|
A
complicated set of processes was needed to turn the fur into a finished
hat. With the cheaper sorts of fur, an early step was to brush a
solution of a mercury compound — usually mercurous nitrate — on to
the fur to roughen the fibers and make them mat more easily, a process
called carroting because it made the fur turn orange. Beaver fur
had natural serrated edges making this unnecessary, one reason why it
was preferred, but the cost and scarcity of beaver meant other furs had
to be used.
Whatever
the source of the fur, the fibers were then shaved off the skin and
turned into felt. This was later immersed in a boiling acid solution to
thicken and harden it. Finishing processes included steaming the hat to
shape and ironing it. In all these steps, hatters working in poorly
ventilated workshops would breathe in the mercury compounds and
accumulate the metal in their bodies.
We
now know mercury is a cumulative poison causing kidney and brain damage.
Physical symptoms include trembling (known at the time as hatter’s
shakes), loosening of teeth, loss of co-ordination and slurred
speech. Mental symptoms include irritability, loss of memory,
depression, anxiety and other personality changes. This was called mad
hatter syndrome.
It’s
been a very long time since mercury was used in making hats, and now all
that remains is a relic phrase with links to a nasty period in
manufacturing history. (Michael Quinion) |
