Mr. Robert Hunt, in a lecture delivered by him at the Russell
Institution, “On the Physics of a Sunbeam,” mentions some experiments
by Lord Brougham on the sunbeam, in which, by placing the edge of a
sharp knife just within the limit of the light, the ray was inflected
from its previous direction, and coloured red; and when another knife
was placed on the opposite side, it was deflected, and the colour was
blue. These experiments (says Mr. Hunt) seem to confirm Sir Isaac
Newton’s theory, that light is a fluid emitted from the sun.