onstruction by the removal of one of the banks to grade over the new structure, as shown in Mr. Buchanan's drawing and record.
The slopes of the old Middlesex Canal have been cut down as far as the conduit is built so as to make a four-foot fill on the center and eight feet wide on top, and from the outer edge of the canal to the inner edge of the back filling it is graded off like the following section.
[Then follows drawing.]
The conduit was finished on October 12, 1864, and on October 31 water was let in as far as the waste-gate near the river and all loose dirt washed out, and on the following day to the pumping station.
Two years and a half had elapsed since the engineers began work.
The entire system, of which this was but an essential part, was also complete and ready for service.
At one time three hundred and fifty men were employed, making a scene of busy activity along its course through Medford.
The completed works supplied not only Charlestown, but Somervi