Solar microscope

Manufacturer	unknown
Date	Circa 1800
Register	00882

This image projection device took the light source directly from the sun's rays and was used to make projections of microscopic elements, which required very powerful lighting that at that time could not be obtained by artificial means. It consisted of two parts. On the one hand, a mirror mounted on a metal frame with adjustable angle. On the other hand, a plate on which a tube was fixed with a lens that performed the functions of a lens. This device was placed in a hole in the wall of a room in the dark. The lens part was placed inside and the mirror part on the outside. The mirror diverted the sun's rays inside the room, illuminating the microscopic preparation, and the lens enlarged and focused the image on the screen. It was a device used essentially for scientific and/or pedagogical purposes, although it could also be used as a public entertainment show, in which spectators could gaze at projections of tiny insects enlarged to the size of an elephant. Kircher, in 1646, already described a projection of small insects using the sun as a light source. Throughout the seventeenth century, other scientists mentioned similar phenomena. In 1738 the German anatomist Johann Nathanael Lieberkühn invented a microscope to illuminate opaque objects that was based on the principle of the Fahrenheit solar microscope. It consisted of a small, concave-shaped piece of silver, which provided intense reflection of the sun's rays directly on the object. In 1740, the well-known English manufacturer of microscopes John Cuff adapted the Lieberkühn model by adding a mirror, which provided better control of the reflection of the sun's rays, and thus produced the first complete solar microscope. The apparatus in the photograph lacks the accessory that contained the microscopic preparation to be projected.

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