Real Mystery Device

Not sure what it is but quite interesting. It is a box made of Mahogony I believe. On one side is frosted glass . There is a knob attached inside to a rail that lifts the items in the interior out of the box. on the back is a viewing portal. On the top is a hinged lid. Inside is a Triangular test tube it is marked E Leitz incorportated New York Germany. The side with the frosted glass can be raised by the knob. on the interior is a scale marked in tenths from 1 - 100. The triangular test tube sets in a brass frame. There is a frame that looks like it would hold a small square test tube about 1 inch tall and 3/4 inch wide and 1/2 inch deep. The viewing portal on the back of the box looks into a V shaped prism that I believe splits the view so you can see the scale and the two test tubes (the triangular one and the rectangular one. Someone suggested it might measure water turbidity with the test sample in the triangular tube and a standard in the rectangular tube. The purpose of moving it up and down would let you get the visibility thru the sample and standard the same and then see the measurement. I think it is close but not quite correct. The back is stamped cannot be sure but I think it reads C Hellige and company Freiburg Germany. there is also the number 1599. I thought it might be something used to measure color in beer.