Examining this chronograph, one is forced to admire the skills and resourcefulness of Breguet. The solution to the activation problem is ingenious.Inking chronographs generally function in the following manner: when the pushbutton in the pendant is depressed, a small drop of ink is deposited on the dial by the chronograph hand. Then, a portion of the chronograph hand is lifted in turn by a further depression of the pushbutton, Although this takes place very rapidly, in precise time measurement even a split second is significant.In this chronograph Breguet has minimized the time interval by an ingenious use of the mainspring barrel's strength. A device similar to an escapement, upon depressing the pushbutton, releases the mainspring barrel which takes over and almost instantaneously lifts a portion of the chronograph hand, causing the ink deposit.This solution is far from intuitively obvious and would never occur to most watchmakers, who would be very reluctant to release the click from the barrel to let it loose. This is how pinions and wheels are broken!However Breguet used this force, via an escapement-like device, to let the barrel down in a controlled manner, allowing secure and, at the time, superior control which then served to measure very small time intervals.In addition, Breguet employed a Garde Temps type movement with a very high quality escapement to ensure that it would be able to measure longer intervals. This is the only watch known to us with this mechanism.The inking chronograph was invented by Rieussec in 1821 and perfected by Fatton two years later. It was further improved by Breguet.Dominique Jean François Arago (1786 - 1853)French astronomer, physicist and statesman, he was educated first in Perpignan, then at the Ecole Polytechnique in Paris. He and Jean-Baptiste Biot traveled to Spain to measure an arc of the terrestrial meridian, which would lead to the determination of the length of the meter. In 1809, at the age of 23, he became the youngest member of the Académie des Sciences. Made professor of analytical geometry at the Ecole Polytechnique, Arago was to become Director of Observations at the Paris Observatorin 1834 and Assistant Director of the Bureau des Longitudes in 1843. Named President of the Académie des Sciences in 1824, he became the "secretaire perpetuel" of that institution in 1830. In addition to his many important scientific activities, Arago was a fervent Republican who participated fully in the social and political events of his time.Elected deputy of the Pyrénées-Orientales in 1830, he remained a member of Parliament until the advent of Napoleon III in 1852. A member of the Conseil Général de la Seine, of which he was twice President, from 1830 to 1849, he was an ardent activist for the Republican cause. After having played a role in the 1848 Revolution - at which time he was a moderate - he was named Minister of War and the Marine in the provisional government which was put into place after the 1848 Revolution. While a memer of that government, Arago introduced many reforms, among other things promulgating the decree abolishing slavery in the French colonies. As President of the Executive Committee in power from May 9 1848 until its dissolution on June 24, he was the de facto President of the Republic for 46 days,Arago's scientific contributions were of capital importance. His early investigations concerned the polarization of light, and he confirmed Fresnel's light wave theory. He also did important work in electro-magnetism, finding that an electric current produces temporary magnetisation in an iron coil. As an astronomer, Arago is known for his discovery and study of the solar chromosphere, the atmosphere immediately surrounding the sun.Despite his status among the elite of the scientific community, Arago remained ever true to his Republican values. He introduced public sessions of the Académie and initiated "comptes rendus" informing the public of its debates. He was a champion of inventors' rights, defending, for example, the photographic work of Daguerre and Niepce. While a Deputy for the Pyrénées Orientales and Municipal Councillor of Paris, Arago constantly fought for the cause of science as a factor of social progress. Hewas in favor of the adoption of the electric telegraph, of steam engines, and of the development of the railroads. Pursuing his ideal of making scientific knowledge available to the public, for 25 years Arago gave lectures on "Popular Astronomy" at the Observatory. These immensely popular lectures were among the earliest efforts aimed at making science popular among the masses.Arago was a colleague of Abraham-Louis Breguet at the Bureau des Longitudes and became a close family friend of the horologist. Besides the present watch, Breguet made a "compteur astronomique à oculaire" for Arago, and when a "double astronomic clock" (horloge astronomique double) and a "double watch" ("montre double"), both built by the Maison Breguet "along the principles of astronomic marine watches" ("établies sur les principes des horloges astronomiques marines") which were tested at the Breau des Longitudes, it was Arago, along with Biot and Bouvard, who was called upon to verify their working. After the death of Abraham-Louis, Arago remained close to the family, and in particular to Breguet's grandson Louis-Clément. The latter continued in his father's footsteps, furnishing instruments used in the physicist's experiments. In the 1850s, Louis-Clément constructed a mechanical apparatus with a rotating mirror for Arago's studies on the nature and speed of light, and he also collabrated with the physicist on work related to the telegraph.