in the Institut de France, and some of these I have already given to the public in my work on “Les Projets Primitifs pour la Basilique de St. Pierre de Rome”, P1. 43.  In 1879 I had the opportunity of examining the manuscript in the Palazzo Trivulzio at Milan, and in 1880 Dr Richter showed me in London the manuscripts in the possession of Lord Ashburnham, and those in the British Museum.  I have thus had opportunities of seeing most of Leonardo’s architectural drawings in the original, but of the manuscripts tliemselves I have deciphered only the notes which accompany the sketches.  It is to Dr Richter’s exertions that we owe the collected texts on Architecture which are now published, and while he has undertaken to be responsible for the correct reading of the original texts, he has also made it his task to extract the whole of the materials from the various MSS.  It has been my task to arrange and elucidate the texts under the heads which have been adopted in this work.  MS. B. at Paris and the Codex Atlanticus at Milan are the chief sources of our knowledge of Leonardo as an architect, and I have recently subjected these to a thorough re-investigation expressly with a view to this work.

A complete reproduction of all Leonardo’s architectural sketches has not, indeed, been possible, but as far as the necessarily restricted limits of the work have allowed, the utmost completeness has been aimed at, and no efforts have been spared to include every thing that can contribute to a knowledge of Leonardo’s style.  It would have been very interesting, if it had been possible, to give some general account at least of Leonardo’s work and studies in engineering, fortification, canal-making and the like, and it is only on mature reflection that we have reluctantly abandoned this idea.  Leonardo’s occupations in these departments have by no means so close 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 of high-level and low-level road-ways.

Pl.  LXXVII, No. 1 (MS. B, 15b).  A general view of a town, with the roads outside it sloping up to the high-level ways within.