A professional who tends steam pressure tanks to extract glue from bones. Respnsibilities include:

• Opens valve to admit steam into tank of bones, and observing gauges, adjusts pressure according to specifications.
• Shuts off steam and releases pressure after required period, and drains glue liquor into storage tank.
• Measures density and temperature of liquor, and records hydrometer and thermometer readings on control sheet.
• Weighs out specified amount of zinc sulfate preservative and adds it to glue in storage tank.