Noah Webster
Infusible
INFU'SIBLE, adjective [from the verb.] That may be infused. Good principles are infusible into the minds of youth.
INFU'SIBLE, adjective [in, not, and fusible, from fuse.] Not fusible; incapable of fusion; that cannot be dissolved or melted.
The best crucibles are made of Limoges earth, which seems absolutely infusible