456 LIGHTHOUSE eye will receive at once rays from several re- flectors, while in the case of a fixed light it only receives them from one. This is the reason why revolving lights are always brighter than fixed lights. The lamps used with reflectors are 1, 2, and 3 represent a vertical central sec- tion, a side elevation, and a rear elevation of a lamp and reflector : a a a a is the reflector ; &, the burner ; &', the glass chimney ; c, the fountain, holding about two thirds of a quart ; d d d d, Fir,. 1. FIG. 2. FIG. 3. FIG. 4. what are commonly called fountain lamps. They are fitted with Argand burners, about three fourths of an inch in diameter. Figs. a frame to which the lamp is fastened ; e and /, guide rods upon which the frame is mova- ble vertically for raising and lowering the lamp ; g, a handle, by turning which the lamp is fas- tened in position; ^, a copper tube for ven- tilation, which is inserted in an elliptical aper- ture in the upper part of the reflector, cor- responding to one in the lower part through which the burner can be moved out and in;
- , a portion of the frame to which the lamps
and reflectors are attached ; Tc &, brass knobs FIG. 5. soldered to the outside of the reflector; Z, an iron band upon which the knobs rest, thus holding the reflector in place. Fig. 3 shows the frame d d on which the lamp is mounted, the guides e e through which the rods slide, the guide rod f, and handle g ; I' is the dripping cup. The communication between fountain and burner is opened by giving the fountain one quarter turn, which opens a slide
