Eye color for a plausible argument stating that some eyes can or do change, based on chemical reactions and hormonal changes within the body. Studies on Caucasian twins, both fraternal and identical, have shown that eye color over time can be subject to change, and major demelanization of the iris may also be genetically determined. Most eye-color changes have been observed or reported in the Caucasian population with hazel and amber eyes. Carleton Coon created a chart by the original Martin scale. The numbering is reversed on the scale below in the (later) Martin–Schultz scale, which is (still) used in physical anthropology.
Forel-Ule scale Vol 5 (2010), ) and can be seen as a simple but adequate scale to classify the color of rivers, lakes, seas and oceans. The Forel-Ule observations belong, besides temperature, salinity and Secchi depth, to the oldest oceanographic parameters dating back to 1890. Forel-Ule scale The Forel-Ule Scale is a method to approximately determine the color of bodies of water, used in limnology and oceanography. By means of mixing different chemical (The standard solutions are made with distilled water, ammonia, copper sulphate, potassium-chromate and cobalt-sulphate) a standard color scale is produced in a series of numerically designated vials (1-21) which