Swiss gold watch with split seconds chronograph Circa 1878

Extremely rare open faced pocket watch
–
A gentleman’s very fine, extremely rare Swiss pocket watch with regulator dial and split seconds chronograph, circa 1878.
A gold 18 carat case, enamel dial, 2/3 plate movement, gold screw compensation balance.

The watch was Delivered to Tiffany & Co. in New York in1878.  According to the current state of knowledge only five other watches are known to exist.
With Patek Philippe extract from the archives.
–
Diameter: 48 mm
–
Weight: 119 g
– 
Signed: Patek Philippe & Co. / Tiffany & Co.  Geneva