1851 Great Exhibition: Official Catalogue: Class X.: Frederick William Holl
13. HOLL, FREDERICK RICHARD, 8 Weymouth Terrace, City Road — Inventor and Manufacturer.
Gold index pocket-chronometer, with short angle-locking spring to the escapement, set-hands at the pendant.
Gold centre seconds eight-day pocket chronometer, independent seconds, train, and stop work, with left- sided, short, angle-locking spring to the escapement.
Silver thirty-hour pocket chronometer, with right-sided short angle-locking spring, etc.
Gold compensated duplex index watch, gold dial, set - hands at the pendant.
Gold compensated lever index watch.
Gold lever index watch (lady's), gold dial.
Silver lever index watch, set-hands on the dial, with a key, locking spring.
The object of the short angle-locking spring is to make the angle of the escapement so short that the balance, being more detached, the chronometer cannot stop in the pocket from the balance receiving a motion.
The index watches are a new invention, intended to answer the double purpose of supplying a lever to bend the main-spring, and also to indicate the number of hours the watch will go before the power is exhausted.
Gold centre seconds eight-day pocket chronometer, independent seconds train and stop work.
Silver thirty-hour pocket chronometer.
Gold compensated duplex index watches.
Gold and silver lever index watches.
Index watches, upon a new principle, kept going from day to day by simply pushing the index.