necessary for enabling me to read
modern mathematics.

"During a part of the time I employed myself in writing out a paper on
the geometrical interpretation of the algebraical expression
sqrt(-1). I think that the original suggestion of perpendicular line
came from some book (I do not remember clearly), and I worked it out
in several instances pretty well, especially in De Moivre's Theorem. I
had spoken of it in the preceding term to Mr Peacock and he encouraged
me to work it out. The date at the end is 1820, January 21. When some
time afterwards I spoke of it to Mr Hustler, he disapproved of my
employing my time on such speculations. About the last day of January
I returned to Cambridge, taking up my abode in my former lodgings. I
shewed my paper on sqrt(-1) to Mr Peacock, who was much pleased with
it and shewed it to Mr Whewell and others.

"On February 1 I commenced two excellent customs. The first was that
I always had upon my table a quire of large-sized scribbling-paper
sewn together: and upon this paper everything was entered:
translations into Latin and out of Greek, mathematical problems,
memoranda of every kind (the latter transferred when necessary to the
subsequent pages), and generally with the date of the day. This is a
most valuable custom. The other was this: as I perceived that to write
Latin prose well would be useful to me, I wrote a translation of
English into Latin every day. However much pressed I might be with
other business, I endeavoured to write at least three or four words,
but if possible I wrote a good many sentences.

"I may fix upon this as the time when my daily habits were settled in
the form in which they continued for several years. I rose in time for
the chapel service at 7. It was the College regulation that every
student should attend Chapel four mornings and four evenings (Sunday
being one of each) in every week: and in this I never failed. After
chapel service I came to my lodgings and breakfasted. At 9 I went to
College lectures, which lasted to 11. Most of my contemporaries, being
intended for the Church, attended also divinity lectures: but I never
did. I then returned, put my lecture notes in order, wrote my piece of
Latin prose, and then employed myself on the subject which I was
reading for the time: usually taking mathematics at this hour. At 2 or
a little sooner I went out for a long walk, usually 4 or 5 miles into
the country: sometimes if I found companions I rowed on