But with a long narrow figure such as an indicator diagram, this ratio is much smaller.
This must, in the indicator diagram for the changes specified, be the area of the cycle or (v2 − v1) ∂p ⁄ ∂T .
The first is known as the maximum theoretical efficiency of a perfect engine (represented by the lines in the indicator diagram).
But if the exhaust valves leak also, one may offset the other, and the indicator diagram would show no leak.
The actual computation of the steam consumption from an indicator diagram is best shown by a practical illustration.
The method of the indicator diagram has since proved of great utility in physics in studying the properties of gases and vapours.
He then described the indicator diagram of the atmospheric gas-engine.