SPIRAL SPRING • FREE TRANSLATOR.ORG • Definition of Spiral spring

... measure of the vertical oscillation of the earth, a weight might be attached to a spiral spring, or a pendulum might be sustained in a horizontal position, and a sliding index be moved by either of them, so that the extreme deviations should be indicated by it. This, however, would not give even the comparative measure accurately, because a difference ...

— On the Economy of Machinery and Manufactures • Charles Babbage

... invented about the year 1500, but who was the inventor is disputed. They were, however, of little value as time-keepers, before the application of the spiral spring as a regulator to the balance; the glory of this excellent invention lies between Dr. Hooke and M. Huygens; the English ascribing it to the former, the Dutch, French, &c., to the latter. Some assert that pocket-watches were first made about 1477, at Nuremberg, in Germany. ...

— A Catechism of Familiar Things; Their History, and the Events Which Led to Their Discovery • Benziger Brothers