The box seems to have been for maybe 3 blank glass photographic plates, but now has only one, which has a remarkably lovely color photo of a flower arrangement. Hard to photograph here, but it is strikingly lovely. A label someone stuck on the box reads "Flowers - Arnold Bldg." so, perhaps the Arnold Building in Houston? Hard to say. But this large glass plate measures 5"x7" (13cmx18cm), and is basically a large Magic Lantern slide. The box is all in French, and reads, "Union Photo...graphique Industrielle", "Autochromes Lumiere" "Plaques", and so forth. The box is somewhat worn, but the slide is in great shape.