SIGNED PATEK PHILIPPE & CIE, GENEVE, SWITZERLAND, RETAILED BY THE FORD COMPANY, NEW HAVEN, CONN., MOVEMENT NO. 162'749, CASE NO. 500'693, MANUFACTURED IN 1911

With Patek Philippe Extract from the Archives confirming production of the present watch in 1911 and its subsequent sale on December 7th, 1916. The extract further confirms the present watch received a Geneva Observatory rating on January 16th, 1914.

Through a series of experiments Charles-Edouard Guillaume discovered invar, an alloy comprised of 36 nickel and 64 iron that didn't change in size when the temperature fluctuated. Further investigation led to the alloy elinvar, which has a negative quadratic coefficient of expansion. Horology realized the benefits of this alloy and incorporated it into a "Guillaume" balance wheel to increase precision.