242 BENJ. PIKE'S, JR., DESCRIPTIVE CATALOGUE. 



To use the Solar Microscope a window must.be selected 

 into which the sun is shining, and a hole is made in the 

 window shutter, or in a board provided for the purpose, of 

 about six inches in diameter, and by means of two brass 

 nuts let into the shutter to receive the milled-head screws ; 

 when passed through holes in the corners of the square 

 frame, firmly fasten the microscope to the shutter, the 

 mirror extending outside. The room is to be darkened as 

 much as possible, that no light may enter but what passes 

 through the body of the instrument. The mirror is to be 

 turned by the milled-head screws, till the beams of the 

 sun's light pass directly through the tube, and form a large 

 and brilliant circle of light on the screen, which may be placed 

 at a distance of ten to twenty feet ; the screen is formed of 

 white muslin, and the object may be seen with equal dis- 

 tinctness on either side. The slider, containing the object 

 to be magnified, is placed between the plates in the micro- 

 scopic tube, where it is held by the pressure of the spiral 

 spring. It now remains only to adjust the magnifier, that 

 the image on the screen may be the most distinct or perfect, 

 which is done by moving the pinion, a small distance one 

 way or the other. If the object is rather large, the least 

 magnifying power is used, if small the greater. 



Solar Microscope for Opaque and Transparent Objects, 

 (Fig. 758, next page.) The body A B C D E F has the part 

 A B C D of a conical, and the part C D E F of a tubular 

 form. A large convex lens is placed at A B, at the end of 

 the conical tube A B C D, which screws into the square 

 plate Q R, which is fastened to a window-shutter opposite 

 a hole of at least the size of the lens A B, by means of the 

 screws, e, d. Upon the square plate, Q R, there is a mova- 

 ble circular plate, a b c. To this circular plate is attached 

 the silvered glass mirror, N P, placed in a brass frame, 

 which moves round a joint, P P, and which may be placed 

 in any position with regard to the sun, so as to reflect his 

 rays into the tube A B C D, by means of rack-work and 

 pinions at Q and R. The pinion, Q, moves the circular plate, 

 a b c (to which the mirror, N O P, is fixed) in a plane per- 

 pendicular to the horizon, while the nut, R, gives it a motion 

 in an opposite plane. The light introduced by this mirror 

 falls upon the lens, A B, which throws it in a condensed 

 state upon any object in the tube. But before it reaches 



