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CHAP XV.



DESCRIPTION OF THE PERPENDICULAR LIFT





	Creating a machine for a descending trade, in which the whole of the water descends, while the trade ascends, yet should it be found necessary, by a further extent of the canal, to form the apparatus for an alternate trade, the water lift may be applied. 



	In the first cafe of a descending trade, there is but one lift, which must be thirty feet diameter, a capacity of forty tons. To let two boats to pass  over the pit a building must be created, to cover and supports the works; in the center of which a drum-wheel of one diameter is plated. On the outside of the drum, two chains and a cage to receive the boat is suspended; alternately between the upper and lower canal a t on the old of the upper canal, and on the side of the pit, there are two gates, balanced so as to rise perpendicular to the gates, parallel to the canal, two lock-cages  worked by rack and pinion, moving on iron rails while the cages arc constructed with one end open, to receive the boat. 



	When the lock-carriage is moved forwards, it fits into a groove in the canal, the gate swings open and water flows from the canal into the carriage which enables the cage to float, after which the gate shuts.



	For the purpose of raising the boat out of the upper canal, in order to move her over the pit previous to the descending, there is a reservoir, D, formed in the side of  the tub near the bottom, Fig 3, Plate 10, and of a size to contain about thirty tons of water: at the time the cage is in the upper canal, the tub will be beneath this reservoir, from which water must be drawn into the tub till a preponderating power is created; the tub will then descend about eight feet, raising the cage and the boat out of the upper canal. The cranes are then moved over the pit, and a portion of water is discharged from the boat, until the boat preponderates; which, descending to the lower canal, will raise the tub to near the upper level, in the situation exhibited in the third Figure, where a valve opening, by means of the lever at E, the water from the tub passes into a pipe, and descends to the reservoir, in order to raise the next boat out of the upper canal, leaving the boat to float in the lower pond.



	To raise a boat from the lower pond, and pass her into the upper canal, water must first be drawn from the upper canal into the tub by the pipe F, till a preponderating power is created; which descending, will raise the boat about one foot above the upper pond; the cranes are then turned over the canal, and the water being discharged from the tub, the boat will immediately float in the upper level.



	To regulate the movement of this machine, the centrifugal fans are applies, as represented in Plate IX. Also the balance chains to the tub, as in Plate X fig. III.



	The operation of this machine is easily performed, and a four ton boat may be transferred through a space of one hundred feet high, in eight minutes, or three hundred and sixty tons in twelve hours.



	The expense of constructing one hundred foot life, averaging the situations, will be about 2,500l.