Laurence, Lionel · London, School of Optics · leaf 117
Fit). 114. Fig. 115. to the axis. The meridian of no refraction—i.e. the axis—and the meridianof power, at right angles to the axis, are the two principal meridians, and thesealone need be considered when treating of cyl. lenses. The other meridians are merely individual elements contributing to…
Optics
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