Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 260
Fig. 5.—Blondel, depolished opal glass. apparently coincident edges, so that theirimages coalesced. But, unlike Bouguer.he used two candles. The two sourcesof light were screened in such a mannerthat each of them only illuminated oneof the plates. This quite accounts forthe want of precision of… … This must be carefully distinguishedfrom the investigations of Blondel andmyself, in which the direction of viewor the angle of emission is fixed foreach experiment, and the angle ofincidence varies. If Wieners plastersurface had justified Lamberts observa-tion that ; the plane surface,…
Lighting
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