Description: Open the lid Wipe the detection prism carefully with a soft cloth Take a few drops of the solution to be tested, put it on the detection prism, and cover the lid lightly to avoid bubbles and allow the solution to spread to the surface of the prism. Insert the instrument into the light board Aim at the light source or bright place, observe the field of view through the eyepiece, and turn the eyepiece to adjust the handwheel 5 Clears the blue-white dividing line of the field of view. The scale value of the dividing line is the concentration of the solution Notes This instrument is a precision optical instrument, the use and maintenance should pay attention to the following matters: Be careful when using it, use it strictly in accordance with the instructions, do not loose the connecting parts of the instrument at will, do not drop, bump, and violently shake It is strictly forbidden to wash it directly in water after use, it should be wiped with a clean soft cloth, and the optical surface should not be bumped or scratched The instrument should be stored in a dry, non-corrosive place Avoid loss of spare parts