Suitable for determining specific rotation of optically active substances. It has Laurent's quartz half-shade device which makes the system sufficiently accurate and at the same time simple, suitable for use with sodium light. The circular head is attached near to the analyser.Vernier movable over the scale enables reading upto 0.1°. A 200 mm tube is provided with the instrument. Mounted on a sturdy tripod stand, adjustable for height.