This Drehzahlmesser or tachometer was manufactured by the German firm Wilhelm Morell in Leipzig in 1918. It has a scale of 0-16 which corresponds to a maximum of 1,600 revolutions per minute engine speed. This example has a serial number of 129692 and has the connecting rod still attached. It is held in a stand apparently because it was used in a German flieger-schule or flight school, possibly after its useful service life. The numbered disk is a semi-transparent material which Morell began to use with Leipzig-made tachometers numbered in the range 111xxx. Two others of this transparent disk type in the same batch are known - No. 11_457 at the Flygvapenmuseum in Sweden and No. 11__37 at RAAF Museum Point Cook in Australia. The Point Cook example is attributed to an aircraft of Manfred von Richthofen. If correct, this would not likely have been taken from his triplane because this tachometer is used for measuring engine revolutions at half the engine speed and therefore used the camshaft drive from a standard inline engine, not a rotary engine drive such as the triplane which run faster than engine speed and this factor would be printed on the dial instead of the 1:2 that’s present.