. The microscope; a simple handbook. Microscopes. A SIMPLE DESCEIPTION OF THEiMICROSCOPE 13 the formation of the images. An enlarged picture of an object placed upon the stage (D) is formed in the neighborhood of the eyepiece at U, and the eyepiece again magnifies this image, projecting the light into the eye as if it came from an object situated at V. The eye, when placed in a small area (T) through which all syepieoe. light passes, and which is known as the eyepoint, sees the final picture of the object as if it were a real object placed at V, 10 inches from the eye. It is assumed for conven
. The microscope; a simple handbook. Microscopes. A SIMPLE DESCEIPTION OF THEiMICROSCOPE 13 the formation of the images. An enlarged picture of an object placed upon the stage (D) is formed in the neighborhood of the eyepiece at U, and the eyepiece again magnifies this image, projecting the light into the eye as if it came from an object situated at V. The eye, when placed in a small area (T) through which all syepieoe. light passes, and which is known as the eyepoint, sees the final picture of the object as if it were a real object placed at V, 10 inches from the eye. It is assumed for convenience of measurement that this picture virtual is actually 10 inches away, though it may be formed at a some- "°'^*" what different position according to the adjustment or condition of the observer's eye. Whether the virtual image is actually at 6, 10, or 20 inches is of no importance. It makes no difEerence to the size of the picture, because when the virtual image is formed farther away it becomes proportionally larger. In Fig. 4, if E is the eye and 0 0' 0" are objects of different sizes, they produce the same size pictures in the eye if placed at such distances that they subtend the same angle. The magnifying power of the microscope will depend upon the size of this final image formed at V (Fig. 1) compared with the size of the object being examined. In this connection it should be under- _ stood that if a microscope is said to magnify'100 diameters, it means that the picture that is seen is 100 times as long and 100 times as wide as the object would appear if it were taken from the stage (D, Fig. 1) and placed in the position V, 10 inches from the eye. In order to express how much larger an object appears when seen through the microscope than when seen by the naked eye, a standard distance must be taken, because an object appears to the naked eye to be of different sizes at difierent distances. A sixpence is almost invisible at a distance of 100 yards, but
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