Newall, H. F · London : Society for Promoting Christian Knowledge · leaf 36
and dimensions «] newtons discovery, 1675 29 of the solar image formed on the paper by the light.This image was oblong and not oval, but terminatedwith two rectilinear and parallel sides, and twosemicircular ends. On its sides it was bounded prettydistinctly, but on its ends very confusedly… … Fig. 17. For the image was eighteen feet and a half distantfrom the prism, and at this distance that breadth ifdiminished by the diameter of the hole in the windowshut, that is by a quarter of an inch, subtended anangle at the prism of about half a degree, which isthe Suns apparent diameter. But…
Spectroscope · Spectrum analysis
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