Dr No[Moderator Omega - Wristscan]
37722
Here is what Gisbert Brunner had to say . . .
. . . about the Mido cal 917:
10.5"'
17 jewels
monometallic screw balance
self-compensating hairspring [as indicated in your description!]
automatic winding in one direction of the asymmetrical swinging weight
energy transmission via a ratchet
I'm guessing it resonates at 2.5 Hz by the number of hash marks; also, the crown looks to be original, as compared to the photo of a circa 1950 specimen printed in Kahlert, Mühe, and Brunner's "Wristwatches - History of a Century's Development".
Tonight, dinner will be camarones diavalo at Letty's, if I can get back in time from my weekly 3-ball tournament - thanks for the inspiration, René!
Art