The Dellebarre microscope body consists of many interlocking parts. From objective to eyepiece, each successive section press-fits into the previous section. This microscope has no Field lens, but instead has up to five eyepiece lenses. These can be screwed in serially to increase magnification. Lenses 2–4 are of flint glass. Lens 5 is greenish crown glass. Even though Dellebarre used a combination of Crown and Flint glass, there is no indication that this was an intentional use to overcome chromatic aberration.
A: Lieberkuhn
B: Objective
C: Body tubes; embossed "A", "D", "B" (L to R )
D: Eyepiece tube with five lenses; embossed "1" through "5"
E: Eyepiece aperture and dust cover
B: Objective
C: Body tubes; embossed "A", "D", "B" (L to R )
D: Eyepiece tube with five lenses; embossed "1" through "5"
E: Eyepiece aperture and dust cover
Top body tube has internal threads at one end. This is probably where a Field lens (or Martin's "between-lens") would have been inserted.
Eyepiece lenses, labeled 1-5. All are 3.2cm in diameter. Focal lengths are:
#1: 4.3cm; #2: 5.5cm; #3:6.5cm; #4:7.5cm; #5:7.0cm
#1: 4.3cm; #2: 5.5cm; #3:6.5cm; #4:7.5cm; #5:7.0cm
Magnification can be increased by adding lenses. With each additional lens, however, light transmittance decreases and aberrations increase.