Τhe Abbe 5 is an affordable refractometer ideally suited for use where a wide refractive index measurement range is required such as in small contract laboratories or applications where sample throughput is relatively low. The instrument is also ideal for practical demonstrations and experiments in chemistry and physics laboratories of schools, colleges and universities. The instrument may be configured to work in either the traditional ‘transmitted mode’ or for non-homogenous or opaque samples, ‘reflected mode’ may be chosen. Dispersion measurements of hydrocarbons or solids materials such as glass, contact lenses and fibre optics may be made in accordance with standard practice.