Optical concept progressed within the mid-17th century with treatises written by philosopher René Descartes, which explained a range of optical phenomena together with reflection and refraction by assuming that light was emitted by objects which generated it.[26] This differed substantively from The traditional Greek emission theory. During the late 1660s https://andrehjhge.blogsumer.com/29435666/5-simple-statements-about-portable-pa-system-explained