Note 272 — ESSAYS. (continued 3)

Linseed oil does not dry well without management, any more than the nut oils. Theophilus directs that it should be simmered in a new pipkin over a slow fire (but by no means boil), till one-third was evaporated; then powdered fornice, i.e. resin from the pitch-tree, stirred in; and observes, that every kind of painting glazed with this becomes glossy and durable. Thus the simple oil varnish was known and used at least as early as the eleventh century, four hundred years before the Van Eycks.

A ground, named by Theophilus, and afterwards by Cennino, for cementing panel, was composed of powdered lime and cheese,—the chief ingredients, if I am not mistaken, of Vancouver’s and other strong cements.