27 | Sa 
844 THOMAS YOUNG. 
The penalty of retaliation was applied to him with inter- 
est; the Hdinburgh Review attacked the man of erudi- 
upheld for what they are worth as such, the weight of a name may not 
be unworthy of due estimation; great experience and high genius may 
add value to a pure hypothesis though it could not to a positive conclu- 
sion. In regard to theories of light this has been conspicuously exem- 
plified, and during a long continuance of controversial discussion it 
has been a matter of triumph to the opponents of the undulatory the- 
ory that the authority of Newton is on their side. And even Arago 
as well as some other supporters of it have spoken as if regretting that 
they were thus constrained to put themselves in antagonism to New- 
ton. They have pictured two rival theories, the one headed by New- 
ton and supported by Laplace, Biot, Brewster and Potter, the other 
upheld in opposition to them by Huyghens, Hooke, Euler, Young, 
Fresnel, Airy and all the Cambridge school. 
But a very slight inquiry into the real facts entirely dispels this 
view of the case. In particular Dr. Young himself in proposing his 
theory, so far from opposing the Newtonian views, expressly endeav- 
ours to conciliate attention by claiming the weight of Newton’s author- 
ity on his own side: thus in his paper “ On the Theory of Light and 
Colours,’ (Phil. Trans. 1801,) he commences by highly extolling the 
optical researches of Newton, and then observes, “those who are 
attached, as they may be with the greatest justice, to every doctrine 
which is stamped with the Newtonian approbation, will probably be 
disposed to bestow on these considerations (7. e. his own views) so 
much the more of their attention as they shall appear to coincide more 
nearly with Newton’s opinion.’’ He then proceeds to examine in de- 
tail a number of passages from Newton’s writings in which the theory 
of waves is distinctly upheld and even applied with some precision 
to the explanation of various phenomena of light, illustrated by their 
analogies to those of sound. 
It is perfectly true that Newton in the actual investigation of several 
phenomena of light adopts other hypotheses than those of waves; and 
chiefly the idea of light (whatever may be its nature) being subject to 
certain attractions and repulsions,—to certain bendings when approach- 
ing near the edges of solid bodies,—to certain peculiar modifications or 
changes in its nature recurring periodically at certain minute intervals 
along the length of a ray,—to the idea of a ray having “sides ’? endued 
with different properties; in a word, a variety of conceptions, which he 
introduces for the purpose of giving some kind of imaginary physical 
representation of the modus operandi in each of the several curious 
j 
