Darkness, Shadow, and the Senses of the Cat
Optical notes on light and the eye, the keen senses of the cat, and a memorandum of a demonstration made at Piombino in 1504
The page mixes optics with a dated memorandum and red-chalk drawing. Leonardo defines darkness as the privation of light and shadow as its lessening, notes that the shape of the light (square, long or round) does no harm to the eye, and observes that the eye set in strong light restrains that light so that dimmer places seem dark. A striking passage praises the cat's foremost senses of sight and hearing, the ear held ready like a funnel to catch sounds. A note at the head records that on the last day of November 1504 he made this demonstration to the lord at Piombino, and a faint red-chalk profile of distant hills runs across the upper sheet above a large red-chalk study.
On this page
Darkness is privation of light; shadow its lessening
Darkness is the privation of light and shadow a lessening of it, and there is no darkness in any place that has some exhalation of air. The eye of man set in a great light of air or other luminous body restrains that light and makes it of less power, so that places of lesser light seem dark to it.
The cat's foremost senses of sight and hearing
The cat has the foremost senses of sight and hearing found among animals, with smell almost as keen. Where sight fails it, hearing comes to its aid, the ear held always ready like a funnel to receive the noises made in the air and send them by wide ways to the common sense.
A demonstration made to the lord at Piombino, 1504
A heading records that on the last day of November, at All Saints, 1504, Leonardo made such a demonstration to the lord in Piombino. It ties the sheet to his service on the Tyrrhenian coast.
Red-chalk profile of distant hills
A faint red-chalk line drawn across the upper part of the sheet reads as the profile of a range of distant hills or a horizon. It is not described in the transcribed text.