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theory of gravitation. If these facts be true, the much-vaunted discovery of 
Neptune is no triumph of abstract science. Every fair defender of the 
Newtonian theory is bound to show, either that the observations of the new 
planet on which the calculations of the elements of its orbit have been made 
are faulty, and the deductions made from them false, or else he is bound to 
demonstrate that both Mr. Adams and M. Le Yerrier were mistaken in their 
calculations of the orbit as deduced from the perturbations of the planetary 
system. In neither case, if the facts and figures quoted by Mr. Reddie be 
true, can we maintain for an instant that the calculations of Adams and 
Le Yerrier confirm the Newtonian law of gravitation, or were any real triumph 
of the powers of modern analysis. In confirmation of my view of the 
unphilosophical procedure of Darwinism as departing from the principle 
of the inductive method of arriving at truth, I would venture to allude to 
another science with which I have no doubt Mr. Warington is as familiar 
as he is with that of astronomy. It is a rule, as I believe, always followed 
by all sound cultivators of natural philosophy, that a hypothesis is only 
considered tenable so long as it accounts for all observed facts. Why has 
the undulatory theory of light been allowed to replace the emission theory 
of Newton? The emission theory of Newton accounts for a far greater 
assemblage of observed facts and phenomena relating to light, I venture to say, 
than that of Mr. Darwin on the origin of species does for the phenomena of 
animal and vegetable life and structure. There are a vast assemblage of 
phenomena — not one or two merely, but a vast number — which can be strictly 
and mathematically demonstrated to be direct consequences of the emission 
theory of light ; that is, the theory, that light consists of material luminous 
particles emitted from a luminous body. But why has this hypothesis — so 
simple, clear, and beautiful in itself, and recommended by such a master 
mind as that of Newton — been so universally abandoned by modern 
physicists ? Because experiments demonstrated the existence of a series 
of facts for which the emission theory could give no explanation. On Mr. 
Warington’s hypothesis, the Newtonian theory of light is not only credible, 
but the contradictory facts might be made to accord with it, by some 
unknown undiscovered causes. Indeed, Sir J. Herschel — the most pro- 
minent supporter of the undulatory theory — has remarked, that the defect 
might lie not in the facts being discordant with the emission theory, but our 
want of power in pursuing the mathematical analysis of Newton so as to 
explain them ; regarding that analysis as like the bow of Ulysses,, which 
none but its owner could wield. Instead of doing this, however, modern 
philosophers have abandoned the theory of Newton and adopted another, 
which not only includes all the facts shown to be in accordance with the 
emission theory, but also the great majority of those facts observed since the 
time of Newton, for which his theory afforded no explanation. But even 
here we pause. The undulatory theory itself is not yet universally accepted, 
as a few facts are still left for which that hypothesis does not afford an 
intelligible explanation. I assume, therefore, that I am right in maintaining 
that that system of inductive philosophy, which has led to the boasted 
