This instrument  comprising of microscope mounted on a adjustable vertical pillar, to adjust the height of the microscope. The microscope has a rack & pinion focussing mechanism which ensures sharp images are observed. It moves on machined, inter-ground guideways  which gives it a smooth motion. The vertical pillar houses a draw tube, operated using twin knobs which engage a separate rack & pinion arrangement. The draw tube has a stainless steel scale engraved on it which is graduated from 0 to 15cm, reading up to an accuracy of + -0.01cm %. A vernier is attached to the pillar, which is read in conjunction with the scale on the draw tube. A guide slot & key ensures that vertical movement is in the same plane. The entire assembly is mounted on a heavy cast iron base which makes it sturdy and safe-guards from minor external disturbances. The base also has levelling screws to ensure that it is perfectly level.