Simple microscopes were widely used until the middle of the last century since, if well made, they could provide performances better than the compound microscopes. The instrument presented here is formed by a convergent lens embedded in a loop diaphragm, placed at the end of a horizontal support fastened to a vertical bar. This is screwed in a wooden case which is used both as supporting base and as a keeping box. The stage is simply made of a round glass plate that a knob allows to move vertically. Observations by transmitted light were also possible thanks to the light reflected by a concave mirror, which unfortunately got lost. The instrument is equipped with four lenses of different refractive power. The shortest focal lenght is about 15 mm. Overall height 17 cm. Signed: "Deleuil". Mid-19th century.
back to Optics