Delmonico, thanks for the informative reply.
Bill
No problem, a few photgraphers used the glass plate yet, some thought it gave a bit better picture, modern digitizing has proved them right. Also according to a late friend (His Great-Uncle took the Wounded Knee pictures, I sure wish Don had not passed on, I have some questions I'd like to ask him.) some used it because they still had a large supply of chemicals.
The dry plate acually was invented in the 1870's and had gained a decent foot hold by the late 1880's and had taken over for most pictures by 1900.