Interesting to see this Longines, with the rotating Minutes bezel (counting up, not down) . . . intended for aviation.

Then, of course, we occasionally see the debate about the longer hash-marks at 3, 6 and 9 . . . some suggest that these longer hash-marks are to time the duration of long-distance calls (which were timed (charged for) in three-minute increments), while I have seen the suggestion that the longer hash-marks at 3, 6 and 9 are for aviation . . . timing turns in a holding pattern, for example.

I am no expert in the history of long distance calling (or aviation), but my guess is that the longer hash-marks are to assist the user reading these first 10 minutes on the minute recorder, perhaps in the context of aviation, and not for the purpose of timing phone calls.

Fun topic!!

It's interesting to see the technical innovations that have been made to support aviation, whether these watches for the early pilots or the technology / engineering that has taken man to the moon. Of course, Heuer was very active in selling stopwatches to aviation supply houses / distributors, before racing / motorsports became the big theme for the Heuer brand.

Jeff

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: This a early second-setting watch used by pilots. These was made by
: Longines, Movado, Omega and others. They are very small by
: todays standard at 29mm. This watch is not waterproof and was
: never intendend for diving.

:
:

: Regards

: Jarl
: www.classicheuers.blogspot.com