Lynde, Carleton John, b. 1872, Gilbert, Alfred C. (Alfred Carlton), 1884-1961 · New Haven, Conn. : A.C. Gilbert Co. · leaf 26
Fig. 30. One candle at one foot is equal to four attwo feet GILBERT LIGHT EXPERIMENTS 23 … number of times greateror less its light is than thatgiven by a standard candle. Put the greased - spotscreen justlfoot fromacan-dle (Fig. 31) and move thelamp until the greased spotis as bright as the paper.Measure the distance fromthe lamp to the screen. Ifthis is 2 feet, the lamp is Fig- 81-…
Light · Scientific recreations
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