Blue View - Mad as a Hatter

Ever wonder where the expression “mad as a hatter” came from? Probably not… I certainly never did. I’d heard the expression, of course, but I’d never really given it much thought or really wondered what hatters might be mad about. When we stopped at the Grand Portage National Monument, however, one small exhibit explained how the expression originated, and it’s an interesting, but sad story.

A beaver pelt

For many decades, the Grand Portage was the major trading point for the fur trade, and millions of beaver pelts passed through there on their way to England and Europe. Literally millions! I knew that most beaver pelts were used to make hats, but the only hat I could imagine being made from a beaver pelt was something a mountain man would wear… certainly not something that would be donned by an English gentleman. Fortunately, there were several exhibits there that explained the hat making process, and how those furry hides became very fashionable hats.

Fashionable mountain man in his beaver hat. From Portrait Of A Mountain Man by Woods Wheatcroft

First, unskilled laborers - often children, scraped the hair off the hide. Next, the hatter would use a process called carroting in which chemicals were brushed onto the hide to dissolve the keratins in the hide. Keratin is a protein and is a major component of hair, nails and teeth; removing it from the hide made it softer, more supple and easier to shape. The chemicals would also turn the hide an orange color… thus the term “carroting”. The next step was to dye the hide the desired color, usually black or grey. The hatter would then cut the hide to the approximate size, and using steam and various tools and forms, would stretch and shape the hide into the desired shape.

Some beaver hats after the hatter processed the pelt

The traditional park ranger hat used to be made of beaver. Now, they’re made from rabbit and hare pelts.

So, what was the chemical used for carroting? Hatters used a mixture of mercury and aqua fortis (nitric acid) to create mercury nitrate. Residue of the chemical would remain on the hide throughout the hat making process, and the toxic mercury would pass to the hatters as they handled the hides and breathed the contaminated steam.

One of the earliest signs of mercury poisoning is a tremor, and by 1860 in England, most older hat makers were known to have “hatter’s shakes”. More advanced symptoms of mercury poisoning included a lurching gate, slurred speech, irrational behavior and memory problems. Since the majority of hat makers in the latter half of the 19th century probably had at least some of these symptoms, it isn’t hard to see how the expression “mad as a hatter” came to be.  Even the Mad Hatter in Lewis Carrol’s Through the Looking Glass may have been an unfortunate hat maker suffering from mercury poisoning.

Amazingly, even though alternatives to mercury nitrate were known as early as 1874, mercury continued to be widely used well into the 20th century. In fact, a study done in 1922 of hat makers in Danbury, Connecticut, found that almost half had symptoms of mercury poisoning. Mercury wasn’t banned in the hat making industry in the U.S. until 1941, and then only because mercury was needed for the war effort as it was used to make bomb detonators.

Come to think of it, I remember playing with mercury as a kid, chasing it around on the floor with a pencil or a playing card. Perhaps that explains a few things.

See you next week…