What They Were Thinking

“Where does your clay come from?” is a common question asked at historical pottery demonstrations. Answer: “The ground.”  Another common inquiry, relating to the widespread use of lead glazes by early potters, is “Didn’t they know lead is toxic?  What were they thinking?”

Lead glazes give people the creeps.  But lead was fairly easy to obtain, it was cheap, it had a wide firing range, and it offered a wonderful variety of glaze colors.  Lead is actually one of the world’s greatest glaze materials – except, of course, exposure to it destroys your central nervous system.

So lead glazes require further comment.  Most early American potters didn’t have access to higher firing stoneware clays, which don’t use lead glazes.  It wasn’t until the early 19th century spread of canals and toll roads that shipping prices lowered enough for stoneware to blossom.

A common glaze recipe in the early US had about 10 parts lead to 3 parts loam or sand.  The best lead source came from sheets used to seal tea – tea chest lead – reduced to a white powder by soaking in vinegar.  But most potters went to dry goods merchants who sold imported lead as a paint ingredient.

People knew of lead’s toxicity by the 18th century.  It was called “potter’s rot.”  But end users weren’t immune.  In 1783, a Connecticut doctor blamed a recent “bilius colic”epidemic on all the local lead glazed redware flooding the market during the English embargoes of the time.

Philadelphia and New York newspapers issued challenges to develop alternative glazes.  Federal and State agencies issued periodic warnings against lead use.  But lead glazing persisted well into the 19th century.

Why were people so obstinate?

Insight to that question can be gained by posing a similar set of questions.  Imagine a visitor from 200 years into the future asking people on the street today:  “Didn’t you known nuclear waste takes hundreds of thousands of years to decay?”  “Why did you dump all that garbage into the ocean and rivers?”   “Didn’t you know about global warming?”  “What on Earth were you thinking?”

Readings:

The Art of the Potter.  Diana and J. Garrison Stradling.  Main Street-Universe Books/New York.  1977.

The Jug and Related Stoneware of Bennington.  Cornelius Osgood.  Charles Tuttle Co./Rutland, VT.  1971.