At the head of the canal where it joins the river, are floodgates, worked by large screws, all of which are driven by a small turbine. The masonry of the canal is constructed of blocks of granite, some of which are of very large dimensions.
The water thus conducted by canal is employed by the various companies in driving powerful turbine water-wheels. The mill gearing, conveying the power from the turbine to the different parts of the mill, is exceedingly well constructed.
The civil and mechanical engineering works employed in adapting water power to driving the machinery of the Lowell mills, have been most ably executed.
51. The first mills commenced operation in Lowell in 1823. Eight of the companies have been founded since 1830.
In 1828 the town contained 3,533 inhabitants: in 1850 its population was 33,385!
It has four banks and two institutions for savings, and a hospital established by the several companies for their sick operatives.
52. Lawrence.—Lawrence is situated about 26 miles north of Boston, on the Merrimack river, 9 miles below Lowell.
