Glossary · Regulation
Free-sprung
A balance regulated by adjusting its own weights rather than by a hairspring index.
Explanation
A free-sprung balance has no regulator index; the rate is set by adjusting small screws or weights on the balance rim itself, and the hairspring breathes freely between fixed stud and terminal. This avoids the disturbance regulator pins cause to the spring, and is the arrangement of chronometers and most high-grade modern watches.
In the object catalogue
Catalogued objects whose own source record mentions “Free-sprung”. The quoted line shows where; it is the seller’s or museum’s wording, not independent verification.
Pocket watch
Albert H. Potter & Co., Geneva Gold Hunting Cased Keyless Pocket Chronometer No. 85
“This 18ct gold hunting-cased keyless pocket chronometer by Albert H. Potter & Co., Geneva, dates to circa 1885 and is numbered 85 on the train bridge. According to the auction c…”
Pocket watch
Dent 18K Gold Pocket Chronometer with Original Box
“This mid-nineteenth-century open-face pocket chronometer is signed by Dent, London, and numbered 29216. Housed in a solid 18K gold case bearing London hallmarks for 1863 and the…”
Marine chronometer
A Boxed Two-Day Marine Chronometer with Auxiliary Compensation, John Poole, No. 2982
“This two-day marine chronometer by John Poole, numbered 2982, is gimbal-mounted in a brass bowl and housed in a brass-bound rosewood deck box. The silvered dial measures 4 inche…”
Pocket watch
Charles Frodsham Gold Openface Six-Minute Tourbillon Pocket Watch
“This openface tourbillon pocket watch was retailed by Charles Frodsham & Co., bearing serial number 09190/12127 and hallmarked circa 1906–1907. Housed in a 60 mm 18-karat gold c…”
Pocket watch
Patek Philippe 18k pink gold pocket chronometer with cylindrical hairspring
“This open-face keyless-winding pocket chronometer in 18k pink gold is signed by Patek Philippe and dates to circa 1880. With a 53 mm diameter case, it features a white enamel di…”
Pocket watch
Gold and enamel half-quarter repeater watch by Brockbanks
“This gold pocket watch with half-quarter repeating was produced by Brockbanks in London and is hallmarked for 1812. The movement is signed 'Brockbanks London No 700' and feature…”