" I am seeking information about a Wheatstone Bridge set that belonged to my father-in-law’s father who was an electrical engineer for the LNER in the early 1900’s and worked in Hartlepool. He used for his work and it must be around 90 years old I would have thought. I see that is made by Siemens Brothers and believe that they were based/had factories in Greenwich and Hartlepool'.
and he attached some pictures - which are shown below.
So - we got in touch with the experts - with the Siemens Brothers Engineering Society - and here is their reply: