The so-called Marly machine

It was in 1807 that the imperial government opened a competition to receive projects of hydraulic machines to replace the one that in Marly that was used to deliver water to the Palace of Versailles from the Seine river . Built in 1684,the original machine located in Bougival,on the Seine river,was pumping up water on a one kilometer distance and an upslope of 150 meters.
The Niépce brothers imagined a new principle for the machine :
“The theory of this machine ,that we call hydrostatic pump,is based on a simple principle that consists in the equilibrium of two water columns, the heights of which are in opposite ratio to their diameters. One of these column represents power,and the other resistance .To transmit the action of the first one,we do not need to resort to wheels and levers.The power force acts in a direct manner.It is independant of the water motion : the loss of this liquid, is only used to determine the succession of effects.Two pump bodies,two pistons ,three valves,and a ram ; this is all that composes the machine mecanism.{….}.
This machine has only be finished for a few days : it is our intention to present it to the Institute."
from a letter to L.Carnot , December 24th 1807.


"As you use no wheels,no levers,this presents a great advantage,Carnot admits{….} I advise you to realize precise experiments on the produce of this machine before you present it.“
Carnot’s answer, December 31st 1807.