[Coggeshall, William Turner], 1824-1867, [from old catalog] ed · Columbus, Follett, Foster and company · leaf 350
l rod parallel to the surface EF ; thenit is evident that aa and bb will be the shadows of CD, inreference to the lights A and B. But the shadow aa beingilluminated by the light B, and the shadow bb by the light A,it follows that if these shadows be perfectly the same in pointof intensity of shade,… … Gas—Illuminating Power. 297 brought nearer to it, until the shades seem to be exactly alike,when the light shed upon EF by A and B must, in point ofintensity, be, as before, the same. But the intensity of light,like that of other emanations proceeding in straight lines froma central point, being…
Printing · Pottery · Gas, Illuminating · Iron industry and trade · Glass manufacture
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