I'm not an expert when it comes to ambrotype or daguerreotype but I'm leaning toward the ambrotype. The measurement of the glass is 2 1/2 X 2 which I believe to be the 1/9th plate. Inside the case it states the following. Are the sole proprietors and the only legal manufacturers of UNION CASES, with the Embracing Riveted Hinge.
Patented October 14,1856, and April 21, 1857. He case is in good shape all the way around with one hinge that has been repaired with a small pin. Don't miss out on this great piece of American History. Please view all pictures as this is the most important part of the description. The item "Civil War Time Ambrotype Daguerreotype Case Boy With Gun Union/Confederate Army" is in sale since Monday, March 07, 2016.This item is in the category "Collectibles\Militaria\Civil War (1861-65)\Original Period Items\Photographs". The seller is "dheathallen" and is located in Germantown, Tennessee. This item can be shipped to United States, to Canada, to United Kingdom, DK, RO, SK, BG, CZ, FI, HU, LV, LT, MT, EE, to Australia, GR, PT, CY, SI, to Japan, to China, SE, KR, ID, to Taiwan, TH, to Belgium, to France, to Hong Kong, to Ireland, to Netherlands, PL, to Spain, to Italy, to Germany, to Austria, RU, IL, to Mexico, to New Zealand, SG, to Switzerland, NO, SA, AE, QA, KW, BH, HR, MY, CL, CO, CR, PA, TT, GT, HN, JM.