[CANAL LOCKS FOR OCEAN STEAMERS.]
t was at one time supposed that the railroads would be able to carry freight so much cheaper and quicker that the canals would gradually become useless, and only the heaviest and most unimportant class of goods would be sent from place to place over the all-water inland routes. One of the reasons for this was that the canals had not advanced in any way since they were first built—that is, the mechanism of locks had not been improved, and no other methods had been devised by which canal traffic might be made speedier. But about six years ago an American engineer, Mr. Chauncey N. Dutton, invented a lock which many experts think will probably revolutionize canal traffic, and make it possible to build a waterway from New York to the Great Lakes, following the line of the Hudson and using Lake Champlain and the St. Lawrence River.
DIAGRAM OF LOCKS.
The lock invented by Mr. Dutton is founded upon the already well-known and widely utilized principle of compressed air, and although at first it looks complicated to the average person, it is said by mechanics and engineers to be a very simple affair. The lock is called a pneumatic balance lock. It is made up of two sections, each of which may very well be compared to elevators. These elevators are in reality huge tanks, each about 510 feet long, 65 feet wide, and capable of holding 26 feet of water. These tanks are placed in other steel tanks which correspond to the shafts of an elevator, and these shafts are placed alongside of one another. Of course the shafts of these great elevators are sunk as deeply into the earth as it is necessary to raise a ship into the air, or up to the higher level of the canal. The sunken portions of the shafts are filled with water, and the tanks, or elevators, are arranged so that they work up and down like balanced scales—that is, when one is at the higher level the other is at the lower level. Compressed air does all the work. Perhaps by looking at the diagram this may be more clearly made apparent.
The two tanks are connected by a great pipe 21 feet in diameter. Where it connects immediately with the locks this pipe is flexible and moves up and down with the tanks, and looks very much like a huge elephant's trunk. Through it the compressed air shifts, at the will of the operator, from one shaft to the other.
Therefore, supposing one of the tanks is at the highest point of one of the shafts, the other will naturally be at the lowest level of the other shaft. The upper tank is supported by compressed air resting on a body of water which fills the lower portion of the shaft—that is, the part sunken down into the earth. All that it is necessary to do now in order to bring the upper tank or elevator down to the level of the lower tank is to open a valve, and allow the compressed air to run out of one shaft into the other, which it will do at a velocity twenty-eight times that of water. The weight of the descending tank, of course, is the power which forces the air through the pipe from one shaft into the other, and as soon as the two tanks reach the balancing-point they will stop. In order to get the elevator down to the bottom level, therefore, it is necessary to allow water to run into that compartment which needs to be made the heavier and to allow water to run out of the other. It is plain to be seen, therefore, that this invention is bound to crowd out the old-fashioned stationary canal lock if it can be constructed cheaply enough.
