_In reference to the table on the next page_, it may be well to say
that it has two uses; by it when the “_head_” is known the _pressure_
can be ascertained to a fraction, thus, _Ex. 1_, If the head is 140
feet, then the pressure is 60·64 pounds per square inch. Again, _Ex.
2_, If the pressure is 15·16 per square inch, then the head is 35 feet.
[Illustration: INSIDE. (_See Page 115._) OUTSIDE.]