And best of all, we’re still in the same forumn(?) in which we started.
Welcome. You’re the first, of many. GD will be a graveyard, when we’ve worked our will on you. Bwhahahahaha!
(pssst! guys! we got another one.) 
Some interesting comments on Newton.
This site mentions its use by hatters as being the late 19[sup]th[/sup] centruy, so no help with Lewis Carrol.
The more searches I do on combinations involving “mercury,” “mercury poisoning,” “felt,” “felt hats,” and “alchemy,” all seem to agree that “mad as a hatter” came from felt hat making, but I must admit a keen lack of description as to time frames as to when hatters started using mercury, not to mention their sources for this data. However, I did find something that may be of help to the dutiful researcher, which I am not.
L. Elbert, Mercury Poisoning in Man (1978)
Also menioned in the same URL as a source was . A. and F. M. D’itri, *Mercury Contamination: A Human Tragedy *(1988).
:keeps digging: These two books are referenced quite a few times, actually. Did anyone else notice this?
sigh This guy says “Back in the 1600s, mercury poisoning affected hat makers who used mercury on the fur in felt hats. Unfortunately for the hatters, their contact with mercury resulted in central nervous system disorders, making them act ‘mad as a hatter.’” Absolutely no sources. I smell an urban legend in this whole affair, and am getting the raven riddle feeling pretty strongly.
More digging reveals another site which mentions its use in the 1600’s. No sources, but I’ve emailed the author and let’s keep fingers crossed for a response. Her article has the smell of urban legend in itself. Listen:
Not to be ruled out of hand in and of itself as mercury certainly was used to treat some diseases… but they worked, of course, as well and in the same manner as a neck tourniquet.
Oh, and fuck all of you. How am I supposed to play CivII when I’m worried about mad hatters? I’m going back to GD. 
I’ll go to the library Monday and check for the works mentioned. Anything else to be on the lookout for?
Had a completely revolutionary theory that the expression came from the French “travailler du chapeau” but it’s not panning out at all. Please don’t leave me hanging, I’ve become quite obsessed. I’m glad that mercury is still called mercury, unlike some of the other alchemist names for stuff…
[advisory] The participants in this particular topic have taken much of the Summer off, much like Congress and most of Europe. We intend to have brand-new weekly installments starting shortly after Laobr Day(US). Please check your local papers for time and station. Thank you. [/advisory]
Nah, I’m not just taking the summer off–I’m taking the rest of my life off.
I may be feeling up to talking about mercury again by Thanksgiving, but don’t count on it. 
[sigh]
[blues]
Got a hatter’s monkey on my back,
Couldn’t sleep all night,
Yes, I got a hatter’s monkey on my back,
Couldn’t sleep all night,
Oh, that hatter’s monkey on my back,
He just wants me to make it right…
[/blues]
Thank you, Water, for being similarly obsessed. It’s nice to know I’m not the only one with this particular dysfunction. But you won’t tell the Better Half that I’m over here again, posting in this thread, will you…?
If I hadn’t left for vacation Monday, July 30, at lunchtime, I would have seen your lovely obsessive research a month ago.
Anyway–what pops out at me is that Thackruh may have only witnessed one particular hatmaking process, in one particular workshop. As we have seen, there were innumerable felting solutions in use, and probably each workshop had a different “secret recipe”. And he may simply have not mentioned, or realized, the fact that in other workshops, they were using mercury. He may have never personally realized that hatters were sometimes rather “odd”, or he may have simply taken it for granted, and not made the connection between hatters’ eccentricities and what they did for a living. Sometimes you don’t make a connection between things that are perfectly obvious to everyone else–I know actual living 21st century people who haven’t made the connection between attending loud rock concerts and becoming permanently hearing impaired.
Just because one person in one book doesn’t mention something, doesn’t mean that that thing doesn’t (or didn’t) exist. Hey, it’s a Straight Dope moment–“absence of evidence is not evidence of absence”.
We don’t know how much actual research Thackruh may have done, whether he may have visited workshops the length and breadth of England, or whether he contented himself with merely visiting the ones closest to his home, as so many other reforming Victorians did. He may have only visited one mirror-silvering workshop, one milliner’s establishment, one hatter’s, etc.
So Goldwatter, I think, sees that Thackruh doesn’t mention mercury, and jumps to the conclusion that this must mean nobody was using mercury. But “absence of evidence…”
Now, can we please put this baby to bed?
waterj, are you gonna check that book out? If not, tell me and I will bring myself to do some research for the fine fellows of the SDMB. As soon as I find out where the library is.
The simplest way to sort out some of the loose-ends is to consult the latest (only?) academic monograph on the subject. Yes, there is a whole book that can help us out. I refer to Michael Sonenscher, The Hatters of Eighteenth-Century France (University of California Press, Berkeley and Los Angeles, 1987). OK, so it’s about the French hatting industry, when what we really need is an exhaustive study of the hatters of eighteenth-century England, but Sonenscher has lots of relevant information.
The big breaking news story about the French hatting trade in the eighteenth century was that French hatters were increasingly using hare fur as a cheaper alternative to beaver fur (pp. 76-9). Producing felt from beaver fur had always been very easy as the fur required very little processing. No chemical agents were needed to felt good-quality beaver fur (p. 62). Beavers however were becoming scarce and regular wars with Britain interrupted supplies from North America. Hares, on the other hand, were readily available at home. The problem was that hare fur was much more difficult to felt. This was where secretage, or, as the French preferred to call it, eau de composition, came in. By the second quarter of the eighteenth century French hatters knew that nitric or sulphuric acid could be used to allow hare fur to be felted (pp. 63, 78-9). This was said to have been introduced (or perhaps re-introduced) to France from England, possibly by Mathieu (p. 63n – citing the anonymous entry in the Encyclopedie methodique of 1787). The next step was the crucial one. At some point around the middle years of the eighteenth century French hatters began adding mercury and tallow to the eau de composition as this made it much easier to felt the hare fur (pp. 63, 80). This was also said to have been copied from the English (p. 122 and n. – citing a manuscript source of 1774), although Sonenscher doesn’t make clear whether he therefore thinks that it had been introduced along with the knowledge of eau de composition. Another ingredient used in the mixture was arsenic. Before long hatters began to show all the classic symptoms of mercury poisoning. Those symptoms were obvious. In 1764 the priors of the confraternity of the hatters of Marseille produced a report on the subject. Sonenscher summarises its findings as follows:
Several of the local doctors were then able to work out that the mercury and the arsenic were to blame (pp. 108-9). This particular discovery does not seem to have been publicised and the use of mercury continued, but the health problems created by the process were widely acknowledged elsewhere in France. The Academie royale des sciences held an essay competition on the subject in 1785 with Lavoisier acting as the judge. The winner seems to have blamed the fibres of the fur (p. 28). Understandably, many of the workers employed as hatters remained opposed to the use of eau de composition. This created a legacy of very troubled labour relations within the industry.
Sonenscher documents his argument with detailed references to the relevant French archives. His book has all the appearance of a good, solid piece of research.
We can therefore say with some certainty that some hatters were using mercury well before 1800 and that its effects were recognised. The problem is that all this relates to France. Can the same conclusions be made about England? Note, in particular, that it cannot be assumed that secretage invariably involved mercury or that the French necessarily learnt to use mercury from the English. The history of the use of mercury in the English hatting industry may well have been rather different.
A small data point to add is that Robert Couvreur, father of the famous actress Adrienne Lecouvreur, was a hatter, and died in an asylum. I don’t know his exact dates, but she was born in 1692.
I have not been able to find either of the two books you mentioned at the library, but I was trying to search by subject, and didn’t find anything. I also never did get around to using the microfiche to search pre-1974 records.
The library is right on Copley Square. Look for the really tall all-glass rectangle in the Boston skyline and aim for it. You’ll end up in a large square, with it in front of you, Trinity Church on your left and the library on your right. It’s one of McKim, Meade, and White’s finest works, with a new section by Phillip Johnson just behind. The McKim building is the research library and the Johnson building the lending library.
Anyone know how to search for articles in journals? We don’t want to leave a stone unturned.
Dear God, this is an addictive question. I think there’s going to end up having to be a twelve-step program for mercury and felting historical research addiction. Then we’ll see future musicians on Behind the Music saying things like: “I think the worst was when we performed in DC and I missed the show because I was at the Library of Congress looking for a Bertholet translation.”
Somehow, I missed APB’s post when responding just now. The research library does indeed have the tome he references. And using that as a starting point for an online search brings up a book on the 19th century American hatting industry: The practice of solidarity : American hat finishers in the nineteenth century by David Bensman. Nothing about England, though.
I’m rather amazed that someone happens to actually have a book on 19th century French hatmaking, but this is the Straight Dope, so I’m not shocked or anything.
Maybe I will give the library another shot.