Diamonds and precious stones, a popular account of gems .. (1874)
Dieulafait, Louis, b. 1830, Sanford, Fanchon, tr · New York, Scribner, Armstrong, and Company · leaf 42
g an inscription, as inFig. 17, two images will be visible of every point, OPTICAL PROPERTIES. 21 and both images will show deviation. This is aninstance of what is called double refraction. When a body, crystallized or not, is perfectlyhomogeneous in all its parts, so that its elementsare disposed… … Fig. 17.—Double refraction of Iceland spar. Crystals belonging to the monometric or tesseralsystem, as the cube or octahedron, since their mole-cular disposition is perfectly regular, never exhibitthe phenomenon of double refraction, in whateverdirection they are traversed by the light ; but…
Precious stones · Diamonds · Gems
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