or rather Heureka (I have found it out). The exclamation of Archimedes, the Syracusan philosopher, when he discovered how to test the purity of Hiero's crown. The tale is, that Hiero delivered a certain weight of gold to a workman, to be made into a votive crown, but suspecting that the workman had alloyed the gold with an inferior metal, asked Archimedes to test the crown. The philosopher went to bathe, and, in stepping into the bath, which was quite full, observed that some of the water ran over. It immediately struck him that a body must remove its own bulk of water when it is immersed, and putting his idea to the test, found his surmise to be correct. Now then, for the crown. Silver is lighter than gold, therefore a pound-weight of silver will be more bulky than a pound-weight of gold, and being of greater bulk will remove more water. Vitruvius says “When the idea flashed across his mind, the philosopher jumped out of the bath exclaiming, `Heureka! heureka!' and, without waiting to dress himself, ran home to try the experiment.” Dryden has mistaken the quantity in the lines -
The deist thinks he stands on firmer ground, Cries `Eureka!' the mighty secret's found.
Religio Laici, 42. 43
But Byron has preserved the right quantity -
Now we clap Our hands and cry `Eureka!'
Childe Harold, iv. st. 81
The omission of the initial H finds a parallel in our word udometer for “hudometer,” emerods for “hemorrhoids,” erpetology for “herpetology”; on the other hand, we write humble-pie for “umble-pie.”
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894