# Eureka and Discovery

#### (a reaction of delight and excitement when someone makes a discovery)

## An Exclamation of Discovery

Eureka! An exclamation of delight at any discovery; is said to have originally been uttered by Archimedes of the Greek city-state of Syracuse in Sicily. As philosopher, mathematician, and mechanical inventor, he figured out how to test the purity of the tyrant King Hiero's "gold" crown.

The Greek mathematician, Archimedes (circa 287-212 B.C.), was commissioned by King Hiero II of Syracuse to find out whether the goldsmith who made a new crown for him had fraudulently mixed some silver in with the gold that the king gave him for construction of the crown.

According to the legend, Archimedes decided to go to the public bath to contemplate the problem. He supposedly got into his bath and observed the water going up as he got into it. He apparently came to the conclusion that a body must remove its own bulk of water when it is immersed and that if silver is less dense than gold, then a given weight of silver would have more bulk than an equal weight of gold and so it would remove more water. Thus it was that Archimedes figured that a pure-gold crown would displace less water if it were immersed than one made from a bulkier alloy or mixture.

To put it another way, he figured that by measuring the water displaced by the crown and then the water displaced by an equal weight of gold, he could tell whether the crown was pure gold or not.

Over joyed by the result of his thought processes, Archimedes is reported to have jumped out of the bath shouting *heureka! heurekai!* "I have found! I have found!" (now translated as, "I have found it! I have found it!") and ran home naked to try out his theories. When he made the test, it proved that the goldsmith did indeed cheat the king.

The above anecdote about the bath can be traced back to the Roman architect and engineer, Vitruvius, who lived two centuries after Archimedes. There is no contemporary source for the legend or folk tale. It is probably true that Archimedes did determine the proportion of gold and silver in a crown for King Hiero by weighing it in water; however, writers continue to embellish the tale with fictitious details.

Did you know that "Eureka" is the state motto of California, which refers to the discovery of gold by the "forty-niners" in 1849? It's written on the state flag. Eureka is also a city in northern California near the remaining redwood-tree forests that have been considerably depleted by various lumber companies; and it is said to be the name of a college in Illinois.

By the way, Archimedes is also given credit for discovering the basic laws of hydrostatics and of levers and pulleys. In addition, he invented the catapult and the Archimedean screw; and his mathematical discoveries included the doctrine of limits.

The "Archimedes' principle" is the explanation by Archimedes of the principle of buoyancy. As stated earlier, he noted that an object placed in water apparently loses an amount of weight equal to the weight of the water displaced by the object; this led to the statement that a body immersed in a fluid is buoyed up by a force equal to the weight of the fluid it disperses.

The **eureka, heuristic** unit of words.