Truth the sun. falsehood a mask. innocence, malignity.
Fire destroys falsehood, that is sophistry, and restores truth, driving out darkness.
Fire may be represented as the destroy of all sophistry, and as the image and demonstration of truth; because it is light and drives out darkness which conceals all essences [or subtle things].
[Footnote: See PI. LXIII. L. 1-8 are in the middle of the page; 1. 9-14 to the right below; 1. 15-22 below in the middle column. The rest of the text is below the sketches on the left. There are some other passages on this page relating to geometry.]
TRUTH.
Fire destroys all sophistry, that is deceit; and maintains truth alone, that is gold.
Truth at last cannot be hidden. Dissimulation is of no avail. Dissimulation is to no purpose before so great a judge. Falsehood puts on a mask. Nothing is hidden under the sun.
Fire is to represent truth because it destroys all sophistry and lies; and the mask is for lying and falsehood which conceal truth.
Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.