Exquisite anchor chronometer movement of the highest class, completely signed and numbered, double signature Patek Philippe and Bailey Banks & Biddle Co. 114829 double quality designation, both "EXTRA" and "SPECIAL". Straight-line counterpoised and calibrated lever escapement, anibal-brass Guillaume balance with "winged" arms, gold temperature adjustment screws and platinum mean time screws, blued steel Breguet balance spring with inner and outer terminal curves, swan-neck micrometric regulator, wolf teeth winding wheels, Geneva stripes, superior polish of the steel parts & screws, screwed gold charton on the center-wheel, beveled jewel holes.
The movement is beautifully preserved and in good working condition. Very nice enamel dial with radial Arabic numerals with red minute ring and red seconds. Signed, beautiful Louis XV hands made of red gold, excellent condition.
Copies that is labeled with "Extra" and "Special" are very rare. The movement was made in 1900 and tested in 1903 at the Observatory in Geneva. When destined for Observatory Timing Contests, the movements of Patek Philippe watches were double-engraved with serial numbers.
The inscription "Extra" on the bridge of the movement refers to the high finishing of all the parts of the movement. The present watch was timed by J.Golay-Audemars, a legendary master adjuster who won many awards. "Extra" quality watches were made to the highest possible standards and were specially adjusted by such masters as Henri Wehrli, J. Batifolier who were the best paid workers in the watch industry. Watches adjusted by them were several times more expensive than the regular ones. Every detail, such as the specially adjusted Guillaume balance with small "wings" at the arm for poising "in the raw" (before the screws are put in), which assures that temperature compensation adjustment will not affect poising, the superior polish of the steel parts, the beveled olive jewel holes, shows that the watch was a special one. Diameter 49mm, weight 105g, movement 19 lines. Accompanied by the Extract from the Archives and a copy of the Observatory bulletin. Retailed by Bailey, Banks & Biddle Co. Anibal (Acier au NIckel pour BaLanciers) An alloy invented by the Nobel prize winner Dr. Charles Edouard Guillaume, it exhibits unusual properties, both in terms of thermal expansion and in changes in elasticity. These properties are very different from those of two other famous alloys invented by Guillaume, Invar and Elinvar.
Around 1900 Guillaume attempted to eliminate the so-called middle temperature error caused by the fact that the change of rate in a timekeeper with a steelbrass bimetallic balance is approximately a linear function of temperature, while the change of rate caused by change in elasticity of a balance spring is approximately a quadratic function. Thus, it equals zero at only two temperatures, causing secondary error. Countless attempts were made to eliminate middle temperature error, usually by means of auxiliary compensation devices.In 1899, Guillaume noticed that steel with an addition of 44.4% nickel had a negative square coefficient of thermal expansion. This alloy, combined with brass in bimetallic lamina, makes its expansion close to quadratic. Balances with bimetallic rims made of anibal and brass are usually called Guillaume balances, or, as their inventor called them, integral balances.
When combined with special balance springs, they exhibit remarkable temperature stability, on occasion not exceeding 1/50 second per day at 1ºC. The love for old things has kept me working as an antique dealer for over twenty-five years. Originally born in Denmark, I have been living in Berlin for a long time. Always on the search for small and large treasures, the quality and the high craftsmanship of the individual pieces mean a lot to me.A fast, customer-friendly and uncomplicated process is particularly important to me. I wish you a lot of fun while browsing, should you have any questions, do not hesitate to contact me carsten berger. The item "Antique Patek Philippe Observatory Chronometer Quality EXTRA SPECIAL 1900 Rare" is in sale since Saturday, July 7, 2018.
This item is in the category "Jewelry & Watches\Watches, Parts & Accessories\Pocket Watches\Antique".antik" and is located in Potsdam. This item can be shipped worldwide.