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.

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

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

Until I was four years old I lived in the house of my paternal grandfather, about two miles from the pretty little village of Wallace, at the mouth of the river of that name.

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

I finally reached the conclusion that mathematics was the study I was best fitted to follow, though I did not clearly see in what way I should turn the subject to account.

Though born in Nova Scotia, I am of almost pure New England descent.