The title of Johan Carl Wilcke’s thesis in 1757 is
Disputatio physica experimentalis, de electricitatibus contrariis.
For his triboelectric series, he listed smooth glass (producing the most positive charge), wool, quills, wood, paper, sealing wax,
white wax, rough glass, lead, sulfur, and metals other than lead (producing the most negative charge).
See also in The book of science:
Readings on wikipedia: