Horology 101 - b.p.h. & accuracy

The term 'beats per hour' (bph) refers to the number of times a balance wheel rotates within a 60 minute span. A single-direction rotation is also called a vibration. The first wristwatches in the early 1900's were converted pocket watches, generally made from smaller size movements found in ladies pendant watches which ran at 18,000 bph.1908 Elgin wire-lug conversion:When better lubricants were developed, faster bph rates could be used since friction was reduced. Starting in the late 1940's sev