Antique Bausch & Lomb Co Colorimeter No 7039 ptd

Description

Antique Bausch & Lomb Optical Co
Rochester NY US No 7039
Colorimeter
This has brass on top portion, it has glass rods and not sure how it was used. This looks like a microscope but is actually a colorimeter. It is a dipping visual colorimeter. To use it you convert a solution of something you wish to measure to a coloured compound, unless it is coloured already. Do the same with a known concentration of the substance (a standard). The colorieter has two test tubes with a glass rod dipping in each. Light from the mirror passes up through the tubes and then through the rods. A prism in the head brings the two beams of light into the eyepiece where you see them side by side. Pour the standard in one tub, the unknown in the other. Looking in the eyepiece you turn the knob to alter the light path through the one tube until the light patches match. The ratio of light paths read off the scale gives the ratio of concentration of the unknown to the standard.
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This a unique piece of history. Has calibration numbers on side screw and a slanted mirror.
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