Notice: a German reader suggested a better pamphlet date may be around 1958. I'm currently researching the matter.
Here are six scans of a pamphlet I bought on Ebay. As best I can tell, they were made sometime after 1938 (there is a reference dated 1938) and before 1946. That last date I figured because most post 1946 German materials read along these lines: Printed in either Occupied Germany or West Germany. The pictured pair of pliers are interesting. I think I once saw a similar pair imported from Poland by Epic Refractometers in NYC. If anyone has used a pair, I'd appreciate a report.
Click each scan to enlarge it for reading.
The 2nd page is particularly interesting because it indicates that the Zeiss people were well aware of the value of brix readings much sooner. First there is reference to using refraction itself as a quality measure "decades" earlier. Then, they mention that they developed the hand refractometer "two decades" earlier. Until told differently, I am going to think of the hand refractometer as a Zeiss development of circa 1919-1926. As some of you may know, table refractometers date back to the 1600s.
PS: if any German readers have access to, or have read, the papers referenced on page 5, I would appreciate a synopsis.
BRIX Q & A