logy is a manly science. It stands out in the open
light. It does not conceal itself behind scratches and periwigs,--nor
does it, like certain false teachers mentioned by St. Paul, go about
from house to house, leading astray silly women......Finally, gentlemen,
you may rest assured that Nosology will not gently submit to insult.
_Noli me tangere!_ Who ever endured a tweak of the nose? It will know
how to take vengeance. As Jupiter metamorphosed the inhospitable Lycians
into frogs, so its contemners will suddenly find themselves [Greek:
Barbarophonoi]!"

Percival has been thought over-tenacious of his opinions. He was
certainly very circumspect in changing them. I have witnessed, however,
several instances in which he yielded to the force of evidence in
the modification of his views. He seemed to recognize geology, in
particular, as a progressive science, in which new facts are constantly
accruing, and therefore compelling re-adaptations of our views. He felt,
indeed, in respect to all knowledge, the mathematics excepted, that
modifications of belief, in well-regulated minds, are unavoidable, as
the result of new information. Approach to higher truth through the
sciences he seemed to regard under the aspect of that of besiegers to a
beleaguered fortress. Principles and deductions, which were a boon and a
triumph for us yesterday, lose their value to-day, when a new parallel
of approach has been attained. He lost his interest in what was
abandoned, necessary as it had been to the present position, only in the
advantage of which, and its sure promise of what was still higher, he
allowed himself to rejoice.

But where evidence was wanting, he was never to be moved to a change by
any amount of importunity or temptation. This trait of character made
him somewhat impracticable as a collaborator, in the philological task
he was employed to perform under Dr. Noah Webster. Disagreements were to
have been anticipated from the striking contrasts in their minds.
They agreed in industry; but Webster was decided, practical, strongly
self-reliant, and always satisfied with doing the best that could
be done with the time and means at command. Percival was timid and
cautious, and, from the very breadth of his linguistic attainments,
undecided. He often craved more time for arriving at conclusions. When
he happened to differ from the great lexicographer, he would never yield
an iota of his ground. These differences led to an early ruptu