OP, dagor types have symmetrical, often identical, front and rear cells that are cemented triplets. If you shine a single light on a cell (in shutter with the shutter closed or out of the shutter), if the cell is a cemented triplet you should see two bright reflections from the two air-glass interfaces and two faint reflections from the two glass-cement-glass interfaces. The faint reflections can be very hard to see.
The air spaces Steven referred to are gaps between elements. For example, the cells of plasmat type lenses (sometimes called air-spaced dagors) have an outer element that's a cemented doublet and an inner element that's a singlet. There is a gap, called air space, between the outer doublet and the inner singlet. Plasmat types will show four bright reflections from the four air-glass interfaces and one faint reflection from the one glass-cement-glass interface.
Steven, I looked in P-H Pont's handy table of diaphragm scales. If I read the table correctly, Stolze 5.4 corresponds to f/7.7. I think f/5.4 is correct. If so, the likely double anastigmat is a dialyte. OP, a dialyte cell contains two singlets, will show four bright reflections and no faint ones.
Further on the ease of confusing unlabeled Dagors and dialytes, Goerz made f/6.8 Dagors and f/6.8 dialyte type double anastigmats. The more expensive dialyte types had names, the cheapies were engraved doppel anastigmat. Year ago a very sincere but not very competent person rooked me, sold me an f/6.8 Goerz doppelanastigmat as a Dagor.
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