Identifying old watch glass/Crystal, some have makers label.

[Graham46]

Hi one and all

I recently joined watchrepair talk and posted for my Introductory new member offering a request for information on how to interpret the information on old watch crystals. Upto now, there has been 67 viewings but no replies. I was gifted about 60...70 assorted crystals, some with labels on bearing makers name, e.g. VOSA, MARQUE DE FABRIQUE with owl motif. The label also has numbers which I presume define physical atributes such as diameter, curvature etc. These numbers, integers plus fractional numbers, I am unable to make out what they stand for, see photos of some examples.

If anyone has information on this subject, I would be so grateful for it to be revealed for general viewing.

[RichardHarris123]

Read this 

https://blog.pocketwatchdatabase.com/2023/07/31/deciphering-watch-crystal-sizes-the-x-16-and-x-8-ligne-systems/#:~:text=In addition to the diameter,8 indicating a shorter one.

[LittleWatchShop]

The decimal number XYZ represents XY.Z mm.  The number XY Z/16 can be found from the attached chart

[RichardHarris123]

The 380 is 38.0 mm

[LittleWatchShop]