effect, to a great and general effect, which will in numberless
instances be found to be a very fallacious mode of reasoning. The
busy and active man may in some degree counteract, or what is
perhaps nearer the truth, may disregard those slight disorders of
frame which fix the attention of a man who has nothing else to
think of; but this does not tend to prove that activity of mind
will enable a man to disregard a high fever, the smallpox, or the
plague.

The man who walks twenty miles with a motive that engrosses
his soul does not attend to his slight fatigue of body when he
comes in; but double his motive, and set him to walk another
twenty miles, quadruple it, and let him start a third time, and
so on; and the length of his walk will ultimately depend upon
muscle and not mind. Powell, for a motive of ten guineas, would
have walked further probably than Mr Godwin, for a motive of half
a million. A motive of uncommon power acting upon a frame of
moderate strength would, perhaps, make the man kill himself by
his exertions, but it would not make him walk a hundred miles in
twenty-four hours. This statement of the case shews the fallacy
of supposing that the person was really not at all tired in his
first walk of twenty miles, because he did not appear to be so,
or, perhaps, scarcely felt any fatigue himself. The mind cannot
fix its attention strongly on more than one object at once. The
twenty thousand pounds so engrossed his thoughts that he did not
attend to any slight soreness of foot, or stiffness of limb. But
had he been really as fresh and as alert, as when he first set
off, he would be able to go the second twenty miles with as much
ease as the first, and so on, the third, &c. Which leads to a
palpable absurdity. When a horse of spirit is nearly half tired,