Читать книгу The Notebooks of Leonardo Da Vinci. Complete - Leonardo da Vinci - Страница 209

The shadow cast by an object on a plane will be smaller in proportion as that object is lighted by feebler rays. Let d e be the object and d c the plane surface; the number of times that d e will go into f g gives the proportion of light at f h to d c. The ray of light will be weaker in proportion to its distance from the hole through which it falls.