This is a Heavy Cast Iron metal Plate for Laboratory Chemistry Physics Equipment
from German Equipment Maker Max Kohl, from Chemnitz, Germany
Company founded in 1876.
From Labaratory at ILL  Institute of Technology Physics Department.
Hand painted Lettering, very Antique Look to it.
Has Atomic symbol for Palladium written on the back of it . Is a precious valuable metal.
Size is approximately 4 inch by 3 inch, 1/2 inch thickness.