Gum chewing independently arose across different cultures and regions at different times, says Jennifer Mathews, an ...

Raised structure tar – Birch bark tar vessel containing hot tar from a recently completed experiment using the ‘raised structure’ technique. Disclaimer: AAAS and EurekAlert! are not ...

Reed wood, being lighter and more flexible, was used for the back sections. Birch bark tar was used as an adhesive and ...