Figure 1. H. Fol and E. Sarasin Photometers. 1. 1884 model. 2. and 3. 1885 model. 4. and 5. 1886 model as published in Fol and Sarasin, 1887. Photometers are instruments to measure light. They are used to study how far light penetrates into the water, sometimes the color of the water, and, also in modern instruments, bioluminescence.
Photo Category: Oceanography - Historical instruments