Grether, Auguste (1817-1879), Pont-de-Martel, made tourbillon carriages for the best makers of his time, in particular for Girard-Perregaux and Jurgensen. V. Boulet, who made the carriage of the chronometer now offered for sale, was also working in Pont-de- Martel and used to be a collaborator of Auguste Grether. Two pocket chronometers only made by Patek Philippe with a detent escapement and a tourbillon regulator, are known to exist, the other one, completed in 1920, was considered as unique, by the time it was sold by Antiquorum in "The Art of Patek Philippe", on 9 April, 1989, lot 298. According to the family, his watch was presented by Henry Clay Frick to Andrew Peebles, celebrated architect from Pittsburgh in recognition of having completed the Frick Building of Pittsburgh six months before the deadline. It was later given to Lewis T. Brown, Peebles' son-in-law, whose monogram is engraved on the back of the watch. Designed by the distinguished Chicago architect Daniel H. Burnham, The Frick Building at 437 Grant Street, Pittsburgh, was ready for occupancy in 1902. As the prominent Pittsburgh architect of the time, Andrew Peebles was probably chosen by the eminent architect from Chicago, as a local assistant, to control the construction and work progress. Peebles could also have been in charge of interior arrangements as he used to be for Clayton House, the private home of Mr. and Mrs. Henry Clay Frick, in 1882.