visual problem. Abbott Payson Usher devotes the tenth chapter 
of his History of Mechanical Inventions  to “The Invention of 
Printing,” saying (p. 238) that more than any other single 
achievement, it “marks the line of division between medieval 
and modern technology. . . . We see here the same transfer to 
the field of the imagination that is clearly evident in all the work 
of Leonardo da Vinci.” From now on “imagination” will tend 
more and more to refer to the powers of visualization.

     The mechanization of the scribal art was probably the 
first reduction of any handicraft to mechanical terms. That is, 
it was the first translation of movement into a series of static 
shots or frames. Typography bears much resemblance to 
cinema, just as the reading of print puts the reader in the role 
of the movie projector. The reader moves the series of 
imprinted letters before him at a speed consistent with