Fig. 2, is that part called the single tooth and pinion microscope, which is used for shewing transparent objects; the cylindrical tube, Y, thereof, being made to fit into the tube E F, Fig. 1. It may be occasionally used as a hand single, or Wilson’s microscope, and for which purpose, the handle, _c_, is fitted by a screw to the body at _g_, and the tube, Y, screwed away. Fig. 3, the slider which contains the six magnifiers; it fits into a dove-tail under P, Fig. 2, at the upper part of the microscope. Fig. 4 represents a brass dove-tail slider, containing a small lens: it is called a condenser. There are three in number, marked 1 and 2, &c. corresponding to the number of the magnifiers used: they serve to condense the sun’s rays strongly upon the object, and enlarge the circle of light. They slide in at _h_, Fig. 2. A B C D E F, Fig. 1, represents the body of the solar microscope; one part thereof, A B C D, is conical, the other, C D E F, is cylindrical. The cylindrical part receives the tube, G, of the opake object box, or the tube, Y, of the single microscope, Fig. 2. At the large end, A B, of the conical part there is a convex lens to receive the rays from the mirror, and refract them convergingly into the box, H I K L. N O P is a brass frame which is fixed to the moveable circular plate, _a b c_; in this frame there is a plane mirror, to reflect the solar rays through the afore-mentioned lens. This mirror may be moved into the proper positions for reflecting the solar rays, by means of rack-work turned by the nuts Q and R. By the nut Q, it may be moved from right to left; it maybe elevated or depressed by the nut, R. _d_ _e_, two screws to fasten the microscope to a window-shutter, or a board fitted entirely before the window. The box for opake objects is represented as open at H I K L; it contains a plane mirror, M, for reflecting the light that it receives from the large lens to the object, and thereby illuminating it; S is a screw to adjust this mirror to its proper angle for reflecting the light. V X, two tubes of brass, one sliding within the other, the exterior one in the box, H I K L; these carry two magnifying lenses: the interior tube is sometimes taken out, and the exterior one is then used by itself. Part of this tube may be seen in the plate as within the box, H I K L. At H, is a brass plate, the back part of which is fixed to a tube, _h_, containing a spiral wire, which keeps the plate always bearing against the side, H, of the brass box H I K L. The sliders, with the opake objects, Fig. 5, pass between this plate and the side of the box; to apply which, the plate is to be drawn back by means of the nut, g. _k i_, a door to one side of the opake box, to be opened when adjusting the mirror, M.