Va multumesc frumos pentru informațiile mai mult decât pretioase. Ia uitați ce mi-a raspuns un domn american pe nawcc.org:
This is an unusual Patek. It was made in 1875 and unlike the majority of Patek Philippe movements at the time, this one was made from scratch in the factory. In other words, the ebauche was made by the company. It is not the first caliber made entirely by Patek Philippe, but one of the earliest. In later years, in the early 1890’s, the ebauche for the caliber was also made by Ambroise Duret, a rare Geneva ebauche maker*, who made at least four more calibers for Patek during 1890-1895. In the early 20th century the ebauche was made also by C.M. Colonnaz, a convenient supplier, having his business in the same building as Patek Philippe. A few Patek Philippes with Colonnaz' 19S took part in the Geneva Observatory Timing Contests.
The majority of those movements are fitted with the 8th Philippe winding/setting system, which is an improvement of his 5th system patented in France in 1860. Its characteristic feature is threaded lower part of the stem.
Patek launched the caliber in the late 1850’s and designated it for their high precision watches including many of the highest precision with spring detent chronometer escapements and free-sprung helical balance springs**.
The movement was designed for a hunting case but they are also found in open face cases, such as an exceptionally rare No. 31,090 with perpetual calendar and equation of time.
The biggest surprise of this watch is the fact that it is one of just a handful of calibers 19S*** with an inexpensive 10-jewel cylinder movement.
The case is similarly unusual. I know of only two other similar Patek Philippe cases (housing this caliber) of which one is in the Patek Philippe Museum (with a lever escapement)(first 3 pictures). The Museum (then just a Private Collection) purchased it very early in their patrimony quest (Inv. P-51).
The blackened case with a black dial suggest that the watch was ordered by someone in mourning
* Geneva watchmakers, although having had a few ebauche makers, specialized in finishing movements – making them accurate and aesthetically pleasing. The movement architecture was developed in Geneva to the highest degree.
** For instance, Nos 47371, 47372, 47372, 47373 47681, 47682, 47683, 66326, 90533, 90534, 90538 and many more.
*** The figure comes from a drawing of the caliber I found in the 1970’s when Mr. Henry Stern let me look through (and copy) some of Patek Philippe archives.
Iar acesta este ceasul despre care vorbea dumnealui aflat la muzeul Patek
https://postimg.cc/5XWjfWxC