Great great Grandfather Dithridge under glass

This is a paperweight made by Dithridge who produced all types of glass in Pittsgurgh PA in the mid 1800's. We could never figure out how he got his photograph inside a glass paperweight without it burning up. Having just discovered the ambrotype, I see now how he was able to put the picture in. He probably sandwiched the ambrotype between to pieces of molten glass to get this result. The picture itself has the tones of an ambrotype.