18k gold Wrist Chronometer no. -
Case: 18k gold (white or yellow gold is unknown)
Dial: jump hour (officially a wandering hour) with minute disk, unsigned.
Movement: in all probability the same caliber as wandering hour wristwatch with movement serial number 5232; oval, nickel, bi-metallic balance with blued steel balance spring with Breguet overcoil with polished steel kidney piece, Eighteen 18 Jewels, All Adj, Niton, Geneve, Swiss", stamped with the Geneva seal. The movement measures 22.75 length x 12.5 width x 3.33 depth. Movement with movement serial number 5232 obtained the Poincon de Geneve quality seals on January 5, 1929 and was part of a batch of 6 (5231-5236). Same date another batch obtained the Poincon de Geneve quality seals (5639-5644). Probably this watch belongs to this last batch.
1929 - Niton, Geneve (in all probability)
1929 - Vacheron Constantin, Geneve
1992 - book "Die Welt von Vacheron Constantin, Geneve" by Carole Lambelet and Lorette Coen
1996 - Book "Armband Uhren, 100 Jahre Entwicklungsgeschichte" (originally 1983)
Source 1; page 386 (Vacheron Constantin's archive book page number 50), inventory pic number 3146 (year 1929), shows this very rare Vacheron Constantin (ladies) wandering hour wristwatch with the same jumping hour display as the jump hour wristwatch which is depicted in the same book at the top of page 377 with inventory pic number 3191 - 257626 (year 1930).
The original title of the book "Die Welt von Vacheron Constantin, Geneve" by Carole Lambelet and Lorette Coen (1992) is "L'Univers de Vacheron Constantin Genève". This book shows pics of watches and calibers from Vacheron Constantin's archive from page 273 till 409.
VC's heritage department/archive do not know which company produced this wandering hour wristwatch. But the picture ref 3146 in the archive is provided with handritten text in pencil; "ne Vach pasetre à nous" this Vacheron not be ours.
Source 2; Book "Armband Uhren, 100 Jahre Entwicklungsgeschichte", by Kahlert, Muhe, Brunner, 1983, page 237, picture reference 498.
The caption accompanies the picture; "Rechteckige Herren-Armbanduhr mit springender Stundenanzeige, vermutlich von C.H. Meylan, Genf, um 1930". In English; "Rectangular men's wristwatch with jumping hour display, probably by C.H. Meylan, Geneva, around 1930". But it is in all probability a wandering hour watch by Niton.