Figure 9. W. F. Ewald's photometer. The photometer is inverted with the lensuncovered. Invented by Wolfgang F. Ewald about 1908. An earlier instrument ofthis type is not part of the museum collection. The test of the original was in a lake near
4/4/2019 1:50:12 PM
Photographer: P. Roggero
Credit: Oceanographic Museum of Monaco
Subject: Oceanography
Subject: Historical instruments