Optical concept progressed inside the mid-17th century with treatises composed by philosopher René Descartes, which discussed a range of optical phenomena which includes reflection and refraction by assuming that light was emitted by objects which made it.[26] This differed substantively from the ancient Greek emission theory. Inside the late 1660s https://soundbar63062.elbloglibre.com/29832261/5-simple-statements-about-portable-pa-system-explained