128
Francini’s Machine.
[Book I.
He erected a chain of pots, E, B, No. 56, which reached from the bot-tora of the well to such a height above its mouth as the water to formthe jet was required to be raised. From the upper wheel or drum, anotfier
chain of pots, D, C, was suspendedand carried round by it, the lower enddipping into the water to be raisedfrom the spring A. By this arrange-ment the weight of the water in de-scending the well in the buckets ofthe first chain, raised a smaller portion(allowing for friction) through thesame space by the second one—and aproportionable quantity still higher.A spout conveyed the water into thebuckets of the driving or motive chainas shown at B. These buckets weremade of brass, and wide at the top,the better to receive water from thespring ; and also that when one wasfilled, the surplus might fall down itssides into the next one below, andfrom that to the third one, and so ob,that none might be lost by Spillingover. The buckets of the other chainwere of the same form and material,hut instead of being open like the for-met, they were closed on all sides,the water being received into them atA, and discharged from them at m,through short necks or tubes, e, s,
_ which are upwards when the buckets
i\o. 56. Francini’s Machine. ascend, being connected to the smaller
part of the latter. A pipe from theupper cistern m, conveyed the water to form the jet. The arrow indi-cates the direction in which both chains move. The vessels on the chainE, B, below B, descending into the well, (the bottom of which is not shown,)full—while those shown at D, C, are empty.
The chain of Pots has been employed to work pumps in mines, to pro-pel thrashing machines, &e. &c. a
There is much confusion in the notices of the chain of pots by ancientauthors, from their referring to it without discrimination as a ‘ wheel,’ andthus confoanding it with the tympanum and noria, and that modificationof the latter, known as the Persian wheel. From the circumstance ofits having been propelled in the same manner as these, viz : by oxen mthe usual way, (through the medium of cog wheels,) or by men walkingupon or within a wheel, &c. it has from custom, madvertence, or frotii asuperficial knowledge of its distinctive features, been classed with them.It was of it that Strabo spoke, “ which by wheels and pulleys raised thewater of the Nile to the top of a very high hill; and which, instead ofbeing moved by oxen, was propelled by one hundred and fifty slaves.And when Julius Ctesar was beseiged in Alexandria by the Egyptians,
E D