Discover the fascinating story of penicillin, an antibiotic that revolutionized the medical world. From its humble beginnings ...

Obverse Image: Dot in the center, surrounded by four Chinese characters in a circle; Chinese text above denoing the date and below denoting mint; small rosaces to the right and left.

To count revolutions of the shafts that ran machinery, engineers used counters like this one. The manufacturer, L. S. Starrett Company of Athol , Mass., called the device a speed indicator, although ...