Erma Refractometer is a device used to measure the salinity of a liquid, such as seawater or brine. It works on the principle of measuring the refractive index of the liquid, which is directly proportional to its salinity.The refractometer consists of a prism that is in contact with the liquid being tested. The prism refracts the light passing through the liquid, and the amount of refraction is measured by a scale on the device. The salinity can then be determined from the scale readings.
The Erma Refractometer is specifically designed for measuring salinity in seawater. It can measure salinity levels from 0 to 100 ppt (parts per thousand), which covers the range of salinity found in most natural seawater environments.