the concav contrast D.R.G.M. letter scale
This letter scale was made by Philipp Jakob Maul from Hamburg in Germany. The model was previously shown as the Fertig, see for example here. The oblique scale is the well-known CONCAV setup. Special about this letter scale are the colors of the scale, a white scale with black lines, blocks and numbers. This is called CONTRAST on the left side of the chart. This color scheme in a lacquered version is quite special with older letter scales. The only other letter scale with this color scheme in my collection is this letter scale from Jakob Maul. More recent letter scales have a more durable enamel version of this color scheme. The letters D.R.G.M. on the chart and under the Ph.J. Maul logo on the left brass strip of the scale mechanism is the abbreviation of Deutsches Reich
Gebrauchs Muster, a design protection, available faster and cheaper than a patent.
Below some more pictures of this letter scale.
back of the letter scale
