Hello admin,
thank you for that note, I had some Emailtraffic with "Wilkens und Soehne", they will look into their old books.
And here another picture of the bottle cooler:
If wanted and permitted I will tell you their achievement.
The five digit number, they told me, is a serial number.
The name, they believe, is the name of C. E. Keyser in Leipzig, a former jeweller, founded in 1822, but still out of business. He once was one of their distributors.
Is it permitted to set up a link to Wilkens?
Best regards Ralf