the glass chimney _b′_, and oil-cup _l_, which receives any oil that may drop from the lamp. Fig. 30 shews the apparatus for moving the lamp up and down, so as to remove it from the reflector at the time of cleaning it. In the diagram (fig. 30) the fountain _c_ is moved partly down; _d d_ shews the rectangular frame on which the burner is mounted, _e e_ the elongated socket-guides through which the guide-rods slide, and _f_ the guide-rod, connected with the perforated sockets on which the _checking-handle g_ slides. The oil-cup _l_ (covered with a lid and wick-holder, as shewn in fig. 31) also serves as a _frost-lamp_ during the long nights of winter, when the oil is apt to turn thick. It is attached to the lower part of the oil-tube by the arm _h_; and is lighted about an hour before sunset, so as to prepare the reflector lamp for lighting at the proper time. The communication between the burner and the fountain is easily opened or shut in the burners used in the Scotch Lighthouses, by simply giving the fountain a turn of one quadrant of the horizon round its own vertical axis by means of the round knob at its top, and thereby moving a simple slide-valve, which shuts off the communication between the fountain-tube and lamp-tube. By this mode, the oil is cut off about fifteen minutes before extinguishing the lights, so that when that is done, the burner is quite free of oil. [Illustration: Fig. 32.] ~Arrangements for Raising or lowering the Argand Wick.~ It would needlessly occupy much time and space to describe the various means (many of them sufficiently clumsy) which have been employed, and in many places are still in use, for raising and depressing the wick; it will be enough to say, that they all involve some application of the rack and pinion. I shall, therefore, only describe the method (invented, it is believed, by M. VERZY) which is adopted in all the Lighthouses in the district of the Commissioners of Northern Lights. The arrangement is as follows (see figs. 32, 33, 34, 35, 36):--The inner tube _t_ of the burner is enclosed by a strong tube _s_, which fits to it tightly, so as not to be easily moved. This strong tube has a spiral groove cut on its outer or convex surface. The wick-holder has two small pegs projecting from it, the one on the inside (not seen), and the other on the outside at _a_ (fig. 33). That on the inside works in the spiral groove of the tube S (figs. 32 and 33), already described as embracing the inner tube _t_; and all that is required for raising the wick is to make the wick-holder turn round on its vertical axis. This is effected by means of the small external peg _a_ of the wick-holder (fig. 33), which moves in a vertical slit _a_ (figs. 32 and 34), cut in a tube standing in the burner, and concentric with it, and which also moves freely round its axis. Small knobs _n_ _n_ (figs. 32, 34, and 36), at the top of this tube, fit into a notch in the upper ring of the gallery, which supports the glass chimney.