The prism method can also be used to measure the refraction index of
a liquid by using special prismatic recipients having two faces made of
plates of flat, parallel glass.
Since the verniers have fifteen lines and allow appreciation to the minute,
in the case of a glass prism having a refractivity index of about 1.5,
homogenous and cut with precision, with this spectrometer it is possible
to measure the refraction index to three exact decimal places.
