ulley
was known to the old Babylonians, as their sculptures testify. But there
is no reason to doubt the general outlines of the story that Archimedes
astounded King Hiero by proving that, with the aid of multiple pulleys,
the strength of one man could suffice to drag the largest ship from its
moorings.

The property of the lever, from its fundamental principle, was studied
by him, beginning with the self-evident fact that "equal bodies at the
ends of the equal arms of a rod, supported on its middle point, will
balance each other"; or, what amounts to the same thing stated in
another way, a regular cylinder of uniform matter will balance at its
middle point. From this starting-point he elaborated the subject on such
clear and satisfactory principles that they stand to-day practically
unchanged and with few additions. From all his studies and experiments
he finally formulated the principle that "bodies will be in equilibrio
when their distance from the fulcrum or point of support is inversely as
their weight." He is credited with having summed up his estimate of the
capabilities of the lever with the well-known expression, "Give me a
fulcrum on which to rest or a place on which to stand, and I will move
the earth."

But perhaps the feat of all others that most appealed to the imagination
of his contemporaries, and possibly also the one that had the greatest
bearing upon the position of Archimedes as a scientific discoverer,
was the one made familiar through the tale of the crown of Hiero. This
crown, so the story goes, was supposed to be made of solid gold, but
King Hiero for some reason suspected the honesty of the jeweller, and
desired to know if Archimedes could devise a way of testing the question
without injuring the crown. Greek imagination seldom spoiled a story in
the telling, and in this case the tale was allowed to take on the most
picturesque of phases. The philosopher, we are assured, pondered the
problem for a long time without succeeding, but one day as he stepped
into a bath, his attention was attracted by the overflow of water. A
new train of ideas was started in his ever-receptive brain. Wild with
enthusiasm he sprang from the bath, and, forgetting his robe, dashed
along the streets of Syracuse, shouting: "Eureka! Eureka!" (I have found
it!) The thought that had come into his mind was this: That any heavy
substance must have a bulk proportionate to its weight; that gold and
silver differ in weight, bul