@misc{65858, note = {{http://vlp.mpiwg-berlin.mpg.de/library/data/lit814 0/index\_html?pn=14\&ws=2.5\&mk=0.0655/0.7042\&wid=dig i\_2844 http://vlp.mpiwg-berlin.mpg.de/library/data /lit8140/index\_html?pn=11\&ws=3.0\&mk=0.7995/0.5441\& wid=digi\_8399 Seems to be M99: "Micrometric shutter for studying minute fields of color. After Münsterberg. By Elbs, Freiburg. \$42." See (Elbs fig. No. 10) http://vlp.mpiwg-berlin.mpg.de/librar y/data/lit13692/index\_html?pn=4\&ws=1.5 and description "Mikrometerblende": http://vlp.mpiwg-b erlin.mpg.de/library/data/lit13692/index\_html?pn=1 \&ws=1.5}}, url = {https://vlp-new.ur.de/images/img30219} }