Fig. 1. [Plate III.] represents the IMPROVED LUCERNAL MICROSCOPE, mounted to view opake objects; A B C D E is a large mahogany pyramidical box, about fourteen inches long, and six inches square at its larger end, which forms the body of the microscope; it is supported firmly on the brass pillar F G, by means of the socket H, and the curved piece I K.
L M N is a guide for the eye, in order to direct it in the axis of the lenses; it consists of two brass tubes, one sliding within the other, and a vertical flat piece, at the top of which is the hole for the eye. The outer tube is seen at M N, the vertical piece is represented at L M. The inner tube may be pulled out, or pushed in, to adjust it to the focus of the glasses. The vertical piece may be raised or depressed, that the hole, through which the object is to be viewed, may coincide with the center of the field of view; it is fixed by a milled screw at M, which could not be shewn in this figure.
At N is a dove-tailed piece of brass, made to receive the dove-tail at the end of the tubes M N, by which it is affixed to the wooden box A B C D E. The tubes M N may be removed from this box occasionally, for the convenience of packing it up in a less compass.
O P a small tube on which the magnifiers are screwed.
O one of the magnifiers; it is screwed into the end of a tube, which slides within the tube P; the tube P may be unscrewed occasionally from the wooden body.
Q R S T V X a long square bar, which passes through the sockets Y Z, and carries the stage or frame that holds the objects; this bar may be moved backward or forward, in order to adjust it to the focus, by means of the pinion which is at a.
b e is a handle furnished with an universal joint, for more conveniently turning the pinion. When the handle is removed, the nut, Fig. 2, may be used in its stead.
d e is a brass bar, to support the curved piece K I, and keep the body A B firm and steady.
f g h i is the stage for opake objects; it fits upon the bar Q R S T by means of the socket h i, and is brought nearer to, or removed farther from the magnifying lens, by turning the pinion a; the objects are placed in the front side of the stage, which cannot be seen in this figure, between four small brass plates; the edges of two of these are seen at k l. The two upper pieces of brass are moveable; they are fixed to a plate, which is acted on by a spiral spring that presses them down, and confines the slider with the objects; this plate, and the two upper pieces of brass, are lifted up by the small nut m.
At the lower part of the stage, there is a glass semiglobe n, which is designed to receive the light from the lamp, Fig. 3, and to collect and convey it to the concave mirror o, from whence it is to be reflected on the object.