Force suspended on a vertical spring scale experiences the force of gravity acting on the object balanced by a force applied by the "spring reaction force", which equals the object's weight. Using such tools, some quantitative force laws were discovered: that the force of gravity is proportional to volume for objects of constant density (widely exploited for millennia to define standard weights); Archimedes' principle for buoyancy; Archimedes' analysis of the lever; Boyle's law for gas pressure; and Hooke's law for springs. These were all formulated and experimentally verified before Isaac Newton expounded his Three Laws of Motion. Dynamic equilibrium was first
Elements of the Philosophy of Newton mutual Action of Bodies upon Light. Of the Resemblance between the seven Primitive Colours and the seven Notes in Musick. Introductory Ideas concerning Gravity and the Laws of Attraction: That the Opinion of a subtil Matter, Vortices, and a Plenitude, ought to be rejected (But not that subtile Aether which Sir Isaac makes the Cause of Attraction, Refraction, Animal Motion, &c. which pervades the Universe). That the Vortices and Plenitude of Descartes are impossible, and consequently that there is some other Cause of Gravity. What is meant by Vacuity and Space, without which there could be neither Gravity nor Motion.