David Thomas (1794-1882) was a Pennsylvania iron manufacturer who introduced into the United States the use of anthracite coal in the manufacture of pig iron. The papers consist of twenty-eight letters received by Thomas between May 1839 and 1842. They contain important new information on one of the textbook examples of nineteenth century technology transfer.

David Thomas (1794-1882) was a Pennsylvania iron manufacturer who introduced into the United States the use of anthracite coal in the manufacture of pig iron. The papers consist of typed transcripts twelve letters, the bulk of which were sent by David Thomas to his niece, Jane Harris Bowen, and nephew, David Harris, in Wales. The letters deal primarily with family news, but Thomas also writes about general business conditions, the level of prices and wages and the Civil War.