English: "Background Illumination" for the light microscope after J. B. Reade (1837) as described by John Queckett, 1855. Description from the original publication:
a b represents the stage of the microscope in an inclined position; c a condensing lens placed below and on one side of the stage; d a lamp also placed below the stage and at some distance from it; the rays of light r r r' r' emanating from the lamp,are thrown obliquely upon the object e, and only those that are refracted by the glass, or by the object under examination, will pass through the comound body to the eye: some objects, when viewed in this way, will appear beautifully illuminated on a field of view that is nearly, if not quite, dark.