I think I have seen enough vintage chronographs with and without the 3 min indicators at the 30-45-60 min recording subdials. I knew - due to my limited knowledge that these 3min markings are for international calls length monitoring. The legend was saying that, when international calls became available to public in post offices they were priced with 3 min always; say you talk 2 min , you pay 3 min price. Or you talk 3,5 minutes you pay 6 min.... ( correct me pls if I am wrong )
But, after seeing some other archive debates about the sense and use of this 3 min marks I became confused because there was no certain info and source. Some were holding stand for naval and air military use like navigation legs, some phone calls thing,and some even have seen 4 min markers in intervals ( which I personally never saw ). Some even have markers which looks like added later ( like the Angelus pic, thats actually the one which I dont see often until 12 min, so tailor made due to needs? )
After seeing also many stopwatches which have 3 min marks in minutes recorders, I thought the phone call story can not be true, nobody would I guess go to post office with a stopwatch. The pictures I saw in bay Gallet, Elgin and Meylan Stopwatches with each 3 min marks in their sub minute recorder dials.
So , what is the reason and use of the 3 min markers in the wrist chronographs? Any certain information revealed since last discussions?
Some more PW with related indicators from Gallet, Elgin and various other producers: Vintage Ten stopwatch's gallet Elgin Meylan | eBay