Jacob Rosenthal     
The "Chocolate Connection"     
This article was published in the August/September 2019 issue of the Butterfly Net.  Karen Easton presented this as a seminar during FAGCA's 2019 convention. Much of this history comes (with permission) from James Measell, Author/Scholar,  and Jason Kendall, President of Greentown Glass Collectors.
"Fenton Art Glass owes much early success to famous glass chemist Jacob Rosenthal, also known as Uncle Jake, whose glass career began shortly after the Civil War. Perhaps Rosenthal's most important contribution to the young company was his role in the creation of iridescent glass, known as carnival glass, which Fenton introduced in 1907. Rosenthal's carnival glass, chocolate glass (sometimes called caramel glass by antique dealers), and golden agate pieces are now much-sought-after collector's items. Rosenthal also helped the company persuade other talented glass workers to relocate to Williamstown." (attributed to Phil Berry, Wonderful West Virginia Magazine, May 2006)