The Jet from a Draining Barrel
Does a spout's throw and flow diminish in equal proportion as the level falls?
This page poses an experiment on efflux from an orifice, framed with a wine barrel. With wine 4 braccia high the spout throws it 4 braccia; Leonardo asks whether, once the level has dropped to 2 braccia, the same spout still throws to 2 braccia, i.e. whether fall and throwing-force diminish in equal proportion. He adds that a barrel filling at 2 boccali an hour when full ought, by this reasoning, to fill only 1 boccale an hour when half empty. He urges that this rule and others like it for water pouring through a conduit be set at the front of the instruments so that trials may proceed by rule.
On this page
Throw of the jet as the level falls
If a barrel holds wine 4 braccia high and throws it 4 braccia from itself, will the same spout, once the wine has fallen to a height of 2 braccia, still throw it to 2 braccia? The question is whether the fall of the level and the force of the jet diminish together in equal proportion.
Flow rate falling with the level
When the barrel is full it fills 2 boccali an hour through its spout; by this reasoning, when the barrel is half empty it should fill only a single boccale an hour through the same spout. The discharge is treated as proportional to the head of liquid above the outlet.
A rule to open the study of instruments
This rule, with all the others like it concerning waters that pour through a conduit, ought to be placed at the beginning of the instruments, so that with more rules one may proceed better in the trials of such devices.