About science, About the Earth's mantle
Conditions Governing Access
If this digital file is not available for listening on the American Archive of Public Broadcasting website due to copyright, please contact us for more information.
Conditions Governing Use
Digital surrogates may be provided in accordance with Special Collections and University Archives duplication policy.
Copyright resides with the creators of the documents or their heirs unless otherwise specified. It is the researcher's responsibility to secure permission to publish materials from the appropriate copyright holder.