Study of simple microscope

The simple dissecting microscope is made up of a single lens which is used to view the object directly. It is úsed during the study of whole or part of an organism like taxonomical studies, embryo separation etc.

It is made up of the following parts-

(a) Base or foot: This is the U or V-shaped lowermost basal portion of the microscope on which the main body stands.

(b) Limb or pillar : This is a short vertical structure of the microscope which stands at the right angle to the foot.

(c) Draw tube: This is a short tube present above the limb and adjusted inside of it by rack and pinion arrange- ment.

(d) Adjustment screw : Two laterally placed adjustment screws are present at the junction of the limb and draw tube. The draw tube can be moved up and downward by adjusting the screw.

(e) Stage: A rectangular or square glass plate is attached at the top of the pillar and at right angle to it parallel to the foot. It is provided with two lateral clips placed in front of the draw tube.

(f) Folded arm: It is a flat and narrow metallic piece present at the apex of the draw tube and attached at the right angle to it. It moves horizontally.

(g) Eye piece: This is a short tube with a single convex lens attached to its upper end. The eye piece is placed within a metallic ring. The base of the metallic ring is attached to the tip of the folded arm by a screw. The magnification of eye pieces are of 5X, 10X or 20X.

(h) Mirror: A movable simple mirror is placed below the stage and attached to the front of pillar.

Setting and working of a dissecting microscope:

Microscope should be placed where light is sufficient. Then an object is placed at the centre of the stage on a clean slide. The lens is moved over the stage, fixed over the object and adjusted by tilting the folded part of the arm as desired. The object is then illuminated by suitably turning the mirror below and viewed properly by the vertical movement