If it is a series 1a then it's a triple convertible eight element lens someqhat similar to the Zeiss Protar. It has a 25 1/2" and a 20" cell, each being an f16 lens when used separately. The larger cell goes on the front. Wollensak said the combined lens would cover a 7" X 15" banquet camera film at smaller stops. If I did the math right, that would mean an image circle of at least 420mm. pretty generous for 8" X 10".
Is this the 13" f/10? It's most likely similar to an Artar with about 46 degrees of coverage. This is of course a wild ass guess, but most older process lenses are spec'd with pretty limited coverage compared to "regular" lenses.