Twentieth century hand-book for steam engineers and electricians, with questions and answers .. (1905)
Swingle, C. F. [from old catalog], Horstmann, Henry Charles, 1858- [from old catalog], Tousley, Victor Hugo, 1875- [from old catalog] · Chicago, F. J. Drake & co. · leaf 609
the water rheo-stat need be used only to keep the load constant whenlights are switched on or off. Photometer. The amount of light given off by anincandescent lamp is measured in candlepower. Todetermine the candlepower of a lamp, an appaiatusknown as the photometer is used. Fig. 106 shows adiagram… … FIGURE 106. A small screen, made of white paper having a greasespot in the center, is mounted on a stand so that it canbe moved along the scale. To operate the instrument,move the screen to such a point that the grease spotbecomes invisible from either side. The two candle-powers are now to each…
