Descartes, Rene Mechanics 1665, tr. Thomas Salusbury  

DISCOURSES
OF THE
MECHANICKS:
A MANVSCRIPT of
Monsieur DesCartes.
The Explication.
Of Engines, by help of which we may raise a very great
weight with small strength.
The Invention of all these Engines de
pends upon one sole Principle, which is,
That the same Force that can lift up a
Weight, for example, of 100 pounds to
the height of one foot, can life up one of
200 pounds to the height of half a foot,
or one of 400 pounds to the height of a
fourth part of a foot, and so of the rest,
be there never so much applyed to it: and
this Principle cannot be denied if we consider, that the Effect
ought to be proportioned to the Action that is necessary for the
production of it; so that, if it be necessary to employ an Action by
which we may raise a Weight of 100 pounds to the height of two
foot, for to raise one such to the height of one foot only this same
ought to weigh 200 pounds: for its the same thing to raise 100
pounds to the height of one foot, and again yet another 100
pounds to the height of one foot, as to raise one of 200 pounds to
the height of one foot, and the same, also, as to raise 100 pounds
to the height of two feet.
Now, the Engines which serve to make this Application of a
Force which acteth at a great Space upon a Weight which it cau