here is an
uninterrupted water-line of about six miles, he tested the water surface
for signs of curvature, and (as he said) found none.

It chanced, unfortunately, that a disciple--Mr. John Hampden, of
Swindon--accepted the narrative of this observation in an unquestioning
spirit; and was so confident that the Bedford Canal has a truly plane
surface, that he wagered five hundred pounds on his opinion, challenging
the believers in the earth's rotundity to repeat the experiment. The
challenge was accepted by Mr. Wallace, the eminent naturalist; and the
result may be anticipated. Three boats were to be moored in a line,
three miles or so between each. Each carried a mast of given length. If,
when the summits of the first and last masts were seen in a line
through a telescope, the summit of the middle mast was not found to be
above the line, then Mr. Hampden was to receive five hundred pounds from
Mr. Wallace. If, on the contrary, the top of the middle mast was found,
as the accepted theory said it should be, to be several feet above the
line joining the tops of the two outer masts, then Mr. Hampden was to
lose the five hundred pounds he had so rashly ventured. Everything was
conducted in accordance with the arrangements agreed upon. The editor of
a well-known sporting paper acted as stakeholder, and unprejudiced
umpires were to decide as to what actually was seen through the
telescope. It need scarcely be said that the accepted theory held its
own, and that Mr. Hampden lost his money. He scarcely bore the loss with
so good a grace as was to have been expected from a philosopher merely
desirous of ascertaining the truth. His wrath was not expended on
Parallax, whom he might have suspected of having led him astray; nor
does he seem to have been angry with himself, as would have seemed
natural. All his anger was reserved for those who still continued to
believe in the earth's rotundity. Whether he believed that the Bedford
water had risen under the middle boat to oblige Mr. Wallace, or how it
came to pass that his own chosen experiment had failed him, does not
appear.

The subsequent history of this matter has been unpleasant. It
illustrates, unfortunately but too well, the mischief which may ensue
from the tricks of those who make a trade of paradox--tricks which would
be scarce possible, however, if text-books of science were more
carefully written, and by those only who are really acquainted with the
subject of which th