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SUppose some Cylindri∣cal or other parallell'd sided Vessel, fill'd with Wool, or Down, or Fea∣thers, or other Elastic Ma∣terials; let the same be covered with a moveable Head (such as in pressing of Pilchards they call a
Buckler;) then first ob∣serve, how low the Buck∣ler descendeth by its own weight; and then upon this Head or Buckler lay a triple weight, to make the whole quadruple, and it will appear, that the Buckler will sink but just as much lower; and being Noncuple, another like Space lower: So as the se∣veral Spaces of Depressi∣ons are the Roots of the depressing Powers. From hence may be seen, how
the Force must be increas∣ed at every Turn or Thred of a Screw-Press; which being done according to the proportions here un∣derstood, I doubt not, but a Light Substance with a convenient Apparatus, might be compressed unto the Density and Weight e∣ven of Gold. But, that Sil∣ver might be so condens'd, I made no question, till I heard of some Anomaly in the practice, which I must better consider of. The
further Truth whereof doth appear in the Vnder-water∣Air within the Vessels of Water-Divers, who the low∣er they go, do find their stock of Air more and more to shrink; and that according to the Roots of the Quantities of the super-incumbent Water or Weight. In like manner take a Bow, and hang any weight to the middle of its string, and observe how low it draweth the said string. Now, if you shall
quadruple the same weight, it will draw down double the first distance, and non∣cuple will draw it down treble, &c. So as in a drawn Bow, let the Arrow be divided into quotcunque partes, each equal part of the Tension carrieth the Arrow to an Equal Di∣stance, notwithstanding each equal part of the Ten∣sion was made by Unequal power, and that each equal Space or Part also of the Arrows first flight requires
Unequal Force, viz. least strength at first, and most at last; and that, in the proportion first mention∣ed. So in the Fuze of a Watch, the greatest strength of the Spring is made to work upon the shortest Ve∣ctis; and the least upon the longest, so as to equalize the whole. The like also happens in the Traction of Muscles upon two Bones with a turning Joynt be∣tween them; which Bones and Muscles make a Tri∣angle,
whereof the Muscle is the Base, subtending the Angle-Joynt. Now in the working, the Muscle is strongest, when the Vectis is smallest, as lying most obliquely; and vice versâ, when the Muscle and mo∣ving Bone come to make a right Angle.