The Indus Civilization c5.52

c5.52

Where one drain entered another from a higher level, a little brick-lined pit was provided at the point of entry so that the water should not escape into the soil, and where a drain had to turn at an angle it was often slightly curved in order to prevent friction. Wedge-shaped bricks were used to make these curves, and after they were laid in position their inner surfaces were carefully rubbed smooth; indeed, much more care seems to have been taken over the drains than with some of the buildings above ground.