a relation to literary work, in the strict sense of the word as we are fairly justified in attributing to his numerous notes on Architecture.*
Leonardo's architectural studies fall naturally under two heads:
I. Those drawings and sketches, often accompanied by short remarks and explanations, which may be regarded as designs for buildings or monuments intended to be built. With these there are occasionally explanatory texts.
II. Theoretical investigations and treatises. A special interest attaches to these because they discuss a variety of questions which are of practical importance to this day. Leonardo's theory as to the origin and progress of cracks in buildings is perhaps to be considered as unique in its way in the literature of Architecture.
HENRY DE GEYMULLER
XII.
Architectural Designs.
I. Plans for towns.
*A. Sketches for laying out a new town with a double system