(1*) This description of the hydraulic organs has been 
thought to be unintelligible: some of the translators have 
shewn their ideas of their construction; but they are very 
far from being just, as will appear by comparing the 
figure given by Barbaro and Perrault with the sketch 
here represented. I have obtained some elucidation of 
the subject from the works of sundry antient authors; 
particularly from Heron's Treatise of Pneumatics, which 
has enabled me to understand Vitruvius so far as to give 
a flight representation of the general construction of thele 
B 0 0 
K X. 
seeing and hearing. From among these, those that I have judged most useful and convenient 
I have selected and treated of in the foregoing book of dialling, and in this of the raising of 
water. The others, which are not for utility but for pleasure, those who are desirous of 
knowing, may find in the Commentaries of Ctesibius. 
C HAPTER XIII. 
Of the Hydraulic Organs. 
Fig. LXXXVIII. MUST not omit to discourse briefly, and as explicitly as I am able, on thè 
construction of the hydraulic organs. Upon a compact base (A) of timber an arca (cistern) (B), 
made of brass, is disposed; and to the right and left, upon the base, timbers (C) united in the 
manner of ladders are erected; between these are included brass buckets (D), with move- 
able pistons (E), very exactly turned, and having bent and jointed irons (F) fixed to their 
middle, with levers (G) adjoined, and being covered with unshorn sheep skins: in the upper 
surface (of the buckets) are holes (P) of about three digits; near to which holes are brass 
dolphins (H) fixed on turning joints, and having cymbals (I) hanging by chains from their 
mouths below the holes of the buckets. 
Within the arca which contains the water is a kind of inverted funnel (K), under which 
wedges (L), of about three digits high, are laid, to level the space between the under lip of 
the pnigeus (K) and the bottom of the arca. Upon the neck of this (pnigeus) is fixed the 
little cistern (M) which supports the head of the machine, called by the Greeks canon musicos. 
antient musical machines. I have been obliged in many 
cases to retain the original names of the members, there 
being no terms in our language suitable. 
(25) This passage — inest in id genus uti infundibulum 
inversum is corrected by Turnebus to-inest pnigeus uti 
infundibulum inversam; and also pbigens, a little below, he 
changes to pnigeos. These corrections appear to be juit; 
for Heron says the inverted funnel, or hemisphere (as he 
calls it), was named pnigeos.