Two acquisitions which arrived yesterday
A sister company to Omega, with a common marketing arrangement and later common ownership since the 1920s
1955 Tissot World Timer, cased in 18k yellow
The inner dial rotates on a 24 hour pace and you read the time in the marked cities on the 24 hour applied mixed Arabic and dart indices. The hands move at a 12 hour pace and are read on the bezel.
Just got it yesterday, and it proved difficult to photo. I only had time for relatively quick snaps.
The reference book shows the bezel appearance much better than my photo
You pull the crown to set the time and press the button @ 2 and it disengages the hands and the 24 hour disk, allowing you to set a proper offset between the 24 hour and 12 hour indicators.
Unlike a GMT, you set the "offset" between 12 and 24 hours indications once and just change the hands to local time. The time back home is still easily readable from the inner disk.
Above, the local time is about 9 pm. Since I am on East Coast USA, New York is shown at 21:15 on the real watch dial, reading the inner disk on the 24 hour indices. The UK for instance, is shown by Greenwich at 2:15.
Incidentally, the photo in the book shows the time offset by a half hour, which the watch is capable of doing. Local time is 10:12 and Greenwich time is 2:42. Less so now, but during the 1950s there were a number of time zones which were n + 0:30 from Greenwich time.
The other watch is also interesting, a Dubey and Schaldenbrand Index Mobile Rattrapante from the 1960s, with a pink gold capped case and interesting copper dial
What does "Index Mobile" mean
The split seconds function is activated by pressing the co-axial button in the crown, which stops the second chronograph hand as long as you hold it. This springs causes the hand to "fly back" to the first hand.
Invented in 1948, this was an innovative and inexpensive way to accomplish the very expensive rattrapante function.
