On the other hand, when the electric light was restored, the glory rose to its first high condition.... During the day-time I compared the intensity of the light with that of the sun, and both looked at through dark glasses. Its light was as bright as that of the sun, but the sun was not at its brightest.” The number of lights on a well-frequented coast being considerable, it is of the utmost importance to arrange them so as to enable the mariner easily to distinguish them from each other. Catoptric lights admit of nine separate distinctions:—1, fixed; 2, revolving white; 3, revolving red and white; 4, revolving red with two whites; 5, revolving white with two reds; 6, flashing; 7, intermittent; 8, double fixed lights; 9, double revolving white lights. Mr. Stevenson thus defines their distinctive features:—“The first exhibits a steady and uniform appearance which is not subject to any change, and the reflectors used for it are of smaller dimensions than those employed in revolving lights. This is necessary in order to permit them to be ranged round the circular frame, with their axes inclined at such an angle as shall enable them to illuminate every point of the horizon. The _revolving_ light is produced by the revolution of a frame with three or four sides, having reflectors of a larger size grouped on each side with their axes parallel, and as the revolution exhibits once in two minutes or once in a minute, as may be required, a light gradually increasing to full strength and in the same gradual manner decreasing to total darkness, its appearance is extremely well marked. The succession of red and white lights is produced by the revolution of a frame whose different sides present red and white lights, and these afford three separate distinctions, namely, alternate red and white, the succession of two white lights after one red, and the succession of two red lights after one white light. The flashing light is produced in the same manner as the revolving light; but, owing to a different construction of the frame, the reflectors on each of eight sides are arranged with their rims or faces in one vertical plane, and their axes in a line inclined to the perpendicular. A disposition of the mirrors, which, together with the greater quickness of the revolutions, which shows a flash once in five seconds of time, produces a very striking effect, totally different from that of a revolving light, and presenting the appearance of the flash alternately rising and sinking, the brightest and darkest periods being but momentary; this light is further characterised by a rapid succession of bright flashes, from which it gets its name. The intermittent light is distinguished by bursting suddenly into view and continuing steady for a short time, after which it is suddenly eclipsed for half a minute. Its striking appearance is produced by the perpendicular motion of circular shades in front of the reflectors, by which the light is alternately hid and displayed.