We must remember, however, that the inks of that period were frequently corrosive, as is proved by the state of many documents now made illegible through the gradual attrition of the paper by mineral acids.

It is also not impossible that artists may have already invented what we call steel pens.

Sarpi, in the seventeenth century, thanks a correspondent for the gift of one of these mechanical devices.

Speaking broadly, the reed and the quill, red and black chalk, or _matita,_ were the vehicles of Michelangelo's expression as a draughtsman.

I have seen very few examples of studies heightened with white chalk, and none produced in the fine Florentine style of Ghirlandajo by white chalk alone upon a dead-brown surface.