A London encyclopaedia, or universal dictionary of science, art, literature and practical mechanics : comprising a popular view of the present state of knowledge : illustrated by numerous engravings, a general atlas, and appropriate diagrams (1829)
Curtis, Thomas, fl. 1820 · London : Thomas Tegg · leaf 291
r both these images the surface ought to bemuch more curved than that which has beenusually considered, and the mean of the cur-vature required for them, which must be thebest for the ground or bottom of a camera ob-scura is equal to that of a sphere of which theradius is three-eighths of the focal… … rays, as ab c, de f, g h i, issuing from all pointsof the object A13, on the side next the convexlens E F, after passing through the lens, willconverge to as many points beyond it, and atthose points of convergent meeting they willform an inverted picture C D of the object on awhite paper. 517.…
Encyclopedias and dictionaries · Aeronautics
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