En cours de chargement...
The gradual development of understanding of the transparency of natural waters and of insight in the cause of their various degrees of clarity and coloration is sketched from the times of Henry Hudson (1600) to those of Chandrasekhara Raman (1930). This historical overview highlights reports of explorers and scientists, many now quite famous, as well as observations of fishermen and other sailors intrigued by ocean and freshwater optics.
A number of instruments, some of great simplicity, that were developed to quantify water transparency and colour, the latter gradually seen as an aspect of water quality and contents, is described. The background of the colour of water remained a mystery until the beginning of the twentieth century. It is argued that this delay was caused by the fact that the subject was mostly treated as marginal.
Moreover, aquatic optics is at the cross section of physics, chemistry and biology, and before the 20th century the understanding of all these disciplines was marginal, let alone grasped by one single person. In the third place, if proper pure-water distillation techniques had been available earlier the time span to understanding and theory development could have been shifted backwards by decades.
The history of insight into the cause of water colour can be considered as a metaphor of scientific progress in general: from observing a natural phenomenon without even trying to understand it but instead using it for various purposes, to analysis of causes and if possible consequences, and the subsequent development of an encompassing theory.