n to
ordinary affairs of life. Thus, for instance, when getting up in a
morning he would sit on the side of the bed half-dressed, and remain
like that till dinner time. Often he would stay at home for days
together, eating what was taken to him, but without apparently noticing
what he was doing.

One day an intimate friend, Dr. Stukely, called on him and found on the
table a cover laid for his solitary dinner. After waiting a long time,
Dr. Stukely removed the cover and ate the chicken underneath it,
replacing and covering up the bones again. At length Newton appeared,
and after greeting his friend, sat down to dinner, but on lifting the
cover he said in surprise, "Dear me, I thought I had not dined, but I
see I have."

It was by this continuous application that the _Principia_ was
accomplished. Probably nothing of the first magnitude can be
accomplished without something of the same absorbed unconsciousness and
freedom from interruption. But though desirable and essential for the
_work_, it was a severe tax upon the powers of the _man_. There is, in
fact, no doubt that Newton's brain suffered temporary aberration after
this effort for a short time. The attack was slight, and it has been
denied; but there are letters extant which are inexplicable otherwise,
and moreover after a year or two he writes to his friends apologizing
for strange and disjointed epistles, which he believed he had written
without understanding clearly what he wrote. The derangement was,
however, both slight and temporary: and it is only instructive to us as
showing at what cost such a work as the _Principia_ must be produced,
even by so mighty a mind as that of Newton.

The first part of the work having been done, any ordinary mortal would
have proceeded to publish it; but the fact is that after he had sent to
the Royal Society his papers on optics, there had arisen controversies
and objections; most of them rather paltry, to which he felt compelled
to find answers. Many men would have enjoyed this part of the work, and
taken it as evidence of interest and success. But to Newton's shy and
retiring disposition these discussions were merely painful. He writes,
indeed, his answers with great patience and ability, and ultimately
converts the more reasonable of his opponents, but he relieves his mind
in the following letter to the secretary of the Royal Society: "I see I
have made myself a slave to philosophy, but if I get free of this
present busi