is an invention which, being derived from the French, still bears its French title, and consists of either a train remontoire, or a gravity or remontoire escapement, in which latter the impulse is not given to the pendulum directly by the clock-train or weight, but by some small weight lifted up or a small spring bent up by the clock-train at every beat of the pendulum, so as to secure a uniform and constant impulse, the remontoire weights being lifted either faster or slower according to need. The train remontoire differs from the escapement but slightly, the chief difference being that the small weight or spring which gives the impulse to the pendulum is not wound up at every beat, but at some larger interval, seldom more than half a minute. Its effect is to counteract the various errors to which large clocks driving heavy hands are always liable, and to diminish the friction which arises from the use of heavy weights--these being in very large clocks almost incredibly heavy; for instance, the weights used by me for my clock in the Great International Exhibition of 1862 amounted to more than two tons. Whatever the cause of inequality of movement in the clock, whether it be dust or dirt, or insufficient oil, or whether it be wind delaying or expediting the progress of the hands on the dial, the remontoire regulates and counteracts. THE DIALS. The utility of a Public Clock is considerably enhanced by its being provided with a dial marking the time in the simplest and most unmistakeable lines, so that it may readily be ascertained at any reasonable distance from the clock-tower what is the hour either by day or night. In order that this important requisite may be attained, it is of course necessary that the dial shall be so constructed as to be visible both by night and day, and so arises the necessity for providing illuminating power either from within or from without. Now the simplest method, and perhaps also in the end the least objectionable, is that followed at the Horse Guards, where the dial forms part of the tower itself, and is lighted not from within, but from without. The advantage of this arrangement is, that the architect can make the dial harmonize with the character of the building, that the illuminating power is kept apart from the clock, and if the centre of the dial be slightly sunk the hands may be brought quite close to the face, so as to prevent any seeming error in time, as is sometimes caused by the convexity of a copper dial. The figures too, having been once carefully divided and cut into the stone, are renewed, so to speak, by merely being painted over. +----------------------------------------------------------------------+ | [Illustration: Memorial Turret Clock Dial.] | +----------------------------------------------------------------------+