138 Mechanick Powers. Book VII.

from the Veſſel L into the lower Veſſel N, and from N intoanother, and ſo ſucceſſively all the Veſſels of one ſide are fill'd;for then the weight of them and the water turn about the Tym-pane, together with the Wheel G of the lower Axis, whichwheel running into the other, moves the upper wheel andturns it about with the Tympane of the Axis D E, that the lit-tle Veſſels draw the water from the Fountain, and raiſe it in-to the Veſſcl B; but becauſe the Hater ought to be raiſed dou-ble che height in B, that it deſcends in C, therefore the uppercrown, or ring of little Veſſels, ought in like manner to be aslong again(or doubly longer) and therefore that it may becarried about, and raiſed from che lower crown, or ring, beingbut half ſo big(or doubly leſſer;) thoſe little Veſſels oughtto be leſſer, ſo that they raiſe upward in the ſame manner ſũb-duple, or half the water, yea, father leſs, becauſe of the reſi-ſtance of the Engin, but the lower little Veſſels receive doublethe water, or ſo much as ſuffices to move both the Wheels.

The lower Tympane may conveniently hang over the Well ,or Pit, deſigned for it, within which the Crown or Ring oflittle Veſſels deſcending, when they come to C, the little Veſ-ſels are unloaded ſucceſſively, ſo that one ſide of the Crown isalways full of water, and out-weighs the other ſide, and turnsabout the Axis: That if the upper Veſſel B being filled withWater , which aſcends upwards, it again flows into the lowerVeſſel A, and the lower part of the Engin is ſo accommoda-ted, that the pouring out of the Water appears not by means,Whereof the lower Tympane is moved, and the Spectators.may eaſily be deceived, thinking that Water only to deſcendwhich at once aſcended, that therefore they may think it a.kind of pe ꝓetual motion.

If the weight of the Water of the lower Tympane be dou-bly greater than the weight of Water which aſcends to theupper Tympane, this Water may be raiſed to a double Alti-tude, and therefore a crown of little Veſſels doubly longer muſtbe uſed; and thoſe little Veſlels of the upper Tympane vill heproportionally leſſer in the ſame manner, vix. if the water be0 be raiſed triple or quadruple higher, the little Veſſels of theupper Tympane, or wheel, muſt be triple, or quadruple leſſerthan thoſe of che under or lower Tympane, or wheel, ſo thatthe length of the upper Croun is made amends by the mag-nil ude Of the little Vellels of the lower Crown.

Bur