Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 453
lament under specified electrical con- This leads us to the third method—direct observation. During the recent-vears there has sprung up a new form ofphotometer adapted for measurementsof surface brightness. When such instruments are used tomeasure illumination the usual plan is toplace a standard… … Fig i View of an artificially lighted interior showing brightness (in candles persquare centimetre) >>i various objects. (Dr. II 1. 1 ditions we can compare the brightness ofothers Ipv Buper-imposing them on itsimage and then varying the current of thestandard filament until both…
Lighting
Internet Archive · University of Toronto Libraries · Public Domain Mark 1.0. Free to use for anything.
