Abrotype comes from the greek word "immortal" this type of early photography was invented in 1854. The image was captured on to glass. Before ambrotypes, was the daguerreotype, this was produced on tin, and you have to angle the image at a 45 degrees in order to see the portrait, this gave these early photographs a ghostly image.
 
This is a lovely image of presumably a mother and daughter, complete with its original leather case with internal velvet linning to protect the glass. Ambrotypes were quite a costly thing to purchase in the 19th century, so would have been from a reasonably comfortable houseold.
 
In good condition
 
Dimensions: when closed 12cm x 10cm