Restorative Power,

original: Potentia Restitutiva

OR

S P R I N G.

The Theory of Springs, though attempted by various eminent mathematicians of this age, has not been published by anyone until now. It is now about eighteen years since I first discovered it, but because I intended to apply it to a specific use, I neglected to publish it.

About three years ago, His Majesty King Charles II was pleased to see the experiment that proved this theory tried at Whitehall, as well as my spring-driven watch.

About two years ago, I printed this theory as an anagram at the end of my book, Descriptions of Helioscopes, namely: ceiiinosssttuu, which stands for Ut tensio sic vis Latin: "As the extension, so the force". That is, the power of any spring is in the same proportion as its tension meaning its extension or stretching. For example, if one unit of power stretches or bends it one space, two units will bend it two, and three units will bend it three, and so on. Now, just as the theory is very short, the method of testing it is very easy.

Take a length of evenly-drawn wire—either steel, iron, or brass—and coil it around a smooth cylinder into a helix a spiral shape of whatever length or number of turns you like. Then, turn the ends of the wire into loops. Use one loop to hang this coil from a nail, and use the other to support the weight you wish to use to extend it. By hanging various weights, observe exactly how far each weight extends the coil beyond the length that its own weight stretches it. You shall find that if—