slope of the banks 1.50 base to 1 rise. The velocity of the water is calculated to be nearly thirteen inches a second, and the slope of the Canal about three and a half inches a mile. " It terminates in a From the south-west large basin near the Barriere of Villette. corner opens the St. Martin Canal, communicating with the Seine on the east side of Paris, and a short distance before coming to the basin, the St. Denis canal is opened, passing down to the Seine near that city, on the north side of Paris. " At the north-west corner of the basin is taken out the water for supplying the city by a subterranean canal or aqueduct on the north side of Paris, (aqueduc de ceinture,) nearly two miles and three quarters long. The work is in stone masonry, and the canal for the water is three feet three inches wide at bottom, five feet three inches deep, and four feet six inches wide at top. On one side is an off-set four inches wide, and on the other a foot-walk one foot six inches wide, making the whole breadth between the side walls above the trunk six feet four inches. These walls rise four feet six inches, covered with a semi-circular arch. At various points there are galleries and staircases, to descend to the subterranean aqueduct. I descended to examine the work with M. Girard, the engineer, by a flight of steps from the cellar of a house where one of the guardians resided. " Convenient arched passages are constructed under three principal streets, where one may walk, and where are laid the different mains taking water from the aqueduct, to conduct it to the various fountains and other points for distribution. They are laid upon stone blocks or cast iron frames, so that they may be easily examined all round, from one end to the other.