F. Hellige&Co

A complete set for an antique visual colorimeter (or liquid colorimeter) from the well-known German manufacturer F. Hellige & Co. from Freiburg im Breisgau. This specific type was used in the first half of the 20th century, around 1910–1940, for laboratory research, including determining the pH value of liquids or soil by color comparison. What do the numbers mean: - 2008 on the acrylic/plexiglass cup in the meter is the part or model number of the cuvette (the liquid cup). - 13086 (impressed on the underside) is the part number of the cast back plate or housing of the instrument. With this kind of mechanical laboratory instrument from the early 20th century, a unique serial number was often not applied to the housing itself. -The cuvettes: These held the liquid mixed with an indicator liquid that changes color based on the pH value. -The ruler/scale: The white strip with the scale (0 to 11) indicates the "wirkliche Schichttiefe" in mm (the actual liquid depth). - The eyepiece (the measuring head when you look through the viewing hole): you see a divided plane. On one side you see the color of your test liquid and on the other side an integrated color standard (often a glass color mirror). By turning the side, you change the depth of the liquid until the colors on the left and right in the viewing hole exactly match each other. At that point you read the value on the measuring scale. A particularly historic object. The height is measured by the ruler/tape measure when in its highest position. When rotated, the colorimeter is 20 centimeters tall.

Stima:€110

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