This is to our knowledge the only triple-complicated Patek Philippe pocket chronometer with Guillaume balance. There are two known Patek Philippe watches with perpetual calendar and Guillaume balance (Nos. 80770 and 174688) but no additional complications.This watch comes from a small series of complicated watches made for Patek Philippe for clients such as James Ward Packard (Nos 174623 and 174749), or Henry Graves, Jr. In the same series are the famous Patek Philippe tourbillon watches with carriages made by James Pellaton. The present watch was especially made for Tiffany & Co., undoubtedly for a very special client.Anibal (acier au nickel pour balanciers), an alloy invented by Dr. Charles Edouard Guillaume, 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 steel-brass bimetallic balance is approximatela 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 brassin 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.