James Boswell's uncle John was a member of a sect known as the Glasites.
Karl Andreas Bel - Professor
Karl Andreas BelBorn Jul 13, 1717 in Bratislava
Died Apr 05, 1782 in Leipzig
Born in Bratislava, son of Matthias Bel (1684-1749) a famous Hungarian-Slovak scholar.
Bel was educated at Altdorf bei Nürnberg, Jena and Strassburg. In 1743 he became extraordinary Professor and in 1756 (or 1757) ordinary Professor of Poetry at the University of Leipzig. From 1754 until his death he was the (last) editor of the famous monthly scholarly journal Nova Acta Eruditorum Lipsiae, and from 1756 he was even librarian of the university.1
Following a suggestion from J. C. Gottsched, Boswell waited on Bel at Leipzig on October 4, 1764. He was well received, and described Bel as “a lively Hungarian, with a degree of French manners”. On the next day, Bel showed Boswell the university library (of which he was the librarian), and also forwarded his name to the poet Gellert, whom Boswell went to visit that same afternoon.
Boswell went back to Bel in the evening, and they had pleasant conversation. In the end, Boswell "gave it him that I would send my son to his care", i.e. have his future son(s) study in Leipzig.2
On October 6, Boswell was joined by Bel at his lodgings. Boswell “gave him bread and butter and cheese and fruit and wine. I called it ‘cena Pythaorica’; but I found that our good Professor would have chosen to be of a sect that lived a little better”. They were still “very merry” however and "renewed our literary covenant to send each other mutual accounts of the state of learning in our different countries”.
Note 1: Main source for this biography is the Allgemeine Deutsche Biographie (1875).
Note 2: Boswell's eldest son Alexander did go to Leipzig, but not until 1795-6 when James Boswell had just died, and Bel had been dead for 13 years. Also, he was not formally enrolled in the University according to Boswell on the Grand Tour I, 1763-1764.
It is sometimes possible to find a few early editions of some of his works on the AbeBooks.com used books search engine. Try searching for author "C. A. Bel".