Ebook Photographic Optics

WE all have a pretty fair notion of what we mean when We talk of light, and yet when an attempt is made to give a precise definition of the term, to limit its meaning closely, the difficulty 18 by no means small. The first idea of light, and one which is strictly correct so far as it goes, is that which enables us to see objects and the question what is this which gives us the power will prob ably elicit from a scientist that it is a form of radiant energy, which statement is also probably strictly correct, but requires a little investigation.