Chronograph A watch equipped with a separate measuring mechanism and a separate seconds hand (chrono hand) that allows the measurement of short time intervals (stopped times).

Column wheel Also: ratchet wheel, sometimes pillar wheel. A steel switching wheel that has upright columns. It controls all important switching operations in a chronograph mechanism.

Flyback This complicated mechanism in the movement of the DATOGRAPH allows the user to instantly set the chronograph seconds hand to zero during an ongoing measurement. When the push-piece is released again, a new measurement starts without delay. This transforms the conventional sequence of "stop", "set to zero", and "start" steps into one single step.

Precisely jumping minute counter This is a function in Lange's chronographs that makes it easy to read stopped times. During a measurement, the minute counter does not advance gradually but instead jumps to the next minute marker when precisely 60 seconds have elapsed.

Blued steel, blued screws Steel parts are slowly and cautiously heated (annealed) to about 300°C. This process coats the metal with an extremely thin, shimmering film of cornflower-blue magnetite (Fe3O4).

Crocodile leather A popular term for alligator skin. Lange uses only crocodile leather from breeding farms that comply with legislation governing species-compatible animal husbandry.

Rhodium This chemical element belongs to the platinum family. Other metals can be electrolytically coated with rhodium. This process gives the coated parts a particularly white metallic sheen.

Sapphire crystal Glass made of artificially produced sapphire. It is very hard (9 on the Mohs scale) and scratch-resistant. It ranks just below the diamond in these two respects.

Tachometer scale Also: tachymetre. Circular scale for speed measurements. If a chronograph is used to measure the time it takes to travel exactly one kilometre, the chrono hand will indicate the average speed on the tachometer scale [km/h].

The DATOGRAPH reflects a totally new approach in the development of | chronographs based on the classic | column-wheel principle; it stands out as a worthy ambassador for the attribute "Made in Germany". With its impressive line-up of complicated mechanisms, it deserves to be called an exceptional phenomenon in the domain of mechanical watchmaking. The DATOGRAPH stops events as long as 30 minutes with an accuracy of one-fifth of a second. Thanks to the precisely jumping | minute counter, the stopped time is very easy to read. The | flyback function allows the chronograph to be instantaneously reset to zero during an ongoing measurement, simply by pressing a push-piece in the case. As soon as it is released, a new timing cycle begins. This eliminates the need to stop a measurement and reset the stop hand before starting a new measurement. The | patented outsize date in the twin gold-framed aperture assures excellent legibility. The luminous hour and minute hands are made of | rhodiumed gold. The hands in the subsidiary dials are crafted from | blued steel. The | tachometer scale along the circumference of the main dial adds a subtly dynamic touch to the personality of this remarkable watch. The DATOGRAPH is available in 18-carat pink gold or platinum. It is worn either on a | crocodile strap or an exquisite precious-metal bracelet. The | sapphire-crystal caseback, secured with six screws, showcases the technical and aesthetic finesse of Lange's L951.1 movement.