504 The Book of the Balance of Wisdom . [October, 
Al-Khazini’s work is made up of eight lectures, each 
leCture includes several chapters and each chapter has 
several sections ; to give the table of contents entire would 
undesirably -lengthen this article, and we prefer to quote 
Al-Khazini’s own summary of his treatise as contained in 
the sixth section of the introduction. 
“ I have divided the book into three parts: — 1. General 
and fundamental topics, such as heaviness and lightness ; 
centres of gravity ; the proportion of the submergence of 
ships in water ; diversity of the causes of weight ; mechanism 
of the balance and the steelyard ; mode of weighing with it 
in air and in liquids ; the instrument for measuring liquids, 
in order to ascertain which is the lighter and which is the 
heavier of the two, without resort to counterpoises ; know- 
ledge of the relations between different metals and precious 
stones in respeCt to [given] volume ; sayings of ancient and 
modern philosophers with regard to the water balance and 
their intimations on the subject. This part includes four 
lectures of the book in their order. II. Mechanism of the 
balance of wisdom ; trial of it ; fixing upon it of [the points 
indicating] the specific gravities of metals and precious 
stones ; adoption of counterpoises suited to it ; application 
of it to the verification of metals and distinguishing of one 
from another [in a compound] , without melting or refining, 
in a manner applicable to all balances ; recognition of 
precious stones and distinction of the genuine from 
their imitations or similitudes in colour. There are here 
added chapters on exchange and the mint, in connection 
with the mode of proceeding, in general, as to things saleable 
and legal tenders. This part embraces three lectures. III. 
Novelties and elegant contrivances in the way of balances 
such as : the balance for weighing dirhams and dinars 
without resort to counterpoises ; the balance for levelling the 
earth to the plane of the horizon ; the balance known as the 
‘ even balance ’ which weighs from a grain to a thousand 
dirhams or dinars by means of three pomegranate counter- 
poises ; and the hour-balance, which makes known the pass- 
ing hours, whether of the night or of the day, and their 
fractions in minutes and seconds, and the exaCt cor- 
respondence therewith of the ascendant star and fractions of 
a degree. This part is in one leCture.” 
In the seventh chapter, which treats of the “ Mechanism 
of the Instrument for measuring Liquids . . . and Appli- 
cation of it according to the philosopher Pappus the Greek,” 
we find a description of a hydrometer. 
“ The length of this instrument, which is cylindrical in 
