Gilbert Lewis, seven years Richard’s junior, was also of old Yankee stock and also home-schooled. He graduated from Harvard with a bachelor’s degree in chem- istry in 1895. Lewis had little interest in descriptive chemistry (he received a ‘D’ in advanced organic chemistry in his senior year), but he excelled at mathematics and physics.41 After graduation, he taught for a year at Phillips Andover and then returned to Harvard in 1896 as a Ph.D. candidate under Richards. Richards was not always an easy mentor. He found it dif cult to give his junior collaborators much freedom: “[A]ssistants who are not carefully superintended may be worse than none, for one has to discover in their work not only the laws of nature, but also the assistant’s insidious if well meant mistakes. The less brilliant ones often fail to understand the force of one’s suggestions, and the more brilliant ones often strike out on blind paths of their own if not carefully watched.” 42 Lewis was later known for giving graduate students almost complete freedom in their research during his time at the University of California at Berkeley, perhaps to distance himself from Richards’ methods.