inclined planes. His most demonstrative experiment was a very
simple one, in which a chain of balls of equal weight was hung
from a triangle; the triangle being so constructed as to rest on
a horizontal base, the oblique sides bearing the relation to each
other of two to one. Stevinus found that his chain of balls just
balanced when four balls were on the longer side and two on the
shorter and steeper side. The balancing of force thus brought
about constituted a stable equilibrium, Stevinus being the first
to discriminate between such a condition and the unbalanced
condition called unstable equilibrium. By this simple experiment
was laid the foundation of the science of statics. Stevinus had a
full grasp of the principle which his experiment involved, and he
applied it to the solution of oblique forces in all directions.
Earlier investigations of Stevinus were published in 1608. His
collected works were published at Leyden in 1634.

This study of the equilibrium of pressure of bodies at rest led
Stevinus, not unnaturally, to consider the allied subject of the
pressure of liquids. He is to be credited with the explanation of
the so-called hydrostatic paradox. The familiar modern experiment
which illustrates this paradox is made by inserting a long
perpendicular tube of small caliber into the top of a tight
barrel. On filling the barrel and tube with water, it is possible
to produce a pressure which will burst the barrel, though it be a
strong one, and though the actual weight of water in the tube is
comparatively insignificant. This illustrates the fact that the
pressure at the bottom of a column of liquid is proportionate to
the height of the column, and not to its bulk, this being the
hydrostatic paradox in question. The explanation is that an
enclosed fluid under pressure exerts an equal force upon all