Hellige Comparators for Analysis of Water, Sewage, and Industrial Wastes, ca. 1920s
"Hellige Comparators for Analysis of Water, Sewage, and Industrial Wastes. Now change to permanent standards and see the difference."
Cover of an advertising leaflet for Hellige Comparators, instruments that were formerly manufactured by the F. Hellige Co. of Freiburg, Germany, and used for the colorimetric chemical analysis of water and other liquids in medical and industrial settings.
Hellige Comparators for Analysis of Water, Sewage, and Industrial Wastes, ca. 1920s
"Hellige Comparators for Analysis of Water, Sewage, and Industrial Wastes. Now change to permanent standards and see the difference."
Cover of an advertising leaflet for Hellige Comparators, instruments that were formerly manufactured by the F. Hellige Co. of Freiburg, Germany, and used for the colorimetric chemical analysis of water and other liquids in medical and industrial settings.