Notes on the Kinematic Effects of Revolution and Rotation, with
reference to the Motions of the Moon and of the earth. By Henry
Perigal, Jun. Esq. London, 1846-1849, 8vo.
On the misuse of technical terms. Ambiguity of the terms _Rotation_ and
_Revolution_, owing to the double meaning improperly {20} attributed to
each of the words. (No date nor place, but by Mr. Perigal,[42] I have
no doubt, and containing letters of 1849 and 1850.)
The moon controversy. Facts _v._ Definitions. By H. P., Jun. London,
1856, 8vo. (pp. 4.)
Mr. Henry Perigal helped me twenty years ago with the diagrams, direct from
the lathe to the wood, for the article "Trochoidal Curves," in the _Penny
Cyclopaedia_: these cuts add very greatly to the value of the article,
which, indeed, could not have been made intelligible without them. He has
had many years' experience, as an amateur turner, in combination of double
and triple circular motions, and has published valuable diagrams in
profusion. A person to whom the double circular motion is familiar in the
lathe naturally looks upon one circle moving upon another as in _simple_
motion, if the second circle be fixed to the revolving radius, so that one
and the same point of the moving circle travels upon the fixed circle. Mr.
Perigal commenced his attack upon the moon for moving about her axis, in
the first of the tracts above, ten years before Mr. Jellinger Symons;[43]
but he did not think it necessary to make it a subject for the _Times_
newspaper. His familiarity with combined motions enabled him to handle his
arguments much better than Mr. J. Symons could do: in fact, he is the
clearest assailant of the lot which turned out with Mr. J. Symons. But he
is as wrong as the rest. The assault is now, I suppose, abandoned, until it
becomes epidemic again. This it will do: it is one of those fallacies which
are very tempting. There was a dispute on the subject in 1748, between
James Ferguson[44] and an anonymous opponent; and I think there have been
others.
{21}
A poet appears in the field (July 19, 1863) who calls himself Cyclops, and
writes four octavo pages. He makes a distinction between _rotation_ and
_revolution_; and his doctrines and phrases are so like those of Mr.
Perigal that he is a follower at least. One of his arguments has so often
been used that it is worth while to cite it:
"Would Mathematicals--forsooth--
If true, have failed to prove its truth?
Would not they--if they could--submit
Some overwhelming proofs of it?
But still it totters _proofless_! Hence
There's strong presumptive evidence
None do--or can--such proof profound
Because _the dogma is unsound_.
For, were there means of doing so,
They would have proved it long ago."
This is only one of the alternatives. Proof requires a person who can give
and a person who can receive. I feel inspired to add the following:
"A blind man said, As to the Sun,
I'll take my Bible oath there's none;
For if there had been one to show
They would have shown it long ago.
How came he such a goose to be?
Did he not know he couldn't see?
Not he!"
The absurdity of the verses is in the argument. The writer was not so
ignorant or so dishonest as to affirm that nothing had been offered by the
other side as proof; accordingly, his syllogism amounts to this: If your
proposition were true, you could have given proof satisfactory to _me_; but
this you have not done, therefore, your proposition is not true.
The echoes of the moon-controversy reached Benares in 1857, in which year
was there published a pamphlet "Does the Moon Rotate?" in Sanskrit and
English. The {22} arguments are much the same as those of the discussion at
home.