A Mad Hatter was recorded in Alice in Wonderland. Why was there a high incidence of mad hatters ?

Question

Hint : Lighthouse Keepers were often affected by the same ailment.

Answer 1

Mercury poisoning.  Mercury was used in the processing of the felt.  

I suspect you already knew that, but did you know the wildcat gold prospectors had the same problem?  They used mercury to collect the gold dust off paper fibers during the processing, then drained the mercury into a hollowed out potato and baked it.  The heat caused the mercury to go into semi-gaseous form.  When the potato was squeezed, the mercury came out and left a gold nugget in the center of the potato.  

Now tell us about the lighthouse keepers and how they got mercury poisoning.

Answer 2

The phrase "mad hatter" came from the fact that the glue used in hat-making was very toxic and caused the person using it to act bizarre, or "mad".

Answer 3

Mercury poisoning.

Mercury was used in hat making to hold the pieces of fabric and fur together, and the workers who did this (the hatters) often went crazy due to the high exposure to mercury.

Answer 4

"Mad" in the use here means angry, not crazy or demented; like "mad as a wet hen," "mad as a hornet...."

http://www.worldwidewords.org/qa/qa-mad2...

The illustration of the tea party  in the original Alice shows the hat with a slip of paper marked "10/6" which as been used recently as an excuse to have a second fool's day on October 6th

http://www.cs.cmu.edu/~ari/madHatter.htm...