Then, reader of these lines, if thou wouldst still
Be helpful to thyself, to others dear,
Will to can alway what thou ought to do.
See the letter addressed by Lionardo to Lodovico Sforza enumerating his claims as a mechanician, military and civil engineer, architect, &c.c. It need scarcely be mentioned that he served Cesare Borgia and the Florentine Republic as an engineer, and that much of his time at Milan was spent in hydraulic works upon the Adda. It should be added here that Lionardo committed the results of his discoveries to writing; but he published very little, and that by no means the most precious portion of his thoughts. He founded at Milan an Academy of Arts and Sciences, if this name may be given to a reunion of artists, scholars, and men of the world, to whom it is probable that he communicated his researches in anatomy. The Treatise on Painting, which bears his name, is a compilation from notes and MSS. first printed in 1651.
The folio volume of sketches in the Ambrosian Library at Milan contains designs for all these works. The collection in the Royal Library at Windsor is no less rich. Among Lionardo's scientific drawings in the latter place may be mentioned a series of maps illustrating the river system of Central Italy, with plans for improved drainage.