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of light, which fall upon bodies, and are reflected or 
refracted, begin to bend before they arrive at the bo- 
dies, and are they not reflected , refracted and infl ected by 
one and the same principle, acting variously in various 
circumstances * ?" If the view which has now been 
suggested be admitted, this question must be answer- 
ed in the affirmative ; for the various phenomena of 
refraction, reflexion, and inflexion, will fall to be 
regarded as modifications of electrical action. And 
thus have we endeavoured to connect the truths, which 
the intellectual eye of Newton perceived at so vast a 
distance, with the facts which the discoveries of Davy 
seem to have brought so immediately within our 
view. 
489. But were the physical cause of refraction and 
reflexion thus attributed to electro-chemical agency, 
still the laws which these motions of light observe, 
become the subjects of mathematical consideration. 
Granting, also, that these motions arise from the va- 
ried exertion of attractive and repulsive forces, yet 
still the greater mass of matter, or its greater densi- 
ty, would necessarily augment the effect, even where 
the composition of the substance continued uniform ; 
and a change in composition would act still more 
powerfully, and independently, in some degree, of 
the quantity of matter. In consistency, therefore, 
with these views, the Newtonian doctrine of density, 
in varying refraction and reflexion, may still, to a 
certain extent, be considered just ; but the mass of 
matter, or its density, would, in such an hypothesis. 
* Optics, Queries 4 and 5. 
