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A descriptive and historical account of hydraulic and other machines for raising water
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Chap. 8.

Water-Clock of CtcsibiusHydraulic Organs.

547

hours the tube would be filled, and the figure near the top of the column.It was then that the siphon came into play. Its short leg, as represented

in the cut, was connected to the lower part -of the tube that contained the float, and itsbend reached as high as the upper end ofthe tube. When the latter therefore wasfull the siphon would be charged, and thecontents of the tube discharged by it intoone of the buckets of the wheel. The figurewith the wand would then descend, havingnothing to support it. The wheel havingsix buckets only, performed a revolution insix days. To its axis was secured a pinion ofsix teeth that worked into a wheel with sixty,and on the shaft of this wheel a pinion often teeth drove a wheel of sixty-one teeth,which last wheel by its axis turned thecolumn round once in 365 days.

As the accuracy of such a clock dependedupon the size of the orifices in the weepingfigure, whence the water escaped, to pre-hj vent their enlargement by the friction of thef liquid, Otesibius bushed them with jeweis.About the year 807, the Caliph Harounsent some valuable presents to Charlemagne ,and among them a water-clock, which Struckthe hours by means of twelve little brassballs falling OK a bell of the same metal.There were also twelve figures of soldiers,which at the end of each hour opened andshut doors according to the number of thehour.(Martigny s Hist. Arabians, iii. 92.)

There is avery simple clepsydrainKirchersMundus Subterraneus, tom. i, 157. M. Amon-tons devised another. Mem. Acad. Science,A.D. 1699, p. 51. See also Phil.Trans, vol. xlv,p. 171, and Fludds Simia. Decaushas givena clepsydra in the fifth plate of his ForcibleMovements. A water pendulum is figuredin Ozanams Recreations, p. 388.

Hour-glasses were formerly placed in coffins and buried with the corpse,probably as Symbols of mortalitythe sands of life having run out. SeeGent. Mag. vol. xvi, 646, and xvii, 264. Lamps found in ancient se-jul-chres were possibly interred with the same viewto indicate the lampof life having become exlinguished.

Garcilasso mentions a dial by which the Peruvians ascertained the timewhen the sun entered the equinox : whether these people or the Mexicanshad water-clocks we have not been able to ascertain.

Hydraulic Organs do not appear to be of so high antiquity as clepsydraa,but their origin is equally uncertain. Perhaps they were derived frommusical water-clocks.

The first organs were probably nothing more than simple combinationsof flutes, pipes, and other primitive wind Instruments. What the cir-cumstances were that led to the idea of uniting a number of these, andsupplying them with wind from bellows instead of the mouth can hardly be

No. 272. Clepsydra by Ctesibius .