I had not yet gotten into the world of light. But I felt as one who, standing outside, could knock against the wall and hear an answering knock from within.

My father followed, during most of his life, the precarious occupation of a country school teacher.

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

A few years later the Naval Academy was founded at Annapolis, and a similar course was pursued to provide it with a corps of instructors.

We are probably nearing the limit of all we can know about astronomy.

James Edward Oliver might have been one of the great mathematicians of his time had he not been absolutely wanting in the power of continuous work.

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