I remember visiting my grandfather's old house in southeast Texas in the 1940's. He had an ancient Victrola with a collection of records, probably 78's, grooved only on one side and quite thick and heavy. They seemed to be made of some sort of black hard rubber-like material or a primitive plastic. The only two names I recall from among the artists were Madame Schumann-Heink and Enrico Caruso. I wish I had them today.