If you asked Canadian petroleum chemist J.S. Charlesworth in 1947 what the most important characteristic of lubricating oil was, he would have said, Viscosity1. After all, he said, “it’s a measure of the oil’s resistance to flow, or of its internal friction…[i]t indicates…the ability of an oil to support loads.” At just about the mid-20th century, the American Society of Testing and Materials (ASTM) published a set of standards for the measurement of viscosity of petroleum products2. Of course, the importance of viscosity is well known today, and there are standard methods worldwide to ensure uniformity of testing.