In case people are not aware, Beckman had invented the pH meter a few years before Hewlett & Packard came up with their audio test equipment. https://americanh

In case people are not aware, Beckman had invented the pH meter a few years before Hewlett & Packard came up with their audio test equipment. https://americanhistory.si.edu/collections/object/nmah_1503 https://americanhistory.si.edu/collections/object/nmah_1503 Just like the one jn my collection :)