Quotation by Leonardo Davinci:
Between the expressions of laughter and weeping there is no difference in the motion of the features, either in the eyes, mouth or cheeks; only in the ruffling of the brows, which is added when weeping, but more elevated and extended when laughing.
...Those who weep, raise the brows, and bring them close together above the nose, forming many wrinkles on the forehead, and the corners of the mouth are turned down-wards. Those who laugh have them turned upwards, and the brows open and extended.
1452-1519 (Age at death: 67 approx.)
Leonardo di ser Piero da Vinci April 1452 May 1519), more commonly Leonardo da Vinci or simply Leonardo, was an Italian Renaissance polymath whose areas of interest included invention, painting, sculpting, architecture, science, music, mathematics, engineering, literature, anatomy, geology, astronomy, botany, writing, history, and cartography. He has been variously called the father of palaeontology, ichnology, and architecture, and is widely considered one of the greatest painters of all time. Sometimes credited with the inventions of the parachute, helicopter and tank, he epitomised the Renaissance humanist ideal.
Many historians and scholars regard Leonardo as the prime exemplar of the "Universal Genius" or "Renaissance Man", an individual of "unquenchable curiosity" and "feverishly inventive imagination". According to art historian Helen Gardner, the scope and depth of his interests were without precedent in recorded history, and "his mind and personality seem to us superhuman, while the man himself mysterious and remote". Marco Rosci notes that while there is much speculation regarding his life and personality, his view of the world was logical rather than mysterious, and that the empirical methods he employed were unorthodox for his time.
Author Information from Wikipedia
Source: A TREATISE ON PAINTING