which is the Bernoulli equation law of the AQB set. Another form of the Bernoulli law, arising from this equation set, was used by Moncrieff and Green (1972). This can be obtained by writing eq.(43), for a steady streamline, as:
and, if is the height of the streamline some distance upstream, then by the fundamental theorem of integral calculus:
and
where the use of the capital in the increment serves to emphasise that these are changes observed along fluid trajectories.