In this way, however, we are led by nature to a definite boundary; for we now find ourselves in a realm where the dimensions of the observation medium and the observed object are more or less the same. The result, unfortunately, is that when the 'light' meets the object, it changes the latter's condition of movement. On the other hand, if a 'light' is used whose wave-length is too big to have any influence on the object's condition of movement, it precludes any exact determination of the object's location.