Engineering Wonders of the World
Volume III

TRANSPORTATION CANALS OF THE UNITED STATES. 167 SUCTION DREDGE “ONEIDA” WORKING; CUTTERS LOWERED. The spoil passes out through the pipes at the stern. acy waned through its very affluence ; and it was not until the National Government had deepened the channel in Wane of the T i ™ r x j ~ , Lakes to 20 feet and Old Erie Canal. Hudson River to 12 feet, the the and the Canadian Government had begun prepara- tions to increase its average canal depth from 12 to 20 feet from Chicago to Montreal, that the Erie Canal began to look to its laurels. Previously the “ Erie ” had been content with its 7 feet for boats drawing only 5 feet. The rude awakening, however, to the fact that competition was increasing on all sides and smothering the Erie Canal, marked the beginning of many interesting ex- periments in steam and electric propulsion, and in the construction of bridges, banks, boats, locks, slips, etc. The first scheme for electric propulsion on the Erie Canal was known as the Milligan, which consisted of a series of 14-foot posts along the bank of the tow-path, carrying Electric Towage. two continuous rails, known as the east and west bound rails, about three feet apart. A tow-line was connected with the boat from a 20 horse-power motor running on the rails. Another scheme—the Lamb system—consisted of a line of poles along the bank support- ing a stationary cableway on which electric motor carriages travelled, towing the attached boats. The present style of canal locks is a simple device based on the original invention of that versatile Italian, Leonardo da Vinci— a sort of tank or chamber placed in a canal in such a manner that a vessel can be lifted from one level to another by simply closing the end gate and filling the tank. This plan, with slight deviations, lias been used for upwards of four hundred years ; but now, in the twentieth century, the method is to be changed radically. Heretofore canal-builders have sought long, easy grades, down which the canal could climb easily, assisted by the interposition