The microscope; an introduction to the microscopic methods and to histology (1911)
Gage, Simon Henry, 1851-1944 · [Ithaca, N.Y.] The Comstock Publishing Company · leaf 26
in the principalfocus. Ai B3. The virtual image on the sameside of the lens as the object. It is indicated■with dotted lines, as it has no actual existence. £2 A-. Retinal image of the object (A*B*).The virtual image is simply a projection of theretinal image in the field of vision. Axis. The… … \J § 13. Obtaining the Principal Focus.—Hold the simple.microscope directly toward the sun and move it away from andtoward a piece of printed paper until the smallest bright point isobtained. This is the burning point or focus and as the rays of thesun are nearly parallel, the burning point…
Microscopy
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