Thank you for your inquiry, and please accept my apologies for the delay in responding. I've been quite busy as of late editing Will and Ariel's audio lectures and haven't had the luxury of time to answer all of the e-mail that has come in until now.
I believe the article you were referring to was entitled, "How to Widen Your World " which was published in "The American Magazine, CXI;" March, 1931 edition on pages 42-43 and continued on pages 160-163.
I do not presently have a copy of this article, and welcome anyone who does to please send it to me at Will Durant On-Line, so that we can share it with others who share your interest in Dr. and Mrs. Durant's philosophy.