He also feared that in such a crooked line as the work would be obliged to follow, the angles of the masonry would be weak, while the velocity of the water, by reason of the crooks in the channel, would be much retarded.

Recurring to the apprehended impurity of an open canal, the Report thus reasons : " Many persons have suggested that the water in the open canal, by its passage through it, would become impure I cannot see the force of the objection, as I have ;

already stated the manner that those impurities can be avoided. It must also be recollected that the principal supply of the city of London is procured from the New River and the River Lea, by the means of an open canal. The canal, to maintain its level, meanders a distance of thirty-nine miles, although the source of supply in a direct line, is not more than twenty miles from the city. Those united streams supply 28,774,000 gallons in twenty-four hours, and provide for 177,400 houses. In 1816, there were on the canal, forty-three sluices, and 215 public bridges over it. There are also several subterraneous passages under roads one is two hundred yards long. At Islington the ;

canal is fourteen and a half feet wide, and four and a half feet deep. From the New River head reservoir, which is fifty-eight feet above the River Thames, the water is raised thirty-five feet by steam engines, into two reservoirs. One is situated near Pentonville, and the other near Tottenham Court road. They each contain five acres, and are ten feet in depth.