5oi 
1 876.] The Book of the Balance of Wisdom . 
vessel in joy, and returning home naked, cried out with a 
loud voice that he had found that of which he was in search, 
for, he continued exclaiming in Greek, E vpijm (I have found 
it out). 
“ After this he is said to have taken two masses, each of 
a weight equal to that of the crown, one of them of gold and 
the other of silver. Having prepared them he filled a large 
vase with water up to the brim, wherein he placed the mass 
of silver, which caused as much water to run out as was 
equal to the bulk thereof. The mass being then taken out, 
he poured in by measure as much water as was required to 
fill the vase once more to the brim. By these means he 
found what quantity of water was equal to a certain weight 
of silver. He then placed the mass of gold in the vessel, 
and on taking it out, found that the water which ran over 
was lessened, because the magnitude of the gold mass was 
smaller than that containing the same weight of silver. 
“ After again filling the vase by measure, he put the 
crown itself in, and discovered that more water ran over than 
with the mass of gold, that was equal to it in weight ; and 
thus from the superfluous quantity of water carried over the 
brim by the immersion of the crown, more than that dis- 
placed by the mass, he found by calculation, the quantity of 
silver mixed with the gold and made manifest the fraud of 
the manufacturer.” * 
Continuing the sketch of the history of the water-balance 
given by al-Khazini in the fourth section of the introduction, 
we find references to several Arabian philosophers, among 
them the celebrated physician Avicenna (Ibn Sina) who 
“ distinguished [the components of] a compound scientifically 
and exactly,” and Abu-r-Raihan “who took observations on 
the relations of [different] metallic bodies and precious 
stones, one to another, as indicated by this balance.” 
Al-Khazini also states that the instrument in question was 
called “the Physical Balance ” by Mohammed Bin Zakariya 
of Rai, and it was named “ the Balance of Wisdom,” by 
the “ eminent teacher Abu»Hatim al-Muzaffar Bin Ismael of 
Xsfazar.” 
Abu-r-Raihan alluded to above is often quoted by ah 
Khazini and deserves our attention. He was a distinguished 
Arabian astronomer, born about 970, and died 1038 a.d. He 
was a member of the Society of Savans founded in the capital 
of Kharizm, and of which the eminent physician Avicenna 
* The Archite&ure of Marcus Vitruvius Pollio, in ten books* Translated 
from the Latin by Joseph Gwilt, London, 1826, pp. 264, 265. 
