I know that many will call this useless work [Footnote:  3. questa essere opera inutile.  By opera we must here understand libro di pittura and particularly the treatise on Perspective.]; and they will be those of whom Demetrius [Footnote:  4.  Demetrio.  “With regard to the passage attributed to Demetrius”, Dr. H. MULLER STRUBING writes, “I know not what to make of it.  It is certainly not Demetrius Phalereus that is meant and it can hardly be Demetrius Poliorcetes.  Who then can it be—­for the name is a very common one?  It may be a clerical error for Demades and the maxim is quite in the spirit of his writings I have not however been able to find any corresponding passage either in the ‘Fragments’ (C.  MULLER, Orat.  Att., II. 441) nor in the Supplements collected by DIETZ (Rhein.  Mus., vol. 29, p. 108).”

The same passage occurs as a simple Memorandum in the MS. Tr. 57, apparently as a note for this ‘Proemio’ thus affording some data as to the time where these introductions were written.] declared that he took no more account of the wind that came out their mouth in words, than of that they expelled from their lower parts:  men who desire nothing but material riches and are absolutely devoid of that of wisdom, which is the food and the only true riches of the mind.  For so much more worthy as the soul is than the body, so much more noble are the possessions of the soul than those of the body.  And often, when I see one of these men take this work in his hand, I wonder that he does not put it to his nose, like a monkey, or ask me if it is something good to eat.

[Footnote:  In the original, the Proemio di prospettiva cioe dell’uffitio dell’occhio (see No. 21) stands between this and the preceding one, No. 9.]

INTRODUCTION.

I am fully concious that, not being a literary man, certain presumptuous persons will think that they may reasonably blame me; alleging that I am not a man of letters.  Foolish folks! do they not know that I might retort as Marius did to the Roman Patricians [Footnote 21:  Come Mario disse ai patriti Romani.  “I am unable to find the words here attributed by Leonardo to Marius, either in Plutarch’s Life of Marius or in the Apophthegmata (Moralia, p.202).  Nor do they occur in the writings of Valerius Maximus (who frequently mentions Marius) nor in Velleius Paterculus (II, 11 to 43), Dio Cassius, Aulus Gellius, or Macrobius.  Professor E. MENDELSON of Dorpat, the editor of Herodian, assures me that no such passage is the found in that author” (communication from Dr. MULLER STRUBING).  Leonardo evidently meant to allude to some well known incident in Roman history and the mention of Marius is the result probably of some confusion.  We may perhaps read, for Marius, Menenius Agrippa, though in that case it is true we must alter Patriti to Plebei.  The change is a serious one. but it would render the passage perfectly clear.] by saying:  That they, who deck themselves