Silver(?) Chinese zodiac ingot

The instructions are correct. When you suspend the item in the water on a piece of string you displace water upward against the atmospheric pressure and so measure the weight of displaced water. As specific gravity is simply a ratio of the object to the same volume of water you simply divide the first number by the second. For precision the purity, temperature of the water and altitude need to be taken into account.
As for conductivity testing, thanks to microprocessors etc it has moved out of the lab and into mainstream in the last few years. All the people I know who have one swear by it as it simplifies finding the fakes although the fakers are learning. A never ending war I think.
Cheers
Stephen

 

Fascinating info,I truly had no idea about any of that until a few days ago . I thought all silver was tested the "OLD" way !