar was the child of a vintner, was orphaned at age 15, but still managed to attend the University of Edinburgh. He taught at Cambridge and was one of the most celebrated and awarded scientists of his generation, though he never won a Nobel prize. Many of his major discoveries were in the field of spectroscopy, but those aren’t important for our discussion of how his failure to know the law had a stupendous impact on his life — and on modern business.

Dewar also did extensive research into the liquefaction of gasses. That research required him to cool those gasses to temperatures close to absolute zero, and in order to study them, he had to find a way to keep them at those low temperatures. To do that, he invented a storage flask that had inner and outer layers separated by a vacuum. The invention — still called a “Dewar” or “Dewar flask” in chemistry circles today (as evidenced by my conversation with my wife) — was immensely successful.

Dewar first perfected the vacuum flask in 1892. Within a short time, it became apparent that it had extensive commercial uses as well as the intended scientific ones. For whatever reason, perhaps scientific pride, perhaps a magnanimous spirit, or perhaps a lack of understanding of the consequences, Dewar refused to patent his invention.

A decade after Dewar perfected the flask, two German glass blowers, Albert Aschenbrenner and Reinhold Burger, realized a much more practical use for the device. They didn’t have any unusual scientific experiments to do, but they found that the vacuum flask kept their hot drinks piping hot and their cold beer icy cold. The Germans decided to hold a contest to name their company, selecting as the winning entry a name derived from the Greek work for “heat” — Thermos.

Once he realized that another company had patented his invention, Dewar sued. But he quickly realized that while a court would recognize that he had invented the flask, it also had to recognize that he had missed his opportunity to patent it. Dewar lost his court case, and Thermos got to continue his invention to keep your coffee nice and warm.

As it turns out, there may be some karma in the law, too. The folks at Thermos, who eventually built a major manufacturing plant in Connecticut, decided that the cheapest way to get advertising was to try to make the word “thermos” synonymous with the vacuum flask itself. The move showed some business acumen, but a total lack of understanding of trademark law. They were so successful that some dictionaries began to define the flask as a “thermos” (lower case “t”). By the time the Thermos company realized their mistake, it was too late.

In 1962, an American court ordered that the word “thermos” had become generic, and therefore any company could market a vacuum flask and call it a thermos. And so, a failure to understand patent law is why we don’t know of the device as a “Dewar,” and a failure to know trademark law is why we call every single one of them a “thermos.”