4. No impending force to the pendulum from inertia of impulse arms. 5. The hold in the stops can be increased or diminished to any practical extent by reason of the inverted impulse arms. 6. Less affected by any disturbing forces of the train in proportion to the pressure on the stops. 7. Will bear more weight and give more power to the train without increasing the arc of oscillation. 8. No possibility of tripping under any increase of motive power. 9. The minimum arc of vibration to unlock is 8-tenths of a degree. Other escapements of similar construction require from 4° to 7°. 10. Take less weight for the motive power in proportion to the difference of pressure and draught on the lockings. 11. Unlocks by gravitation instead of by the pendulum and at the time of impulse. 12. Requires no fly nor remontoir, and thus reduces the weight of the motive power by one half. 13. The impulse giving motion to the pendulum increases as the force of gravity on the pendulum decreases. A great advantage over those escapements in which the unlocking is done by the pendulum when its momentum is nearly expended and at the extremity of its arc of vibration. 14. The angle of the detent planes can be set so as not only to offer no resistance to the unlocking, but to give an actual impulse in the same manner as the impulse pallets of a dead escapement. This completely frees the impulse which gives motion to the pendulum from any retarding influence of the train. 15. The arc of vibration is more equal in this than in any other gravity escapement. 16. It is not so liable to stop in consequence of a diminution of arc from the variation of motive force in train. 17. It will answer for regulators as well as for turret clocks, its arc of vibration being from 1° to 3°. DOUBLE THREE-LEGG'D ESCAPEMENT. +----------------------------------------------------------------------+ | [Illustration: Double Three-legg'd Gravity Escapement.] | +----------------------------------------------------------------------+ This escapement is chiefly designed for turret clocks with heavy dial-work requiring much power on the scape-wheel. The peculiarity consists of two locking wheels with one set of lifting pins between them. The wheels are set so that the pallets may lie between, and the pallets fall with the pendulum clear of all other contact. The pallet D for instance has its stop in front for the wheel A B C to act upon, and the E stop is acted upon only by _a b c_, the E and A being on different planes. In this escapement, by making the teeth longer and the pallets shorter, the resistance of the pendulum is much reduced, and the stride of the pallets being wider, the actual weight required of them is considerably lessened,--a point of some importance. THE REMONTOIRE.