My father was the most rational and the most dispassionate of men.

I was taught the alphabet by my aunts before I was four years old, and I was reading the Bible in class and beginning geography when I was six.

My first undertaking in the way of scientific experiment was in the field of economics and psychology.

Ten decimal places of π are sufficient to give the circumference of the earth to a fraction of an inch, and thirty decimal places would give the circumference of the visible universe to a quantity imperceptible to the most powerful microscope.

Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible.

In 1858 I received the degree of D. S. from the Lawrence Scientific School, and thereafter remained on the rolls of the university as a resident graduate.

The beginning of 1856 found me teaching in the family of a planter named Bryan, residing in Prince George County, Md., some fifteen or twenty miles from Washington.