|Robert Hooke's Compound Microscope
The 1665 publication of Robert Hooke's "Micrographia" illustrates this compound microscope with stage and illumination. A ball and socket joint ( see letter "F" in the illustration) allowed positioning of the instrument. The microscope was attached to its limb ("C") with a height adjustable ring ("D"). Optics consisted of three lenses, one on the nose piece near the object, another at the top of the barrel acted as an eyepiece, and a third field lens inside the barrel close to the objective. Sliding tubes in and out shifted the relationship of the lenses and acted as a crude type of magnification. A bullseye condenser focused the flame to illuminate the subject. This instrument is a true optical and mechanical forerunner of the modern microscope.