FRONT VIEW OF A BOAT,
passing over an inclined Plane or Glacis.
In the passage from Han-tcheou-fou to Tchu-san (which was the route of part of the Embassy), the face of the country is mountainous; therefore the communication of the canals is continued by means of this sort of locks, two of which were passed over on the 14th of November, 1793.
In this subject, the difference of level between the two canals was full six feet; in the higher one, the water was within one foot of the upper edge of the beam over which the boat passes. The machinery consisted of a double glacis of sloping masonry, with an inclination of about forty degrees from the horizon. The boats are drawn over by capstans, two of which are generally sufficient, though sometimes four or six are required for those of greater burthen; in this case, there are holes in the ground to receive them. When a boat is ready to pass over, the ropes from the capstans (which have a loop at their extremities) are brought to the stern of the vessel; one loop is then passed through the other, and a billet of wood thrust into the noose, to prevent their separation; the projecting gunwalle at the same time keeping the ropes in a proper situation. This being adjusted, the men heave at the capstans till the boat has passed the equilibrium, when, by its own gravity, it is launched with great velocity into the lower canal, and is prevented from shipping too much water, by a strong skreen of basket-work, which is placed at the head. On the left hand stands a mutilated triumphal arch, and a small temple inclosing an idol, to which sacrifices are frequently made for the preservation of the vessels passing over.
For a plan and section of the above, vide Sir George Staunton's Account, Plate 3-1 of the folio volume.
