ARCHITECTURE
What is an arch?:
"An arch is nothing other than a strength caused by two weaknesses; for the arch in buildings is made up of two segments of a circle, and each of these segments being in itself very weak desires to fall, and as the one withstands the downfall of the other the two weaknesses are converted into a single strength."
- Excerpt taken from MacCurdy, 1954, p. 1039.
From a letter to the Signoro padri diputati of Milan Cathedral, c. 1487-88:
"You know that medicines when well used restore health to the sick. Good practice is when the doctor, together with an understanding of their nature, also understands what man is what life is, what constitutes the temperament and thus, health. When these have been well understood, he will also understand their opposite, and when this is the case he will well know how to heal...
The very same is required by an ailing cathedral, that is, a doctor-architect who well understands what a building is, and from what rules correct building derives, and fram where such rules are drawn and into what number of parts they be divided, and what are the causes whereby the building is held together, and is made to endure, and what is the nature of weight and the propensities of force, and how these are apportioned and related to each other, and when joined, to what effect they give rise. Whoever shall have understanding of the above mentioned things will leave you satisfied both to his theory and practice."
- Excerpt taken from Kemp, 1989, p. 256.
On palaces:
"The rooms which you mean to use for dancing or to make different kind of jumps or various movements with a crowd of people should be on the ground floor, for I have seen them collapse and so cause the death of many. And above all see that every wall, however thin it may be, has its foundations on the ground or on well-planted arches."
- Excerpt taken from MacCurdy, 1954, p. 1033.