It is only the tap you turn to let Thirlmere come into your basins.

In the Thirlmere aqueduct the greatest pressure is nearly 180 ℔ on the square inch, the pipes where this occurs being 40 in.

In the Thirlmere tunnels, driven through very hard Lower Silurian strata, the progress was about 13 yds.

Beyond those pastures stretched the dark waters of Thirlmere, looking like a broad river.