Look along the shelves holding your laboratory apparatus and into the demo-prep room, and you will find apparatus by “Cenco” and “The Central Scientific Company” sharing space with your new PASCO equipment. At the 1989 AAPT meeting in San Luis Obispo I was asked to talk about Cenco in honor of one of its long-term employers and innovators, Paul E. Klopsteg, and I was hard put to limit my talk to the allotted 55 minutes. (It was one of our best meetings ever, and many wished that there were openings for us at the California Polytechnic State University!) In this article I want to remember the company and the apparatus that it made and sold.

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The Ritchie Company is still in existence in Pembroke, MA, and makes a wide range of high-quality nautical compasses.
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Readers can view the supplemental material at TPT Online, http://dx.doi.org/10.1119/10.0003459, under the Supplemental tab.
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Supplementary Material

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