Nivarox An alloy composed of iron and nickel with additions of chromium, titanium, and beryllium. It is very suitable for the manufacture of hairsprings, or balance springs, due to its antimagnetic and temperature-compensating properties. The addition of beryllium dates back to a patent awarded to Richard Lange. This chemical element enhances the hardness and elasticity of the alloy.

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).

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.

Outsize date display Depending on the size of the watch, this useful function makes it possible to display the date up to five times larger than in a conventional watch of similar dimensions. It is based on the patented two-disc mechanism.

Screw balance A balance wheel that has adjustable screws and tiny washers along its rim.

German silver Special alloy composed of copper and zinc, with a nickel concentration of about 10%. German silver is stronger than brass and has been traditionally used by Lange for the manufacture of plates and bridges. The addition of nickel minimises the oxidation of German silver and thus eliminates the need to electroplate the alloy - it can remain "untreated".

Glashütte ribbing A linear decoration. It is produced by a rotating grinding wheel that is slightly inclined and moved along the surface of the workpiece in parallel lines.

Balance cock Small metal plate screwed to the visible side of the movement. It carries the balance wheel shaft bearing.

Chamfering Also: angling, bevelling. The breaking and polishing of sharp edges on bridges and levers. The inclined surface has the same width along its entire circumference or length.

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.

Whiplash precision index adjuster An adjusting device composed of a steel spring in the shape of a swan's neck, a pointer, and a setscrew. The screw is used to adjust the beat, or the timing, of the watch in very small increments.

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.

Escape wheel Together with the lever, it constitutes the escapement. It is the last wheel in the going train.

Gold chaton The gold setting of a bearing jewel - in Lange watches, chatons are often secured to the three-quarter plate with two or three screws.

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.

Synthetic ruby Friction-reducing, wear-resistant functional jewel for bearings, switching elements, and clicks. Its crystalline structure is more homogeneous than that of natural ruby.

Synthetic ruby Friction-reducing, wear-resistant functional jewel for bearings, switching elements, and clicks. Its crystalline structure is more homogeneous than that of natural ruby.

The accrued know-how and inventiveness of Lange's watchmaking heritage is manifested in the 390 individual parts of the DATOGRAPH movement. With a diameter of 30.6 mm and a height of only 7.5 mm, it is a veritable treasure chest of technical and horological marvels. It does take some familiarity with the art of watchmaking to fully grasp the extraordinary richness of this masterpiece: A glance through the sapphire-crystal caseback reveals the underside of the movement with the levers and springs of the | chronograph, | flyback, and | minute counter mechanisms. A variable-position switching lever allows the precise jumping point of the | minute counter hand to be adjusted without disassembling the movement. Lange received a patent for this invention. Another patent was granted for its twin-disc | outsize date. The heart of the movement, a large, shock-proofed | screw balance with a | Nivarox-1 balance spring and shaped terminal curve, is calibrated to 18,000 vibrations an hour. All parts of the movement are lavishly decorated. The plates and bridges, made of untreated | German silver, are finished with | circular graining and | Glashütte ribbing. All edges are | chamfered and polished. This also applies to the leaf spring of the | whiplash precision index adjuster and the classic | column wheel. The | balance cock is manually engraved with a master's personal free-hand technique, making each DATOGRAPH a one-of-a-kind watch. Additional design features and highlights in the DATOGRAPH movement: - Four | gold chatons secured with screws - 40 synthetic | ruby jewels to minimise mechanical friction - Four-jewel | escape wheel bearing system - Mirror-polished cover plate on the escape wheel bridge - Separate bridges for fourth wheel and escape wheel - Adjustable chronometer coupling lever in the centre of the fourth wheel - Chronograph switching lever with stable shaft in opposed bearings - | Minute counter switching lever with jewel bearings on both sides - Stepped pinion with a synthetic | ruby sliding head for precisely jumping | minute counter - Movement adjusted in five | positions.