OCR Text |
Show Light Measuring. The candle power of two sources of light cannot bo compared by looking nt the lumps themselves. Tho color of light and tho Intensity nre very deceiving de-ceiving to tho eye. Tho following" Is n simple method of comparing Illuminating values: I "An extremely simple light measur-' measur-' lug device, or photometer, can ho Improvised Im-provised by placing a sheet of paper so that the light from two lamps full on It nt tho same angle and then holding a pencil or other small opaque object nt n little distance from tho paper so that It costs two shadows side by side. "If tho lamps are equally distant, the ono of higher cnndlo power will enst tho darker shadow; If the paper Is moved so as to mnko tho shadows equally dnrk, tho more distant lamp Is tho more powerful In proportion to tho. square of tho distances." Electric Merchandising. |