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 a young lady with a reading book in hand. Ambrotypes were quite a costly thing to purchase in the 19th century, so would have been from a reasonably comfortable household.
 
In reasonable condition, but missing its velvet and leather cover
 
Dimensions: 7cm x 8cm.