500 The Book of the Balance of Wisdom . [October^ 
story, familiar as it is, is not unfrequently erroneously related, 
even as al-Khazini himself has done, and compilers of text- 
books of natural philosophy, content to copy from each other 
instead of seeking the original sources, transmit the errors 
of detail. 
These reflections are in part suggested by a singular con- 
struction given to the narrative in a recent and really excel- 
lent text-book on the “ History of Natural Science,” in which 
the authoress commits the remarkable anachronism of 
representing (in a woodcut) the crown and the metallic 
masses suspended in water from spring-balances of modern 
appearance and construction. 
To dispel any lingering ideas of this character we here 
revive the passage in Vitruvius,* “ De Architectural the 
original source of the narrative, and in which it appears that 
the “ greatest geometer of antiquity” arrived at his results 
by a comparison of unequal volumes of water obtained by 
displacement, and not by direCt weighings in that liquid. 
“ Book IX. Chapter 3. Of the method of detecting silver 
when mixed with gold .” 
“ Though Archimedes discovered many curious matters 
which evince great intelligence, that which I am about to 
mention is the most extraordinary. . Hiero, when he obtained 
the royal power in Syracuse, having, on the fortunate turn 
of his affairs, decreed a votive crown of gold to be placed in 
a certain temple to the immortal gods, commanded it to be 
made of great value, and assigned an appropriate weight of 
gold to the manufacturer. He, in due time, presented the 
work to the King, beautifully wrought, and the weight 
appeared to correspond with that of the gold which had been 
assigned for it. But a report having been circulated that 
some of the gold had been abstracted, and that the deficiency 
thus caused had been supplied with silver, Hiero was indig- 
nant at the fraud, and unacquainted with the method by 
which the theft might be detected, requested Archimedes 
would undertake to give it his attention. 
“ Charged with this commission, he, by chance, went to 
a bath, and being in the vessel, perceived that as his body 
became immersed, the water ran out of the vessel. Whence, 
catching at the method to be adopted for the solution of the 
proposition, he immediately followed it up, leaped out of the 
* Marcus Vitruvius Pollio, a distinguished Roman archite< 5 l and author, 
served as military engineer under Julius Caesar in Africa, b.c. 46. His work, 
“ De Architedtura ” (written in his old age), comprising ten books, is the only 
ancient treatise on the subjedt extant. Of Vitruvius’s biography very little is 
known. 
